| Abstract |
Limited labor, cost, and time regarding hybrid formation and expanded yield trials encourages breeders to identify potential F1 hybrids without crossing all possible combinations by line screening based SSR-genetic distance. Therefore, this study aimed to (i) determine combining ability of 24 hybrids, (ii) assess the genetic distance of 11 parental lines employing SSR markers, and (iii) study the association between SSR based-genetic distance and hybrid performance for yields characters. 11 parental lines, 3 waxy and 8 sweet corns, originated from diverse climatic zones (tropical Thailand, subtropical China, and temperate USA) were crossed following North Carolina Design II and were genotyped applying 30 polymorphic SSR markers. 24 hybrids, 11 parents, and 3 check varieties were evaluated in two seasons (2017/2018) at Khon Kaen University, Thailand. Among eleven lines, 101LBW (6.8 ton ha-1; 1.10**) and Y.18 (6.9 ton ha-1; 1.08**) were good combiners focusing on high-yielding performance. Minor contribution of SCA effects on yields revealed an essential role of parental adaptation. SSR based-genetic distance between sweet and waxy lines was wide enough ranging from 0.67 to 0.92. Contrasting dendogram pattern and insignificantly poor correlation between SSR and phenotypic based-genetic distances indicated that agreement between SSR and phenotypic markers was lacking. SSR based-genetic distance failed to predict hybrid performance, heterosis, and SCA as poor correlation was revealed. Absence of dominance effect and high genetic distance among parental lines were suspected being plausable factors for poor prediction. |
Publication
Journal Publication
ไทย