ABSTRACT
Garden pea (Pisum sativum L.) is an important crop to growers of the northwestern Himalayas. The commercial varieties used are susceptible to powdery mildew disease. Reduction of yield quantity and quality, nutritive value of fresh green pods, and income to growers could occur as a result of infection. Consumer preference is for long, dark green pods with a high shelling percentage. Gene action for green pod yield and its component traits in garden pea were studied using a triple test cross-analysis. The objective was to determine the nature and magnitude of genetic effects for different biometrical traits that could lead to further improvement of quantity and quality of green pea pods through breeding. Ten lines of garden pea were crossed with three testers following a triple test cross method. The 30 triple test progenies were evaluated at Kukumseri (high hill, dry, temperate zone) and Palampur (mid-hill, wet, temperate zone) during summer 2004 and winter 2004–2005, respectively. Epistasis was detected for the majority of traits at both locations. Mean squares due to sums and differences were significant for most traits at both locations except pod length at Kukumseri (sums) and shelling percentage at both locations and seeds/pod at Kukumseri (differences). Average degree of dominance was in the range of partial dominance for most traits. The directional element was nonsignificant indicating the ambidirectional nature of dominance for the majority of traits at one, or both, locations, which implied that alleles with increasing and decreasing effects appears to be dominant and recessive to the same extent. The presence of j + l type of epistasis (homozygote × heterozygote and hetrozygote × hetrozygote) for a majority of traits can be exploited to develop improved lines by adopting reciprocal recurrent selection and diallel selective mating design.