玉米不同自交世代产生的姊妹系组配改良单交种的研究

 以不同世代分离的7个姊妹系和5个姊妹系间杂交种为母本，与4个自交系配成20个改良单交和28个单交组合，进行了姊妹种与其亲本系之间，以及改良单交与对应单交之间的产量和农艺性状的比较试验。结果表明：与利用自交系配制单交种相比，以早代（S#-2、S#-3）系姊妹种配制改良单交，可提高制种产量60%以上；以高代（S#-4、S#-5）系姊妹种作亲本，制种产量约提高5%-25%。不同分离世代产生的姊妹系配制的改良单交，其产量和农艺性状的整齐性与其对应单交无显著差别。鉴此，采用系谱法选育作为改良单交亲本的姊妹系，应从S#-2或S#-3代分离产生。

A STUDY ON CORN MODIFIED SINGLE CROSSES COMBINED BY SIB LINES SEPERATED IN DIFFERENT GENERATIONS

Each of 7 siblines separated in different generations and 5 sibcrosses was mated with 4 male in inbred lines to produce 28 single crosses and 20 modified single crosses.The differences in grain yield and main agronomic traits between sibcross and their parental lines,modified single cross and corresponding single cross were tested.The results showed that the grain yield of sibcrosses between S2 or S3 lines increased more than 60% of those yields of their parental lines;while 5-25% higher yields than parental lines are gained by sibcrosses between S4 or S5 lines.There were nonsignificant differences in grain yields and uniformity of main agronomic traits between the modified single crosses including siblines which seperated respectively in different generations and the corresponding single crosses.Therefore,to develop siblines as the parents of modified single crosses by pedigree method,it would be suitable to separate them in S3 or S4 generation.