Heterosis and Combining Ability Studies for Grain Yield and some Contributing Traits in Bread Wheat (Triticum aestivum L.) under Normal and Late Sowing Conditions. | ||||
| Journal of Plant Production | ||||
| Article 12, Volume 8, Issue 12, December 2017, Page 1363-1372 PDF (260.05 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jpp.2017.42006 | ||||
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| Author | ||||
M. H. Motawea 
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| Department of Agronomy, Faculty of Agriculture, Sohag University, Sohag, Egypt. | ||||
| Abstract | ||||
| Seven parental cultivars of bread wheat (Triticum aestivum L.) were used in a half diallel mating design at the Experimental Farm of Faculty of Agriculture, Sohag University, Egypt, during the two successive seasons of 2013/2014 and 2014/2015 to study combining ability and heterosis and their interactions under two sowing dates , 15th November ( normal sowing date) and 15th December ( late sowing date ) in two adjacent experiments, for days to heading, No. of spikes/plant, 1000- grain weight and grain yield/plant. Sowing dates mean squares was highly significant for all studied traits. Genotypes mean squares was highly significant for all studied traits at the two sowing dates and their combined. The overall means of genotypes were (88.98, 83.76 and 86.37days) for days to heading; (13.87, 10.00 and 11.94) for No. of spikes/plant; (47.26, 35.41 and 41.34g) for 1000-grain weight and (39.43, 24.58 and 32.01g) for grain yield/plant on the normal, late sowing dates and their combined, respectively. Late sowing date (heat stress) caused reduction for days to heading (5.87%), No. of spikes/plant (27.90%), 1000-grain weight (25.07%) and grain yield/plant (37.66 %), compared with normal sowing date (favorable). Interaction of sowing dates with genotypes was highly significant for all studied traits. General combining ability (GCA) and specific combining ability ( SCA ) mean squares was significant for all studied traits at the both sowing dates and their combined, except general combining ability mean squares for 1000-grain weight and grain yield/plant for the combined data. Genetic analyses of these traits confirm the participation of both additive and non-additive gene effects in controlling their inheritance. The interactions of sowing dates with general combining ability were found to be not-significant for all studied traits, whereas the interactions of sowing dates with specific combining ability were found to be significant for all studied traits. The ratio of GCA to SCA variance (predictability ratio) was closer to 1 for all studied traits, except for No. of spikes/plant and grain yield/plant at normal sowing date that revealed the predominance of additive gene action in the inheritance. The parental line (P5) proved to be the good general combiner for grain yield/plant at the two sowing dates and their combined. Hybrid combination (P1 × P4) showed highly significant desirable SCA effects for days to heading, No. of spikes/plant, 1000-grain weight and grain yield/plant. Six cross combinations (P1 × P2), (P1 × P4), (P1 × P6), (P2 × P4), (P4 × P5) and (P4 × P6), exhibited significant desired heterosis for grain yield/plant which varied from ( 10.8% ) to ( 35.38% ) relative to their better parents at both normal and late sowing date levels. | ||||
| Keywords | ||||
| Wheat; diallel crosses; Combining ability; Heterosis; sowing dates; heritability | ||||
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