Trainers’ Manual
Produced by the Fruit and Nut Tree Propagation Project, Agricultural Livelihoods Unit, Community Sector Program with assistance from Koko Siga (Fiji) Ltd.
Funding support provided by AusAID
Text by Digby Gotts, all photographs courtesy Alison and Digby Gotts, Cape Trib Exotic fruit Farm. Design & Illustrations - Simione Tukidia Š Copyright 2009
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Table of contents Table of figures...................................................................................................................................... 4 01. Grow what grows - selecting your trees ................................................................................ 5 02. Starting a nursery ......................................................................................................................... 9 03. Pest management .......................................................................................................................... 11 04. Mineral nutrition ........................................................................................................................... 14 05. Plant structures and functions ................................................................................................... 16 Growing fruit trees from seeds ............................................................................................. 21 Growing fruit trees by budding ............................................................................................. 20 Growing fruit trees by grafting .............................................................................................. 23 New fruit for Solomon Island ................................................................................................ 24 06. Sexual propagation – growing fruit trees from seeds........................................................... 25 07. Vegetative propagation – growing fruit trees as clones ....................................................... 27 Cuttings ....................................................................................................................................... 27 Air layering ................................................................................................................................. 28 Suckering ..................................................................................................................................... 29 Budding ........................................................................................................................................ 29 Grafting ....................................................................................................................................... 31 Recommended propagation methods .................................................................................. 34 08. Pruning fruit trees ......................................................................................................................... 35 Tree spacing................................................................................................................................ 36 09. Why is there no fruit on my mango? ....................................................................................... 37 10. Carambola - star of the rainforest ............................................................................................ 38 11. Rambutan - hairy thing from the forest ................................................................................... 39 12. Positive insects .............................................................................................................................. 40 13. Want more mangoes next year? ............................................................................................... 41 Appendix - Insect groups ................................................................................................................... 42
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Table of figures Figure 1. Taproots deep below the tree ...............................................................................................16 Figure 2. Root bunch ................................................................................................................................16 Figure 3.Very thin root hairs ..................................................................................................................16 Figure 4. Stem showing nodes ................................................................................................................17 Figure 5. Stem cut through ......................................................................................................................17 Figure 6. Terminal bud position .............................................................................................................18 Figure 7. Location of lateral bud ...........................................................................................................18 Figure 8. Adventitious buds growing from a cut tree .......................................................................18 Figure 9. Cut flower ..................................................................................................................................19 Figure 10. Cut male flower......................................................................................................................19 Figure 11. Cut female flower ..................................................................................................................20 Figure 12. Growing fruit trees from seeds ..........................................................................................21 Figure 13. Growing fruit trees by budding ...........................................................................................22 Figure 14. Growing fruit trees by grafting............................................................................................23 Figure 15. New Fruits for Solomon Island ...........................................................................................24 Figure 16. Simple air layer........................................................................................................................28 Figure 17. Marcot ......................................................................................................................................29 Figure 18. Prepared rootstock................................................................................................................29 Figure 19. Prepared chip bud ..................................................................................................................29 Figure 20. How to T bud ..........................................................................................................................30 Figure 21. Preparing to approach graft .................................................................................................31 Figure 22. Completed approach graft ...................................................................................................31 Figure 23. Cleft grafting ............................................................................................................................32 Figure 24. Wedge grafting .......................................................................................................................32 Figure 25. Top working an old tree ......................................................................................................32
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01Grow what grows -
selecting your trees
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ruit and nut trees may take several years before they start to produce fruit, so planting them is a long term commitment where a mistake may not be obvious for years and then can be a costly and drawn out experience. Learn as much as you can about the available trees and what their needs are before taking your first step. Your first question must be why are you planting them? Here are some suggestions as to the type of things you should be thinking about for this decision. Do you just want to have some interesting food around the house? Then you would plant a mix of everything you can find that might grow in your environment. Then something may be in season all year, rather than having a massive harvest only at one time. You might choose trees which can do other things besides simply make fruits and nuts, such as windbreaks, shade trees, ornamental, building materials, firewood, nitrogen fixing, animal food, edible leaves, or even to dry out wet land.
Do you want an excess of fruit to let you sell some and eat the rest? Then you might select a few different trees to get fruit over a range of seasons, but you will have to learn to manage your trees by feeding them and pruning them, to ensure that your production is as high as it can go. Quick and easy fruit like bananas, pineapples and papaya are unlikely to sell well, as everyone grows them, because they thrive even when neglected. Fruit trees will always produce some fruit, but a little knowledge about them and some work on them can give you many more. You may be able to supply local markets with fruits that are too soft to be moved any distance, or with fruits that no-one else has growing.
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My mother always said that money doesn’t grow on trees. She was wrong!
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Do you want to supply a market to earn money? Make sure that it is a fruit people will want to buy, rather than simply grow them or buy them from someone else. There may be too many growing in your area already. Does the price of the fruit in the market justify your costs in getting it to market?
trees in a dry season. Some big trees such as rambutan or macadamia need machinery for harvesting, while others such as cashew, coffee, cocoa or tea need processing machinery and you may have to work with a large group of farmers to have enough fruit to make the cost worthwhile.
You might look at planting as many trees as you can fit into the space available, and learn how pruning can keep a tree small while not making the crop any smaller. You would also need to be certain that the planted trees will grow well in your environment and that you learn to manage them for maximum production. You might choose several different fruits that ripen at different times of the year to spread out your income, and your work.
Some fruit will be too soft to survive transport to a market, so while they may be perfect as family food, they may be useless commercially in a remote area (solo papaya, granadilla, abiu, rollinia). Some fruit trees can be grown from seed (soursop, mangosteen), while others must be grown from suckers or grafted stock (citrus). You may have to learn to do your own grafting as grafted trees can be very expensive.
If you only want to grow one type of fruit, then you could make sure that they are of different varieties, again to spread out the season and the work. How soft are they? Will they survive transport to a market? Many nut trees mature very slowly but the nuts can be partly sun-dried to give them a long life, so they can be moved long distances, or stored to allow a large amount to build up before shipping.
Some fruit trees are more likely to die of disease than others. Make sure that you don’t depend totally on disease prone plants, or you may find yourself suddenly wiped out. Especially in the hot and wet climate of SI, fruits like avocado and durian are unlikely to grow well, while mango will grow well but rarely produce much fruit.
Have a look at the costs of planting and looking after your trees. You may need to build frameworks or trellising (passion fruit, kiwi fruit), or even water the
Have a good look around your area to see which trees do well and are productive before gambling on a lucky break.
Here is a list of some of the fruit and nut trees that can be found growing in Solomon Island and some information about them. Have a look at the centerfold photos (on Page 22) of New Fruit for Solomon Island as well. Fruit Tree Name
Size of tree
Harvest Time
Other Uses
Acerola
Small
Summer
High vitamin C, juice
Alite nut
Medium
Summer
High energy
Avocado
Very large, only prune when too big!
Autumn but variable
Shade, high energy
Breadfruit
Very large, prune heavily
Summer
Energy food
Bush Lime
Small
Any time
Juice, prickly barrier
Cashew
Very large
Summer
Shade
Chempedek
Very large
Summer to autumn
Timber, high energy
Cocoa
Prune to keep it small
Anytime, mainly summer
Grows in shade
Coffee
Prune to keep it small
Late summer
Grows in shade
Custard Apple
Prune to keep it small
Autumn to winter
Puree
Cut nut
Medium
Anytime
High energy
Durian
Large
Summer
Very high energy, but disease prone
Guava
Prune to keep it small
Anytime
Juice, attracts pests
Granadilla
Vine
Anytime
Sight screen
Grapefruit
Medium
Summer to winter
Juice
Grapes
Vine
Summer
Disease prone
Jakfruit
Very large, prune it for size.
Summer to autumn
Dried flesh, windbreak, firewood, energy food
Lemon
Small
Autumn
Juice, Prickly barrier
Icecream bean
Very large, pruning ok
Summer to winter
High energy, firewood, leaves for animals, nitrogen fixer
Longan
Prune to keep it small
Late summer
Lychee
Very large
Summer
Windbreak
Macadamia
Prune to keep it small
Autumn to winter
Windbreak, firewood, high energy
Autumn
Juice, windbreak
Summer
Windbreak, firewood
Mandarin Mango
Medium, prune back after harvest Very large, prune regularly after harvest
Mangosteen
Very slow to grow
Summer to autumn
Very tasty
Ngali nut
Very large
Anytime
High energy, firewood, timber
Okari nut
Very large
Autumn
High energy
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Sweet Orange
Prune to keep small
Autumn
Juice
Bush Orange
Medium
Anytime
Juice, prickly barrier, rootstock.
