陆海渐渗系16号染色体纤维长度及强度QTL分子标记辅助选择及聚合效应研究

Molecular marker-assisted selection and pyramiding effect related to fiber quality traits on chromosome 16 using the populations of chromosome segment substitution lines from Gossypium hirsutum×G.barbadense

【目的】明确主效数量性状位点(quantitative trait loci,QTL)在陆海渐渗系群体中的分子标记辅助选择效应以及QTL聚合对纤维长度和纤维强度的影响。【方法】以陆地棉中棉所45与海岛棉海1的优质渐渗系MBI7561(BC_(4)F3∶5)为母本,与其轮回亲本中棉所45构建次级分离群体BC_(5)F_(2)和BC_(5)F_(2∶3),选择单株继续与轮回亲本杂交后自交,获得BC_(6)F_(2)及BC_(6)F_(2)∶3共2个世代群体材料。利用16号染色体上与已知的3个纤维长度主效QTL(qFL-16-1、qFL-16-4、qFL-16-5)和3个纤维强度主效QTL(qFS-16-1、qFS-16-4和q FS-16-5)连锁的4个简单重复序列标记(CGR6894a、PGML02608、NAU5408和NAU3594)进行检测,评价关联QTL对纤维长度和强度的影响。【结果】q FL-16-1、q FL-16-4、q FL-16-5、qFS-16-1、qFS-16-4和q FS-16-5在陆海渐渗系群体2个世代中均具有显著的遗传效应,4个连锁标记的辅助选择效应明显。3个QTL两两聚合均能表现出显著的累加效应;并筛选出同时聚合到2个以上QTL的纤维品质优良单株。【结论】选择的16号染色体纤维长度与强度相关的QTL在陆海渐渗系群体2个世代中均具有显著的遗传效应,聚合效应显著。该研究为纤维长度及强度的分子标记辅助选择聚合育种奠定了重要基础。

[Objective]The purpose of this study was to evaluate the selection and pyramiding effects of quantitative trait loci(QTL)related to fiber length and fiber strength through molecular marker-assisted selections using populations of chromosome segment substitution lines(CSSLs)from Gossypium hirsutum×G.barbadense.[Method]In this study,CSSL MBI7561 with excellent fiber quality selected from BC_(4)F3:5of CCRI 45(G.hirsutum)×Hai 1(G.barbadense)was used to construct the secondary segregating populations of two generations BC_(5)F_(2)and BC_(5)F_(2:3).Then two populations(BC_(6)F_(2)and BC_(6)F_(2:3))were obtained through backcrossing with the recurrent parents and selfing.Four simple sequence repeat markers,CGR6894a,PGML02608,NAU5408 and NAU3594,linked to three major QTL for fiber length(qFL-16-1,qFL-16-4,qFL-16-5)and three major QTL for fiber strength(qFS-16-1,qFS-16-4 and qFS-16-5)on chromosome 16,were used to screen individuals of BC_(6)F_(2)and BC_(6)F_(2:3).[Result]Four markers related to qFL-16-1,qFL-16-4,qFL-16-5,qFS-16-1,qFS-16-4 and qFS-16-5 indicated obvious and significant single marker selection effect and pairwise marker pyramiding effect for fiber length and fiber strength in the two populations of BC_(6)F_(2)and BC_(6)F_(2:3).Furthermore,the excellent individual which contain more than two QTL was screened.[Conclusion]The analyzed QTL related to fiber length and fiber strength on chromosome 16 had significant genetic effects in different generations of the CSSLs,and the fiber length and fiber strength of individuals were significantly increased by pyramiding two QTL.This study laid an important foundation for molecular marker to assist the pyramiding selection of fiber length and strength.