烟草赤星病抗性因素遗传的双列分析

对烟草赤星病两个抗性因素遗传的1／2＊7(7+1)双列杂交分析表明，病斑数量和病斑大小的遗传都符合加性-显性模型。病斑数量的遗传属部分显性类型，显性基因主要表现为减效；病斑大小的遗传属完全显性类型，显性基因为增效基因。1996、1997两年的田间试验结果和苗期离体叶片接种的结果基本一致。烟草对赤星病病菌侵入的抗性较抗病斑扩展的能力更容易通过品种间杂交传递给后代。配合力分析表明，一些组合具有较好的抗侵入特殊配合力，另一些组合具有良好的抗扩展特殊配合力。抗×感组合Beinhart1000-1×NC82两个抗性因素特殊配合力均较好，在抗病育种中有较高的利用价值。

Diallel cross analysis on inheritance of resistance components to tobacco brown spot disease

A 1/2p(p+1) diallel cross with 7 parents was designed to determine inheritance of two resistance components to tobacco brown spot disease. Both the components, lesion-number and lesion-size, were found genetically consilient to theAdditivity-Dominance Model, with the former of incompletely dominant while the latter of completely dominant nature. For the inheritance of lesion-number, the dominant genes are mostly negative, and for lesion-size, the dominant genes are positive. The results from field investigation in 1996 and 1997, and from detached-leaf-inoculation all supported the identical conclusion. The invading-resistance of tobacco plant was proved to be more ready to be delivered to offspring than spreading-resistance to the disease. Analysis on the combining ability indicated that there were some crosses had desirable special combining ability of lesion-number, others had good lesion-size special combming ability. The resistant×susceptible type cross Beinhart1000-1×NC82 showed good special combming ability of both the resistance components. It's very useful in breeding for brown spot resistance.