Sapindaceae Litchi chinensis Sonn.
Origin and distribution The origin of the Lychee is – South China (‘Guangdong’ province) and North Vietnam
Origin and distribution
The Litchi chinensis Sonn. Belongs to the subtropical trees.
Origin and distribution
Lychee tree in China (1,000 years old)
Production and Marketing
Young litchi plantation in China
Origin and distribution
Litchi distribution • From China to neighboring countries in southeast Asia: • Burma (Myanmar) in the 17 century • India in the 18 century • Hawaii California Florida – in the 19 century • Philippines, South Africa, Israel – in the 20 century
Origin and distribution
Huang et al., 2005
Origin and distribution
Litchi and Longan distribution around the world
Huang et al., 2005
Growing conditions
Effect of winter temp. regime on the flowering / Stern and Gazit, 2003
Conclusion: Optimal temp. for flowering of all cvs: 10-15°C
Growing conditions Lychee Symp. China, 2005
Growing conditions
conclusions : 1. Photoperiod has no influence
2. 12° Min. optimal temp. 3. >17° Min. no differentiation
Growing conditions
Why is litchi not grown successfully in the tropics? • Needs low temp. (<14°C) for 6-8 weeks to induce flowering ("differentiation") • The lower the temp. (down to 0°C) the better the differentiation
• In the tropics, the trees grow well but do not flower • In temperate zones where temp. drop below 0°C, the trees die
• Conclusion – Litchi trees can only grow and fruit in the subtropics
Production and Marketing
Litchi industry around the world
1980 ď § 50,000 ton in China 2010 ď § 2.5 million ton
Production and Marketing
Marketing season of litchi
Total world production = 3 million ton
Cultivars
Cultivars
Litchi cultivars show very large variation worldwide. The differences are expressed in some fruit characteristics: 1. Color â&#x20AC;&#x201C; from light green ('FZS') to pink ('NMC'), light red ('Mauritius') and dark red ('Floridian' = 'Brewster') 2. Shape â&#x20AC;&#x201C; elongated, round, heart-shaped, etc.
Cultivars
Shapes of litchi fruit
Cultivars
Litchi cultivars show very large variation worldwide. The differences are expressed in some fruit characteristics: 1. Color – from light green ('FZS') to pink ('NMC'), light red ('Mauritius') and dark red ('Floridian' = 'Brewster') 2. Shape – elongated, round, heart-shaped, etc. 3. Seed size – small and shriveled ('NMC') to very big ('Floridian') 4. Fruit size/weight – from 15 g ('Wai-Chee') to 40 g ('FZS') 5. Taste – from mild flavor ('Floridian') to excellent flavor ('FZS', 'NMC')
Cultivars
Names of litchi cultivars around the world
Cultivars
Harvest time of the main cvs. in China
Cultivars
Litchi harvest time â&#x20AC;˘ When sugar concentration reaches 16% or more and acid concentration (especially malic acid) decreases to 0.2% (sugar/acid ratio of at least 1:70)
â&#x20AC;˘ At the same time, red pigments (anthocyanins) accumulate in the peel and the green pigments (chlorophyll) disintegrate
(Menzel, 2004)
Cultivars
Origin: China, strong tree, high yield, medium fruit size (22-26 gr.) with big seed
(Menzel, 2004)
Cultivars
Origin: India, strong tree, high yield, big fruit size (2630 gr.) with big seed
(Menzel, 2004)
Cultivars
Origin: China, tall tree, medium yield, small fruit size (20 gr.) with big seed, high quality
(Menzel, 2004)
Cultivars
Origin: China, tall tree, medium yield, small fruit size (20 gr.) with big seed (high % of shriveled seed), good quality
(Menzel, 2004)
Cultivars
Origin: Australia, small and compact tree, high yield, small fruit size (18gr.) with very small seed in all fruit, excellent quality
(Menzel, 2004)
Cultivars
Origin: China, small and compact tree, high yield, small fruit size (18gr.) with big seed, excellent taste
(Menzel, 2004)
Cultivars
Origin: China, strong tree, medium yield, very big fruit size (40 gr.) with small seed, excellent taste
Cultivars
No Mai Chee The best cv. from China: compact tree, high yield, big fruit size (25gr.) all seeds are shriveled, excellent taste, very easy to recognize this fruit
Cultivars
No Mai Chee
Cultivars
Floridian = Brewster
SapindaceaeLitchi Litchichinensis chinensis Sonn. Sapindaceae Sonn.
