title: Seed Coat Cracking in Soybean Isolines for Pubescence Color and Maturity.
abstract: Seed coats of soybean crack under various stress conditions. Cracking of seed coats degrades the external appearance of soybean seeds and reduces their commercial value. Previous studies revealed that the T gene responsible for pubescence color, and the maturity genes, E1 and E5, had inhibitory effects on low-temperature induced seed coat cracking. The objective of this study was to evaluate the effects of the T gene and five maturity genes (E1 to E5) on the intensity of seed coat cracking induced by pod-removal treatments. Soybean cv. Harosoy (te1e2E3E4e5) and its near-isogenic lines for T and E1 to E5 loci were used in the experiment. Cracking was induced by removing the upper 50% of pods on the plant 40 d after anthesis. Frequency and degree of cracking were not different among the isolines in the control group. In contrast, there were significant differences among isolines subjected to the pod-removal treatment. Frequency and degree of cracking was low in Harosoy, Harosoy-E1, e3, and e4, and high in Harosoy-T and E2. The results suggest that genotypes at T and E2 loci were associated with severity of seed coat cracking induced by pod-removal. There was a positive correlation (r = 0.90**) between individual seed weight and frequency of cracking among isolines in the pod-removal treatment. Seed coat cracking was probably exacerbated in part by the genes that allow enlargement of individual seeds in response to pod-removal. The differences among isolines suggest that the mechanism of seed coat cracking induced by pod removal may differ from that induced by low temperature treatment.
authors.affiliation: R. Takahashi, National Institute of Crop Science, Kannondai, Tsukuba, Ibaraki, 305-8518 Japan. Faculty of Agriculture, Tamagawa University, Machida, Tokyo, 194-8610 Japan. Graduate School of Agriculture, Hokkaido University, Sapporo, 060-8589 Japan.
authors.forename: Daijun
authors.initials: D
authors.lastname: Yang
authors.forename: Takehiro
authors.initials: T
authors.lastname: Nakamura
authors.forename: Norihiro
authors.initials: N
authors.lastname: Ohtsubo
authors.forename: Koji
authors.initials: K
authors.lastname: Takahashi
authors.forename: Jun
authors.initials: J
authors.lastname: Abe
authors.forename: Ryoji
authors.initials: R
authors.lastname: Takahashi