玉米亲本间遗传距离与杂种优势及配合力的关系

以6个玉米自交系及其双列杂交组合进行试验,用3种方法计算的遗传距离来研究距离与杂种优势及配合力的关系。结果为:(1)PD~2(表—主—欧法计算)和GD~2(基—主—欧法计算)与穗粒重平均优势具有显著抛物线关系,PGD~2(表—主—道—欧法计算)与穗粒重平均优势亦有抛物线关系的趋势。(2)亲本的一般遗传距离(GGD~2)和一般表型距离(GPD~2)与亲本吐丝日数的一般配合力呈现高度负相关。(3)GD~2和PD~2与穗粒重、吐丝日数、穗长、千粒重的特殊配合力无确定关系,与穗行数、果穗重、穗位高、株高的特殊配合力略呈抛物线关系。PGD~2与上述8个性状的特殊配合力有抛物线关系的趋势。(4)杂交组配时应考虑:在类间选择亲本;双亲间PGD~2较大;双亲自身产量较高。

RELATIONSHIP BETWEEN GENETIC DISTANCE OF PARENTS AND HETEROSIS,AND COMBINING ABILITY IN MAIZE

6 inbred lines and its 1 5Fi hybrids from diallel crosses of maize were used to investigate the relationship between genetic distances (D2 's calculated by three methods) of parents and heterosis, and combining ability. The resules as follows; (1 )It showed a significant parabola relationship between PD2 (Phenotypic correlation matrix - principa component - Euclidean Distance),or GD2(genotypic correlation matrix - principa component - Euclidean Distance) and heterosis over mid - parent on grain weight per ear . There was a tendency of parabola relationship between PGD2 (phenotypic correlation matrix - principal component-genetic vector-Euclidean Distance) and heterosis over mid -parent on grain weight per ear. (2)There presented a highly negative correlation between general genetic distance (GGD2) or general phenotypic distance (GPD2) and general combining ability (GCA) on days to silk (3) There Was no definite relationship between GD2 or PD2 and special combining ability SCA on grain weight per ear ,days to silk ,ear length and thousand - kernel - weight. There was a slightly parabola relationship between GD2 or PD2 and SCA on number of kernel line per ear, ear weight, ear height plant height . There was a tendency of parabola relationship between PGD2 and SCA on the eight traits above. (4)Parents should be selected from different groups and specific combination should hava larger PGD2 values between parents with higher yields.