GENETIC VARIABILITY, HERITABILITY AND DIVERGENCE ANALYSIS IN WHEAT (TRITICUM AESTIVUM L. AND TRITICUM DURUM DESF.) GENOTYPES FOR YIELD AND YIELD-RELATED TRAITS
Study of genetic variability and divergence among quantitative traits and their contribution to gain yield is prerequisite for wheat improvement programmes. The present investigation was carried out to evaluate the genetic parameters and divergence in thirty genotypes of varieties in wheat Triticum aestivum L. and Triticum durum Desf. in agro-climatic conditions of Punjab. Analysis of variance showed highly significant differences among treatment for all the traits. High values of PCV were shown for number of productive tillers per plant (23.57), number of grains per plant (23.03) and grain yield per plant (g) (20.41), whereas moderate values of GCV were shown for number of productive tillers per plant (16.98), grain yield per plant (g) (13.63), number of grains per plant (13.00), biological yield per plant (g) (12.98), number of grains per spike (10.90) and spike length (cm) (10.21). The estimates of heritability recorded high for spike length (cm) (81.80), plant height (cm) (73.00) and peduncle length (cm) (70.50). High estimates of heritability coupled with moderate genetic advance as percent of mean was recorded for spike length (cm), plant height (cm) and peduncle length (cm). Therefore, a plant breeder should emphasize on these traits while practicing selection of high yielding wheat cultivars. Based on result of diversity, 30 genotypes were grouped into six clusters. Cluster II and cluster VI had largest genotypes (09 each) followed by cluster IV (04). The inter-cluster distances were higher than intra-cluster distance, indicating wide genetic diversity among genotypes of different groups. The maximum intra- cluster distance was observed for cluster III (D2=13.00) followed by cluster II (D2=8.31). Cluster V and VI (D2=66.56) showed maximum inter-cluster distance indicating that crossing between the varieties of these clusters will create wide spectrum of variability in wheat followed by cluster II and VI (D2=56.97). Cluster VI exhibited highest mean value for biological yield per plant (g) (27.81), 1000- grain weight (g) (44.61), plant height (cm) (104.10), days to maturity (119.33) and number of productive tillers per plant (10.00). Further, cluster III had highest mean values for spike length (cm) (12.36), number of grains per plant (356.44) and grain yield per plant (g) (11.03), and lowest mean for days to maturity (116.73) i.e. early maturity genotypes were also found in this cluster. Thus, it may be suggested that crossing of genotypes from these clusters may be considered as donor parent for hybridization programme for creating desired variability as well as for effective selection criteria.