甘蓝型油菜抗寒相关基因的QTL初步定位

低温是影响油菜生产和产量最重要的非生物逆境胁迫因子。为了阐明油菜抗寒性的遗传基础并定位相关的数量性状位点,利用甘蓝型油菜强抗寒GZ恢和弱抗寒10B杂交获得的147个F_2单株为定位群体、以双亲及F2∶3家系为辅助研究材料,利用SSR分子标记结合生理学指标及自然条件下抗寒性调查对抗寒基因QTL进行初步定位。结果表明:630对SSR引物中有160对在双亲间具有多态性,多态率25.40%;160对多态性引物中有102对在F_2群体中有多态性,多态率63.75%,102对多态性引物共检测出多态性位点229个。102个SSR标记构建连锁图,图谱总长974.70 c M,平均距离为5.70 c M。在自然越冬条件下,对F2及F2∶3家系的抗寒性及叶片相对电导率、组织相对含水量、SPAD值、丙二醛(MDA)含量进行测定,分析生理指标与抗寒性的相关性,结果呈显著或极显著相关,表明这些指标可以作为抗寒性评价的参考指标。共定位出5个与抗寒性相关的QTL位点,SPAD值与MDA含量2个指标之间检测到的QTL具有重叠区,这可能是由一因多效或基因紧密连锁引起,可以作为后续分析候选基因的1个热区。为进一步进行甘蓝型油菜抗寒性状相关基因的精细定位及克隆奠定了基础理论。

QTL Primary Mapping of Cold Tolerance Related Genes in Brassica napus

The low temperature is a major cause of yield loss in Brassica production.The object of this study was to understand the genetic causes underlying cold tolerance and to identify relevant quantitative trait locus.An F2 population(1 47 individuals)derived from GZ hui(Brassica napus,high cold tolerance)and 1 0B(Brassica napus, low cold tolerance)were used as gene mapping population.The two parents and F2 ∶3 families were used as seconda-ry research material.SSR molecular markers in combination with physiological index and natural conditions of hardi-ness survey were developped to map QTLs associated with cold tolerance genes.The results showed that 1 60 SSR primers could amplify polymorphic bands between the two parents among 630 SSR primers,the polymorphism rate was 25.40%;1 02 SSR primers showed polymorphism between F2 among 1 60 SSR premiers with polymorphism rate was 63.75%.A total of 229 loci were finally identified.The genetic map covered 1 9 linkage groups with 974.70 cM in length,and average destiny was 5.70 cM.Under the condition of natural wintering,relative conductivity,relative water content,SPAD and MDA were measured in F2 and F2 ∶3 ,respectively,and the correlation was analyzed among them showing correlation or significant correlation which indicated these indexes could be regarded as targets to e-valuate the cold tolerance in Brassica.Five QTLs were identified associated with cold resistance.There was an over-lap area between the QTLs of SPAD and MDA,which could be regarded as a hot area of candidate genes.This re-search can lay further foundation for fine mapping and cloning of the cold tolerance genes in Brassica napus.