美洲黑杨×青杨F_2代抗杨叶枯病遗传变异研究

Research on the Variation of Populus deltoides×P. cathayana F 2 Generation against Alternaria alternata

以美洲黑杨与青杨杂交三代谱系为材料，在室内外进行了美洲黑杨与青杨的杂交种对杨叶枯病抗性的研究。结果表明：亲本及Ｆ１、Ｆ２代在室内与室外及人工与自然发病表现较一致，美洲黑杨×青杨Ｆ２代抗性基因型分离比例均符合１∶２∶１，将Ｆ２代分离与感合作为感病，抗病株与感病株分离比例为１∶３，说明美洲黑杨对杨叶枯病的抗性是由一对纯合隐性等位基因控制。

The study was carried out using three generations,with the F 1 produced by interspecific hybridiations between a resistant Populus deltoides female and a susceptible P. cathayana male. F 1 inbreeding made the F 2 generation. The susceptibility of parents, F 1 and F 2 to Alternaria alternata was tested both in the nursery and laboratory. The results show that the clones that were scored as being Ⅰ,Ⅱ, and Ⅲ in the nursery were also scored as Ⅰ,Ⅱ, and Ⅲ(Ⅰ: 0,Ⅱ: ≤15%,Ⅲ: >15%) in the laboratory. F 2 segregated in a 1∶2∶1 ratio for the resistance to A. alternata (Fr.) Keissler. The data suggest that the resistance be detemined by a single recessive gene for P. deltoides. The study is the basis for future identifying molecular markers linking to the locus against A. alternata by Bulked Sergeant Analysis (BSA) and molecular markers.