利用双向导入系定位再生稻外观品质的QTL

再生稻具有较好的外观品质。为解析再生稻外观品质的遗传基础，本研究利用籼稻明恢63和粳稻02428构建的双向导入系为材料，连续两年在湖北荆州考察了双向导入系头季和再生季的外观品质。结果表明，明恢63头季和再生季的外观品质均显著优于02428，双向导入系的所有性状均表现为连续分布。同一性状在头季和再生季间表现为显著正相关，同一季节内不同性状间也表现出显著的相关性，其中粒宽对外观品质的影响最大。结合双向导入系已有的4 568个Bin的高密度基因型数据，共定位到57个影响再生稻外观品质的数量性状点位（QTL），位于全部12条染色体上。其中25个QTL在两年间稳定表达，17个QTL在两个遗传背景下被重复鉴定到。此外，第3号染色体16.28～17.33 Mb、第5号染色体3.35～4.28 Mb、第7号染色体24.68～25.46 Mb和第11号染色体6.19～6.97 Mb这4个区间同时影响4个以上性状，来自明恢63的等位基因在这4个区间均可提高外观品质。最后，利用分离群体验证了第11号染色体6.19～6.97 Mb具有真实性。本研究结果为分子育种改良再生稻的外观品质提供了遗传基础。

QTL Identification of Appearance Quality of Ratoon Rice Using Two Sets of Reciprocal Introgression Lines

Ratoon rice has high appearance quality. To understand the genetic basis of appearance quality of ratoon rice， two sets of reciprocal introgression lines derived from Xian variety Minghui 63， and Geng variety 02428 were evaluated for appearance quality in both first and ratoon seasons at Jingzhou for two years. The results indicated that Minghui 63 had significantly higher appearance quality than 02428 in both the first and ratoon seasons，and all appearance quality traits showed continuous distributions in the two sets of populations. There was significantly positive correlation between first and ratoon seasons within one trait， and there were significant correlations among different traits in the first or ratoon seasons. Grain width had the larget effect on appearance quality. Combined with 4 568 Bin genotyping， a total of 57 QTLs were identified in two years and distributed on all 12 chromosomes. Among them， twenty-five QTLs were simultaneously identified in both years， and seventeen QTLs were stably expressed in both backgrounds. Moreover， regions of 16.28~17.33 Mb on chromosome 3， 3.35~4.28 Mb on chromosome 5， 24.68~25.46 Mb of chromosome 7 and 6.19~6.97 Mb on chromosome 11 had pleiotropic effects on more than four traits， the alleles carried by Minghui 63 at all 4 regions could increase appearance quality. Finally， the region of 6.19~6.97 Mb on chromosome 11 for percentage of endosperm with chalkiness and degree of endosperm chalkiness in the first season was validated by an F₂ population. Our results provide genetic basis for improving appearance quality of ratoon rice by molecular breeding.