Managing Global Resources for a Secure Future

Climate change is causing an increase in temperature worldwide by affecting the yield of crop plants around the globe. Wheat, a temperate crop, is sensitive to higher average temperatures. For every increase of 1¡C over average temperature during the flowering stage results in approximately 3-4% losses in yield. With an objective to study variation in the wheat germplasm and to identify heat tolerant lines, screening of more than 700 wheat lines from around the world was performed under simulated field conditions up to highest temperature of 40¡C. To identify lines carrying heat tolerance for various agronomic traits, four experimental protocols were designed to target growth stages starting from early vegetative growth to seed maturity. Based on our preliminary phenotypic screening a subset of 45 plants was found carrying different mechanisms of heat tolerance. Further evaluation of these 45 wheat accessions was performed using the heat stress protocols and resulted in the identification of 19 genotypes carrying complimentary mechanisms of heat tolerance. The final 19 genotypes were evaluated again using the four heat stress protocols with composite data analysis. 12 lines have been selected as potential donors of different heat tolerant traits. These lines maintain vegetative biomass, plant height, spikelet number per spike, primary spike weight, secondary spike weight and grain yield per plant under heat stress. These selected lines are currently being used in doubled haploid (DH) production and marker-assisted background selection (MABS) in order to transfer the heat tolerance traits to recipient lines. Further characterization of the lines is being performed for various physiological and molecular approaches to understand the various mechanisms of heat tolerance in wheat.