节瓜果肉颜色遗传规律及SSR标记连锁分析

Genetic Law of Flesh Color of Chieh-qua and Its Linkage Analysis of SSR Markers

以7-2-1-3-2-2-1(绿肉)和2号(白肉)节瓜高代稳定自交系为试验亲本,构建P1、P2、F1、F2、BC1、BC2六个世代,利用加性显性遗传模型,对节瓜果肉颜色性状的数量遗传学进行研究,结果显示,节瓜果肉颜色是由多基因控制的数量性状,符合加性显性遗传模型,中亲值m为3.74,加性效应值d为0.039,显性效应值h为0.211。结合SSR分子标记,构建了160棵单株的F2群体,以复合区间作图法对节瓜果肉颜色的QTL进行分析,结果获得2个低密度的连锁群:连锁群(c1)包括4个标记C5、CMTC168、AAC6和SSR02895,连锁群长度为92.9 cM,平均间距为23.23 c M/maker,最小距离19.5 cM;连锁群(c2)包括2个标记S10和E14,连锁群长度为48.6 cM,平均间距为24.30 c M/maker。检测出1个与节瓜果肉颜色性状相关的QTL,其位于连锁群(c1)上的标记SSR02895和AAC6之间,距离标记SSR02895较近,为9.85 cM,LOD值为2.76,贡献率为20.69%。本研究为进一步筛选与控制节瓜果肉颜色基因更加紧密连锁的分子标记及相关基因的精细定位与克隆提供帮助。

Six generations of P1,P2,F1,F2,BC1 and BC2 were constructed using 7-2-1-3-2-1(green flesh)and 2(white flesh)high-generation stable inbred lines as experimental parents.Quantitative genetics of flesh color traits of chieh-qua was studied by additive dominant genetic model.The results showed that the flesh color of chieh-qua are quantitative traits controlled by multiple genes,which conform to the additive dominant genetic model.The median parent value m is 3.74,the additive effect value d is 0.039,and the dominant effect value h is 0.211.Combined with the SSR molecular marker,the F2 population of 160 individual plants was constructed,the QTL of the flesh color of chieh-qua was analyzed by composite interval mapping method.The results showed that two low-density linkage groups were constructed:linkage group(c1),including 4 markers(C5,CMTC168,AAC6 and SSR02895),and a linkage distance of 92.9 c M,an average distance of 23.23 cM/maker,and the minimum distance of 19.5 cM;linkage group(c2),including 2 markers(S10 and E14),the linkage distance was 48.6 cM,and the average distance was 24.30 c M/maker.One QTL linked to the flesh color of chieh-qua was detected,it was located between the marker SSR02895 and AAC6 on the linkage group(c1).The distance was 9.85 cM and closed with marker SSR02895.The LOD value was 2.76,and the contribution rate was 20.69%.This study could be helpful for further screening the molecular markers closer linked to flesh color genes of chieh-qua and gene fine mapping.