Passionfruit
Vine
Anytime
Sight screen, ornamental, juice
Pawpaw
Small
Anytime
Very fast growing
Pepper
Vine
anytime
Pummelo
Large, pruning ok
Autumn to winter
Juice, long shelf life, easily handled fruit, rootstock
Rambutan
Very large, 1/3 prune back every year
Late winter to late summer
Windbreak, firewood
Rose apple
Very large
Spring to summer
Windbreak, firewood
Saba nut
Large, ok to prune
Summer to winter
Energy food, firewood
Sapodilla / Chiku
Prune to keep it small
Winter
Dried flesh, high energy
Soursop
Prune to keep it small
Anytime
Juice, jam
Star Apple
Very large, ok to prune
Spring
Shade, firewood
Star fruit
Prune to keep it small
Anytime
Firewood, juice
Two leaf nut
Small
Anytime
Fibre for string and rope, long life as a dried nut, not for children!
Water Cherry
Small
Spring to summer
Ornamental, firewood, sight screen
Questions and activities for further study: Go for a walk around your home and identify the fruit and nut trees growing there. Answer the following questions for each type of tree: 1. What type of tree is it? How many trees are there the same as this one? 2. What is it doing this month? (What month is it?) Flowering or fruiting or growing leaves or just resting. 3. Has it ever produced fruit or is it still too young? 4. How healthy is it? Are there any dead or diseased branches? Are all the leaves bright green? 5. Do people like the fruits or nuts, or are they left to rot on the ground? 6. Are these fruits for sale in the local market? What do they sell for? 7. Are the fruits damaged easily? Can they be moved to a market and still look good? 8. Would it be worth your while to grow more of this tree?
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02
Starting a nursery
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ruit and nut trees can be grown from seeds or from specially grafted plants, which ensures the quality of the fruit produced. Whichever you are going to use, both need to be well looked after because healthy and fruitful trees can only come from healthy and strong young trees. Young trees must be grown under perfect conditions in a nursery for several months to make sure that they are as strong as possible before planting them out into the field. If your young plants are in pots on the ground, then rapidly growing roots may leave the pot and grow into the ground, only to get broken off when you shift the plant. The damaged ends may then allow infections to weaken or kill your young tree. It is much better to place the pots on a bench at a comfortable working height; they will then also be more accessible for grafting or other work later on.
Make sure that you have water easily available to water the pots. If you have to have water carried in buckets for several hundred meters to water your trees, then you can bet that whoever is made responsible for the chore, will not do it often enough to keep the trees happy. This is where piped water and a tap with a hose in the nursery is essential to make sure the job is done well. If your nursery area is well shaded, the young plants may grow tall and spindly, making them weak and likely to be broken; while if it is too bright they may dry out or get sunburned leaves. So aim for some shade by setting up in an area surrounded and partly covered by trees. This will give you a dappled light with patches of sun and shade moving across the nursery as the sun moves. You could use shade-cloth but natural lighting through surrounding trees is much better for your plants. Shade cloth can cut down the air movement which will encourage diseases to spread in the nursery. The soil in the pots must allow water to drain, while still holding some for the use of the plant. Heavy clay-like soil will hold too much water, causing root disease, or dry out completely if you forget to water them. Sand will not hold enough water, allowing the plants to dry out very easily. So a mix of sand and clay can work, especially if you add some well rotted organic matter like compost, peanut shells or coconut fibre.
It’s not being lazy to pipe your water, just more efficient.
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Fit and healthy doesn’t mean over fed Too much of a good thing can also be bad for the growing plants. You will need to make sure that you are not giving them too much water, too much shade
or too much sun. Your best tools for making sure of this are your eyes. Watch what’s happening and make corrections to your setup if they are needed.
Questions and activities for further study 1. Find out what you need to do to your soil to make the perfect potting mix. Follow these steps: a. Dig out a cupful of soil from a place you could use for filling pots. Squeeze a handful in your fist, then put it down gently. b. Does the soil stay together as a hard ball? Then it has too much clay. Add sand and compost. c. Does the soil break apart into small grains? Then it is too sandy. Add clay and compost. d. Does the soil just break apart a little but stay as a ball? Then it could be good for using as a potting soil. 2. Make a bucketful of good potting soil. Record how much soil, sand, clay and compost you use for next time. 3. Sometimes plastic pots are too difficult or expensive to buy. Here are some suggestions for more natural pots that you plant with the young tree. See if you can make some. a. Use ginger or banana leaves folded over and tied with bush string. b. Cut cardboard boxes or cloth (not nylon) into strips and use as for large leaves. c. Half coconuts can be used if the shell inside is broken a little to allow water out. d. Old woven matting can be rolled and folded, then tied with bush string.
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03Pest management A
s soon as you grow something worth eating, every animal that likes eating it will appear, to help you harvest your crop. These pests need to be kept under control, so that you get the main part of your harvest to use as you see fit. Don’t expect to get rid of all the pests, just hope to keep the amount of damage down to an acceptable level. The children of your village may be one of the most difficult pests to control, but then maybe that’s why you’re growing fruit anyway, so they can get an improved diet. It’s hard to have the same attitude for insects or birds stealing your fruit, so here are some suggestions to minimize the damage. Use many different plants so that your productive area is more like a forest of mixed plants, than a large number of the same plant. This makes sure that conditions are not perfect for any one pest, so numbers of all pests remain small.
If damage to fruit is noticeable from insect attack, it can be very tempting to use a poison spray to wipe them all out. If poison is used then not only is the insect that is eating the fruit killed, but the insects that ate it are also killed off. Some from both groups survive, but the plant eaters reproduce much more quickly than the insect eaters, so their numbers return quickly to high levels before the insect eaters have even started to increase. So the poison needs to be used again, and again. Eventually the few insects that were unaffected by the poison (resistant) are the only ones left breeding, and they have passed on their resistance to their children. After a few generations the poison has no effect on the plant eaters while the insect eaters have probably been wiped out because their numbers were lower when you started. You are left with a worse problem than before the poison was used.
The best fruit always belongs to some one else.
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Your most useful tools are your own eyes. Use them! Watch what’s happening so that you know what is doing the damage, and how you might approach a solution. Some of the typical SI pests and simple solutions are found on the following pages.
Fruit fly laying eggs into citrus
Use beer baits to attract female flies into a bottle where they drown. Small bottles, and maybe the dead flies in the beer, will help prevent alcoholic friends helping themselves. Remove sooty mould and rotten fruit as they are attractants. Use paper bags or fine mesh nets around developing fruit.
Fruit piercing moth sucking juices
Caterpillars eating leaves
Send children to swat the moths at night. Cover fruit with a paper or mesh bag. Use a homemade repellant spray such as chilli or garlic or sprinkle with pepper. Pick caterpillars off leaves and squash them.
Thrip eating surface layers of fruits
Flour and water mix splashed onto the leaves on a sunny day will glue down all the bugs giving the birds a free feed of bugs in batter. Rain will wash the mess away.
Aphid sucking juice from stems
Use soapy water or the flour/water mix splashed onto the stems and leaf junctions where there are groups of aphids.
Mites damaging flowers and leaves
Use flour/water spray.
Surface mould Birds eating the fruit
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Use soapy water sprayed or splashed onto the flowers and young fruit.
The black sooty mould is growing because of a honey like secretion usually from aphids. By itself it is not a problem but use soapy water to get rid of the aphids and clean the fruit. Some old CD’s or ribbons of video tape hanging from the tree can frighten birds away for a while.
Recipes for pest control Spray bottle: A one litre soft plastic bottle with a screw-on cap can be made into a fine sprayer. Just drill or use a nail to punch 10-20 small holes in the cap. Fill the bottle with your spray, put the cap on and squeeze. You will have to use this one pointing downwards, but a little creativity can let you use it in any direction. Bug juice: Three parts water to one part of your problem pest. Grind or blend well and leave for a day in a warm place. Strain through some cloth and add another 50 parts of water. Spray onto your plants. Works well some of the time. Repellent sprays: These generally vary in effectiveness, so if one doesn’t work try again or try a different recipe. 1.
2.
Soak chilli in just enough vinegar to cover them for two to seven days. Strain and dilute with five parts of water for every part of chilli juice. Spray is very pungent so don’t sniff it! Also repels vampires, especially if mixed with garlic.
5.
Grind four chillies, one capsicum and an onion. Add four cups of water and leave for a day. Strain and spray every few days to repel mild invasions of grasshoppers.
Soap spray: Dissolve 100gm of washing soda into five litres of water and add 50 gm of soft soap. Spray to kill small insects such as thrip, aphid and mealy bug.
Crush basil leaves and pour on boiling water. Bugs in batter: Mix ½ cup of flour and ½ cup of Wait until water is dark brown then strain and milk, so there are no lumps, then add enough water so that it can be sprayed. Mix well and spray onto top spray undiluted onto problem insect. and bottom of leaves where any bugs hang out. Boil 500g of lantana leaves in one litre of water. Strain and spray for aphid control.
