옥수수의 胡麻葉枯病抵抗性과 收量形質의 遺伝 및 相互關係

Inheritances of Resistance to Helminthosporium maydis Nisikado and Yield Components and Their Relationships in Maize (Zea mays L.)

A series of experiments were conducted to study the inheritance of resistance of corn (Zea mays L.) to Helminthosporium maydis and yield components to provide the basic informations. Segregating and non-segregating generations derived from the crosses among 8 inbred lines and F₁’s of a 9-entry diallel set were used for the genetic studies on resistance to H. maydis. The 9-entry diallel set was also used for the study on the relationships among yield components and H. maydis resistance. The results were summarized as follows: 1. Dominant effect was more important than additive effect among the crosses resistant x resistant inbreds and susceptible x susceptible inbreds, while additive effect was more important than dominant effect among the crosses of resistant x susceptible inbreds and resistant x intermediate inbreds. 2. The inheritance of resistance to H. maydis could be explained satisfactorily by the additive and dominance model and no epistasis effects were detected. 3. Additive effects were found to be more important than other genetic effects in the inheritance of resistance to H. maydis in the diallel analysis. 4. General combining ability effects were found to be more important than specific combining ability effects for the inheritance of yield components studied. Heterosis effects were highly significant for all the characters studied. 5. Partial or over-dominance was detected in the inheritances of kernel weight per ear, kernel number, ear lenght and ear diameter, while complete dominance wes noticed for 100 kernel weight. 6. There were highly significant correlations among yield components studied while resistance to H. maydis showed the highly significant negative correlation coefficient with 100 kernel weight. 7. Pathway analysis revealed that the effects of H. maydis did not change the direct or indirect effects of yield components on kernel weight per ear. Kernel number per ear and 100 kernel weight had the highest direct effects on kernel weight per ear in that order. Ear length and ear diameter showed indirect effects on kernel weight per ear through kernel number per ear and 100 kernel weight.