切花菊茎秆性状的生长动态与遗传分析

为明确切花菊茎秆性状在不同遗传背景下的生长动态和遗传特性,本研究以亲本茎秆性状差异较大的寒小白×蒙娜丽莎白(MH)和亲本茎秆性状差异较小的QX097×蒙娜丽莎白(MQ)两个杂交F₁群体为试验材料,调查了定植后15、30、45、60、70 d时的株高、茎粗和节间数,比较分析切花菊茎秆性状的生长动态、杂种优势和主基因效应。结果表明,两个组合的茎秆性状生长动态基本一致,与亲本性状的差异程度关系不大。其中,株高和茎粗总体符合S型生长曲线,而节间数的生长曲线不明显;各茎秆性状的相对生长速率在定植后45 d前均较快。MQ组合株高、茎粗和节间数等茎秆性状的平均值在大部分测定时期均高于MH组合;而MH组合株高和定植45 d后节间数的变异系数都高于MQ组合,但是在茎粗性状上没有明显规律性。各茎秆性状的中亲优势率在MH组合中多表现为正值,而在MQ组合中,除了定植后15 d时茎粗的中亲优势率为正值,其他各时期茎秆性状的中亲优势率均表现为负值。主基因+多基因混合遗传模型分析在MH组合的株高和MQ组合的茎粗上检测到2对加性主基因效应,主基因遗传力分别为97.12%和9.33%,而在其他组合或茎秆性状上未检测到主基因效应。本研究结果为菊花营养生长期栽培调控和茎秆性状的遗传改良提供了参考依据。

Growth Dynamics and Genetic Analysis of Stem-related Traits in Cut Chrysanthemum

To understand the growth dynamics and inheritance pattern of cut chrysanthemum’s stem traits, Hanxiaobai × Monalisa White (MH) and Qx097 × Monalisa White (MQ) with contrasting segregating patterns were used as materias the plant height, stem diameter, and internode number at 15, 30, 45, 60, and 75 days after planting were investigated, and the growth dynamics, heterosis and major gene effect of stem traits were dissected. Results showed that the stem traits of the two crosses expressed a similar dynamic growth trend, independent on the parent differential performance. The accumulative growth curve fits S-type for plant height and stem diameter but not for internode length, and the relative growth rate for all stem traits increased relatively higher within 45 days after planting. The average plant height, stem diameter and interrade number in MQ cross were higher than those in MH cross at most investigated stages, while the coefficients of variations of plant height at every investigated stage and internode number at 45 days afterplanting and later stages in MH cross were higher than those in MQ cross, but no clear trend was found for stem diameter. The stem traits demonstrated a positive mid-parent heterosis at most investigated stages in MH cross, whereas a negative heterosis was estimated for all stem traits in MQ cross at every investigated stage except for stem diameter at 15 days after planting. The analysis of mixed inheritance model of major gene plus minor gene demonstrated that two pairs of major genes with additive effects were observed for plant height in MH cross and stem diameter in MQ cross, while no major gene effect identified for other stem traits in both crosses, and the heritability of major genes was 97.12% and 9.33%, respectively. The findings provide a useful guide for future efficient cultivation and improvement of stem traits in cut chrysanthemum.