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.

分组双列杂交设计（Abstract Diallel Designs）广泛应用于植物育种领域，用于筛选亲本及研究性状遗传规律。本研究旨在提出一种针对两类分化亲本群体的评估方法：其中一组亲本可作为另一组对照群体的测验种。具体实施时，将每个亲本与另一组亲本的种子平衡混合物进行杂交，随后对亲本及顶交组合开展实验评估。本研究采用两组各10个玉米自交系，通过双列杂交方案获得组间顶交组合与双亲杂交组合。采用两种模型对所得数据进行方差分析与参数估计。结果表明，该方法用于评估自交系及预测杂交群体均值具备可靠性，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，可推荐采用该方法。