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模式的概念。然而，到目前为止，还没有关于杂种优势群在杂交育种中必要性的理论证明。因此，我们的目标是(1)检验杂种优势群概念和模式在杂交育种中的优缺点，(2)评价不同的杂种优势群识别、建立和管理方法，(3)探索扩大可用的杂种优势群的方法。应用数量遗传理论研究了杂种优势群间的遗传差异对特殊配合力(2scA)和一般配合力(2GCA)方差的影响。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资源的杂种优势模式，将采用新的基于模型的聚类方法，并在小黑麦的实验数据中进行验证(实验2)。此外，还将在计算机模拟的基础上对管理杂种优势群的各种方案进行比较，并提出最优策略。在实验3中，我们研究了利用分子标记对已建立的杂种优势模式的遗传基础进行有效拓宽的方法。我们期望我们的研究为有效地识别、建立、管理和拓宽自交和异交作物的杂种优势模式提供有价值的信息，从而保证杂种优势的最佳利用。

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.