Effect of sowing date, cultivars and irrigation scheduling on physiological parameters of wheat (Triticum aestivum) with climate change adaptation in perspective

A field experiment was conducted during rabi (November to April) season of 2011–12 and 2012–13 on the farm of IcAR-Indian Agricultural Research Institute New Delhi to study the physiological response of wheat (Triticum aestivum L.) varieties to terminal heat stress and to identify adaptation options like change in sowing date and irrigation scheduling for alleviating terminal heat stress. The experiment consisted of (1) three dates of sowing (DOs) i.e., normal date of sowing during 2^ndweek of November (D1), late sowing during first week of 12 (D2) and very late sowing during last week of 12 (D3); (2) three varieties of wheat i.e., HD 2932, WR 544 and HD 2967and (3) three irrigation schedules i.e., forecast-based irrigation (I1), conventional farmers practice (I2) and light and frequent irrigations (I3) in a split-split plot design. The crop sown at normal date of sowing (D1) showed significantly higher photosynthesis, stomatal conductance, membrane thermo stability, SPAD values and LAI compared to late and very late sown conditions. Variety WR 544 however showed fewer declines in physiological parameters and LAI compared to other varieties signifying its thermo-tolerant characteristics. Because of well-distributed rainfall, the irrigation treatments did not make much difference in the growth and yield of crop. The study showed that selection of variety and adjustment of date of planting could reduce the physiological loss due to terminal heat and help in climate change adaptation