Abstract:

Vegetable traits are a major target of genetic improvement on chrysanthemum (Dendranthema morifolium) cultivars. Heterosis and genetic analysis of vegetative traits such as plant height, plant crown, and leaf type will provide a very important guidance for chrysanthemum breeding program. In this study, genetic analysis was carried out for eight vegetative traits of chrysanthemum based on phenotypic data collected in 2008-2009 from 142 plants of a F₁ population derived from the crossing between creeping ground-cover chrysanthemum cultivar 'Yuhualuoying’ (female parent) and erect potted chrysanthemum 'Aoyunhanxiao’ (male parent) by using single generation segregation analysis method of major gene plus polygene mixed genetic model. The result indicated that the 8 vegetative traits were widely segregated in F₁ population with coefficient of variation (CV) ranging from 11.54% to 41.89%. The phenomena of heterosis and extra-parent segregation existed generally in F₁ pogeny. Compared with mid-parent value (MPV), the heterosis value of mid-parent (H_m) of the 8 investigated vegetative traits, except leaf width, showed a significant difference (P=0.01). The mixed genetic analysis suggested that plant height, leaf length and width were fitted to A-0 model and no major gene was detected; plant crown was fitted to A-2 model with an additive effect, and the heritability of major gene was 78.61%; the ratio of plant height to crown, the raito of leaf length to width, and length of flower neck accorded with B-2 model with an additive-dominant effect and their major gene heritability was 40.33%, 45.19% and 99.56%, respectively. The inter-node length fitted A- 4 model with a negative complete dominant effect with major gene heritability of 51.46%. Detection of these major genes controlling the vegetative traits would provide a theoretical basis for the further study of QTL analysis and molecular marker assisted breeding program for elite vegetative traits in chrysanthemum.

Key words: chrysanthemum (Dendranthema morifolium), vegetative traits, heterosis, major gene plus polygene, genetic analysis