Heat unit utilization of new apple cultivar under high density plantation in Kullu valley of Himachal Pradesh.

摘要

A field experiment was conducted at Horticultural Research Station, Seobag (Kullu) during 2007-2011 on two new cultivars of apple viz. Scarlet Gala and Red Fuji on five rootstocks EMLA-9, EMLA-26, EMLA-106, EMLA-7, and EMLA-111. The phenology of Scarlet Gala and Red Fuji on each rootstock was observed on every second day on three plants of each root stock with three replications from bud-bust, green-tip, pink-bud, full-bloom to physiological maturity. GDD, HTU, PTU, HYTU and heat use efficiency was computed from the meteorological data recorded from observatory and averaged of for five years. The heat unit utilization and PTI was observed at par among all the five root stocks for the different phenological stages for both the cultivars. No effect of the root stocks was observed on the occurrence of different phenophases and utilization of heat units. Thermal units explain more than 66-97% variation in fruit yield of Scarlet Gala and 63-90% in Red Fuji. The performance and thermal use efficiency of Scarlet Gala was observed better on EMLA-7 whereas that of Red Fuji was observed better on EMLA-111. The Scarlet Gala used 2640 GDD and matured in the first fortnight of August about 15-20 days earlier than Delicious group cultivars whereas Red Fuji required 3671 GDD and matured quite late in mid October thus extending the apple season beyond September in Kullu Valley. Both were observed suitable for diversification in apple cultivation under changing and prevailing climatic conditions of Himachal Pradesh in general and Kullu valley in particular.