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本文以21个玉米自交系和按15×6不完全双列杂交设计配制的90个单交种为材料,对遗传距离测量方法进行了初步探索,对遗传距离与产量的杂种优势及特殊配合力的关系进行了研究。方法的探索包括主成分法(刘来福,1979)与枢轴凝聚法(C.R.R(?)o,1952)2种遗传距离计算方法的比较,以及对作者提出的分类指标(性状)选择的新方法的分析。结果表明,按作者提出的从经济产量形成的源、流、库3个生理环节选择性状作为分类指标,并运用主成分法计算遗传距离,对于预测经济产量杂种优势更为有效。这样测出的自交系间遗传距离 D~2与F_1产量的杂种优势及组合特殊配合力均呈显著的抛物线回归关系。进而还看到,杂种优势与 D~2的关系有时也受自交系遗传基础的影响。这种影响再加上其他综合因子降低了前述抛物线回归关系的决定度。
In this paper, 21 maize inbred lines and 15 single crosses designed and made by 15 × 6 incomplete diallel cross were used as materials to explore the genetic distance measurement method. The genetic distance and yield heterosis and special combination The relationship between force has been studied. Methods include the comparison of two genetic distances between the principal component method (Liu Laifu, 1979) and the pivot cohesion method (CRR (?) O, 1952), and the new method of selecting the classification index (trait) analysis. The results showed that it was more effective to predict the heterosis of economic output by selecting the traits of three physiological stages from the economic yield formation as the classification index and using the principal component method to calculate the genetic distance. The results showed that there was a significant parabolic regression relationship between the heterosis and the special combining ability of the measured genetic distances between D ~ 2 and F_1 in inbred lines. Furthermore, it is also seen that the relationship between heterosis and D ~ 2 is sometimes also affected by the genetic basis of inbred lines. This effect, combined with other synthetic factors, reduces the degree of certainty of the aforementioned parabolic regression.