Molecular and field characterization of Pea (Pisum sativum L.) accessions and breeding lines for powdery mildew resistance genes and yield

Abstract

Pea is an essential grain legume; a protein source, as well as a large quantity of carbohydrates, minerals, and the complexes of vitamin B. The present research project was designed to investigate field characterization and genetics of powdery mildew diseases resistance. Erysiphe pisi causes a significant decrease in production and impairs pea harvest quality. 10 local cultivars 100 pea accessions and 72 breeding lines were chosen for field evaluation and genetic characterization. In assess for the presence of powdery mildew resistant genes in the new lines, each pea line was assessed morphologically and molecular markers. These lines have been further examined for genetic variation and marker trait associations. Twenty-two morphological traits were analyzed in the pea germplasm. All the accessions under study were characterized for disease severity. There was a substantial variance in genotype across all investigated factors. Eighty-nine pea accessions and 7 local cultivars were categorized in eight clusters based on multivariate analysis of morphological characters recorded. Analysis of variance showed substantial variance in only four among 22 parameters. Interestingly, fresh pod thickness and fresh pod width, dry pod width and fresh pod width, dry pod thickness and fresh pod thickness were correlated with grain yield per plant which can be used as selection criteria for breading high yield in pea. To assess genetic diversity and genetic association with the yield and disease related traits; 100 SSR markers were genotyped in entire population. Genetic diversity has been observed among pea lines, with two alleles per locus (range from 1-3). The genetic variability of 89 polymorphic markers was estimated to vary from 0.00 to 0.49. For each of the 89 SSR markers, the PIC score varied from 0.0 to 0.37. The total PIC values were lower than the expected. Total four markers associate with powdery mildew resistance these four markers are S016989-8-8, S016989-8-64, S016989-8-85.1 and S016989-8 96. Two new high yielding and disease resistant accessions of pea (029705 and 026915 of Pakistani and Indian origin respectively) were selected for further characterization. More than 80 markers linked with other morphological traits also 30 crosses successfully set for the future purpose.