EVALUATION OF DROUGHT TOLERANCE INDICES AND RELATION WITH YIELD IN BREAD WHEAT GENOTYPES UNDER DROUGHT STRESS CONDITIONS
Published: 7 Oct 2018
Abstract: Drought stress is a main abiotic stress factor constraining wheat production in some years. Rainfall fluctuation during vegetative and generative growing periods causes grain yield reduction in Trakya Region, Turkey. This research was carried out in 2008-2009 and 2009-2010 growing years. Experiments were set up in a randomized completely blocks design in split-plot with three replications with 15 genotypes. The main plots were assigned for five moisture regimes, which included 3 drought stress environments (GS31-94, GS31-51 and GS51-94) one non-stress and non-treatment (control) environment. Droughts were created under mobile rain shelter at various plant growth stages from shooting up to maturating stage. Based on grain yield stress susceptible index (SSI), stress tolerance index (STI), tolerance index (TOL), mean productivity (MP), and geometric mean productivity (GMP) were calculated with their relation. The results of variance analyses for Yp, Ys and other drought tolerance indices indicated that genotypic differences were highly significant. Effect of drought stress on grain yield of all tested genotypes was different. Drought stress caused an average reduction of 59.9% on yield. Bereket was the highest yielding cultivar under fully drought stress condition. STI, MP and GMP showing the highest correlation coefficient with grain yield were the most desirable selection criteria for high yielding and drought tolerant genotypes. A positive and significant correlation was observed between Yp with TOL, MP, STI, GMP and HM, and negative correlation with YSI. These indices are the most suitable indices to screen genotypes in drought stress conditions.
Keywords: bread wheat, drought stress, drought tolerance index, yield
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