对辽宁省 1 990～ 1 998年玉米审定品种双亲分析表明 :玉米自交系选育主要来源于系谱法、二环选育及回交改良 ;通过对辽宁省 1 986～ 1 998年参加玉米晚熟组区试组合最高产量分析表明 :玉米杂交种优势水平不但没有提高反而下降了 ,只是在抗病性、品质上得到了一定改善。基于这一分析 ,结合育种实践 ,提出选育优良自交系的对策。 Parental analysis of Liaoning Province from 1990 to 1998 showed that the breeding of maize inbred lines mainly came from the pedigree method, the second-ring breeding and the backcross improvement. Through the study on the late maturity of maize from 1986 to 1998 in Liaoning Province, The highest yield of the combination of regional test group showed that: the dominant level of maize hybrids did not increase but declined, but the disease resistance, quality has been improved. Based on this analysis, combining with breeding practice, the countermeasures of breeding elite inbred lines were proposed.