小麦抗赤霉病3B-QTL和6B-QTL的遗传互作模式分析

Genetic interaction model analysis of 3B-QTL and 6B-QTL with resistance to wheat scab

为明确来自抗赤霉病的小麦品种望水白的2个主效抗扩展3B-QTL和6B-QTL的抗性遗传和互作模式,基于分子标记辅助选择方法,构建了回交分离群体,以病小穗数(NDS)和病轴长(LDR)为鉴定指标,采用单花滴注接种法对携带3B-QTL和6B-QTL的BC_3F_1、BC_3F_2、BC_3F_3世代以及抗感对照进行了抗赤霉病扩展的表型鉴定和评价。结果表明,3B-QTL和6B-QTL在烟农19和矮抗58不同的背景中,杂合基因型与纯合望水白基因型之间的NDS和LDR差异显著;携带3B-QTL和6B-QTL株系的抗扩展性与只含有单个3B-QTL的株系无显著差异,但显著高于只携带单个6B-QTL株系的抗性,抗感分离比经卡方检验符合4∶3∶9的分离比例,遵循2个独立孟德尔遗传因子控制的隐性遗传模式,且3B-QTL隐性上位于6B-QTL。研究表明,望水白的3B-QTL和6B-QTL抗扩展效应强且稳定,可以作为抗赤霉病基因资源在育种实践中充分利用。

To clarify the resistance heredity and interaction model to wheat scab, 3B-QTL and 6B-QTL deriving from resistant landrace Wangshuibai were identified and evaluated by using single floret inocu- lation in the BC3FI, BC3F2 and BC3F3 backcrossing generations. The results showed that one or two QTL of heterozygous and homozygous recurrent parent genotypes had significant difference with homozy- gous donor parents under Yannong 19 and Aikang 58 genetic backgrounds. Meanwhile, the wheat plant stacking 3B-QTL and 6B-QTL represented a better spreading resistance than that of the homozygous do- nor genotype with single 6B-QTL, but had no significantly difference with the plant of single 3B-QTL. 3B-QTL and 6B-QTL were two independent and recessive factors of Mendelian genetics according to the segregation ratio of the 4：3：9, and 3B-QTL showed the obvious recessive epistasis to 6B-QTL. The results indicated that the spreading resistances of 3B-QTL and 6B-QTL from Wangshuibai were strong and stability, and could be fully utilized as the fine resource of resistance genes in wheat scab breeding.