利用双向导入系剖析水稻源、库相关性状的QTL

QTL Mapping of Sink-Source Related Traits Using Two Sets of Reciprocal Introgression Lines in Rice

以我国高产籼稻特青和美国优质粳稻Lemont为亲本培育的双向回交导入系为材料,采用单核苷酸多态性标记定位源相关性状(剑叶长、剑叶宽、剑叶面积、叶干重和比叶重)和库相关性状(穗总粒数、千粒重和穗实粒重)的QTL。特青剑叶长、穗总粒数和穗实粒重显著大于Lemont,剑叶宽则显著小于Lemont。双向导入系群体检测到影响源、库相关性状的QTL 62个,平均每个QTL解释群体表型变异的9.0%,变幅为3.0%～27.9%。Lemont背景导入系在第2、3、4、6、9和11等6个染色体的区段同时定位到影响源、库相关性状QTL 17个,占Lemont背景导入系定位QTL总数的50%。特青背景导入系在第1、3、4、8和12等5个染色体区段同时定位到影响源、库相关性状的QTL 13个,占特青背景导入系定位QTL总数的28.3%。Lemont背景下绝大多数位点导入特青等位基因均增加性状值,而特青背景绝大多数位点导入Lemont等位基因都减小性状值。两个背景共同检测到影响源、库相关性状的QTL有18个,占定位到62个QTL的29.0%,表明源、库相关性状QTL定位存在明显的遗传背景效应。发现第3染色体影响剑叶长、剑叶面积、叶片干重、每穗总粒数和穗实粒重的35576704～36341768区间和第4染色体影响比叶重、穗总粒数和穗实粒重的4560663～13503095区间,在以往不同群体中均被检测到,是影响水稻源、库相关性状的重要染色体区域,对标记辅助选择培育源、库协调的超高产水稻品种具有重要的应用价值。

QTL for source-related traits including flag leaf length（FLL）,flag leaf width（FLW）,flag leaf area（FLA）,leaf dry weight（LDW） and specific leaf weight（SLW） and sink-related traits including spikelet number per panicle（SNP）,thousand grain weight（TGW） and filled grain weight per panicle（FGWP） were detected using two sets of reciprocal introgression lines（ILs） derived from a cross between Chinese indica cultivar Teqing and American japonica cultivar Lemont and 384 single nucleotide polymorphism markers.Teqing had significant larger FLL,SNP and FGWP but smaller FLW than Lemont.Total of 62 QTL for sink-source（SS） related traits were identified,each averagely explaining 9.0% of phenotypic variation in the population with a range of 3.0%~27.9%.In the ILs in Lemont background（LT-ILs）,17 QTL affecting SS-related traits were simultaneously detected in the six regions on chromosomes 2,3,4,6,9 and 11,accounting for 50% of number of QTL identified in LT-ILs.Similarly,13 QTL affecting SS-related traits were simultaneously detected in the five regions on chromosomes 1,3,4,8 and 12,accounting for 28.3% of number of QTL identified in the ILs in Teqing background（TQ-ILs）.Introgression of Teqing alleles at most QTL increased trait values in LT-ILs while the opposite is true in TQ-ILs.Only 18（29.0%） QTL for SS-related traits were commonly detected in the reciprocal backgrounds,indicating there is obvious genetic background effect on QTL detection.Two regions,one of 35576704–36341768 on chromosome 3 harboring the QTL affecting FFLL,FLA,LFW,SNP and FGWP,and the other of 4560663–13503095 on chromosome 4 harboring the QTL affecting SLW,SNP and FGWP,were previously detected in different populations and could be considered as most important regions affecting SS-related traits in rice.The two regions are greatly useful for developing high yield potential rice cultivar with good harmony between sink and source by marker-assisted selection.