利用水稻MAGIC群体关联定位白叶枯病抗性QTL和创制抗病新种质

摘要

Three genetically interconnected multi-parents advanced generation inter-cross (MAGIC) population, including two populations (DC1 and DC2) derived from four parents and one population from eight parents (DC3) were used to detect QTLs for resistance to two strains, a weak virulent C2 and a strong virulent GD-V ofXanthomonas oryzaepv. oryzae(Xoo) and to screen resistant breeding materials. Most parents were resistant to C2 and susceptible to GD-V. Transgressive segregations of lesion length for the two strains were observed in the three MAGIC populations and showed continuous distributions. A total of seven QTLs affecting lesion length of two strains were detected. Most QTLs showed quantitative resistance and obvious genetic back-ground effect. Among the seven QTLs,QBbr11-1andQBbr11-2 had less genetic background effect, which is valuable in rice breeding for disease resistance. Eight resistant lines pyramiding different QTLs were screened from the three MAGIC populations, indicating the combination of qualitative resistance gene and quantitative resistance gene can significantly improve resistance level. The eight resistant breeding lines could be used as resistant donors in rice breeding for resistance. The results indicated that the MAGIC populations are ideal material for genetic study and marker-assisted breeding, showing a tight integration of genetic research and breeding application in rice.%以8个不同亲本构建的遗传上相互关联的多亲本高代互交系(multi-parents advanced generation inter-cross, MAGIC)群体,包括2个4亲本群体(DC1和DC2)和1个八亲本群体(DC3)为材料,接种我国白叶枯病强致病力V型菌系(GD-V)和弱致病力 II 型菌系(C2),关联分析定位 MAGIC 群体对白叶枯病的抗性 QTL,筛选抗病种质。结果表明,大多数亲本对C2菌系表现抗病,而对GD-V菌系表现感病,3个MAGIC群体的病斑长度均出现超亲分离。共检测到7个白叶枯病抗性 QTL,大多表现数量抗性,而且抗性 QTL 表达存在明显的遗传背景效应。QBbr11-1和QBbr11-2受遗传背景影响较小,具有一定的育种应用价值。从3个群体筛选出8份不同抗病QTL聚合的抗病材料,表明质量抗性基因和水平抗性数量性状位点的结合可以显著提高抗性水平。8份不同抗病QTL的聚合系可以用作抗病育种的中间抗源。研究结果表明, MAGIC群体可以将遗传研究和育种应用有机结合,是遗传研究和开展标记辅助育种的理想群体。