Genetic variability and diversity analysis for yield and its components in wheat (Triticum aestivum L.)

Forty nine genotypes of wheat were studied for generating scientific information on nature and magnitude of genetic variability and diversity for designing breeding programme. The experiment was conducted in randomized complete block design in three replications. The data were recorded on days to 50% flowering, plant height, peduncle length, number of productive tillers per plant, days to maturity, spike length, number of spikelets per spike, number of grains per spike, 1000-grain weight, biological yield per plant, grain yield per plant, harvest index and gluten content. Analysis of variance revealed significant differences among the genotypes for all the characters under study. The highest estimates of phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) were observed for grain yield per plant. High heritability coupled with high genetic advance was observed for grain yield per plant. Based on D2 –Statistics, 49 genotypes were grouped into eight clusters. The highest inter-cluster distance was found between cluster VII and VIII followed by III and VII. This indicates that genotypes included in these clusters possess wide genetic diversity. Grain yield per plant (31.46%) showed highest contribution towards genetic divergence; therefore, this character was major determinant of genetic diversity. On the basis of divergence and cluster mean it may be suggested that maximum heterosis and good recombinants could be obtained in crosses between genotypes of cluster VIII, VII and III in varietal improvement programme. Thus, crosses between the genetically diverse genotypes of cluster VIII with genotypes HUW 655, HP 1937, DBW 88 and HD 3058 and cluster VII with genotypes like HP 1938, HUW 656, K1006, DBW83, DBW 84, K1004, UP2822 and NW5050 are expected to exhibit high heterosis and are also likely to produce new recombinants with desired traits.