Analysis of heterosis components and prediction of hybrid means based on intergroup topcrosses in maize

Abstract Diallel designs are widely used in plant breeding to select parents and to study trait inheritance. The present work aimed to present a method to evaluate two divergent groups of parents, in which one group is used as a tester of the contrasting group. Each parent is crossed with a balanced mixture of seeds from the parents of the other group, and the parents and topcrosses are experimentally evaluated. Two groups of ten inbred maize lines were used to obtain intergroup topcrosses and biparental crosses in a diallel scheme. The data were subjected to analysis of variance and parameter estimation using the two models. The results showed the reliability of the method for the evaluation of lines and prediction of means of hybrid populations and can be recommended when the number of parents to be evaluated is large, making it difficult to evaluate biparental crosses in a diallel scheme.

摘要：双列杂交设计（Diallel designs）已被广泛应用于植物育种领域，用于亲本筛选与性状遗传规律研究。本研究旨在提出一种针对两组差异显著亲本的评估方法，其中一组可作为另一组的测验种（tester）。每组内的各亲本均与另一组亲本的混合平衡种子进行杂交，随后对亲本及其顶交组合（topcrosses）开展实验评估。本研究选取两组各10个玉米自交系（inbred maize lines），用于制备组间顶交组合及双列杂交方案下的双亲杂交组合。研究采用两种模型对所得数据进行方差分析与参数估计。结果证实，该方法用于自交系评估与杂交群体均值预测具备可靠性；当待评估亲本数量较多、难以通过双列杂交方案开展双亲杂交组合评估时，可推荐采用此方法。