3.
4.
Chop garlic and cover with mineral oil. Leave overnight. Strain and dilute with 20 parts of water for every one part of oil.A little detergent will help the oil dissolve in the water.
Birds eat about 40% of common garden pests, so do whatever you can to encourage birdlife in your area. Prickly bushes, tall trees for perching, a birdbath under cover of a bush, lots of flowering grevillias and as few cats as possible will get your pest control forces at their maximum.
Questions and activities for further study • Have a close look at some fruit trees near your home and see if you can find some pest insects. Identify its family from pest drawings. Is it a beetle, a bug, a moth or a fly? What damage is it doing? Which control method(s) could work on that pest? Make up a spray bottle and the spray and test them on your pest. Can you find any insect eaters such as beetles, wasps, ants, mantis? What could you do to encourage these to live in your trees? Have a look at the insect drawings on page 42.
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04
Mineral nutrition
J
ust as we need water, air and a mix of different foods to keep us healthy and growing, so do plants need water, air and a mix of different minerals from the ground to stay healthy and growing. While these are usually easily available just about everywhere in SI, there can be problems if the soil is too sandy or the water is salty or the soil has been used up after heavy cropping. There are a range of different minerals found in rich soil that all plants need for healthy growth. The most important of these are listed below with some ways of recognizing a problem and suggestions for fixing the problem. Nitrogen (N): If nitrogen is lacking in the soil the first thing you will notice is that the older leaves are starting to go yellow, while the plant is smaller and new growth is also smaller. While Nitrogen fertilizers can be used, such as urea and ammonium nitrate, these cost money while the air around you is made of mostly nitrogen. This free source of nitrogen in the air can be converted to fertilizer in the soil (nitrogen fixing), by many plants from the legume or pea and bean family. Simply grow many more than you need around your fruit trees, so they can benefit from the release of nitrogen while you get some peas and beans to eat as well. Some other nitrogen fixing legumes that are useful include; glyricidea which is commonly seen as a small tree for supporting vanilla; pigeon pea as used for growing lentils; pinto peanut as a ground cover to stop weeds; bush peanut as an extra crop for harvest. Too much nitrogen will give you heavy growth of leaves with high water content, making them more prone to disease and less likely to produce fruit. Phosphate (P): Levels are rarely low in soil as most rocks contain phosphate which is released by the action of bacteria and fungi. These are encouraged by neutral and alkaline conditions, but if the soil is acid and or sandy, then problems with low phosphate may appear. It is also not easily washed out of soil by rainfall, so mulching and encouraging soil organisms is the best way to ensure high phosphate levels.
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Potassium (K): If potassium levels are low in the soil, old leaves will go yellow between the veins and along the edges, often showing black spots and curling into a cup shape. Good levels are important for flowering and filling of fruit. Available potassium is easily washed away by rain or water, especially in sandy soils, while it can still be in the soil but locked away in soil minerals. It can be made available to plants by increasing the living parts of the soil with mulch and compost. Potassium is also found in wood ash, banana trash, and well rotted manures. Calcium (Ca): Plants need calcium for active growth and strength to hold the plant upright. It is found commonly in most soils but if leaf tips and buds are distorted or dying then crushed coral, limestone or dolomite may need to be added. Chicken manure is also a very good source of calcium.
Soil can get used up just like your money. But at least it can grow back to goodness with just a little help
Micronutrients: These are often called trace elements.There are about another 11 minerals that are needed by plants in small amounts. Low levels in soils are not likely to cause problems in SI as most of the soil is new and volcanic and should contain high levels. Compost tea made where there is known to be good nutrition can be used as a leaf spray on trees suspected of having a problem, especially if they are growing on sandy soil. Soil analysis must be used to be sure of a diagnosis, and this would be organized by an agriculture officer if necessary. Here are some of the symptoms of micro- nutrient deficiency, but note that any of these can show if the plant is stressed by lack of water as well.
Boron
Cracks and splits appear in leaf stem, terminal bud dies, older leaves misshapen.
Chlorine
Never deficient but poisonous in large amounts. Common in seawater.
Cobalt
Needed for nitrogen fixing to occur.
Copper Iron Magnesium
Sodium
Young leaves curled and wilted. Young leaves uniformly go yellow with veins staying green. No spots. Older leaves go yellow with veins and edges staying green. Dark green veins with yellowing between shows up in young leaves first with brown or black spots. Older leaves first start to yellow with leaf edges drying out and dying. Citrus show yellow spots on old leaves. Never deficient but poisonous in large amounts. Common in seawater.
Sulphur
Young leaves smaller and internodes shorter with veins going yellow.
Zinc
Deficiency possible in high rainfall areas. Young leaves malformed with yellow between the veins.
Manganese Molybdenum
Commercial fertilizer may have one or all of the above minerals and you will have to read the label to find out how much of each it contains. Agricultural supply companies will often sell a mix where the label will say something like 3N:2P:1K. This means that the bag contains a mix of 3% Nitrogen, 2% Phosphate and 1% Potassium.
Urea will be labelled as something like 30N:0P:0K, meaning that it contains 30% Nitrogen and no other minerals. The minor minerals or trace elements may also be contained in the mix and the label should tell you if the bag contains a “complete� fertilizer .
Questions and activities for further study 1.
2. 3. 4. 5.
Find a bag or a bottle of a commercial fertilizer. Read the label to find out what it contains. a. What are the minerals it contains? What are their amounts in the mix? Is it a complete fertilizer with trace elements or is it just one mineral? b. If you used this fertilizer, what other minerals would be needed to make healthy plants? If your plant needs 100gm of phosphate a year and your fertilizer contains 5% phosphate. How much fertilizer would you need to use on that plant each year? NPK is a common SI word meaning chemical fertilizer. Why is this incorrect? Plants suffering from a missing mineral often show yellowing in their leaves. Does this mean the leaf is diseased? What do you think is happening in the leaves? Many chemical fertilizers mix easily into water making them easy to spread as sprays onto trees. What do you think will happen to fertilizers like these in the wet climate areas of Solomon Island?
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05
Plant structures and functions
Roots Roots provide an anchorage for the stem, absorb minerals and water from the soil and store nutrients as sugar and starch. There are several types of roots that act in different ways:
1. Taproots are deep penetrating roots that bring minerals and water up from deep in the ground. They give a strong anchorage in windy conditions and can hold a large nutrient store which helps the plant to survive harsh conditions. Eg: dandelions, carrots, many nut trees, mangosteen. The deep root makes these plants difficult to grow in pots or to transplant.
Figure 1.Taproots deep below the tree
2. Fibrous root systems are made up of many shallow and branched roots. Eg: Most grasses, beans, corn, bananas, marcotted fruit trees. They are easy to transplant and can be grown in containers, but they are likely to be damaged by harsh conditions, especially wind.
Figure 2. Root bunch 3. Root hairs are found on all root types, they are very fine and delicate hair like extensions which absorb water and minerals, and are easily damaged by transplanting and drying out. Figure 3.Very thin root hairs
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Stems The stem is the main trunk of the plant giving strength and structure. It transports water and minerals up to the leaves, and sugar and starch nutrients made in the leaves, to storage or to use, throughout the plant. Buds and shoots develop on the stem. Stems hold several different types of tissue.
1. Nodes are the places on the stem where lateral buds form. The internode is the space between the nodes.
Figure 4. Stem showing nodes 2. Bark is the outermost protective layer shielding the stem from damage. 3. Cambium is the layer of rapidly growing tissue just under the bark. This is what makes the plant grow wider, and is responsible for healing wounds made in the stem and it is critical in grafting. 4. Phloem is the nutrient carrying tissue near the outside of the stem, but still well under the bark. This can carry nutrients in either direction to wherever it is needed by the plant. Because it is wet wood and sappy, it is often called sapwood. 5. Xylem is the water conducting tissue in the middle of the stem. This is typically the heartwood of a tree. Water is carried up the xylem from the roots to the leaves.
Figure 5. Stem cut through
Leaves The green colour of the leaves is the factory where all the sugars and starches are made. To make these nutrients, all the leaf needs is a supply of water and minerals from the ground and carbon dioxide from the air. As water evaporates from the surface of the leaf, more water is drawn up from the roots, and so delivers to the leaf, the needed dissolved minerals. There is a waterproof layer protecting the leaf which allows it to conserve water in dry conditions. There are holes (stomata) in the waterproofing which allow water to leave. They can be opened and closed by most plants, to control water use and ensure that the leaf doesn’t dry out. Some tropical plants such as rambutan are unable to close their stomata and die easily in dry conditions.
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Buds Buds are the growing points of the plant and can develop as shoots or flowers depending on the needs of the plant at the time.You will need to be able to identify actively growing buds, as this is the first step needed for learning how to bud graft new plants, of a superior variety.
1.
