两种轮回选择方案对玉米群体改良的效应

 应用全姊妹轮回选择和S#-1家系轮回选择两种方案对基础群体M#-4进行了改良；对基础群体M#-5只进行了全姊妹轮回选择的改良。结果表明：对同一群体用两种方案进行改良皆有显著效果。从遗传进展比较，全姊妹轮回选择方案所取得的产量遗传进展较大，但二方案未有显著差异，其它大部分农艺性状也以全姊妹方案的遗传进展较大。从群体变异程度变化的比较，S#-1家系方案要优于全姊妹方案。不同群体采用同一种轮回选择方案，表现出变异程度大的群体，选择的遗传进展也大。多元方差分析表明，改良群体和基础群体间在产量平均数向量上皆有显著差异，全姊妹方案使群体的多元方差变小，S#-1家系方案则使群体多元方差增大。通径分析结果表明，不同群体的有关性状对单株籽粒产量的影响有差别，同时其作用程度也不尽相同。

EFFECTS OF TWO RECURRENT SELECTION PROGRAMS ON POPULATION IMPROVEMENT OF MAIZE

Fun-sib recurrent selection and S_1 family recurrent selection were used for improvement of base population M_4. The improvement of base population M_5 was conducted only with full-sib recurrent selection. he results show as follows. Two recurrent selection programs applied in the same population achieved good results. The full-sib recurrent selection had greater genetic progress of yield than S_1 family recurrent selection, however, there was no significant difference between the two methods, andthegenetic progress of many other agronomic traits achieved by the full-sib recurrent selection was greater than that of S_1 family selection. With regard to coefficient of variation, the S_1 family program was better than the full-sib program. When the same recurrent selection porgram was used in various population, the greater the coefficient of variation of the population, the greater the genetic progress it made. Analysis of multivariateshowed that there was significant difference between improved population and the basic population in yield character vector and multivariate variance of the population under fullsib method became smaller, while under S_1 family method, became bigger. According to the results of path analysis, population varied in the traits which had significant effect on kernel yield per plant, and varied in their affecting extent. Thepopulation under imporovement program adjusted the relationship among traits.