STUDIES ON POLLINATION RESOURCES OF APPLE ORCHARDS IN HIMACHAL PRADESH

摘要

Apple Mains pumila Mill, is a cross-pollinated crop which has perfect flowers and some of the cultivars are self-incompatible. For successful apple cultivation, self pollinated cultivars (25-30%) are interplanted in the orchard. Large number of insects visit the bloom and help in transfer of pollen from flower to flower. Studies were therefore planned to record the pollination resources of apple and their role in fruit setting. Studies showed that among two species of honey bees, Apis cerana F. was the most abundant visitors to the bloom responsible for higher fruit set and yield. Dipteran flies particularly syrphid flies migrated in large numbers to the bloom but their role as efficient pollinators could not be established. Thus for adequate pollination and fruit set in apple, honey bees were found to be the most useful resources as they possessed requisite characteristics like flower fidelity and constancy, long working hours and amenability to change in numbers. A. cerana being a feral species is reared locally in wall hives and could tolerate low temperatures. But due to deforestation and excessive use of pesticide, there was a decline in population of A. cerana during the last decade. Thus exotic bee, A. mellifera could be relied upon for assured pollination. This species was found to possess higher pollination efficiency depending upon more number of flowers visited/minute followed by more numbers of top workers resulting in better fruit set and yield. Studies on flowering behavior of pollinizing varieties revealed that flowering in self-pollinated cultivars like Golden Delicious, Golden Spur, Red Gold, Tydeman Early Worcestor, Granny Smith and Lord Lambourne coincided with blooming of commercial cultivars like Starking Delicious.