Reproductive biology
To set fruit, the tree has to pass through 5 steps: 1. Differentiation to flowering 2. Flower development – male and female 3. Pollination – pollen movement between flowers 4. Fertilization – pollen (n) tube growth in the style until the male gamete conjugates with the female gamete – egg cell (n) to create the zygote (2n) 5. Fruit development
Agrotechnical techniques to improve flowering: water stress
Agrotechnical techniques to improve flowering: water stress
One of the main limiting factors for low yield is poor flowering
Agrotechnical techniques to improve flowering: water stress
One of the main limiting factors for low yield is poor flowering 1.water stress
2. Pruning 3. growth retardation by "anti-gibberellinsâ&#x20AC;&#x153; 4. tree ringing
Agrotechnical techniques to improve flowering: water stress
1. Fall water stress This technique was developed in Israel by Stern et al according to the following data :
Rain (mm)
A. In South China (where litchi originated) the period of differentiation (Oct-Jan) is usually dry. Most of the rain falls during the summer.
Month
Rain quantity (mm) in Guangdong (S. China) (average of 7 years)
Agrotechnical techniques to improve flowering: water stress
1. Fall water stress B. The vegetative flush must stop its growth before differentiation can begin. The leaves must be mature (dark green) with mature terminal buds before the signal for differentiation (decrease in temperature) appears.
Young flush in fall
Mature flush in fall
Agrotechnical techniques to improve flowering: water stress
1. Fall water stress C. Flowering inhibitors (gibberellin) or inducers (cytokinins) are produced in the root. Water stress can change the balance between the two hormones
Agrotechnical techniques to improve flowering: water stress
Autumnal water stress inhibits new vegetative flush ď § better flowering ď § higher yield
Agrotechnical techniques to improve flowering: water stress
mm/day
Irrigation regime
Soil Water Stem Water Potential (Kpa) Potential (MPa)
100%
6
-18
-1.2
50%
3
-52
-1.7
25%
1.5
-65
-2.2
0%
0
-90
-2.8
Agrotechnical techniques to improve flowering: water stress 1995.
Agrotechnical techniques to improve flowering: water stress
Results – reducing the amount of water to the plant inhibits the new flush improves differentiation more flowering more yield
Agrotechnical techniques to improve flowering: water stress
Effect of autumnal water stress on litchi yield
Agrotechnical techniques to improve flowering: water stress
Autumnal water stress has become commercial practice in orchards: reduction of the irrigation amount to about 25% of controls in October reduces the vegetative flush ď § increases flowering ď § increases yield without any damages to the tree
Agrotechnical techniques to improve flowering: Pruning
2. Pruning The aim â&#x20AC;&#x201C; remove the young vegetative flush which grows in the autumn to expose the mature buds (and leaves) to low temperature, which induces differentiation.
Agrotechnical techniques to improve flowering: Pruning
2. Pruning Results
â&#x20AC;˘ Improves flowering and yield â&#x20AC;˘ Pruning must be performed no later than midDecember. After that there is not enough time for accumulation of cold temperature signal (minimum cold requirement is 6-8 weeks)
Agrotechnical techniques to improve flowering: anti-gibberellins
3. Autumnal growth retardation by "anti-gibberellins" Reducing gibberellin in the buds at the beginning of the differentiation period (autumn) dramatically increases flowering intensity the following spring. Possible GA-biosynthesis inhibitors are "Magic" (uniconazole) or "Cultar" (paclobutrazol).
Agrotechnical techniques to improve flowering: tree ringing
4. Autumnal tree ringing
The aim – increase carbohydrate concentration in the canopy, especially in the buds, during the differentiation period Result – increased flowering The risk – the litchi tree is very sensitive to ringing compared to avocado, mango etc., therefore the scoring must be performed very carefully (width of only 2 mm, spiral shape, not on the main trunk, etc.)
Agrotechnical techniques to improve flowering: tree ringing
Spiral barking on main branch
The movies Pruning a lychee tree
Picking and Pruning Lychees
The inflorescence and the 3 flower types
The inflorescence and the 3 flower types
The inflorescence and the 3 flower types
inflorescence from terminal bud
The inflorescence and the 3 flower types
• Normal inflorescence consists of 1,000 flowers. • It is composed of 3 flower types which open sequentially in 3 waves: 1. Male 1 (M1) 2. Female (F) 3. Male 2 (M2) Each type makes up about 1/3 of the inflorescence.
