Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/8/2003
Publication Date: 1/15/2004
Citation: Feng, L., Burton, J.W., Carter Jr, T.E., Pantalone, V. 2004. Recurrent half-sib selection with testcross evaluation for increased oil content in soybean. Crop Sci. 44:63-69. Interpretive Summary: Protein mean and oil are two commodities from soybean that give the crop its value. Increasing the content of either/or both protein and oil in soybean seeds increases their intrinsic quality. Such increases may add value depending on the relative prices of oil and protein. Efficient plant breeding methods are needed to improve oil and protein in soybeans. Such a method was devised which evaluated families of soybean plants. Each family had the same male parent (a tester having seeds with high or low oil) but different female parents. Those families which had the most oil were selected, and seeds from the female parent of those families were used to generate new families for additional selection and breeding. With this method, average oil in the soybean seed increased 0.1 percentage points each selection cycle when the high oil soybean was used as the tester parent. Because 1 cycle can be completed each year, oil was increased 0.1 percentage points each year.
Technical Abstract: Protein meal and oil are the two commodities produced from soybean that give the crop its value. Increasing seed concentrations of either/or both may add value. A recurrent half-sib selection system was devised for soybean [Glycine max (L.) Merr.] and selection for increased oil content was conducted in a population for seven and three cycles using a high and a low-oil tester, respectively. The base population was a high-oil composite with gray pubescence (tt) that was segregating for nuclear genetic ms1 male sterility. Male sterility was used to aid in random mating selected progenits. Objectives of this study were to investigate the effectiveness of recurrent half-sib selection for increased seed oil, to evaluate the effect of tester oil content on selection response, and to investigate testcross heterosis and inbreeding depression for seed oil content. Random progenies from the base populations and selected progenies from each cycle of selection were evaluated in a replicated field experiment at three locations in North Carolina. Cycle x tester hybrids and cycle x cycle sib hybrids were also included in the tests. The results showed that oil content was significantly increased at a rate of 0.11 plus/minus 0.02 g 100g-1 cycle-1 in the high-oil tester populations but not in the low-oil tester populations. The realized heritability estimate for the high-oil tester population was 0.12 plus/minus 0.03. Evidence of heterosis indicated that some dominance effects on oil content existed.