不同群体（系）之间杂交第一代具有不同程度的杂种优势是生物界的一种普遍现象，杂种优势现象已经被广泛应用在商业化育种实践中。然而，杂种优势形成的遗传基础也仅仅还停留在假说阶段，主要包括显性假说、超显性假说，以及上位性、杂种优势基因、等位基因特异表达等理论解释，进一步推动杂种优势形成的遗传机制具有重要的理论与实践意义。在利用数量遗传学理论解释杂种优势上，前人提出了杂种优势的数学表达式HF1=Σdy2。经多年的玉米自交系和杂交种的选育实践，本文在综述不同杂种优势假说的基础上，结合玉米育种实践，阐述了HF1=Σdy的实用性。探讨了上位性对杂种优势可能存在的影响，深度讨论了杂种优势HF1=Σdy2在玉米育种中的指导作用。
英文摘要:
Heterosis is a common phenomenon in biology, which has been widely used in commercial breeding practice.?However, the genetic basis of heterosis has been still at the stage of hypothesis, mainly including dominant hypothesis, super dominant hypothesis, epistasis, heterosis gene, allele specific expression and other theoretical explanations.?Based on the theory of quantitative genetics, the mathematical expression of heterosis was defined as HF1=Σdy2.?Based on the breeding practice of maize inbred lines and hybrids, this paper had summarized different heterosis hypotheses, expounded the practicability of HF1=Σdy2. Except that, the possible effect of epistasis on heterosis was also discussed, and the guiding role of HF1=Σdy2 in maize breeding was discussed in depth.
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