Genetic Analysis of Yield, Protein, and Oil Traits in Soybean Diallel Crosses for Enhanced Crop Quality and Productivity

The study was conducted at Sakha Research Station, ARC, Egypt, during three successive seasons from 2021 to 2023. A half diallel cross of fifteen F1 and F2 generations in addition to the six soybean parental genotypes namely, Japanese 13, Giza 111, Crawford, H18L54, Nc92-2231 and Linford were evaluated to determine the genetic behavior of yield and its components traits in both F1 and F2 generations, as well as seed protein and oil contents in F1. Results indicated that mean squares of General Combining Ability (GCA) and Specific Combining Ability (SCA) were significant and highly significant for all the studied characters of soybean genotypes in F1’s and F2’s, except SCA for 100-seed weight in F2’s only. The GCA/SCA ratios were less than unity in all traits, indicating that, the non-additive gene effects seemed to be responsible for the inheritance of these traits. The parental genotypes; H18L54, Nc 92-2231 and Linford seemed to be excellent combiners for days to flowering and maturity; however, Giza 111 and Japanese 13 were good combiners for seed yield. Meanwhile, Giza 111 was a good combiner for protein and oil content; also, H18L54 and Nc 92-2231 were good combiners for protein content. The crosses C7, C9, C10, C11 and C13 were earlier for maturity date, and also showed the most negative significant desirable Ŝij effects. The best (Ŝij) values in F2 were shown in the C1, C5, C8 and C15 crosses for seed yield/plant, these crosses also had the highest seed yield values in F2. The crosses; C5 and C8 showed significant to highly significant positive heterotic effects relative to the better parent for protein% and seed yield per plant. In addition three crosses; C13, C14, and C15 had highly significant positive heterotic effects relative to the better parent for oil % and seed yield per plant.