Manifestation of phenotypic heterosis in F1 and F2 hybrids of garden pea in reciprocal crosses

Abstract

Increasing pea grain production depends largely on the development of new high-yield varieties. Intraspecific hybridization plays a key role in this process. However, the mechanisms of inheritance of agriculturally valuable traits in hybrids still require further study. The research was conducted in 2021–2023 in the Krasnoyarsk forest-steppe. The subjects of the study were eight hybrid combinations of F1 and F2 garden peas, obtained through intervarietal reciprocal crosses using the Vityaz, Salamanka, Stoyan, Pamyati Valko, and Zh-58 accessions. The inheritance patterns of phenotypic traits were studied: plant length, pod number, seed number, and seed weight per plant. The degree of phenotypic expression of a trait was assessed using the B. Griefing's method, and true and hypothetical heterosis were assessed using the D.S. Omarov's method. In the first generation, the degree ofdominance for the "plant length" parameter varied from 0.33 (intermediate inheritance) to 3.20 (positive overdominance), while true heterosis values ranged from 2.97 to 36.62%. In the second generation, the degree of dominance varied from –1.82 (depression) to 1.56% (positive overdominance), while true heterosis values ranged from –29.07 to 5.34%. In terms of pea productivity traits in F1, overdominance of hybrids over seed parents was predominantly observed. In terms of the number of beans, positive heterosis in the first generation was found in five out of eight combinations, and in terms of the number and weight of seeds, overdominance was noted in seven hybrids. In the second generation, the effect of heterosis sharply decreased, and depression was observed in most cases. The dominant effect for productivity traits in direct and reverse combinations was different. Positive true and hypothetical heterosis, as well as positive overdominance in both F1 and F2 for seed number and weight per plant, were detected only in the Stoyan × Vityaz combination.