| Authors: | Zeng, G., Li, D., Han, Y., Teng, W., Wang, J., Qiu, L., Li, W. |
| Abstract: | Soybean isoflavones are valued in certain medicines, cosmetics, foods and feeds. Selection for high-isoflavone content in seeds along with agronomic traits is a goal of many soybean breeders. The aim of the study was to identify the quantitative trait loci (QTL) underlying seed isoflavone content in soybean among seven environments in China. A cross was made between ïZhongdou 27, a soybean cultivar with higher mean isoflavone content in the seven environments (daidzein, DZ, 1,865 _g g_1; genistein, GT, 1,614 _g g_1; glycitein, GC, 311 _g g_1 and total isoflavone, TI, 3,791 _g g_1) and ïJiunong 20, a soybean cultivar with lower isoflavone content (DZ, 844 _g g_1; GT, 1,046 _g g_1; GC, 193 _g g_1 and TI, 2,061 _g g_1). Through single-seed-descent, 130 F5-derived F6 recombinant inbred lines were advanced. A total of 99 simple-sequence repeat markers were used to construct a genetic linkage map. Seed isoflavone contents were analyzed using high-performance liquid chromatography for multiple years and locations (Harbin in 2005, 2006 and 2007, Hulan in 2006 and 2007, and Suihua in 2006 and 2007). Three QTL were associated with DZ content, four with GT content, three with GC content, and five with TI content. For all QTL detected the beneficial allele was from Zhongdou 27. QTL were located on three (DZ), three (GC), four (GT) and five (TI) molecular linkage groups (LG). A novel QTL was detected with marker Satt144 on LG F that was associated with DZ (0.0014 > P > 0.0001, 5% < R 2 < 11%; 254 < DZ < 552 _g g_1), GT (0.0027 > P > 0.0001; 4% < R 2 < 9%; 262 < GT < 391 _g g_1), and TI (0.0011 > P > 0.0001; 4% < R 2 < 15%; 195 < TI < 871 _g g_1) across the various environments. A previously reported QTL on LG M detected by Satt540 was associated with TI across four environments and TI mean (0.0022 > P > 0.0001; 3% < R 2 < 8%; 182 < TI < 334 _g g_1) in China. Because both beneficial alleles were from Zhongdou 27, it was concluded that these two QTL would have the greatest potential value for marker-assisted selection for high-isoflavone content in soybean seed in China. GC, TI, 2,061 _g gç1). Through single-seed-descent, 130 F5-derived F6 recombinant inbred lines were advanced. A total of 99 simplesequence repeat markers were used to construct a genetic linkage map. Seed isoXavone contents were analyzed using high-performance liquid chromatography for multiple years and locations (Harbin in 2005, 2006 and 2007, Hulan in 2006 and 2007, and Suihua in 2006 and 2007). Three QTL were associated with DZ content, four with GT content, three with GC content, and Wve with TI content. |