Terminal buds are on the tips of branches. Typical of avocado, lychee, rambutan and mango, the terminal bud will either go into producing a flower if the tree is stressed by cold and dry conditions or it can go into leaf growth if water and mineral fertilizers are available. Terminal buds are typically used for wedge or cleft grafting. Figure 6.Terminal bud position
2. Lateral buds are on the side of the stem, typically tucked inside the corner of a leaf stem, and are commonly used for bud grafting.
Figure 7. Location of lateral bud
3. Adventitious buds can form from the cambium at any location, including the internode, a leaf edge, or as in this drawing at a cut on the stem. These are relied on for root development on leaf and stem cuttings.
Figure 8. Adventitious buds growing from a cut tree
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Flowers Flowers are the absolutely essential step in the growing cycle of seed, plant, flower, fruit, seed. Without flowers there can be no seeds, so although the plant may be able to be grown vegetatively (see chapter on propagation, page 25), there will be no variation possible without the sexual reproduction involved to develop seeds. New and slightly different types produced from seeds are important to allow survival in a changing environment and to allow people to identify new variants which may be better suited to human use. The role of the flower is to grow seeds by encouraging pollen from the male parts (stamen with anther) to contact the female parts (style with stigma). The pollen can then grow down the style to the ovary (egg), to make a fertile seed.
Many different ways have developed in nature to accomplish this pollination, using insects or other animals by attracting them with colour and smell. Long stamens (eg gum tree flowers, sweet corn tassels) suggest that wind is responsible for spreading pollen. Petals are usually the brightly coloured and often perfumed parts of the flower. The tough protective petals around the outside of a flower bud are called the sepals. The male and /or female parts are inside the surrounding petals and sepals. It can pay off to study your flowers closely so you know which of the following three types you have and how you can best ensure the best pollination and therefore the most fruit possible.
1. Some plants have male and female parts present in the one flower, and so are called complete or perfect flowers. Eg passion fruit, tomato, beans. Many plants with this type of flower can self pollinate without help and so the seeds will generally grow plants very similar to the parent. Different varieties can therefore be grown close together and the seeds produced from each can be saved for the next planting, as the pollen doesn’t spread easily. Figure 9. Cut flower to show male and female parts.
2. Some plants have flowers where male and female parts are on separate flowers in the one plant. (Monoecious) eg Jakfruit, watermelon, and pumpkin rely on insects such as flies and bees to carry pollen from the male flowers to the female flowers. Sweet corn relies on wind to blow the pollen from the male flowers at the top of the plant, to the developing fruit (cobs) on the side.
Figure 10. Cut female flower
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3. Some plants have male and female flowers on different trees (dioecious).These must be grown close together to ensure pollination can occur. (Eg pawpaw, rambutan). It can be very frustrating to grow a fruit tree from seed for several years and discover that your tree is a male and cannot produce fruit.
Figure 11. Cut male flower
Fruit If pollination is successful, then the seeds develop and their surrounding ovary enlarges to form the fruit (fruit set). The word fruit has a double meaning in English. Correctly used, it is the structure holding the seeds, but the word is also used to mean sweet and juicy plant part. While ‘vegetable’ means anything edible from a plant. Fruits such as eggplant, zucchini, tomato, should perhaps be called ‘fruit vegetables’! In the same way that we call potatoes and carrots ‘root vegetables’.
Fruit can form singly around one ovary (as with apples, peanuts, tomatoes), or a cluster of flowers can produce a multiple fruit as with pineapples or jakfruit. Fruit can sometimes form around infertile or undeveloped seeds, giving the appearance of a ‘seedless’ fruit, like bananas, breadfruit and seedless oranges.
Questions and activities for further study. 1. Choose a fruiting plant from your garden. Record by drawings the changes as a bud grows into a flower and then into a fruit. 2. Open up some flowers and look for the male and female parts. Many ornamental flowers have no ovary and so cannot make seeds or fruits.
20
Growing fruit trees from seeds A granadilla being pollinated. The role of the flower is to grow seeds by encouraging pollen from the male parts (stamen with anther) to contact the female parts (style with stigma). The pollen can then grow down the style to the ovary (egg) to make a fertile seed.
1
3
Finger on the male parts (anther) to collect pollen.
Pollen smeared onto the female part (stigma).
2
Pollen on the finger.
4
3 days later the fruit is growing.
If pollination is successful, then the seeds develop and their surrounding ovary enlarges to form the fruit (fruit set).
Granadilla, mature and ready for eating.
Seeds in the cut fruit.
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Growing fruit trees by budding Chip budding
1
Remove a chip from a root stock seedling about 3cm long and ½ cm wide. Use two clean cuts just into the wood.
Good fit
3
22
2
Remove a chip from a good quality plant exactly the same size as the piece removed from the seedling. Trim off the leaf, leaving a stub to hold onto.
The chip is too big
Wrap up the chip to keep water out, but leave the leaf stem out so you can see if the wound has healed.
Growing fruit trees by grafting
There are many ways of joining pieces of two plants together, but the fundamental rule is that the cambium layer of both pieces must come into close contact with no air leaks.
Good
Poor
Demonstration of approach grafting Bring the seedling up to a branch on the good tree so that the two stems of equal diameter are comfortably close for several cms.You may have to raise the seedling on a drum or box.
Cut a strip of the contact zone on both plants several cms in length just into the wood. Make sure that the two cuts are identical in size.
Hold the two wounds together and bind with grafting tape.They must fit together comfortably, with no air gaps.
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NEW FRUITS FOR
SOLOMON ISLAND
BREADFRUIT Artocarpus altilis Starch food for energy
PACIFIC LONGAN Pometia pinnata The dragon’s eyeballs
ROLLINIA Rollinia deliciosa Lemon meringue pie
YELLOW SAPOTE Pouteria campechiana Special fruit of the Aztecs
STAR APPLE Chrysophyllum caimito Think of marshmellow
SOURSOP Annona muricata Tangy lemon sherbert
MIRACLE FRUIT Synsepalum dulcificum Makes sour taste sweet
DRAGONFRUIT Hylocereus sp Weird and wonderful
POMMELO Citrus maxima World’s largest citrus
ABIU Pouteria caimito Taste of crème caramel
BLACK SAPOTE Diospyros digyna Chocolate pudding fruit
RAMBUTAN Nephelium lappaceum Tasty and hairy
MAPRANG Bouea gandaria Like a sweet mini mango
CARAMBOLA Averrhoa carambola Crunchy like an apple
CUSTARD APPLE Annona sp. Sugar sweet custard
JAKFRUIT Artocarpus heterophyllus World’s largest tree fruit
ROSE APPLE Syzygium malaccense Smells of roses
DURIAN Durio zibethinus Tastes like blue cheese
MANGO Mangifera indica Everyone’s favourite
AVOCADO Persea americana Buttery smooth
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06
Sexual propagation -
growing fruit trees from seeds Issues and problems
1. Diversity Seeds are produced when the ovules within the ovary of the female part of a flower are joined with the pollen from the male part of a flower. If these parts are in the same flower, then the seeds are likely to grow up to be the same as the parent (self-pollination). If the parts are on different trees, then each seed is likely to grow up to produce fruit with a different set of characteristics, compared to either parent or one another (cross-pollination). If fruit is needed for market, then it needs to be of consistent quality, so fruit from cross pollinated seedling trees are usually too variable to be acceptable. 2. Tall trees Seedling trees are typically taller, making fruit harvesting more difficult, and making them more likely to be damaged by wind. 3. Poor quality and inconsistent fruit Fruit from seedling trees are often of poor quality, with many seeds, small size, or some other undesirable characteristic. Some fruit such as
At least seedling trees are free!
guava, soursop, Kensington Pride mango run true to type, with little or no variation from generation to generation. These fruit trees are often grown from seed that can be collected and saved for use. Other trees that are likely to have too much variation to be worth growing are usually grown for use as rootstock.
Seed collection 1. Pollination This is the process where the male pollen is carried to the female parts of the flower. Poor pollination often means poor fruit set and low harvest. It is essential to know how the fruit tree you wish to grow is pollinated, so that you can ensure the right conditions are provided for the pollen to be moved. For example, honey bees near a mango or lychee orchard can improve fruit production by 50% or more, and give you honey for free! Granadilla, even with male and female parts in the one flower, rarely sets fruit without help as shown in the photos (page 19). 2. Hybrid Hybrids are produced when two plants are deliberately cross-pollinated in an effort to find a new plant with the best characteristics of both parents. Most hybrids are worse than either parent but sometimes they can produce better fruit, and it’s these rare ones that enthusiasts and breeders look out for. However their seeds cannot produce another identical generation, as every seed has a different combination of both parents. A good hybrid can only be continued into another generation by cloning it asexually in some way. Never collect seeds from plants known to be hybrids, except for use as rootstock. 3. Lifetime Tropical seeds often have a short life, rarely lasting more than a few days after removing them from the ripe fruit. Make sure that they are washed clean and dried if they are not to be sprouted immediately, as they will rot very quickly if this is not done.
