引入美国种质对我国玉米育种的影响

我国育种者从美国商业杂交种中分离了许多二环系,逐渐形成了PA(Reid)和PB(non-Reid)两大种质群,并利用这些二环系改良国内种质,取得了明显成效。PA种质是目前我国玉米育种利用的主要A类种质,在很大程度上稳定了我国玉米育种的杂种优势模式。而PB种质在引入抗病、耐逆基因的同时,倾向于破坏我国玉米杂种优势模式的稳定性和集中性,瓦解了我国的玉米杂种优势模式,同时也造成对热带种质的盲目利用,使得玉米育种的技术路线和杂种优势模式变得复杂化。目前直接对商业杂交种的分离选系在很大程度上造成育种思路与杂种优势模式的混乱。正确利用国外商业杂交种选育二环系和改良种质,对于制定今后玉米育种的技术路线和指导产品创新具有重要的实践意义。

The Impacts of US Germplasm on Maize Breeding Efforts in China

The germplasm derived from US commercial hybrids has contributed a lot to maize breeding efforts in China. Two opposite heterotic groups, PA(Reid) and PB (non-Reid), were developed from US commercial hybrids, and the germplasm was also used in the improvement of domestic germplasm. PA is of the typical and leading germplasm of heterotic group A, and it has an important impact on heterotic patterns and breeding efforts in China. In the meantime of introduction of genes for disease resistance and stress tolerance, PB tends to break up the stability, and disorganize the heterotic patterns. This breeding practice also brings forth the overemphasis of tropical germplasm utilization, and therefore disturbs the breeding technique and strategy. The inbreds development directly from US hybrids or other commercial hybrids have disarranged the heterotic patterns and breeding strategy to a great extent. Therefore, it is of great importance to guide the technique in germplasm enhancement with the commercial hybrids from aboard and other sources.