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Researcher Dubey, Rachana
Advisor Pathak, H.
Source KrishiKosh-Indian National Agricultural Research System
Content type Text
Educational Degree Doctor of Philosophy (Ph.D.)
Publisher Centre for Environment Science and Climate Resilient Agriculture ICAR-Indian Agricultural Research Institute New Delhi
File Format PDF
Language English
Subject Domain (in DDC) Social sciences ♦ Social problems & services; associations ♦ Other social problems & services ♦ Natural sciences & mathematics ♦ Life sciences; biology ♦ Ecology
Subject Keyword Adaptation Options For Alleviating Terminal Heat Stress In Wheat ♦ Environmental Science
Abstract India is the second largest producer of wheat (Triticum aestivum L.) in the world. High temperature spell towards the end of the crop season i.e., terminal stage is a major determinant of wheat yield, especially under Indian conditions. In this study, field experiments and simulation models were used to understand the impacts of changing climate, particularly increase in temperature on growth and yield of wheat and develop adaptation strategies in the north-west India, the main wheat growing-belt in the country. 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 response of wheat varieties to terminal heat stress and to identify adaptation options such as identifying suitable varieties, change in sowing date and précised irrigation scheduling for alleviating terminal heat stress. The experiment consisted of (1) three dates of sowing i.e., normal date of sowing during 2nd week of November (D1), late sowing during first week of December (D2) and very late sowing during last week of December (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. Observations for physiological parameters were taken at tillering, flowering and milking stages of the crop. It was observed that late sowing of wheat induced high temperature stress leading to reduction in membrane stability index (MSI), chlorophyll content, photosynthetic rate, stomatal conductance and canopy temperature depression (CTD) in all the varieties but the impacts were low with variety WR 544. The crop sown at normal date of sowing (D1) showed significantly higher number of tillers m-2 (444), plant height (93.2cm),1000-grain weight (37.9 g), grain yield (5.45 t ha-1 ) and harvest index (0.38) compared to late and very late sown conditions. With delay of sowing, yield loss was about 53, 12 and 62 kg ha-1day-1 in varieties HD 2932, WR 544 and HD 2967, respectively. The late-sown crop encountered higher temperature in its terminal stages i.e., flowering, grain filling and maturity resulting in lower yield. Variety WR 544, however, showed less decline in growth and yield parameters compared to other varieties signifying its thermo-tolerant characteristics. Because of well-distributed rainfall in Delhi in the years of study (2011-12 and 2012-13), the irrigation treatments did not make much difference in the growth and yield of crop. InfoCrop-wheat model was used to analyze the impacts of future climate change scenarios. Simulated yield of wheat in terminal heat stress year was less compared to normal year. In terminal heat stress year, yield of wheat can be enhanced using adaptation options such as applying additional doses of nitrogen fertilizer, preponing date of sowing from mid November to first week of November and providing an additional irrigation especially at grain filling stage. The best adaptation option for alleviating terminal heat stress in wheat is to use tolerant variety, preponing date of sowing to first week of November with application of 30 kg additional N ha-1 and forecast-based irrigation
Educational Use Research
Education Level UG and PG
Learning Resource Type Thesis
Size (in Bytes) 2.40 MB