Breeding Research On Plant Type Improvement Of Pot Spray Chrysanthemum

Chrysanthemum(Chrysanthemum×morifolium Ramat.) is one of the most important potted flowers in the world, occuping an important share in the market. At present, the consumption of potted plants in China increased year by year, and pot Chrysanthemum become the indispensable autumn flowers for the festival. In the course of cultivation we found that most germplasm resources have a bad plant shape and need higher requirements for the cultivation techniques. It’s difficult to maintain uniform and not suitable for large-scale cultivation. The purpose of this research is to improve the existing resources of plant type, in order to produce natural branched, compact plant type, natural flowering during National Day pot chrysanthemum cultivars. This research crossed the existing germplasm resources with the introducted excellent germplasm, analysised branching characteristics of hybrids. Finally selected excellent strains which had good plant type using the Analytica Hierarchy Process and The Grey Correlation Method. This study has achieved the following results.1. Evaluated the430pot Chrysanthemum strains. By a comprehensive analysis of pot Chrysanthemum characteristics and its application characteristics,15evaluation index which is closely related to plant traits、flower characters and reproduction and resistance were selected. Established a comprehensive evaluation system, using the analytic hierarchy process (AHP) method to determine the weight of each index value, the grey correlation analysis method to rank all strains. Finally a total of43strains r≥.9701were selected.These strains have good plant shape, dense flowers, pure and bright color or rare flower types. They have potential to become new cultivars through further evaluation and selection and also can be used as good breeding materials.2. Using the introduced multifora and the good strains183and388as parent, and crossed them as female respectively.All hybridized combinations can produce seeds. We harvested1655seeds and they finally grew up to be791plants. The seed setting setting rate is high under natural hybridization.lt may because that both disc flowers and ray flowers accepted pollen under the condition of natural hybridization.3. The research of branching patterns of hybrids revealed that there are4different branch types in hybrid plants. Type A, semi-cushion, the plant has several main branches; type B, upright, long stem and relatively less branches; type C, tower shape, the plant shape looks just like a tower, inflorescence distribute from top to bottom; type D, cushion, forming a sphere or hemisphere plant shape. The main related traits such as plant height, terminal height, stem leaf numbers and primary branches did reveal significant differences. The branching time and way can determine the formation of the final plant shape. Over all, type A、C and D have stronger branching ability and the potential to form a round compact plant shape. Type B is difficult to outbreak a large number of lateral buds naturally, so it’s not easy to form a good plant shape.4. Through analysis of791hybrid strains, we discovered that the A、C and D type, a total of264plants, accounting for33%of the total. Statistical analysis of branching patterns of all hybrids showed that in the124hybrids which German multiflora chrysanthemum were used as female parent, the strong branching type (i.e., A, C and D) plant occupied82plants, accounting for66.1%. While type B only accounted for33.9%. On the contrary, in the667hybrids Dutch chrysanthemum were used as female parent, the proportion of type A, C and D is only27.3%, while type B accounted for72.7%. It can be seen that branching patterns of hybrids are affected by the female parent.5. Using the grey con-elation analysis method combined with analytic hierarchy process (AHP), evaluated the264hybrids with strong branch ability.Established an evaluation system with the main target of good plant shape and early blooming. Finally58plants were selected. These plants have traits conform the breeding goal, such as branch many, compact plant shape, early flowering and dense flowers. They are suitable for using as further breeding materials.