利用双向导入系和重组自交系解析水稻加工品质的遗传基础

水稻加工品质直接影响水稻的商品价值。为解析水稻加工品质的遗传基础,以粳稻秀水09和籼稻IR2061构建的2套双向导入系和1套重组自交系为材料,在温州和三亚环境下考察了稻米加工品质,并进行了加工品质性状的数量性状位点(QTL)定位。本研究构建了一张包含145个简单重复序列(SSR)分子标记的遗传连锁图,该连锁图总长1 567.8 cM,秀水09和IR2061背景导入系的平均背景回复率分别为90.15%和85.82%。双亲的糙米率和精米率无显著差异,秀水09整精米率显著高于IR2061。3套群体的加工品质均表现为连续分布,且糙米率、精米率和整精米率3个性状间彼此均呈显著正相关。在两个环境下共定位到影响糙米率、精米率和整精米率的29个主效QTL和20对上位性QTL,其中6个QTL在其中的两套群体中被重复定位到,2个QTL在两个环境下稳定表达,10个QTL与环境互作,说明遗传背景和环境显著影响加工品质QTL的表达。此外,在第7号染色体RM432~RM11区间、第8号染色体RM80~RM458区间和第9号染色体RM257~RM278区间均同时定位到影响糙米率、精米率和整精米率的QTL,秀水09等位基因在这些QTL处均提高加工品质。研究结果可为分子改良水稻加工品质提供重要基因资源的参考依据。

Genetic Dissection of Rice Milling Quality Using Two Sets of Reciprocal Introgression Lines and Recombinant Inbred Lines

Rice milling quality directly affects its market value. To understand the genetic basis of rice milling quality, two sets of reciprocal introgression lines and a set of recombinant inbred lines derived from geng variety Xiushui09, and xian variety IR2061 were evaluated for milling quality at Wenzhou and Sanya. A linkage map containing 145 SSR markers with length of 1 567.8 cM was constructed. The average background recovery percentages were 90.15% and 85.82% in Xiushui 09 and IR2061 introgression lines, respectively. The brown rice rate (BRR) and milled rice rate (MRR) were no significant difference between the two parents, while Xiuhui09 had higher head milled rice rate (HMRR) than IR2061. All of BRR, MRR and HMRR showed continuous distributions in the three populations, and there were significantly positive correlations among BRR, MRR and HMRR. A total of 29 main-effect QTLs (M-QTLs) and 20 epistatic QTLs (E-QTLs) were identified under the two environments. Among them, six QTLs were simultaneously identified in the two backgrounds, two QTLs stably expressed across two environments, and ten QTLs interacted with environments, suggesting that genetic background and environment had large effects on QTL detection of milling quality. Moreover, regions of RM432~RM11 on chromosome 7, RM80~RM458 on chromosome 8, and RM257~RM278 on chromosome 9 had pleiotropic effects on all the three milling quality traits, the alleles of Xiushui 09 at all regions increased milling quality. Our results provide valuable gene resources for improving rice milling quality by molecular breeding.