Effective Selection Criteria For Evaluating Some Barley Crosses For Water Stress Tolerance

Drought is a wide-spread problem seriously influencing barley production. Drought tolerance indices were used for screening tolerant genotypes. Twenty one diallel crosses among seven Egyptian barley cultivars showing clear differences in reaction to drought were made in 2010/2011 season and evaluated under full and stress irrigation regimes at the Agricultural Experiments and Research Station, Faculty of Agriculture, Cairo University, Giza Governorate, Egypt during 2011/2012 and 2012/2013 seasons. The objective was to identify tolerant genotypes based on drought tolerance indices and introduce the best index as an indirect criterion for selecting drought tolerant accessions in barley breeding programs. Water stress caused significant reductions in grain yield/plant of F1ʹs showing maximum reduction (31.33%) in 2011/2012 season. Genotypic differences were found in grain yield/plant under both irrigation treatments at both seasons. Based on most of the drought tolerance indices, the findings of present study showed that the breeders should pay attention to the genotypes Giza 123 and Giza 131 (as parents), and Giza 126 X Giza 129, Giza 129 X Giza 130 and Giza 129 X Giza 123 (as F1 crosses). These genotypes exhibited high yield under both stressed and non-stressed conditions. So, these genotypes should be involved in breeding programs for developing new tolerant varieties to water stress. On the other hand, selection indices showed different ranks of genotypes. However, stress tolerance (ST), yield index (YI), relative performance (P), stress susceptibility index (SSI) and tolerance index (TOL) are suggested to differentiate genotypes for water stress tolerance.