Estimation of genetic components and association of quantitative and qualitative traits in wheat (Triticum aestivum)

Wheat is one of the most important cereal crop and present study was conducted to assess the type of gene action, inheritance pattern and correlation among valuable traits for the improvement of wheat. Ten wheat cultivars/ lines were hybridized according to Line × Tester fashion in randomized complete block design with triplicates. Data was recorded for various quantitative and qualitative traits and then it was subjected to biometrical analysis. The results of the genetic studies showed that almost all the traits except total soluble sugars showed additive genetic effects with moderate to high heritability. Additive variances were greater than the non additive variances for most of the traits. The ratio of dominance to additive variance was lower than one for all the traits except total soluble sugars which clearly indicated that most of these traits were under control of additive type of gene action. Higher estimates of narrow sense heritability calculated showed preponderance of additive gene action. Significantly high narrow sense heritability has been recorded for days to maturity, plant height, number of spikelets per spike, number of grain per spike, grain yield per plant, seed length and grain protein contents. Medium narrow sense heritability has been observed in number of tillers per plant, flag leaf area, days to heading, peduncle length and seed width while spike length, grain weight per spike, 100 grain weight and total soluble sugars showed low narrow sense heritability. Grain yield per plant is most important and preferred in wheat breeding that revealed significant positive association with flag leaf area, plant height and number of grains per spike but it had strongly negative correlation with grain protein contents. It is concluded that selection on the basis of degree of inheritance and additive variance would be preferred in early generations for improvement in wheat grain yield. Furthermore, information acquired from association of various traits is supportive to develop high yielding and more nutritive varieties which can produce economic yield.