abstract
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Climate change is unequivocal and reams of literature alert India is at the verge of its adverse impact owing to distinct geography and large dependency on agriculture. Heat stress is one of the serious abiotic problems posed by climate change wherein the rising mean temperature affects crop yield as well as grain/straw quality. Wheat, the cold loving plant, is highly sensitive to heat stress and the season during which it is being cultivated in India has been predicted to experience the increased temperature. In the milieu, the present investigation is a pioneer attempt to predict the heat stress sensitive environments – hotspots – in Indian wheat production for prioritizing the research locations and investment decisions. The study, sourcing the past 30 years (since 1984) daily data on minimum temperature, maximum temperature and rainfall, develops a novel methodological approach by integrating statistical downscaling of climate information and principal component analysis for computing the heat stress intensity index (HSII). The HSII was calculated for 17 trial locations of the All India Coordinated Research Project (AICRP) on Wheat where heat stress field experiments are being conducted presently. The indices were estimated for the existing environment followed by prediction for three periods’ viz., early-future (2026-2050), mid-future (2051-2075) and far-future (2076-2100) under two emission scenarios namely RCP 4.5 and RCP 8.5. The methodology has ranked the 17 locations based on the composite HSII for all the four periods under consideration with weights assigned through principal component analysis. The results alarmed a radical shift in the HSII of trial locations from one period to another as the emission scenario changes. Trail locations with high index values for the existing environment has moved almost to lower ranks in the early-future and subsequently shifted to higher position in the mid-future and far-future. The investigation also found that under projected RCP 4.5, trial locations in peninsular zone need more emphasis, whereas in RCP 8.5, peninsular zone coupled with central zone and north eastern plains zone have to be focussed. The novel approach will help in location prioritization across predicted periods and calls for rational allocation of research funds to carry out field trials on heat stress for sustaining the national wheat production. Further, the approach can be taken forward to track the sensitive crop growth stages to heat stress under changing climate scenario which will be useful to devise suitable region-specific breeding programs, climate-smart farming practices and investment plans.