关键词: 切花小菊, 分枝性状, 配合力, 遗传力

Abstract:

Branching is a major component trait of plant architecture and ornamental quality of spray cut chrysanthemum，and understanding of combining ability of major branching traits offers some references for parental selection in crossbreeding. In the present study，seven branching traits，i.e. total lateral bud number，primary branch number，primary branch length，primary branch angle，total secondary branch number，secondary branch length，and secondary branch angle of the twelve F1 progenies derived from a 4 × 3 diallel design（NCII）were investigated to dissect the combining ability effects and other population genetic parameters. Combining ability analysis showed that total lateral bud number was controlled by non-additive genes；and the primary branch number，total secondary branch number，primary branch length and secondary branch length by both additive and non-additive genes；and the primary branch angle and secondary branch angle by additive genes. A great difference was observed for general combining ability（GCA）effects of parental cultivars and for different branching traits and the hybrid combinations with contrasting special combining ability（SCA）and total combining ability（TCA）effects. Especially，‘Monalisa’exhibiting positive GCA for most branching traits except the primary branch number was capable of breeding cultivar with large plant architecture and loose branching type；whereas ‘Qx-021’（except for secondary branch number）and‘Qx-096’showing negative GCA for all investigated branch traits would be elite parents in crossbreeding targeting for cultivars of compact branching type. The crosses‘Qx-021’בQx-098’and‘Qx-081’בQx-098’showed high TCA for primary and secondary branch number but negative TCA for the other five branching traits，so it was likely to develop new cultivars of compact type from these crosses. In addition，a high level of broad-sense heritability ranging in 73.81%–94.41% was calculated for the seven branching traits，and a moderate high level of narrow-sense heritability larger than 60% was estimated for all the investigated branching traits except total lateral bud number（1.88%）. Findings of the current study reveal the combining abilities and genetic inheritance mode for the investigated branching traits and will be of vital importance for future efficient crossbreeding targeting plant architecture of spray cut chrysanthemum.

Key words: spray cut chrysanthemum, branching trait, combining ability, heritability