Breeding Of Green Chrysanthemum

As one of the world's four major cut flowers,chrysanthemum(Chrysanthemum morifolium)is rich in type and color,with high ornamental value and economic value.Its main color is still yellow,white,red or purple,while green is very scarce.Therefore,it is of great significance for the germplasm innovation and breeding of green cut chrysanthemum by means of hybridization.With the resources of green,white green and some other cut chrysanthemum as materials,the research studied on the isolation of green color among F1 generation and the breeding of green plants.Aiming at the problems that green female parent could not bear seed or low seed setting rate,the research also studied on the technology of overcoming the obstacles and improving the breeding efficiency.Through the study,we expected to select new green cut chrysanthemum cultivars with excellent quality of the ornamental traits,and provide a reference for the genetic separation and the characteristics of the inheritance of green chrysanthemum.The main results were as follows:1.Analysis of the reason of the hybrid barrier between cultivatied varieties of green chrysanthemum:two hybrid combinations of cut chrysanthemum 'Lvyi'(green)x 'Mary'(green)and 'Anastasia dark green'(green)x 'Jinba'(white)were arranged,respectively.Pollen viability of male parent was tested in culture medium just before pollination,and germination behavior of pollen grains on the stigma after pollination and the seed setting rate were examined.The results showed that:both of he two crosses('Lvyi' × 'Mary' and'Anastasia dark green'×'Jinba')were unable to obtain hybrid seeds.Average pollen vitality of male parent 'Mary' and 'Jinba' was low,respectively 5.4%and 7.7%,at 24h after pollination,average number of pollen grains germinating on stigma were 5 and 12.Most pollen of 'Mary' was ungerminated,a handful of pollen tube which entered stigma also failed to reach the ovary to complete fertilization effect.The germinated pollen tubes of'Jinba' was wrapped by callose and stopped growing at the surface of the stigma eventually.Therefore,the low pollen viability and low-affinity of pollen and stigma were the main factor leading to no seed setting of hybridization between cultivated varieties of chrysanthemum.2.Study on the high efficient cross breeding system for the green cultivars of chrysanthemum:with 'Lvyi' as female parent,and 'Mary' as male parent,we used different methods before pollination to obtain the hybrid seed.At the same time,we established aseptic seeding system,in order to obtain the F1 hybrid lines.The results showed that:repeat and mixed pollination could improve the hybrid seed setting rate obviously,100mg·L-1 BA processing and decreasing single inflorescence leave flowers had some effect on improving the hybrid seed production.while,50mg·L-1 NAA treatment processing and 100mg·L-1 NAA treatment processing seems could not affect hybrid seed production.75%alcohol disinfection for 15s,and then 5%sodium hypochlorite treatment for 50min was the optimal disinfection asepsis sowing system,The seed had no pollution and the germination rate reached 63.3%.When 15gmL-1 sucrose was added to medium,the germination percentage of the seeds was the highest.There were no significant differences in the germination rates for all the mediums like MS,1/2MS and 1/4MS.Using the aseptic seeding system,we successfully got 16 F1 hybrid lines of 'Lvyi'x'Mary'.3.Breeding of new cultivars of green cut chrysanthemum and analysis of F1 representative type:The green,white green and light green cut chrysanthemum cultivars were selected as parents for hybridization.By using colorimeter,the quantitative classification of color phenotype about the F1 hybrids of green-flowered chrysanthemum cultivars was made.Green color group could be divided into four degrees:green,light green,pale green and white green,through the analysis of the clustering of L*,a*,b*color value.It provided reference for the definition and classification of chrysanthemum green varieties.Of the total population of hybrids,the green plants accounted for 15.8%.The more green the parent petals were,the more likely that the darker green plants appeared in the hybrids.The heredity of white color was higher than that of green color,white green plants accounted for 42.7%,while,there were also 3.7%plants showed pink which color the parents did not have.At the same time,considering other traits,we selected out of 93 preferred plants and 24 new cultivars.