Institute of Plant Breeding, Seed Science and Population Genetics, University of Hohenheim, Postfach 70 05 62, W-7000, Stuttgart 70, Germany.
Theor Appl Genet. 1992 Aug;84(5-6):672-81. doi: 10.1007/BF00224167.
Restriction fragment length polymorphisms (RFLPs) have been proposed for the prediction of the yield potential of hybrids and the assignment of inbreds to heterotic groups. Such use was investigated in 66 diallel crosses among 6 flint and 6 dent inbreds from European maize (Zea mays L.) germ plasm. Inbreds and hybrids were evaluated for seven forage traits in four environments in the Federal Republic of Germany. Midparent heterosis (MPH) and specific combining ability (SCA) were calculated. Genetic distances (GD) between lines were calculated from RFLP data of 194 clone-enzyme combinations. GDs were greater for flint x dent than for flint x flint and dent x dent line combinations. Cluster analysis based on GDs showed separate groupings of flint and dent lines and agreed with pedigree information, except for 1 inbred. GDs of all line combinations in the diallel were partitioned into general (GGD) and specific (SGD) genetic distances; GGD explained approximately 20% of the variation among GD values. For the 62 diallel crosses (excluding 4 crosses of highly related lines), correlations of GD with F1 performance, MPH, and SCA for dry matter yield (DMY) of stover, ear, and forage were positive but mostly of moderate size (0.09≤r≤0.60) compared with the higher correlations (0.39≤r≤0.77) of SGD with these traits. When separate calculations were performed for various subsets, correlations of GD and SGD with DMY traits were generally small (r<0.47) for the 36 flint x dent crosses, significantly positive (r<0.53) for the 14 flint x flint crosses, and inconclusive for the 12 dent x dent crosses because of the lack of significant genotypic variation. Results indicated that RFLPs can be used for assigning inbreds to heterotic groups. RFLP-based genetic distance measures seem to be useful for predicting forage yield of (1) crosses between lines from the same germ plasm group or (2) crosses including line combinations from the same as well as different heterotic groups. However, they are not indicative of the hybrid forage yield of crosses between unrelated lines from genetically divergent heterotic groups.
限制片段长度多态性（RFLP）已被提议用于预测杂种的产量潜力，并将自交系分配到杂种群体中。在来自欧洲玉米（Zea mays L.）种质的 6 个硬质和 6 个马齿自交系的 66 个完全双列杂交中，对这种用途进行了研究。在德国联邦共和国的四个环境中，对 7 个饲草性状对自交系和杂种进行了评估。计算了中亲杂种优势（MPH）和特殊配合力（SCA）。从 194 个克隆-酶组合的 RFLP 数据中计算了系间的遗传距离（GD）。硬质 x 马齿系间的 GD 大于硬质 x 硬质和马齿 x 马齿系间的 GD。基于 GD 的聚类分析显示，硬质和马齿系的分组分开，与系谱信息一致，但有 1 个自交系除外。完全双列杂交中所有系组合的 GD 被分为一般（GGD）和特异（SGD）遗传距离；GGD 解释了 GD 值之间变异的大约 20%。对于 62 个完全双列杂交（不包括 4 个高度相关系的杂交），GD 与干物质产量（DMY）的 F1 表现、MPH 和 SCA 的相关性为正，但与 SGD 与这些性状的相关性（0.39≤r≤0.77）相比，相关性中等（0.09≤r≤0.60）。当对各种子集分别进行计算时，GD 和 SGD 与 DMY 性状的相关性在硬质 x 马齿杂交中一般较小（r<0.47），在硬质 x 硬质杂交中显著为正（r<0.53），在马齿 x 马齿杂交中则无结论，因为缺乏显著的基因型变异。结果表明，RFLP 可用于将自交系分配到杂种群体中。基于 RFLP 的遗传距离测量似乎可用于预测（1）来自同一种质群体的系间杂交或（2）包括来自同一和不同杂种群体的系组合的杂交的饲草产量。然而，它们不能说明来自遗传上不同杂种群体的无关系间杂交的杂种饲草产量。
