COMBINING ABILITY ANALYSIS ON HEAT TOLERENT WHEAT GENOTYPES (Triticum aestivum L.)

Abstract

Studies on combining ability including components of genetic variance and magnitude gene action in wheat were done in six diallel crosses including reciprocals. The experiment was conducted at the experimental field of Wheat Research Centre, BARI, Nashipur, Dinajpur during 2007-2008 and 2009-2010 winter season. The parental genotypes were six high yielding viz. Shatabdi, Sufi, Bijoy, Prodip, Line-1040 & Line-1018. The study covered yield and contributing characters along with morphological marker for DUS test. Combining ability studies on 11 economic characters had significant mean squares for general combining ability (gca), specific combining ability (sca), and reciprocals. Both general combining ability (GCA) and specific combining ability (SCA) variances were significant for all the characters except spike length Preponderance of additive gene action was noticed for these characters. The parent Shatabdi was the best general combiner for grain yield and some other yield contributing characters. ‘Shatabdi x Sufi’ and ‘Bijoy x Prodip’ were the best specific crosses for attaining higher grain yield per plant. The cross combination “Bijoy x Prodip, Shatabdi x Sufi the best specific crossess which could be exploited to produce prospective genotypes with desirable spike architecture. Significant positive reciprocal effects were obtained from ‘Shatabdi x Sufi, Bijoy x Line1040’ and ‘Shatabdi x Bijoy for 1000-grain weight .The partial dominance was estimated for plant height, spikes /plant and spike length. Gourob possessed most of the recessive genes for spikes/plant, 1000-grain weight and grain yield/plant. Shatabdi possessed most of the dominant genes for grains/spike, 1000-grain weight, harvest index and grain yield. Estimates on the component of variance revealed that dominant and recessive alleles were unequally distributed in the parents for all the traits and satisfying the additive-dominance genetic model. Number of dominant gene block was the highest in grains/spike and the lowest in spikelet/spike.