甘蔗实生苗群体主要经济性状的遗传变异及选择

Genetic Variation and Selection of Main Economic Traits in Sugarcane (Saccharum spp.) Seedling Populations

以LCP85-384和崖城82-108杂交后代120个无性系为材料,研究产量和品质性状的遗传变异及其分布。结果表明,不同经济性状变异系数差异较大,其中丛含糖量变异系数最大(51.31%),视纯度变异系数最小(3.43%)。除单茎重、丛重和丛含糖量分布为左偏正态分布外,株高、茎径、有效茎数、旋光读数、锤度、转光度和视纯度7个性状符合正态分布。通径分析结果表明,除锤度外,株高、茎径和有效茎数对丛含糖量有极显著正效应(p<0.01),旋光读数对丛含糖量有显著正效应(p<0.05)。逐步判别分析结果表明,株高、茎径、有效茎数和旋光读数对丛含糖量分类有显著影响,并以这4个性状为指标建立丛含糖量判别模型,误判率为4.73%。对12个杂交组合后代验证结果表明,判别模型入选率与实际入选率基本一致,分别为6.30%和6.85%。

Genetic variation and frequency distribution of yield and quality traits were investigated in 120 clones from the progenies of the crosses of LCP85-384 × YACHENG82-108. Different traits had different coefficients of variance. The maximum coefficient of variance （51.31 %） was found in sugar weight per stool, and the minimum coefficient of variance （3.43 %） was found in apparent purity. Left-skewed distributions were presented in single stalk weight, stool weight and sugar weight per stool. Moreover, normal distributions were presented in stalk height, stalk diameter, number of millable stalk （NMS）, polarimeter reading （PR）, brix （total soluble solids percent） in juice, pol in juice and apparent purity. Path analysis showed that except for brix in juice there were extremely significant （p〈0.01） effects of stalk height, stalk diameter and NMS on sugar weight per stool and significant （p〈0.05） effects of PR on sugar weight per stool. Indexes of stalk height, stalk diameter, NMS and PR that significantly affected classification of sugar weight per stool were selected through stepwise discriminant analysis, and a discrimination model for sugar weight per stool was established with an error rate being only 4.73 %. The twelve crosses were validated by the discrimination model, and the results suggested that the model selection rate was 6.30 %, very similar to the actual selection rate （6.85 %）.