利用染色体片段置换系定位水稻粒型QTL

水稻粒型是衡量稻米外观品质的重要指标之一,鉴定和定位水稻粒型QTL对开展水稻粒型分子育种具有重要意义.本研究以8个染色体片段置换系为材料,选用分布水稻12条染色体上的153个SSR标记检测染色体片段置换系的置换片段,采用代换作图法对控制水稻粒型的3个主效QTL进行定位.结果表明:153个SSR标记中有104个标记在亲本间具有多态性,多态率为68.0%;8个染色体片段置换系在第3和第5染色体分别有6个和2个置换片段,置换片段长度分别为14.8 cM、16.6 cM、 15.5 cM、18.9 cM、29.1 cM、35.0 cM、17.9 cM 和17.0 cM,平均长度为20.6 cM;8个置换片段上共鉴定出3个粒型QTL,控制粒长的qGL-3-1 和qGL-3-2分别被界定在水稻第3染色体RM5551与RM6832及RM6832与RM3513之间,遗传距离分别为14.8 cM和5.3 cM的范围内,控制粒宽的qGW-5被界定在水稻第5染色体RM267与RM169之间遗传距离约11.7 cM的范围内.利用染色体片段置换系能准确地定位水稻粒型QTL,qGL-3-1、qGL-3-2和qGW-5的鉴定和初步定位为其进一步精细定位及分子标记辅助选择奠定了基础.

Substitution Mapping of QTLs for Grain Shape Using Chromosome Segment Substitution Lines in Rice(Oryza sativa L.)

Grain shape plays an important role in rice appearance quality.In the paper,with an indica variety 93-11,a japonica variety Nipponbare and 8 chromosome segment substitution lines(CSSLs) with the genetic background of 93-11 introgressed from Nipponbare as the materials,using 153 SSR markers distributed on 12 rice chromosomes,the substituted segment and the QTLs for grain shape were analyzed.The results showed that 104 markers displayed polymorphism bands between two parents,the rate of polymorphism was 68.0%;These CSSLs had 8 substituted segments on rice chromosome 3 and 5.The genetic distance of the 8 substituted segment were 14.8 cM,16.6 cM,15.5 cM,18.9 cM,29.1 cM,35.0 cM,17.9 cM and 17.0 cM,respectively;Three QTLs were identified,qGL-3-1 was mapped in the region of RM5551-RM6832,which was 14.8 cM in genetic distance on rice chromosome 3.qGL-3-2 was mapped in the region of RM6832-RM3513,which was 5.3 cM in genetic distance on rice chromosome 3.qGW-5 was mapped in the region of RM267-RM169,which was 11.7 cM in genetic distance on rice chromosome 5.The QTLs for grain shape in rice can be mapped primely using chromosome segment substitution lines.Mapping of the QTLs has laid a foundation for fine mapping and cloning of the QTLs and molecular marker-assisted selection of appearance quality in rice.