25
4. Sprouting It is often best to get the seeds started by placing them with damp moss or coconut fibre in a plastic bag and keeping them out of direct sunlight. You can see when they start to shoot, and remove them for planting gently into a small pot. Seeds can be planted direct into the polybags, but they can be eaten by pests like ants and beetles and they are gone without you knowing. 5. Plant selection Poor quality fruits can only give you poor quality seeds. Collect seeds from your best fruit, and not the ones which didn’t sell in the market. 6. Storage Keep seeds dry and cool, inspect them for mould growing on the surface, and wash them with dilute bleach if mould appears. 7. Weeds Some seeds sprout very easily, and can be spread by animals eating the fruit flesh and dropping the seeds. These plants often grow where they are not wanted and can become a threat to the plants that you do want. Be careful that you are not releasing a new threat into your neighbours’ land. Some problem plants include guava, passionfruit and icecream bean. 8. Identification Use a permanent marker to label your seed container so that you can remember where they came from, what they are and when they were collected. An alternative is to use aluminium tags which can be made from old cans. Write on them by denting the metal with an old pen.
Sowing 1. Growing media The soil used for the new plants first growth needs to be fine, loose and well drained, so that the
roots can penetrate easily and no mould or rots can take over. A good mix is 3 parts rotted ground coconut husk with 3 parts soil and 1 part chicken manure. Peanut shells can also form part of a good potting mix. Use a layer of stones in the bottom of the pot and fill it to the brim with your potting mix. It is best if the soil can be sterilized first. If you let boiling water soak into the soil and then allow it to drain away, then you have sterilized the soil without using chemicals. 2. Containers Any container that will allow water to drain away will do. The best containers are made from banana leaf, coconut fibre or cardboard and will rot away as the plant grows. Plastic polybags are more convenient for large numbers of plants, but the plant must be removed from the bag for planting out, or repotting into a larger pot as it grows. 3. Transplanting When you have sprouted a seed, you must handle it only by the shoot or the hard part of the seed, as the root hairs are easily damaged. Poke a hole in the soil down a few cm and place the sprouted seed in the hole, with the nut just under the soil surface. Press with your fingers around the seed to ensure that there are no air spaces. Water gently, ensuring that the water has wetted all the soil. If you are planting out a potted plant, dig a hole just bigger than the pot, then cut the bottom off the polybag and place it into the hole, and then gently lift the bag to encourage the plant and its soil to stay intact in the hole. Back fill the soil and press down around the plant. Water well. 4. Feeding The young seedling can live for a while on the nutrient contained in the seed, but it will need something when it develops its first leaves. Manure tea can be used for watering. Make this by stirring a shovel full of animal manure into a drum of water and then leaving it for a few days to settle. Take the ‘tea’ from the top of the drum, but don’t drink it yourself! 5. Hardening Off Most young trees will have been growing in a shaded place, but if they are left in that place, then they will develop as thin and spindly trees. They need to be brought gradually out into sunnier locations over several months, until they can tolerate full sun without sunburn.
26
Not too dry or you can kill them
07 Vegetative propagation growing fruit trees as clones
Issues and problems 1. Lack of diversity If you have a large number of identical plants growing together, then any problem that emerges on any one of them will affect them all. Pest populations are encouraged and diseases are more likely to spread quickly. 2. Weaknesses in the structure Grafted plants especially have been cut and rejoined. Scar tissue around the wound is a line of weakness that can reduce the plant’s chance of survival in wind, and can provided a pathway for fungal attack. 3. Incompatibility Some rootstocks tend to reject the graft, or heal poorly, preventing full nutrient flow up around the plant. This will allow the rootstock to grow more quickly than the budwood. This may not show up for some years as the size of roots and stem will not differ at first. 4. Effort required, cleanliness Sharp and clean tools used as quickly as possible, are essential to allow the plant to heal quickly without infection. Care has to be taken to maximize the plants survival chance, but even so many people have low rates of success at grafting. 5. Labelling It is very important that you record permanently on a label the name of the species and the variety if you know it, where it came from, when it was grafted. Other details like the rootstock information may also be helpful. Make sure that the label is attached to the plant with a soft and flexible tie, so that it won’t cut the plant as it grows. A good label can be made by cutting up a soft drink can and pressing hard with an old pen to dent the aluminium.
6. Potting medium The soil used must hold water, but must drain well so that fungi don’t build up in the soil. The soil should also be sterilized, the easiest way of doing this is to pour boiling water over it before planting.
Cuttings This is the simplest way of making a copy of a good plant. When a vigorously growing shoot is cut from a plant, the damaged cells plug the xylem and phloem, to stop the shoot losing water and nutrient, and then grow over the wound as a scab or a callus. Cambium tissue near the callus can then grow new roots from adventitious buds. There are several ways of taking cuttings. 1. Soft wood stem cuttings are 5 to 25 cm stem pieces taken from first year branches that are still soft and actively growing. These are best taken in the early morning or evening after rain or watering. Cut the shoot away with a sloping cut just below a leaf node. Remove the leaves that will be underground. Dip the bottom of the cutting into rooting hormone if it is available. Cut the top off the cutting just above a bud, this time with a flat cut, so you know which way is up. Poke a hole into the rooting medium, (so the hormone is not wiped off), and insert cutting into the hole. Press soil down lightly to ensure that there are no large air spaces and water well. Cover with a plastic bag to keep humidity high, or use a box with a hinged lid covered in clear plastic. Remove the plastic when the shoot has started to produce roots, this might be from several days to several months.
27
2. Single node softwood cuttings have been used in SI for propagation of large numbers of ngali nut and cutnut trees. The last 5-6 nodes on a branch can each be cut away, its leaf trimmed in half, and planted in a poly-propagation chamber to produce 5-6 new cloned trees. For mass production of nodes, good quality trees are grown until they are 10cm thick. They are then cut cleanly at 50cm high and allowed to produce shoots, this process is called pollarding. The new shoots can then be harvested to produce many easily accessible single node cuttings. 3. Hardwood stem cuttings are not used in the tropics, as they are taken when the plant is resting over winter in a cold climate. These are often stored in cold conditions until they are healed, and then they are planted in the spring when it has warmed up. Adventitious buds near the scar tissue will produce roots when the shoot warms up. 4. Leaf cuttings are rarely used for fruit trees, as it really only works well for plants with heavy succulent leaves, such as vanilla and jade. Some others, like African violet and begonia will also take well from leaf cuttings. Cut leaves can produce roots from adventitious buds near the cut edge.
Figure 16. Simple air layer
28
5. Root cuttings are also rarely used for fruit trees, but are commonly used for some garden plants, probably when gardeners saw new plants growing from pieces of roots left accidentally in the soil. It works best with new root growth 1-2cm thick and 2-10 cm long. Make sure that the root pieces are from the plant you want and not from another nearby!
Air Layering When a plant stem is damaged, it can often grow roots directly from the exposed cambium. Air layering exploits this tendency and is a very simple way if no seeds are available for rootstock. However it produces plants with fibrous rootstocks with all the problems typical of that group. Simple Bend a branch down to the ground, (or a pot soil surface). Cut the bark at the area of contact and use metal stakes to pin the branch to the ground. Cover the damaged area with soil and keep it damp. Roots may grow from the damaged area. Knowing when to cut the plant free, and knowing how well the new roots are growing are the drawbacks with this method. Removal of half the leaves from the branch at this time may help survival, by reducing the water demand on the small root system.
Marcot Remove half the bark from 2-4 cm of a branch suitable for potting. Wrap a handful of damp moss or soil around the wounded area then wrap the moss in coconut fibre and then in clear plastic, tying it firmly in place above and below the damaged area. If roots develop, you can see them through the plastic. After 1-2 months, cut partly through the branch between the tree and your plastic wrapped part. After another 1-2 months you may be able to cut the branch away completely and place it into its own pot. Removal of half the leaves from the branch at this time may help survival by reducing the water demand on the small root system. Figure 17. Marcot
Budding Budding is the process of cutting away a single bud which is just beginning to grow, and placing it into the cambium layer of a seedling tree. The bud most commonly used is just under the point where a leaf is attached to the stem. Choose a bud near the end of a branch, but not on the end, and one which appears to be swelling with new growth. See also the photographs on page 20.
Chip budding 1. Prepare the root stock, choosing a place to insert the bud just above the oldest leaves. Cut down the stem for 2-4 cm, just touching the wood. The second cut is still cutting down but more flat to remove the chip.
Figure 18. Prepared rootstock
2. Cut the leaf stem above the bud selected for implanting, to a 1-2 cm length, to give yourself a finger hold on the bud. Remove the bud with a first cut down just into the wood at a 45 angle about 1-2 cm below the chosen bud, then a second cut about 1-2 cm above the chosen bud down just touching the woody tissue. Hold by the leaf stem.
