Growth, Development, and Fruit Quality and Yield of Varieties of Pear under Rain-shelter Cultivation

  Objective  Application of rain-shelter for pear cultivation in southern hot and humid regions was evaluated according to the growth, development, and fruit quality and yield of the selected varieties.

  Method  Indicators on shoots, leaves, flower buds, phenology, fruit quality, and fruit yields of different types of pear varieties were monitored with individual tree tracking to compare the effects of rain-shelter and open-field cultivations.

  Result  Compared with open field cultivation, rain-sheltering prolonged the fruit development and vegetative periods, increased the fruit forming percentage of inflorescence and individual flower, weakened the growth of shoots and leaves, improved the fruit appeal, and lowered the firmness and acidity but increased the total sugar content of the fruits. Grown under rain-shelter, the 3 early maturing pear varieties that were susceptible to early defoliation significantly or extremely significantly increased on their flower-to-bud ratio, weight of 100 flower buds, yield per plant, and weight of single fruit; while Cuiyu and Cuiguan, among them, significantly increased in soluble solids. The two mid-season maturing varieties that were less prone to early defoliation decreased significantly or extremely significantly on their flower-to-bud ratio, weight of 100 flower buds, and single fruit weight; while Huanghua showed a 22.42% decrease on yield per plant and a significant reduction on soluble solids. For the 3 green pear varieties, rain-sheltering helped them to become less susceptible to fruit rust, as Cuiyu turned out to be extremely significantly reduced on the appearances of rust-infected fruits, rusty peels, and spotty fruits.

  Conclusion   The early maturing, early defoliation-susceptible varieties of pear that are resistant to rust could be candidates for the perennial film-covering rain-shelter cultivation. Whereas, fruit bagging would be necessary on the rust-sensitive, early maturing varieties to avoid early defoliation under rain-shelter cultivation. For the mid-season maturing varieties that are not prone to early defoliation, open field cultivation would be more appropriate. If rain-sheltering was applied to these mid-season maturing varieties, they should be covered with film only in the early and middle stage of growth and development, and the film should be removed following fruit harvesting.