EVALUATION OF GRAIN YIELD IN FIFTY-EIGHT SPRING BREAD WHEAT GENOTYPES GROWN UNDER HEAT STRESS

In Mediterranean region, terminal heat stress in late sown wheat is one of the major constraints to harvest good wheat yield. Therefore, this is desired to identify and develop wheat varieties that can grow under heat stress conditions of Mediterranean environments. In this study, fifty-eight wheat genotypes of diverse origin were planted at optimal (optimal conditions; October 1, 2015) and late sowing (high temperature; March 1, 2016) times at the Agricultural Research Area, Cukurova University, Adana, Turkey. Wheat sown at optimal time had better growth and yield-related traits, which lead to better grain yield. Considering the correlation between various yield-related traits. When planted at optimum time, the highest grain yield and related traits were recorded from the genotype 'Misr-2' that was followed by genotypes 'Shandaweel-1' 'Misr-1', 'Sakha-94' and 'Giza-171', while the genotype 'Shirogane kamugi' produced the lowest grain yield. In late sown (heat stress conditions) crop, grain yield of all tested genotypes was significantly decreased. In this regard, the genotypes 'Norin' and 'Eagle rock' were more sensitive to high temperature, while genotypes 'Misr-1' and 'Misr-2' were tolerant to heat stress and produced the highest yield under late sown conditions. Based on GGE biplot analysis, genotype 'Misr-2' performed better both under optimal and late sown conditions, this was followed by genotypes 'Misr-1' and 'Shandaweel-1'. Biplot analysis indicated that the genotype 'Misr-2' is highly adaptive to late sown (heat stress) condition, this was followed by the genotypes 'Misr-1' and 'Shandaweel-1'. These genotypes could be used in future breeding programmes aimed to develop heat tolerant wheat genotypes and more appropriate for cultivation under a changing climate. In conclusion, correlation, stepwise regression and biplot analysis could be successfully used for the identification of heat adaptive wheat genotypes. The genotypes 'Misr-2', 'Misr-1' and 'Shandaweel-1' may be recommended for planting under hot environmental conditions and may be included in breeding program aimed to develop heat tolerant varieties for the Mediterranean region.