Combining Ability of wheat yield and Some yield Attributes Under Normal and Water Stress Conditions

Abstract

A half diallel cross among six parents of wheat (Triticum aestivum L.) was achieved for combining ability under recommended irrigation and water stress at Etay EL-Baroud Agricultural Research Station, Agricultural Research Center, Egypt, during 2009/2010 and 2010/2011 seasons in RCBD with three replications. Data were recorded from F1 generation for days to heading, days to physiological maturity, plant height, flag leaf area, spike length, number of spikelets spike-1, number of kernels spike-1, number of spikes plant-1, 1000-kernel weight and grain yield plant-1. Mean squares for genotypes, parents, crosses and parent vs. crosses were significant for all the studied traits in both irrigation treatments. General combining ability (GCA) and specific combining ability (SCA) mean squares were significant for all the studied traits in both irrigation treatments. High GCA/SCA ratios which largely exceeded the unity were detected for all studied traits, except for grain yieldplant-1 under the study in both conditions. Wheat genotype Line 1 (P6) showed the maximum desirable GCA values for days to heading, days to physiological maturity, flag leaf area, spike length, under water stress, number of kernels spike-1and 1000-kernel weight under both conditions. For shortness, the cultivar Sakha 93 (P2) proved to be the best general combiner for plant height under both environments. Meanwhile, Sham 6 under normal conditions and Sahel 1 under water stress conditions were the best combiners for plant height concerning breeding for tallness. The cultivar Gemmeiza 9 proved to be a good general combiner for number of spikelets spike-1 under both conditions. The cultivar Misr 1 found to be the best general combiner for number of spikes plant-1 and grain yield plant-1 under normal condition, while the cultivar Sakha 93 found to be the best general combiner for number of spikes plant-1 and grain yield plant-1 under water stress condition. The cross (Sahel 1 x Sham 6) showed the maximum desirable SCA values for days to heading and days to physiological maturity under both water regime treatments. The cross (Misr 1 x Line 1) exhibited the maximum SCA for plant height under normal conditions, while (Sahel 1 x Gemmeiza 9) showed the maximum SCA for plant height under water stress condition. The cross (Sahel 1 x Misr 1) showed maximum SCA value for flag leaf area under both environments. The cross (Sham 6 x Line 1) was the best specific combiners for spike length under normal conditions, while (Sahel 1 x Sham 6) was the best for spike length under stress conditions. The best specific combiner for kernels spike-1 under both conditions was the cross (Misr 1 x Line 1). The cross (Sakha 93 x Misr 1) showed the best SCA for number of spikes plant-1 under normal conditions while the cross (Sakha 93 x Line 1) was the best one under water stress conditions. For 1000-kernel weight the cross (Gemmeiza 9 x Misr 1) was the best specific combiner under both irrigation conditions. The cross (Sakha 93 x Line 1) exhibited the maximum SCA for grain yield plant-1 under normal conditions while the cross (Sakha 93 x Gemmeiza 9) was the best one under water stress conditions. The crosses (Sakha 93 x Gemmeiza 9), (Sakha 93 x Line 1) and (Misr 1 x Line 1) were prospective in wheat breeding programs since they expressed significant and desirable (ŝij) effects for most traits.