【作者】 阚贵珍；

【导师】 邓德祥；

【作者基本信息】 扬州大学 ， 作物遗传育种， 2003， 硕士

【摘要】 玉米是我国主要粮食作物之一，它在我国的经济发展中发挥重大作用。我国玉米育种目标是：稳定面积，以大幅度提高单产为基础，以改善品质为中心，以增强抗性为保证，充分发挥玉米在食用、饲用、加工、出口等方面的作用。 目前我国玉米的单产已达到较高水平，品质育种工作正日益受到重视，同时抗逆性尤其是抗病育种也取得了一定的进展。但近十年来，玉米生产上纹枯病发展蔓延较快，对玉米生产造成的损害越来越大，已成为制约玉米增产的因素。 虽然玉米纹枯病已引起生产部门和科研单位的关注，但仅有少部分人对玉米纹枯病生物学特征、病原学作了一些报道。迄今为止，国内外未见有关玉米纹枯病抗性遗传的机理报道，因此玉米抗纹枯病的育种工作进展缓慢。本研究以对纹枯病抗性不同的5个玉米自交系完全双列杂交所获得的六个世代为材料，用纹枯病病菌进行接种，根据接种后的发病级数，分析探讨玉米对纹枯病抗性的遗传规律，主要结果如下： （1）在玉米的基因库中存在着纹枯病的抗性基因。研究所用的5个自交系中，U8112和双二黄对纹枯病的抗性较强，B77、RA、黄早4对纹枯病的抗性则较弱。 （2）5个自交系完全双列杂交得到10个组合及其它们的正反交，亲本和杂种F₁代的方差差异极显著，表明玉米对纹枯病抗性受其基因型的遗传基础控制。 （3）F₁代的t测验中，有5个组合对纹枯病的抗性未检测到明显的细胞质效应，而在F₂代的t测验中，有3个组合对纹枯病的抗性是不受细胞质效应影响的，虽然这两种测验结果不完全相同，但是都表明玉米不同组合对纹枯病抗性的遗传基础是不同的（与后面的结论相同）。玉米纹枯病抗性主要受细胞核遗传控制，一般不受细胞质效应的影响，但有的组合可能受细胞质效应的影响。 （4）玉米对纹枯病抗性的广义遗传率较高，大都在45％以上，分离世代群体中抗性的变异主要是由遗传变异引起的。 （5）玉米纹枯病抗性的配合力方差分析表明，整个群体是不受细胞质效应的影响，试验所用的各自交系纹枯病抗性的一般配合力和特殊配合力效应间存在显著差异。对一般配合力进一步分析表明，自交系US 1 12、双二黄抗性的一般配合力较高，自交系RA、B77和黄早4抗性的一般配合力较弱，这与前面自交系间抗性分析基本一致。进一步对特殊配合力的分析表明，自交系US 112可以把抗病性稳定地传递给所有杂交组合，而双二黄可以组配特殊的高抗组合。 （6）F:世代抗性遗传分析和六世代联合抗性遗传分析都表明，不同玉米组合的纹枯病抗性遗传规律不一样。有的受主基因控制，有的受多基因控制，还有的受主基因和多基因共同作用。等位基因之间存在显性效应，非等位基因之间存在互作作用。 （7）玉米对纹枯病抗性的遗传受主基因和多基因共同作用，即是质量一数量性状遗传，初步探明有2对主基因。更多还原

【Abstract】 Corn is one of the main crops in our country, which plays an important role in the development of national economy. In our country the objects of com breeding are: stabilizing the cultivated area, increasing per unit-area yield significantly as the foundation, improving quality as the center, strengthening resistance as the guarantee, and showing totally the contribution of com to the field of edibility feed, process export and so on.Nowadays per unit-area yield of corn has already reached the higher level in China, and people pay more and more attention to quality, at the same time, breeding for stress tolerance particularly breeding for disease resistance has also obtained a certain progress. But in the recent decade, sheath blight spreads quickly in corn production, and makes the loss bigger and bigger. It has become the restrictive factor that affects com production.Although some production departments and research institutions have showed much concern on corn sheath blight, there are only few people having made some reports about its biological character and aetiology. Up to the present, there is no relevant report about inherited mechanism of resistance to com sheath blight at home and abroad, therefore, corn breeding for resistance to sheath blight is progressing slowly. This experiment uses 6 generations as its materials which are from complete diallel cross of 5 corn inbred lines whose resistance to sheath blight is different. Inoculate by sheath blight, get the grade of disorder after inoculation, and analyze the regulation of inheritance of resistance to corn sheath blight. Main results are summarized as follows:(1) It exists genes which can resist sheath blight in com gene pool. Among 5 inbred lines, resistance to sheath blight of U8112 and Shuang er huang is strong, while that ofB77, RA and Huang zao 4 is weak.(2) 10 combinations from complete diallel cross of 5 corn inbred lines and their reciprocal cross, analysis of variance of parents and F1 reaches significant difference, which implies that the resistance to corn sheath blight is controlled by hereditary basis of its genotype.(3) There are 5 combinations that can not be examined apparent cytoplasm effect of resistance to sheath blight in t test of F1 , but in t test of F2 there are only 3 combinations whose resistance to sheath blight is not affected by the cytoplasm. Although the result of these two kinds of tests is not completely alike, both show that different combinations have different hereditary basis of resistance to corn sheath blight (same to the conclusion that follows). Resistance to corn sheath blight is primarily controlled by cell nucleus, generally not affected by cytoplasm effect, but some combinations may be suffered by the cytoplasm effect.(4) The heritability in broad sense of resistance to com sheath blight is higher, mostly above 45%, variation of resistance in the population of separated generation is mainly caused by hereditary variation.(5) The analysis of variance of combining ability of resistance to com sheath blight shows, the whole population is not submitted to the influence of cytoplasm. In this experiment, resistance to sheath blight of inbred lines of general combining ability (GCA) and special combining ability (SCA) effect exist significant difference. Further analysis of GCA shows, resistant GCA of U8112 and Shuang er huang is high, that of RA B77 and Huang zao 4 is weak, it is consistent with analysis of resistance above. The further analysis of SCA shows, U8112 can deliver resistance stably to all cross combinations, but Shuang er huang can form special and highly resistant combinations.(6) The genetic analysis of resistance of F2 and 6 genetions shows, different combinations have different genetic regulation of resistance. Some are controlled by major gene, some are controlled by polygene, and others are operated by major geneand polygene together. Dominance effect exists among allele, and interaction exists among non-allelic genes.(7) Inheritance更多还原