Suckering Many food plants use this system in nature without the help of people. We simply use it to give us more plants. It is also commonly used for plants without seeds such as many gingers, bananas and pineapples, as well as many types of garden plants like tulips, lilies, onions, garlic. 1. 2. 3.
Replanting rooted bud bananas, pineapples. Breaking up tubers and rhizomes Taro, sweet potato. Dividing bulbs and corms Lilies, garlic.
Figure 19. Prepared chip bud
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3. The chip removed from the root stock, and the chip selected for implanting, should be the same size, so that the selected chip fits perfectly into the notch cut for it in the rootstock.
T budding 1.
2. 4. Bind the chip into place with grafting tape, leaving the leaf stem in place and exposed. In a week or so, the leaf should pull away cleanly from the stem. If the bud dies, the leaf will remain attached.
3.
4. 5.
Figure 20. How to T bud
30
Cut horizontally into the rootstock stem, just into the wood, 1-2 cm long. In the centre of this cut, cut down about 4cm, again just into the wood. Use the brass end of the knife to separate the bark away from the wood a little bit, without breaking the bark. Select your bud, cutting its leaf away leaving enough for a handle. Use a single cut down behind the bud just into the wood, so that there is a gentle taper top and bottom. Slide the bud into place under the bark of the rootstock, ensuring that the cambium layers are in contact. Bind the bud into place with grafting tape, leaving the leaf stem in place and exposed. In a week or so, the leaf should pull away cleanly from the stem. If the bud dies, the leaf will remain attached.
Grafting
This is the process of cutting off a growing shoot from a good quality plant, and joining it to a healthy seedling in such a way that that shoot survives and takes over the root system.This produces a new plant with identical fruit and qualities of the parent. It is best done in the cool of the morning or evening. There are many ways of joining pieces of two plants together, but the fundamental rule is that the cambium layer of both pieces must come into close contact with no air leaks. There are four methods described on the following pages, with colour photos on page 21.
the low branch, such that several cms of the seedling stem can be brought easily into contact, under the low branch. Where the two branches make contact, cut down to the cambium of both, then bind them together so that healing can take place and the two branches will fuse together. The seedling top can be cut off after a few days. This method can also be used to transfer budwood from a good tree in the field to a potted seedling. You must be able to look after the potted seedling in the field for several months, so this method is not appropriate for a lot of plants. It does give the best success rate for beginners. 1.
Selection of rootstock The more closely the rootstock is related to the budwood, the higher the likelihood of success of a graft. Most citrus are sufficiently closely related to give good chances of success. There is a range of citrus rootstocks available commercially as seeds which can give good survival and growth rates under a range of environmental conditions. The most likely best ones to be used for Solomon Islands are local pommelo as they do grow well throughout the country, and so are readily available. Citrus trifoliata is also available and is good to use for plants going to inexperienced growers, as rootstock overgrowth can be easily identified. Healthy and well balanced root stocks having started to flush with new growth are the best for success.
Approach and inarching for support
2.
3. 4.
Bring the seedling up to a branch on the good tree so that the two stems of equal diameter are comfortably close for several cms. You may have to raise the seedling on a drum or box. Cut a strip of the contact zone on both plants several cms in length down to the cambium. Make sure that the two cuts are identical in size. Hold the two wounds together and bind with grafting tape. They must fit together comfortably, with no air gaps Four to seven days later cut away most of the seedling top.Two weeks or so later cut part way through the budwood stem below the graft, and remove one cm of bark half way around the stem, leaving half the bark intact. One month or so later, cut the budwood stem right through, allowing the now grafted pot plant to go back to care in the nursery.
Living supports can be grafted into a fruit tree with low spreading branches that are likely to be broken (inarching). Plant a seedling of the same species under
Figure 22. Completed approach graft
Figure 21. Preparing to approach graft
31
Cleft graft
Wedge graft
2.
Wedge graft is about the same, except that a wedge of wood is removed from the seedling rootstock.This is sometimes needed if the rootstock splits apart easily when the budwood is pushed in.
1.
3.
4.
Cut off the seedling at about the 4th leaf height. Split the stem vertically down the middle. Cut the budwood at a matching diameter, then cut the end into a flat point with a cut from both sides down to the centre, also matching 2-3 cm length. Insert the budwood wedge into the rootstock cleft and bind with grafting tape to form an airtight seal. Use a splint if necessary to support the join. Remove most of the leaves of the budwood, leaving only a couple of cut leaves.
Figure 23. Cleft Grafting
Figure 24. Wedge grafting
Top working or bark graft This method is used when a tree becomes too big and has to be cut down, or if it is damaged severely, or if it is no longer worth growing and you want to change the variety of the fruit.
32
1. After the tree has been cut down to a useful height, split the bark with a vertical cut and carefully separate the bark away from the wood. 2. Prepare a shoot of budwood from your best tree by removing the leaves and making a single angled cut at the bottom. 3. Slide the shoot into the separated bark slice until the cambium layers are together. Several shoots can be inserted into one trunk. 4. Seal the wound with beeswax, soft clay or something similar.
Figure 25.Topworking an old tree
Suckering dominance It is absolutely essential to cut off the growing branches below the graft, as these are receiving full nutrient flow without the restriction of the scar tissue at the graft. If allowed, these rootstock branches will take over and eventually the grafted bud wood will die. Your grafted sweet orange tree has now turned into something not worth eating.This problem is very common with citrus trees, where farmers have not learned to identify which branches
are coming from the rootstock and which are coming from the budwood. One type of citrus rootstock, called trifoliata, has very different leaves from other citrus, making it easy to tell the difference between rootstock branches and budwood branches. Trifoliata has leaves in threes whereas most citrus have single leaves. In SI we will be using trifoliata, as well as some local seeds from pommelo and mandarin as rootstock.
Questions and activities for further study 1. 2. 3. 4.
5. 6.
7.
Sharpen a small knife until it cuts through the bark layer cleanly without tearing. Prepare a supply of grafting tape ribbons from plastic shopping bags. Prepare a supply of drink can ribbons for use as labels on young trees. Practice each of the described methods for a. air layering - simple - marcot b. budding - chip bud - T bud c. grafting plants - approach - inarch - cleft - wedge - topwork Find and prepare a supply of clean clay for sealing wounds. Identify the best fruit or nut trees in your area. If any of them are especially good, then they may be valuable as budwood for sale as grafted plants. Make sure that the owner of the tree knows not to burn his tree or chop it down. Collect seeds from this tree as these will be the best rootstock for grafting as they will the most closely related. Collect seeds from local pommelo or orange trees and get them growing in a shaded area for later use as rootstock.
33
Recommended Propagation Methods
34
Avocado
Persea americana
Banana Cashew
Musa spp. Anacardium occidental
Citrus
Citrus spp.
Cocoa
Theobroma cacao
Coffee
Coffea sp.
Custard Apple
Annona cherimola
Guava
Psidium spp.
Jakfruit
Artocarpus heterophyllus
Longan
Euphoria longan
Lychee
Litchi chinensis
Macadamia
Macadamia spp.
Mango
Mangifera indica
Mangosteen
Garcinia mangostana
Passionfruit
Passiflora edulis
Pawpaw
Carica papaya
Persimmon Pineapple
Diospyros spp Ananus comosus
Rambutan
Nephilium lappaceum
Sapodilla / Chiku
Achras zapota
Star fruit
Averrhoa carambola
Seeds only used for rootstock. Cuttings poor root development. Grafts by budding, wedge all ok. Best done with sword suckers 90-180cm high. Usually grown as seedlings. Seedlings typically slow, tall and thorny and best as rootstocks. Chip budding most common. Careful matching of budwood and rootstock to soil conditions is required. Selected fresh and clean seeds from high yielding clones. Budding and air layering ok. Generally from seed from selected superior mother trees. All vegetative methods ok. Seedlings poor quality. Wedge or budding ok. Some layering ok. Usually grown from fresh clean seed. Air layering common, but bud and grafts work also. Seed ok from selected trees. Budding, grafting and air layering all ok. Seedlings very slow, tall and variable. Marcots preferred but cuttings and grafts can work. Seeds are slow and variable and only good for grafting. Marcotting is most successful. Seeds ok but variable. Cuttings also work but roots are too fibrous. Side grafting ok. Some seeds are polyembryonic and run true. Budding, grafting, airlayering all ok. Seeds are very slow but clones of the parent. Wedge grafts have been done. Clean seeds from fresh fruit. Wedge grafts ok. Seeds from controlled crosses can run true. Heeled cuttings over heat and with mist ok. Budding can also work. Wedge grafting onto seedling rootstocks. Slips, suckers and crowns. Seedlings variable and tall. Single sexed tree. Patch budding and marcot most successful. Approach grafts also ok. Seedlings very variable and slow to fruit. Ok as rootstock. Approach, budding and air layering. Seedlings usually revert to sour. All bud and graft methods ok. Air layering most successful.
