玉米茎秆糖含量的遗传分析

Genetic effects on sugar content of stalk in corn

较高的茎秆糖含量有助于提高青贮玉米的饲料品质和适口性,本研究选用7个茎秆糖含量不同的玉米自交系为亲本,按Griffing双列杂交方法Ⅱ配置21个组合,对玉米茎秆糖含量性状的遗传进行分析。结果表明:在7个自交系中,Y53-164、YXD053-646和98A-04糖含量的一般配合力较高,可以提高杂种后代的茎秆糖含量,但特殊配合力存在明显的组合差异。玉米茎秆糖含量性状的遗传符合加性-显性-上位性模型,但以基因非加性效应为主,存在着显著的显性与上位性效应。控制茎秆糖含量遗传的增效等位基因为隐性,减效等位基因为显性。玉米茎秆糖含量的变异71.07%是由遗传控制的,但狭义遗传率不高(40.11%)。对茎秆糖含量的选择不宜早代进行,利用茎秆高糖自交系作为亲本并广泛测配有助于茎秆高糖杂交种的选育。

Increasing the sugar content in silage corn stalk will improve the forage quality and palatability,and its inheritance has been rarely studied yet,the study on its inheritance can provide valuable information for silage corn breeding on stalk with high sugar.Seven corn inbred lines varying in stalk sugar content（Brix varying from 5.9 to 13.9） were used as the parents for making 21 crosses by Griffing diallel crossing modelⅡ,and genetic effects on stalk sugar content were evaluated.The results showed that inbred lines Y53-164,YXD053-646 and 98A-04 had the higher General Combining Ability（GCA） in stalk sugar content than the other four inbred lines,therefore,it is possible to increase stalk sugar content in their progenies.However,Special Combining Ability（SCA） significantly varied among combinations in stalk sugar content.The inheritance mode of stalk sugar content was in agreement with the additive-dominance-epistasis model,Furthermore,compared with the additive genetic effect,the dominant and epistatic genetic effects played a more important role.The alleles increasing stalk sugar content were recessive,and the alleles decreasing stalk sugar content were dominant;71% of the variation in stalk sugar content was contributed by genetic factors,however the narrow sense heritability of stalk sugar content was relatively low（40.11%）.This characteristics cannot be used for selection in the early generations,inbred lines with high stalk sugar content being widely crossed might be usefor in inbreeding of hybrids with high stalk sugar content in corn.