Estimation of heterosis, heterobeltiosis, and gene action in F1 plants from small-seeded soybean crosses

Soybeans with small seed sizes and high seed yield potential are crucial for addressing the needs of soybean-based industries. The objectives of the study were to investigate the maternal effect and quantify the value of heterosis, heterobeltiosis, and gene action in F1 plants from soybean crosses with small-seeded. In the present investigation, the experiment was conducted in the screen house of the Indonesian Legume and Tubers Crop Research Institute (ILETRI) located in Malang (East Java, Indonesia) from March to July 2021. The F1 plants were derived from crosses of Lokal Jember ? Tidar, Tidar ? Gepak Kuning, Gepak Kuning ? Detam 3, and their reciprocals. The parental genotypes and F1 plants were all planted. The observed data were plant height, number of branches, number of nodes, number of filled pods, the weight of 10 seeds, and seed yield/plant. The performance of the F1 plants showed variation for all observed traits, which is mostly averaged between the two parents, including 10 seed weight and seed yield. There was no maternal effect for almost all agronomic traits on all crosses and their reciprocals, except for the number of nodes in the cross of Gepak Kuning ? Detam 3. Heterosis (hMP) and heterobeltiosis (hHP) of F1 derived from six cross combinations for seven agronomic traits ranged from -25.93 to 186.27 and -94.83 to 114.71, respectively. Based on the potence ratio, the gene action was differed from a cross to cross for seed yield and its components. The degree of dominance for seed size and seed yield varied from overdominance, incomplete dominance, and complete dominance. Thus, based on the present investigation, it is possible to develop soybean varieties with small seed sizes and high yield by using pedigree selection on F2.