Preliminary Study On Crossbreeding In Chrysanthemum Morifolium

Chrysanthemi flos(Chrysanthemum morifolium Ramat.) is the capitulum in the genus Chrysanthemum L.(Compositae), which is the traditional crude drug for medicine and food. Development of herbal tea in resent years brings strong social demands of high yield and varieties of Chrysanthemum. Chrysanthemum has some history of cultivation in the saline areas, but long-term propagation caused variety of degradation, plant diseases and insect pests. It is necessary to carry on breeding work for variety innovation, increase germplasm and make improvment for poor flower and bitter taste to meet maket demand maintaining the medicinal value. The main results are listed as follows:1With fresh pollen as the experimental material, culturing in vitro to determine the pollen viability. The optimum culture solution was1/2ME3+PEG40008%+sucrose6%, and the suitable culture condition was at25℃. The result showed that the major influencing factors to pollen germination were culture medium composition, culture condition, weather, cultured types and opening degree. With test for stigma receptivity using benzidine-H2O2, stigma was hardly granted. Low pollen vitality and stigma receptivity may be main factor for low seeding rate.2Interspecific hybridization were made between Chrysanthemum morifolium ’Hongxinju’(♀),’Xinbaiju’(♀) and Chrysanthemum morifolium’Huangju’((?)), Chrysanthemum indicum((?)), Chrysanthemum nankingense((?)). Interspecific hybridization of Chrysanthemum morifolium Ramat. were made by bud pollination. Study on interspeeies hybridization and observation of pollen tube germination in Chrysanthemum. morifolium. Observe the microspore germination and pollen tube growth of interspecies hybridization with fluorescence microscopy. Results showed bud pollination got seeds, and the fruiting rate of self-pollination in ’Xinbaiju’ and ’Hongxinju’ are separately0and0.3%.’Xinbaiju’×’Huangju’ got higher fruiting rate.’Hongxinju’×Dendranthema indicum,’Hongxinju’×’Huangju’ and ’Hongxinju’×Dendranthema indicum were proved crossability. The microspore hardly germinate on condition of cross-pollination in ’Hongxinju’×Dendranthema mankingens. and’Xinbaiju’×Dendranthema mankingens. Seed is almost ungainable from the crossing combinations with Dendranthema mankingens((?)). The pollen tube grow but incapable to arrive the ovary in ’Xinbaiju’×Dendranthema indicum. The compatibility is low in cross-pollination and lower in self-pollination of Chrysanthemum morifolium. The microspore hardly germinate and the pollen tube is incapable to arrive the ovary.3Morphological, cytological and RAPD analysis were used for the identification of interspecific hybrids. The hybrids showed interspecific morphological traits of their parents or unique morphological traits their parents did not possess. RAPD results indicated that the hybrids produced specific bands of male parent or new bands absent in both parents. Chromosome number of F1hybrids were the average of their parents. Bud pollination improved seed set rate of interspecific hybridization. Genes of Chrysanthemum morifolium ’Hongxinju’ and ’Xinbaiju’ were highly heterozygous. Hybrids were aneuploid chromosomes and showed significant segregation of character.4Evaluation on quality of F1hybrids. Conponent and content of volatile oil affects taste of Chrysanthemum and total flavone content related to resistant of plant. Analysis of chlorogenic acid, luteolin glycosides, iso-chlorogenic acid A, total flavone and volatile oil content among parents and F1hybrids to make Comprehensive evaluation of Chrysanthemum.The result showed Chrysanthemum morifolium ’Xinbaiju’ held highest contention of chlorogenic acid, luteolin glycosides, and lowest of iso-chlorogenic acid A. Hybrids with Ch. morifolium’Xinbaiju’(♀) showed lower contantion of chlorogenic acid and luteolin glycosides, and average lever of iso-chlorogenic acid A compared with their parents. Hybrids with Ch. morifolium ’Hongxinju’(♀) showed higher or average lever than parents. All hybrids got higher total flavone content than parents. Dendranthema indicum held higher volatile oil content than Ch. morifolium ’Hongxinju’ and ’Xinbaiju’, and hybrids held the average of their parents.5Evaluation of appearance of F1hybrids. Appearance such as flowers, petal layers, color, single flower weight and internal quality traits is important criterion for evaluation of Chrysanthemum, on behalf of all the parents and F1appearance of traits in different growth stages were analyzed and compared to the appearance of characters on the medicinal Chrysanthemum. Hybrid F1plant showed advantageous than parents or between parents in height, flower type, number of ray florets, etc. Flower color showed partial maternal inheritance. 6Research of salt stress tolerance of F1seedlings.Comparison of salt stress tolerance on Hongxinju, Huangju and F1seedlings from orthogonal and reciprocal cross under different salt treatments. Grope for transmissibility of salt tolerance between parents and F1seedlings, and relativity between flavone, chlorogenic acid contents and salt tolerance. Put material in5different concentrations of Hoagland nutrient solution (0,40,80,120,160mmol·L-1) containing NaCl, keeping grads while raising the consistency of NaCl day by day. Mensurate and analyse the injured leaf area per plant, proline, betaine, MDA, flavones and chlorogenic acid contents after treatment. F1seedlings held higher or average lever of salt tolerance compared with parents, and salt tolerance of F1is more influenced by female parent, relativity showed between flavonoids, chlorogenic acid contents and salt tolorance.