玉米茎秆糖含量的遗传模式分析

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，本研究以YXD053和98A-04两个高茎秆糖含量玉米自交系为母本，Y6-1低茎秆糖含量玉米自交系为父本，通过自交、杂交及回交产生2个组合的6个世代(P₁、P₂、F₁、F₂、BC₁和BC₂)；运用主基因+多基因混合遗传模型6个世代联合分析方法，探明控制玉米茎秆糖含量的遗传模型，并进行遗传参数估计。结果表明，玉米茎秆糖含量遗传受2对加性-显性-上位性主基因+加性-显性-上位性多基因共同控制。YXD053×Y6-1及98A-04×Y6-1两个组合的主基因遗传率分别为53.50%和52.63%，多基因遗传率分别为7.96%和17.31%，总遗传率分别为61.46%和69.94%，显性度(h/d)均小于1。茎秆糖含量以主基因遗传为主，且主基因又以加性效应为主，但环境因素对茎秆糖含量的遗传有一定的影响。这一研究结果为玉米茎秆糖含量性状的基因定位和育种选择提供了理论依据。

Inheritance Analysis of Stalk Sugar Content in Maize

Increasing sugar content in silage maize stalk improves forage quality and palatability. However, the mechanism of inheritance of stalk sugar content in maize has not been clear yet. To this end, joint analysis of a mixed genetic model of both major gene and polygene was conducted to investigate the inheritance of stalk sugar content in maize. Maize inbred lines YXD053 (high sugar content, Brix = 11.32%), 98A-04 (high sugar content, Brix = 10.69%) and Y6-1 (low sugar content, Brix = 6.3%) were used as parents in this study. Stalk sugar content of three parents and four populations of F₁, F₂, BC₁, and BC₂ generated from two crosses of YXD053×Y6-1 and 98A-04×Y6-1, was surveyed. Results showed that sugar content in maize stalk was controlled by two major genes with additive-dominance-epistatic effects and polygene with additive-dominance-epistatic effects, and mainly governed by major genes. For cross YXD053×Y6-1, the heritabilities of major genes in BC₁, BC₂ and F₂ were 34.52%, 52.94%, and 73.05%, respectively. The heritability of polygene could only be detected in BC₂, which was 23.87%. For cross 98A-04×Y6-1, the heritabilities of major genes in BC₁, BC₂ and F₂ were 60.49%, 28.79%, and 68.62%, respectively. The heritability of polygene was not detected in F₂. The total heritability of major gene and polygene for crosses YXD053×Y6-1 and 98A-04×Y6-1 was 61.46% and 69.94%. The degree of dominance of major gene (h/d) in two crosses was less than one, and the additive genetic effects might play a more important role in breeding of hybrids with high stalk sugar content. Additionally, sugar content in maize stalk could be also subject to environmental factors. Results presented here provide valuable information for stalk sugar content improvement in silage maize breeding program, and lay a foundation for the following maize stalk sugar content QTLs mapping.