Studies on Pollination, Fruit Set and Self-Incompatibility Index in Apple Varieties under Wet Temperate Conditions of Himachal Pradesh

In the present study, floral biology, the extent of fruit set under different modes of pollination, the relationship between fruit shape and seed number, and the compatibility status among different apple varieties were studied. Fruit characters and yield are directly influenced by floral characteristics, flowering time, flowering duration and pollen fertility. Flowering duration varied from 10 days (Scarlet Spur II and Schlect Spur) to 15 days (Granny Smith). Pollen viability ranged from 72.43 per cent (Ace Spur) to 96.83 per cent (Coe Red Fuji) in 1 per cent acetocarmine solution, and from 76.21 per cent (Schlect Spur) to 90.85 per cent (Gale Gala) in 0.04 percent erythrosine B. The findings showed that, Gale Gala and Granny Smith were superior pollinizers. Seed number was maximum (9.40) under hand/controlled pollination and minimum (2.40) under bagging conditions. When the seed number was low, there was a higher percentage of lopsided fruits, and vice versa. All the main varieties were completely self-incompatible, whereas the pollinizing varieties were found to be partially as well as fully self-compatible. It was concluded that a cross compatible variety is required for optimum fruit set in apples, and that the number of seeds in fruit has a direct effect on its shape, size and weight.