Optimum exploitation of heterosis utilizing the concept of heterotic groups and patterns in hybrid breeding

为了系统地利用杂种优势，提出了杂种优势群和杂种优势模式的概念。然而，直到今天，杂种优势群在杂交育种中的必要性还没有得到理论上的证明。因此，我们的目标是：（1）检查杂种优势群和模式的概念在杂交育种中的优点和缺点，（2）评价鉴定，建立和管理杂种优势群的不同方法，（3）探索扩大可用杂种优势群的方法。本文应用数量遗传理论，研究了杂种优势群间遗传分化对特殊配合力方差与一般配合力方差比值的影响。这些理论结果将在下文中与实验数据（实验1）进行比较。为了识别具有复杂群体结构的种质中的杂种优势模式，将采用基于模型的新型聚类方法，并在小黑麦的实验数据中进行测试（实验2）。此外，还将根据计算机模拟对杂种优势群管理的各种方案进行比较，并提出最佳策略。在实验3中，我们研究的方法，有效地扩大了遗传基础的杂种优势模式，利用分子标记。我们希望我们的调查提供了有价值的信息，有效地识别，建立，管理和扩大杂种优势模式的自花授粉和异花授粉作物，从而保证最佳利用杂种优势。

For a systematic exploitation of heterosis the concept of heterotic groups and patterns has been advocated. However, until today, the theoretical proof for the necessity of heterotic groups in hybrid breeding has not been presented. Therefore, our objectives are to (1) examine the advantages and disadvantages of the concept of heterotic groups and patterns in hybrid breeding, (2) evaluate different methods for the identification, establishment, and management of heterotic groups, and (3) explore methods to broaden available heterotic groups. The influence of the genetic divergence between heterotic groups on the ratio of the variances due to specific (2scA) and general combining ability (2GCA) was examined applying quantitative genetic theory. These theoretical results will in the following be compared to experimental data (Experiment 1). For identifying heterotic patterns in germplasm with a complex population structure novel model-based clustering methods will be adopted and tested in experimental data in triticale (Experiment 2). In addition, various scenarios for the management of heterotic groups will be compared based on computer simulations and optimal strategies will be suggested. In Experiment 3 we examine methods for an efficient broadening of the genetic basis of established heterotic patterns using molecular markers. We expect that our investigations provide valuable information for an efficient identification, establishment, management, and broadening of heterotic patterns for autogamous and allogamous crops thus guaranteeing an optimal exploitation of heterosis.