The inflorescence and the 3 flower types
Male flower (M1)
The inflorescence and the 3 flower types
Female flower (F)
The inflorescence and the 3 flower types
Male flower (M2)
The inflorescence and the 3 flower types
Flowering phenology
pollination
pollination
VS.
pollination
Pollen grains of litchi
pollination
VS.
pollination
Litchi pollen grains on honeybee legs - SEM
Hundreds of pollen grains (during M2 flowering)
Tens of pollen grains (during M1 flowering)
pollination
pollination
Number of pollen grains on honeybees visiting the 3 flower types 1. Few pollen grains on honeybees visiting M1 flowers and F flowers at the beginning of female flowering. 2. Hundreds of pollen grain on honeybees visiting M2 flowers and F flowers at peak of female flowering
pollination
The differences in nectar volume and sugar concentration among the 3 flower types • Female – highest volume and concentration • M2 – medium volume and concentration • M1 – lowest volume and concentration
pollination
pollination
Nectar characteristics (volume and sugar concentration) are the main factors influencing the flower's attractiveness to bees. There is a high positive correlation between sugar concentration and honeybee visits to the inflorescence.
pollination
The differences between the 2 male flowers M1 and M2:
1. Amount of pollen grains â&#x20AC;&#x201C; M2 > M1 2. Viability of pollen grains â&#x20AC;&#x201C; M2 > M1
fertilization
The increased pollen viability of M2 flowers is expressed in:
1. A higher percentage of normal pollen 2. A higher percentage of germination 3. More rapid growth of longer pollen tubes
4. Lower sensitivity to extreme temperatures
Fertilization
Pollinated female flowers (UV)
Pollen tube growth in the transmission tissue of the style Germination of pollen grain on the stigma
fertilization
Higher fruit set of M2 pollen after hand pollination
The inflorescence and the 3 flower types
Advantages of M2 flowers for pollination and fertilization 1. Pollination – Higher nectar volume and sugar concentration higher attractiveness to bees more bee visits to the flowers higher pollen load on the body of bees visiting both M2 and F flowers higher pollination rate of F flowers that overlap with M2 flowers. 2. Fertilization – Higher viability of M2 vs. M1 pollen. Higher pollination and fertilization Higher fruit set and yield
The inflorescence and the 3 flower types
Flowering phenology
Fertilization and fruit development
To understand the fertilization process in litchi, we have to study the anatomical structure of the female flower from which the fruit emerges.
Fertilization and fruit development Longitudinal section of female flower (pistil), Stern and Gazit, 2003
(A)- Style and ovary with 2 ovules (Ov) Right â&#x20AC;&#x201C; normal ovule Left â&#x20AC;&#x201C; degenerated ovule
(B)- Normal ovule composed of funiculus (F), obturator (O), 2 integuments (Int.) and embryo sac (ES)
(C)- Embryo sac containing egg cell between the 2 synergids (S), polar nucleus (P)
Fertilization and fruit development
The fertilization process consists of 2 stages:
1. Polar germination on the stigma 2. Pollen tube growth in the style until the male gamete fuses with the female gamete (egg cell) to produce the zygote
Fertilization and fruit development
The beginning of fruit development:
Rapid cell division of the zygote to create the embryo and cell division of the polar nuclei to create endosperm
3-week-old fruitlet Pro-embryo (PE) at the base of the embryo sac (ES) surrounded by endosperm nuclei (En)
Fertilization and fruit development
4-week-old fruitlet "heart-stage embryo" (E) with the beginning of cotyledon development surrounded by the endosperm (x 100)
The embryo is still very small at the base of the seed space (x 25)
Fertilization and fruit development
5-week-old fruitlet
The cotyledons (C) are growing very fast (in 1 week they will fill the seed space). The endosperm disappears. The seed stops growing and the "aril" begins to grow
Fertilization and fruit development
Fruitlet abscission
Fruitlet abscission Litchi undergoes 2 main waves of abscission: 1. In the first 3 weeks after pollination (90% of the fruitlets)
2. Between 5 and 7 weeks after pollination (50% of the remaining fruit)
Fruitlet abscission
Fruitlet abscission
Stern et al. found that the 2nd abscission wave always occurs in parallel with the rapid stage of embryo growth in the seed
Fruitlet abscission
Fruitlet abscission
Fruitlet abscission
• The 2nd abscission wave was found to coincide with a drastic decrease in auxin concentration. • Stern and Gazit developed an auxin treatment to reduce the extent of abscission.
• Treatment with synthetic auxins at exactly 5 weeks (fruitlet weighing 2 g = 12 mm) reduced abscission.
Fruitlet abscission
Fruitlet abscission Pattern of fruitlet abscission from treatment to harvest
Litchi propagating
Litchi propagating
חיגור באביב
Litchi propagating
Litchi propagating
Rooting after 2 months
Litchi propagating
Litchi propagating
Litchi insects
Litchi insects
Litchi insects
Litchi marketing in China
Photos: M. Goren (Israel)
Its lychee Picking Time!!
Lychee Flowering