08
Pruning fruit trees
I
t seems strange to many people that you can make a tree produce more fruit by cutting some of it away but this is in fact true, and is an essential part of training a young tree, and of helping a mature tree to produce as much fruit as it can. Any fruit tree will generally produce some fruit during the year, even if it is neglected. Many people believe that that is normal for only a few fruits to be produced. If that were the case a farmer could not make any money by selling his fruit, as he wouldn’t have enough to make it worth selling. By learning how to prune a tree, it is possible to make sure of a good harvest every year, instead of just hoping for a good crop sometimes. This becomes the difference between the villager who just trusts to luck to get some fruit, and the farmer who knows how to get the best out of his trees.
•
What to prune
•
There are several rules for pruning fruit trees which will keep them healthy, well shaped and increase fruit numbers. Here are some of the most important for the tropics: • Keep the trees healthy by cutting away any dead or dying wood, as soon as you see it. Cut the branch away by cutting into healthy wood below the diseased or discoloured wood, and take the remains well away from the healthy trees, for burning or composting. Use clean and sharp tools to make sure that you are not spreading diseases. • Keep the trees low and spreading out by cutting off tall growing stems.This will encourage sideways growing branches lower down, where the fruit can be reached more easily. • Keep the trees well balanced by allowing evenly spaced branches to remain. Many branches on one side may make the tree fall over with the weight of fruit. You may also have to remove other nearby trees, which are blocking the light, forcing your tree to grow on one side only. • Keep 3-4 main branches so they grow thick and strong. If you allow many main branches to remain, they will be thin and weak and more likely to break under a fruit load.
•
Keep branches which spread sideways and cut away those which stay close to the main stem with a narrow angle. These will break more easily under a load, and should not be allowed to grow once they appear. Some trees like mandarins will have many branches which grow straight up. These can be bent down and held down with a rock on a rope until they are growing in that position. Later on a crop of fruit may do the same thing. Encourage an open cup shape by cutting out any branches which grow across the middle of the tree. This will allow more light and air into the middle of the tree helping to stop the spread of disease.This will also encourage more flowers and fruit to grow on the inside. Encourage new leaf growth by cutting the tip off many branches. This will make the tree produce 4-5 new tips where before there was only one. Citrus, passion fruit, breadfruit and others which fruit on the tips will all make more fruit.
When to prune Cut away diseased wood whenever you see it. When they are young and growing, it is important to prune fruit trees to ensure that the shape is best for supporting a load of fruit, and that the size is kept down for you to reach the fruit. The best time to cut away the branches is when new leaves go hard but before the next wave of new growth starts. As the tree matures and starts to have fruit, then the best time to prune is just after the harvest. Take out high growing branches to keep the height down, then cut off the tips of branches to get more new growth.
35
Tree Spacing Some recommended spacings for mature fruit orchards. Species Acerola Alite nut Avocado – grafted Avocado – seedling Breadfruit Carambola Chempedak Coconut Custard apple Cut Nut Durian – grafted Durian – seedling Grapefruit Grapes Guava Jakfruit Macadamia nut Malay apple Mango Mangosteen Marang Ngali nut Okari nut Orange Passionfruit Rambutan Sapodilla Soursop Star apple
36
Meter spacing 4x4 15x15 7x7 10x10 9x9 4.5x4.5 9x9
Number per hectare 625 44 204 100 123 493 123
6x6 8x8 8x8 20x20 6x6
278 156 156 25 277
6x6 9x9 9x9 8x8 8x8 6x6 9x9 16x16 10x10 6x4
278 123 123 156 156 278 123 39 100 416
Recommended pH 5.0-5.4
6.5-7.5 6.0-7.5 3.4-9.0
6.5-7.5 5.0-8.0 6.0-7.5
5.5-7.0 6.0-7.5
6.0-7.5 9x9 4.5x4.5 4.5x4.5 9x9
123 493 493 123
09
Why is there no fruit on my mango?
M
any mangos in Solomon Island have no fruit at this time of year, for one of several reasons. Firstly the soil here is very rich, and unless the tree is stressed by cold or dry conditions, this will keep the tree producing leaves instead of flowers, and so no fruit can even start.Then if your mango does produce flowers, many of these will be killed by a very common fungus (anthracnose), that is encouraged by the warm and wet climate. You can recognise the fungus by the black spots appearing on the leaves. This fungus can also cause small fruit to drop off the tree and can cause even large fruits to be split open before they mature.
Only use fertiliser on the tree if it is turning a pale green to yellow in colour. I see trees like this usually near the beach, where the sandy soil has lost its nutrients to the rain. If you do you use fertiliser on the tree, only ever do so at Christmas or when you are picking fruit. Used later in the year this fertiliser will be enough to also force the tree back into producing leaves instead of flowers.
If your tree is at least 6 years old and still hasn’t flowered this year, then one possible trick to do before the end of January is to cut off every branch where it is about 8 cm wide, leaving no leaves on the tree at all. Take away all the leaves and small branches You can help your mango tree resist the fungus by and leave the tree to grow a new set of leaves. This cutting out any branches going straight up in the will help reduce the nutrient available and will put middle of the tree and removing any other trees that stress on the tree helping it to flower next season. are close to the mango. New mangos should only be Every Christmas, give your tree a haircut, especially planted on high points, exposed to wind and sun. All taking out the highest branches, keeping its size down of these actions will increase the amount of sun and to one where you can reach all the fruit. It is the size wind into the mango tree and so help it to dry out, of the root system that determines how much fruit killing the fungus. However, only cut branches off your is on the tree, so a smaller tree doesn’t mean less mango after harvest, usually near Christmas time, as fruit! cutting branches will also force the tree to make new The local seedling trees are resistant to anthracnose leaves and will block it from making flowers. but only produce small and fibrous fruit.They are best There are also chemical sprays available, based on used as rootstock on which to graft fungus resistant copper solutions, which can also help control the varieties. For new trees, grafted trees are a much fungus. These can be very expensive, as they have to better choice than seedling trees. Resistant varieties be applied at least every 2 weeks or every time it will become more readily available in Solomon Island rains for the flowering time! Opening up your tree as the CSP/ Agriculture Livelihoods Fruit and Nut Tree project gets underway. These varieties include to sun and wind is a lot cheaper. Golek, Nam Doc Mai and Zillate. Other local seedling varieties showing fungal resistance and low fibre will also become available through this project. The Fruit and Nut Tree team can be contacted through CSP.
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Carambola - star of the rainforest
C
arambola, aka star fruit or five corner, is a common fruit seen in many places around Solomon Island. The seeds grow easily from dropped and discarded fruits, and it is the fruit from these seedling trees grown to adulthood that have created the reputation of this as a sour fruit. This is a pity, because there is no other tropical fruit as sweet, crisp and refreshing as the fruit from one of the grafted varieties.These have been selected for their sweetness and are usually highly accepted when offered around at fruit workshops. The fruit are usually eaten fresh, but even the sour fruit make a most acceptable pickle when cooked up with various spices and vinegar or as a jam when cooked with sugar. They can be picked when the yellow colour just starts to develop and the fruit will continue to ripen after picking. They are best eaten when they are mostly yellow, after trimming away any green edges on the wings. The green colour contains oxalic acid which has a very bitter taste and is best removed. At home in the rainforests of Indonesia, these trees can grow to 15 meters, so it is a good idea to keep them smaller, removing any branches going vertically or tying them down to a rock. Fruit grow in large bunches just back from the actively growing ends, so these can be cut back a little at a time without losing fruit. Feeding the tree is also best done a little at a time, with up to 2 kilograms of NPK for each adult tree every year, along with a micronutrient spray every month. Happy trees can produce hundreds of kilograms of fruit through most of the year!
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Pest problems mainly revolve around control of the fruit piercing moth, which also prefers the sweet varieties. For the home tree this is most easily done using old newspaper to cover most of each bunch of fruit as they approach full size. Use staples or clothes pegs to hold the bag closed and arrange the paper so that no water sits on it. This will last for several months in the weather, ample time for the final ripening to take place. Check the bunch every few days to ensure that you don’t miss the harvest. For commercial growers, there is no real alternative to covering the whole tree with moth proof netting for every harvest. They also need to ensure that the tree is kept pruned, preventing it from growing through the net and damaging it. The fruits are also attractive to mealy bugs, which can be controlled by stopping the movement of ants up and down the tree with sticky bands. If you have a sweet carambola nearby, then it is possible to grow some seeds in your nursery and graft a branch from the sweet tree onto your seedling.You can then have your own tree to plant where you want it. Carambola can also be grown from the end section of an actively growing branch placed into clean soil mix in a humidity chamber where it can grow its own roots. Other articles will pass on some details about how to grow your own good varieties of fruit trees and the CSP/Agriculture Livelihoods Fruit and Nut tree team will be running workshops if you need more hands on help. More information about workshops can be obtained from the CSP office near you.
