Pollination of apples in China

by Uma Partap and Tej Partap, ICIMOD, Nepal

In Maoxian County apples planted on a large-scale in the 1980s are now an important cash crop. Dr Uma Partap explains, “Pollination problems started right at the beginning. There is very low proportion of polliniser trees and scarcity of pollinating insects because of pesticides”.

Introduction

Maoxian County is in Aba Prefecture in Sichuan Province, South China. Apple cultivation started in 1935 with the planting of 30 trees of six different varieties. Large-scale cultivation started in the early 1980s, when apple became main cash crop of the County. Apples from this region are known as ‘Moawen Apples’ and are famous for their quality. They are sold in markets in Beijing, Tianjing, Guangzhu and Hong Kong, and also are exported to Russia and south-east Asian countries.

In Maoxian County there are 2,830 hectares of apple trees producing around 30,000 tonnes of apple, worth 33.9 million Yuans (US$ 4.2 million) every year. However in recent years, apple production has dropped in both yield and quality. We therefore investigated whether the pollination of the apples was adequate.

Study methodology

We prepared questionnaire, surveyed the apple area, and interviewed farmers. Because apple is the main cash crop, farmers aim for maximum yield and quality by using every possible orchard management technique like irrigation, fertilisers, pruning, and use of pesticides and fungicides. Field investigation revealed that almost every apple flower is pollinated by hand instead of by insects like honeybees.

Pollinating apples by hand

Pollination of apple flowers by hand is very common in Maoxian County despite the fact that beekeeping is popular in the area. The following issues emerged:

1. Average land holdings are very small: around 0.2 hectares. Therefore to make best use of the land, farmers have planted only the main variety of apple and very low proportion (5-7%), of polliniser trees. The minimum requirement is 20%. The farmers simply do not want to increase the proportion of polliniser trees, as they are commercially less important. With such low proportion of pollinisers, honeybees can play only small role in pollination.

2. Because apple is the main cash crop of the area, farmers want higher yields of better quality apples, at any price. They want to ensure that each flower is properly pollinated. Therefore they believe only in pollination by hand and feel that this is way to achieve certain pollination when the polliniser proportion is very low.

3. Farmers also believe that pollination by hand is the surest method of pollination even under adverse climatic conditions. It is still possible to hand pollinate apples in low temperatures and bad weather, when bees and other insects are not flying.

4.The apple farmers use pesticides excessively. They spray 10-15 times each season, even during flowering time. Past experiences indicate that pesticides used during flowering seasons killed many bee colonies and other natural insect pollinators, in addition to killing apple pests.

5. Though beekeeping and migratory beekeeping are common in the area, beekeepers are now not interested to rent bee colonies for apple pollination. Therefore farmers continue to pollinate their crops by hand.

Pollination by hand

Pollinating apples by hand is community effort. Apple flowering begins at lower altitudes and progresses upwards. Thus all apple farmers in the higher areas of the County are free of work and are hired to pollinate apples in lower areas. Since orchards are very small, larger families are able to pollinate their whole crop by themselves.

In hand pollination the anthers are picked from flower of the polliniser variety when the flower is at the balloon stage (partially open flowers) and is dried to release pollen grains. Farmers usually dry the anthers by spreading them out in the sun for day or two. Some use cardboard boxes provided with an electric bulb, and others even use electric blankets to dry the anthers. The pollen grains are stored in cool, dry place and remain viable for three to four days. These are mixed with little white flour or skimmed milk powder and are applied to the flowers of the main variety (within two days after flower opens) with the help of hand made brush, the filter side of cigarette, or pencil rubber. The farmers pollinate three out of the five flowers in an each apple inflorescence. Hand pollination is carried out three times in each season to ensure pollination of late flowers.

Economics of pollinating flowers by hand

Pollinating flowers by hand is very laborious and time consuming. About 20-25 people are needed to pollinate apples in one orchard in one day. The fee for one person is about 20 Yuans per day, and this means that farmers pay about 600 Yuans (US$ 70) for pollination of their apples. Farmers could hire less labour, as apples bloom about week, but they want to rush case of adverse weather conditions.

Economics of bee pollination

A maximum of two colonies of honeybees are needed to pollinate an apple orchard. The rental fee for one honeybee colony is US$7, which means that farmers would pay only US$14 to pollinate their orchards using honeybees. This calculation shows that bee pollination would be five times cheaper, but the farmers are still using hand pollination for the reasons described above.

Role of Government

A farmer, Li Jicai of Jingzhao Village, was the first to start pollination by hand. The County Government then took over and with its extension services spread the technology of hand pollination. Field experiments to standardise the technique were completed by 1990, after which farmers were given training in 1991. At that time only some farmers accepted the technique. But as the impact of pollination by hand became apparent other farmers in the County were also convinced. In 1994, 1,300 hectares of apples were pollinated by hand, and by 1997 the whole 2,000 hectares of apples were pollinated this way.

Acknowledgements

We are grateful to Dr He Yonghua and Xie Jiasuei for accompanying us to the field sites and assisting with interviewing farmers. Also to our Chinese colleague in ICIMOD, Dr Tang Ya who helped co-ordinate our study. Our special thanks go to the mountain farmers of Maoxian County for sparing time from their already busy schedule to provide us with valuable information.