The present investigation was carried out to study the “Variability, character association and diversity studies on qualitative and quantitative traits in bread wheat (Triticum aestivum L.)” among forty-four genotypes of bread wheat for grain yield and its attributing traits. The experiment was arranged in a randomized block design with four replications at the Agronomy Instructional Farm, C. P. College of Agriculture, S. D. Agricultural University, Sardarkrushinagar during rabi 2019-20. The observations for this investigation were recorded for various thirteen traits viz., days to heading (N), days to maturity (N), plant height (cm), number of tiller per meter (N), number of grain per spike (N), spike length (cm), peduncle length (cm), grain yield per plant (g), 1000 grain weight (g), leaf area per plant (cm2), protein content (%), sedimentation value and harvest index (%).
The analysis of variance revealed significant differences among the genotypes for all the characters studied indicating presence of adequate amount of variability among forty-four genotypes. High genotypic and phenotypic coefficient of variations were exhibited by peduncle length followed by leaf area per plant, grain yield per plant, number of grains per spike, number of effective tillers per meter, spike length, plant height, days to heading and 1000 grain weight, which suggests the possibility of improving these traits through simple selection. The highest heritability was recorded for leaf area per plant followed by 1000 grain weight, peduncle length and number of effective tillers per meter. The highest genetic advance as per cent of mean was recorded for peduncle length followed by leaf area per plant, number of grains per spike and number of effective tillers per meter. High heritability associated with high genetic advance as per cent of mean was found for the characters viz., number of effective tillers per meter, number of grains per spike, grain yield per plant, leaf area per plant and peduncle length, which indicates that the traits were simply inherited in nature and controlled by few major genes or possessed additive gene effects.
High values of genotypic correlations than their corresponding phenotypic correlations were recorded for the all the characters under study. This indicated that, there was high amount of relationship between two variables at genotypic level and its phenotypic expression was let down by the influence of environmental factors and also indicated the importance of these characters in improvement of grain yield in wheat. Grain yield per plant showed highly significant and positive association with number of grain per spike, harvest index, 1000 grain weight, leaf area per plant and spike length both at genotypic and phenotypic levels suggesting utility as selection indices in grain yield improvement.
The path coefficient analysis revealed that harvest index recorded the highest direct effect towards grain yield per plant, followed by plant height, number of grain per spike and protein content. However, some characters viz. days to maturity, 1000 grain weight, peduncle length, leaf area per plant, sedimentation value and number of effective tillers per meter shows negative direct effect on grain yield per plant, it can be emphasized that for the improving grain yield in wheat more attention should be given to harvest index, plant height, grain yield per spike, protein content, days to heading and spike length while making selection for developing high yielding wheat genotypes.
The genetic divergence measured by Mahalanobis D2 statistic, clustered forty-four genotypes studied for seed yield were grouped into eight clusters. The maximum inter cluster distance was observed between clusters VIII and VII followed by VII and IV. The attributes, viz., spike length, leaf area per plant, peduncle length, plant height and number of grains per spike would be useful for generating transgressive sergeants if commercially practicable as these five traits contributed maximum towards total genetic divergence.
On the source of all the above studies, it can be concluded that more emphasis should be given to number of grains per spike, spike length, peduncle length, grain yield per plant, leaf area per plant, number of effective tillers per meter and plant height while doing selection for genetic improvement in bread wheat. Based on the mean performance of grain yield per plant, genotypes viz., GW-451, GW-173, GW-496, HI-1544, HI-1620 and C-306 were categorized as high yielding genotypes. So, for the improvement of yield and their components traits more emphasis could be given to these genotypes and with planning of research for more number of seasons and locations to get more precise results.