DETERMINATION OF TOLERANCE LEVEL OF SOME WHEAT GENOTYPES TO POST-ANTHESIS DROUGHT

Drought, especially after anthesis, is one of the major abiotic stress factors limiting wheat production in Mediterranean basin. Tolerance level of seven wheat genotypes to drought conditions in post anthesis stage were evaluated based on some tolerance indices in four years field experiments differing in rainfall distribution and quantity. Six selection indices including Relative Decrease in Yield (RDY), Stress Tolerance Index (TOL), Mean Productivity (MP), Geometric Mean Productivity (GMP), Stress Susceptibility Index (SSI) and Stress Tolerance Index (STI) were calculated based on grain yield under dry and wet conditions. Higher grain yield was recorded in Basribey-95 during both dry and wet seasons whereas Menemen-88 had considerably lower yield than other genotypes. It was concluded that MP, GMP and STI values were convenient parameters to select high yielding wheat genotypes in both stress and non-stress conditions whereas RDY, TOL and SSI values were better indices to determine tolerance levels.