Soybean Research Institute, Nanjing Agricultural University; National Center for Soybean Improvement, Ministry of Agriculture; Key Laboratory of Biology and Genetic Improvement of Soybean, Ministry of Agriculture; National Key Laboratory for Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China.
Theor Appl Genet. 2015 Jun;128(6):1061-72. doi: 10.1007/s00122-015-2490-4. Epub 2015 Mar 10.
After two cycles of marker-assisted breeding on three loci, lines with transgressive segregation of 8.22-9.32 % protein content were developed based on four original soybean parents with 35.35-44.83 % protein content. Marker-assisted breeding has been an innovative approach in conventional breeding, which is to be further demonstrated, especially for quantitative traits. A study on continuous transgressive breeding for seed protein content (SPC) in soybean using marker-assisted procedures is reported here. The SPC of the recombinant inbred line (RIL) population XG varied in 38.04-47.54 % under five environments with P 1 of 35.35 %, P 2 of 44.34 % and total heritability of 89.11 %. A transgressive segregant XG30 with SPC 45.53 % was selected for further improvement. The linkage mapping of XG showed its genetic constitution composed of five additive QTL (32.16 % of phenotypic variation or PV) and two pairs of epistatic QTL (2.96 % PV) using 400 SSR markers with the remnant heritability 53.99 % attributed to the undetected collective of minor QTL. Another transgressive segregant WT133 with SPC 48.39 % was selected from the RIL population WT (44.83 % SPC for both parents). XG30 and WT133 were genotyped on the three major additive QTL (Prot-08-1, Prot-14-1 and Prot-19-2) as A 2 A 2 B 2 B 2 L 1 L 1 and A 1 A 1 B 1 B 1 L 2 L 2 , respectively. From WT133×XG30, surprising transgressive progenies were obtained, among which the recombinants with all three positive alleles A 2 _B 2 _L 2 _ performed the highest SPC, especially that of Prot-08-1. The five F 2-derived superior families showed their means higher than the high parent value in F 2:3 and F 2:4 and more transgressive effect in F 2:5:6, with the highest as high as 54.15 %, or 4.82 and 9.32 % more than WT133 and its original high parent, respectively. This study demonstrated the efficiency of marker-assisted procedure in breeding for transgressive segregation of quantitative trait.
在对三个基因座进行两轮标记辅助选择后，基于四个原始大豆亲本的蛋白质含量为 35.35-44.83%，开发出蛋白质含量具有 8.22-9.32%超亲分离的品系。标记辅助选择是常规育种中的一种创新方法，特别是对于数量性状，需要进一步证明。本研究报告了利用标记辅助程序对大豆种子蛋白质含量（SPC）进行连续超亲育种的情况。在五个环境下，重组自交系（RIL）群体 XG 的 SPC 变化范围为 38.04-47.54%，P1 为 35.35%，P2 为 44.34%，总遗传率为 89.11%。选择蛋白质含量为 45.53%的超亲分离子 XG30 进行进一步改良。利用 400 个 SSR 标记进行 XG 的连锁图谱分析，发现其遗传组成由 5 个加性 QTL（占表型变异的 32.16%或 PV）和 2 对上位性 QTL（2.96%PV）组成，剩余的遗传率为 53.99%，归因于未检测到的小 QTL 群体。另一个超亲分离子 WT133 从 RIL 群体 WT（亲本的蛋白质含量均为 44.83%）中选择。对 XG30 和 WT133 进行三个主要加性 QTL（Prot-08-1、Prot-14-1 和 Prot-19-2）的基因型分析，结果分别为 A2A2B2B2L1L1和 A1A1B1B1L2L2。从 WT133×XG30 中获得了令人惊讶的超亲后代，其中带有全部三个正等位基因 A2_B2_L2_的重组体表现出最高的 SPC，特别是在 Prot-08-1 中。五个 F2 衍生的优良家系在 F2:3 和 F2:4 中表现出高于高亲值的均值，在 F2:5:6 中表现出更高的超亲效应，最高可达 54.15%，分别比 WT133 和其原始高亲值高 4.82%和 9.32%。本研究证明了标记辅助选择程序在数量性状超亲分离选育中的效率。
