选拔是生物演化(天然选拔)及动植物改良(人为选拔)的有效工具。生态环境的多元化差异、遗传基因的多样性、基因的不同变异方式以及与环境的互作是玉米育种的遗传学基础。本文依据多年形成的选系理论，对选系实践经验加以探讨。

Selection is an effective tool for evolution(natural selection) and animal-plant improvement(artificial selection).The foundation for selection is based on clear diversity of natural environment,genetic variation or polymorphism of genes and genetic-environment interaction.The basic theory and certain practical methods in selection were discussed.

国家“863”计划课题“强优势玉米杂交种的创制与应用”(2009AA101103)