高密度条件下不同生态区变换地选育优良玉米自交系的研究

在吉林省、北京和河南省3个生态环境中对同一来源于X系单交种的早代S₁、S₂和S₃等后代群体进行变换地选择，研究在90 000株/hm²的高密度种植条件下，各世代群体的非有利基因型植株的淘汰效果和入选优良植株的选择效果，并对不同生态区的变换选择途径进行评价。结果表明，在河南省生态环境下对影响产量潜力的子粒败育、果穗畸形植株淘汰效果较为突出。北京和吉林省生态环境对影响抗旱和耐低N等抗性性状的雌雄不协调植株淘汰效果突出；在S3代入选植株的平均粒重高达130 g/穗，显示出较高的单株产量潜力，其相关农艺性状和果穗产量性状得到进一步改善。在3个生态环境中，河南省环境胁迫性最强，入选果穗最少，入选果穗平均单穗粒重最低，对玉米植株与产量间接相关的抗性选择更有利；吉林省和北京则入选果穗多，入选果穗的平均粒重相对较高，对玉米产量直接性状选择更为有效。因此，在北京、吉林省和河南省不同生态区变换地选择育种可以选出产量潜力高、综合抗性理想的基因型。

Studying on Elite Inbred Lines Breeding in Maize by Selecting in High Density Under Different Ecological Conditions

Low generations S₁, S₂ as well as S₃ progenies from one hybrid developed from X germplasm were planted in high density(9×10⁴ plants/ha) for selecting under Jilin, Beijing and Henan ecological conditions. The elimination effects of high density on progenies under different ecological conditions and the characteristics of selected excellent plants were analyzed. In this paper, the selecting ways among 3 ecological conditions were also evaluated. The results showed that, the prominent elimination on badly performing plants with kernel abortion and abnormal ear which directly related to yield was made in Henan ecological condition representing Huanghuaihai area, in contrast, Beijing and Jilin ecological conditions representing Northeast area were more favorable for eliminating plants with inharmony of anthesis and silking which directly related to drought and low N resistance. The average kernel weight per ear of the selected plants from S₃ progenies was as high as 130 g, showing high promising yielding potential. And the agronomic traits of them were also improved greatly. Among 3 different ecological conditions, the environment stressing in Henan was the strongest with the least numbers of selected ears and the lowest average kernel weight per ear, and more advantageous the resistance selection indirectly related to yielding, by contrast, more ears were selected with high average kernel weight per ear under Beijing and Jilin ecological conditions which were considered more effective to traits selection directly to yielding. Ideal plants with high yielding potential and prominent resistance could be selected through selecting under Jilin, Beijing and Henan ecological conditions.