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Rambutan - hairy thing from the forest Any day from December through to June in your local market, you should see some golf ball size, bright red fruit covered in hairy threads. These are rambutan, a fruit native to Indonesia that have proven to grow very well in Solomon Island, preferring the hot and wet climate of the coast to the cooler climate of the hills. Rambutan translates from Indonesian as “hairy thing from the forest� and is a word I have often heard said about me with my full beard, as I push my way through Indonesian markets. These fruits may look a little unusual, but once you break open the hairy shell the sweet melting flesh has few equals. It is much sweeter and a little larger than the lychee (a similar but non-hairy fruit from China that needs a cold winter and so would not do well in Solomon Island). Rambutan is eaten fresh, but is so delicious that it is very difficult to simply eat one or two. The trees can produce fruit in four years and by the time they are ten years old, can produce 400 kilograms of fruit every year. Seeds grow well, but unfortunately about half of these grow up to be male, and will never produce fruit. The female trees can produce fruit but the flesh is often strongly attached to the seed and very stringy, a bit like mango, making it difficult to eat. Seedling trees are also very big, with branches often not starting until 3m off the ground. These problems mean that rambutan trees are normally grafted, producing a smaller tree with branches close to the ground and loaded with easy eating and well-flavoured fruit. The rich soils of much of Solomon Island means that rambutan do not need a lot of fertilizer to stay healthy unless they are growing them on a sandy area or if you have harvested a heavy crop. If you need to feed your tree, give it one kilogram of NPK at flowering and another at harvest, along with a monthly micronutrient spray. Rambutan mainly needs a good supply of water, as they have no way of shutting down the flow of water through their
leaves. If the soil dries out, the leaves will start to die immediately. However, the trees will also die if left standing in water as their roots need a lot of air. This means that well drained soils on hillsides, in wetter areas of SI are perfect. Rambutan trees are mainly pruned during the harvest, when bunches of fruit are cut away along with a little wood. This will encourage new growth from the cut end with the possibility of a second crop that year. If the fruit are picked individually, a second crop cannot start as new shoots cannot start quickly. For this reason you should use a pole picker to harvest bunches of fruit. This can be made from a pair of secateurs with one handle attached to a bamboo pole, with a cord running from the ground through a pulley on the fixed handle, then to the other handle. Pull the cord to cut off a bunch of fruit. The timber in the branches is particularly weak and careless climbers can break off large limbs in their hunt for fruit. As the trees get very big, some of the highest branches can be cut back severely, but no more than one-third of the tree, or you could stress the tree too much for it to flower that season. Grafted trees are not yet available in Solomon Island, although there is a large collection of good eating varieties available. The CSP/Agriculture Livelihoods Fruit and Nut Tree Project will be grafting many of these top quality trees for distribution around SI over the next few years, and can provide budwood to people who have grown rambutan seeds in pots. The project will also be running workshops to teach interested people about growing and grafting fruit and nut trees. More information is available from CSP.
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Positive insects
I
believe that use of chemicals on farms is responsible for many of the agricultural problems on earth today. Notice that I mean the use of all chemicals, not just pesticides, but fertilizers also. Fertilizers spread onto farmland in high rainfall areas like Solomon Island are dissolved by the rain and run off to the sea and its surrounding reefs. Green algae respond quickly to the free food, and cover much of the surface with green slime, use up available oxygen and cause massive die off of the animals, including fish, in that area. Insecticides can cause more obvious damage by not only killing the pest insects but also wiping out all the other insects including hunters, pollinators and parasites. These are all beneficial insects, without which life on the farm becomes that much harder. The most significant of these is the honey bee, responsible for pollinating a wide range of fruit trees including mango. Without the bee to carry the pollen, the following fruit would fall by at least 50%, possibly disappearing from the market place: avocado, beans, citrus, coconuts, coffee, cucumber, mango, passionfruit, and pumpkin and many of the exotic fruits. Although the bee produces many other products of economic value including honey, wax, propolis, bee venom, and royal jelly, these are far outweighed in value by its role in pollination. It is criminal to me that many farmers are encouraged to spray insecticides knowing that bees are killed just as easily as the pest for which the poison was intended.
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For example, mealy bugs are probably one of the problem pests on SI, in that they make fruit look unattractive and carry diseases. By themselves they do little damage. Insecticides can be used to keep the fruit clean but in doing so the mealy bug predator insects (ladybirds) and parasites (small wasps) are also killed. Not all the mealy bugs are hit by the spray and those that survive breed, and return quickly in numbers. Predator insects were much fewer on the tree and so are slower to breed back as there is little food immediately available for the survivors. The spray must be used again, not because the insect has become resistant, but because its natural killer has been wiped out. The natural ecological balance has been destroyed by the spray, and a more severe problem has been created. The permanent use of an area of land for food production can fit comfortably into the local ecology, while still allowing most of that food to be left for human use. My own farm in Australia produces fruit for sale and eating by deliberately designing the farm as part of a balanced rainforest ecosystem. The name given to this type of agriculture is “permaculture�. More information and other links about permaculture can be found on my website at www.capetrib.com.au
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Want more mangoes next year? S
o the mango season is over for another year. How many fruit did your tree give you? For many of the mango trees in Solomon Island, the answer would be few or none. The rain, heat and humidity produce perfect conditions for the growth of various fungal diseases that kill the flowers and force fruit to drop early. There is not much the grower can do to change the weather, but there are a few things that you can do to help your tree fight off the diseases without chemicals and the time for action is almost over for the year.
about 3-4 meters, and taking the leafy ends off every spreading branch.You should now have a spreading leafless skeleton of a tree, not much good for shade for a while, but it will repair itself. New shoots will appear within two weeks and when these are about two months old you will need to go through and thin them. Remember that the goal is an open spreading tree. So remove the shoots growing towards the centre, and where they appear to be too close together. Leave the strongest and the outward spreading shoots.
Rain on flowers is the main killer so the aim in this exercise is to get the tree to make flowers during the dry season in August or September when they have the greatest chance of staying dry and disease free. On mango trees, flowers develop on the ends of new leafy growth after those leaves have grown then rested for four months or so. Fruit will be formed if the flower is pollinated successfully, (bees help), and fungi do not develop in the dying flower. I’m sure you’ve seen how when mango trees have branches cut or broken, they characteristically grow many new shoots along the remains of the branch. If you can force the tree to make new shoots before March, they will be around five months old and ready to flower for the dry season. So chop off the branches!
So if you can cut back your mango before the end of February, the new growth can be six months old by July/August and the flowers will appear for the drier time. If you leave the pruning until March, the new growth may not have enough rest time to flower during the dry. But it might. And that’s what makes this an art form.
Radical? Yes, but what have you got to lose?
Another option for those of you who are willing to wait a while for a young tree to grow up, is to plant some mango seeds in pots and come to one of the nursery workshops being run by CSP Agriculture Livelihoods Fruit and Nut Tree Project.You will learn how to grow seeds properly and then to be able to graft a new top onto your seedlings, giving you a top class fungus resistant fruit tree when it grows up. Contact CSP for more information.
Take out the centre of the tree at whatever height you are comfortable to work. (For me that’s about two metres from the ground). Leave the tree with the centre open to the sky. This will allow air movement helping the tree to dry out and kill off growing fungi. Now move around the tree cutting off every vertical branch, limiting the final height to
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Appendix Insect groups There are many thousands of insects everywhere on earth. Here are some of the more common groups of insects with a picture of one member. Just about every group of insects will have some members which are pest problem and others which help kill pests.(All images developed from Australian Insects, John Child, Lansdowne Press, 1968) Name
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Picture
Activity
Good or Bad
Solution
Weevil
Tunnels into stems
Pest
Poke wire up hole to kill grubs
Ladybird beetle
Hunts small insects
Good
Dragonfly
Hunts small insects
Good
Cockroach
Under bark
Not a problem. Converts waste to mulch
Praying Mantid
Hunter
Good
Grasshopper
Leaf eater
Bad
Flour sprays. Breeding slows with wet weather
True bugs
Sap suckers
Bad
Soap sprays
Aphid
Sap sucker, Bad disease carrier,
Butterfly or Moth
Grubs eat many things, adults suck fruit, etc
Many wasp parasites Many bad, some lay eggs on neutral grubs, trap adults
Fruit fly
Lay eggs in fruit
Bad
Gall Wasp
Eggs laid in stems and leaves cause lumps (galls)
Bad
Chalcid wasp
Lay eggs in grubs of many pest species
Good
Many sprays
Traps and baits
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Notes
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