Diversity Analysis and Identification of Promising Powdery Mildew Resistance Genotypes in Field Pea (<i>Pisum sativum</i> L.)

Abstract

In the present study, seventy-one field pea gene pools including three released varieties were evaluated in an augmented block design for assessing genetic divergence and level of resistance to powdery mildew for exploitation in a breeding program aimed at improving yield potential of field pea by using cluster and principal component analysis. Among the 10 studied traits, four (Eigenvalue >1.0) contributed more than 68.45% variability among the materials. Cluster analysis grouped the 71 field pea genotypes into seven distinct classes. The genetic divergence between all possible pairs of clusters were highly significant (P<0.01). The inter-cluster D² value ranged from 311.63 to 2850.61 indicated that the evaluated gene pools were highly divergent. The genetically more divergent materials present in cluster five and six as indicated by inter-cluster distance value (2850.61). Selecting genotypes of these clusters and crossing them probably provide promising recombinants and better sergeants for future breeding program. Considerable variation was also found for resistance against the powdery mildew diseases. Out of the total 71 genotypes 12 were resistant, 29 were moderately resistant, 25 were moderately susceptible and 5 were susceptible to powdery mildew disease. Among 12 resistant genotypes; GPHA-9 and GPHA-19 were high yielder and GPHA-29, GPHA-48, GPHA-45 and GPHA-42 genotypes were found to be high yielding among 29 moderately resistant genotypes. The resistant genotypes identified could be exploited directly and/or may be transferred through hybridization to high yielding disease susceptible genotypes after checking their yield and disease stability in a number of locations and seasons for more confirmation with the present finding, since the present result was from one location and one season (year) data.