Studies on Combining Ability, Heterosis and Selection Parameters in Garden Pea (Pisum Sativum L.)

Abstract

Thesis Title: "STUDIES ON COMBINING ABILITY, HETEROSIS AND SELECTION PARAMETERS IN GARDEN PEA (Pisum sativum L.)". A line x tester analysis involving 12 lines and 3 testers were carried out for 10 quantitative characters in garden pea (Pisum sativum L.). Analysis of variance revealed substantial amount of variability for all the characters, indicating wide spectrum of variation among the genotypes. High heritability coupled with high genetic advance for plant height, productive branche~ per plant, num.ber of pods per plant, pod length, number of see~per pod, 100 seed we1ght and seed y1eld per plant showing the influence of additive gene action on these traits hence, may be useful for effective selection. Higher magnitude of genotypic correlations than the corresponding phenotypic ones, indicating the inherent association the various traits. Seed yield was found to be positive and significantly correlated with number of pods per plant followed by pod length, pod width, number of seed per pod, 1 00-seed weight at genotypic and phenotypic level. Thus any selection based on these characters will enhance performance and improvement in garden pea. Path coefficient analysis revealed high positive and direct influence of 100 seed weight followed by number of pods per plants, pod length, number of seed per pod and plant height. Indirect contributed towards seed yield mainly via pod length. Thus, effectiveness of selection for high seed yield could be enhanced by inclusion of pod length as a selection criterion along with the number of pods per plant and seeds per pod. Besides, selection on the basis of 100 seed weight and plant height can lead to considerable improvement of seed yield in garden pea. Among lines KS-156 x KS-256 were identified as a good general combiner for all the characters days to flowering, days to maturity, plant height, productive branches per plant, number of pods per plant, pod length, pod width, number seeds per pod, 100- seed weight and seed yield per plant weight. Wheref~among the testers AP-1 was good general combiners for most of the yield contributing 1raits. Specific combining ability effect estimates showed a very wide range of variation for most of the characters. The crosses KS-175 X E-6 had the highest SCA for seed yield. Both the parents involved in these crosses is average general combiners, thus these crosses can be exploited for seed yield by heterosis breeding programme. For most of the major traits including seed yield both additive and no~ additive gene action were of prime importance.