Pheno-thermal response of exotic high density apple varieties under temperate conditions of Kashmir

Abstract

The present study evaluated the effect of mean temperature and rainfall on phenology attainment of twenty cultivars of apple grown temperate region of Kashmir, India during 2018 and 2019. The results showed that increase in accumulated heat units decreased the time for attainment of phenological stages. The minimum requirement of heat units were recorded in Elstar (17 day 0C), Jona gold (18 day 0C) and Red braeburn (18 day 0C) for attainment of silver tip stage while as dormancy break was recorded earliest in cv. Red braeburrn and Red velox. The attainment of pink bud stage was recorded earliest in Red delicious followed by Elrosa and Gala redlum. However, fruit setting was found earlier in cv. Jona gold (50.1 day 0C) and late in Gala redlum and Gala mast. Highest heliothermal units were found in cv. Gala Mast (478 day 0C h) and Braeburn (461 day 0C h) and lowest in Jona gold (336 day 0C h) while as maximum hydrothermal units were found in Gala red (484 day 0C h) and Gala mast (471 day 0C h). Yield and yield associated traits were also found significantly influenced by accumulated heat units with maximum yield recorded in cv. Golden clone B (90.54 t ha-1) followed by Gala redlum (75.93 t/ha) and Red chief (71.13 t ha-1) with maximum heliothermal use efficiency (0.22), heat use efficiency (1.46) and hydrothermal use efficiency (0.22), respectively.