Germplasm Innovation Of Garden Chrysanthemum For Flower Hedgerow

The garden chrysanthemum is a variety group of chrysanthemum(Chrysanthemum morifolium)which characteristics are round plant shape,flowers numerous and leafy,rich colors,strong resistance etc,and it is mostly used for landscape collocation and city beautification.However,due to the low height of most garden chrysanthemum varieties and poor space effect,they have certain limitations in landscape application,which restrict their landscape utilization.Therefore,on the basis of ensuring the ornamental characteristics of garden chrysanthemum,breeding new varieties of garden chrysanthemum with tall and hard branches,compact plant shape and colorful flowers can enrich the germplasm resources of chrysanthemum,and play a positive role in promoting the application of garden chrysanthemum in landscape space.In this experiment,seven garden chrysanthemum varieties with excellent characters were selected from the Chrysanthemum Germplasm Resource Preservation Center of Nanjing Agricultural University,according to the principle of parent-parent complementary advantages,artificial hybridization and parent-parent intercross tests were conducted,12 hybrid combinations were selected,totally 10,466 seeds were harvested and sowing and seedling were carried out.The seedling formation rate of the 12 combinations were between 83.82% and 98.77%,among which the survival rate of ‘Zhongshanyanhong’× ’Zhongshanyanghong’ was the highest,reaching 98.77%,and the survival rate of‘Chenghongqiuxiaoju’×’Secaihuoshan’ was the lowest,at 83.82%.The field phenotypic traits of the progenies of 12 hybrid combinations were observed and analyzed at the flowering stage,and Genetic diversity was analyzed based on phenotypic traits such as plant height,crown width,crown height ratio,number of main branches,branch strength,plant shape,inflorescence diameter,number of flowers per plant,number of lingual flowers,flower color,days from planting stage to color stage,etc.Found that in terms of quantitative traits,plant height and crown width showed a certain superparent advantage,Ultra-high parent individuals accounted for 20.1% in plant height and 43% in crown height;The main branch number also showed superparent advantage,and the average branch number of progeny was 92.8% of the middle parent value;The inflorescence diameter also showed a certain superparental advantage,and the average inflorescence diameter of hybrids was 84.8% of the median parental value;The genetic trend of lingual flower number was no significant advantage,and there was no significant difference in the proportion of ultra-high parent individuals,between parents and ultra-low parent individuals;The genetic tendency of flower number per plant was too high affinity or too low affinity,and the genetic tendency of progeny was different among different combinations.In terms of quality traits,the plant shape traits showed a certain genetic superiority,and the plant shape of grade I and II in the hybrid progenies accounted for45.6%;The intensity of branches also showed a certain superparent advantage,the intensity of primary and secondary branches accounted for 42.6% and 39.1% in all the cross progeny populations;In terms of flower color,the proportion of each flower color in offspring varies greatly,among the progenies obtained from the hybridization of yellow flowers with purple flowers,red flowers and orange-red flowers,yellow,purple,red and orange-red single plants accounted for 15.4%,14.1%,10.4% and 17%,the four colors accounted for 56.9%;The orange-red flowers were respectively hybridized with pink purple flowers,red flowers and orange flowers,and in the resulting hybrid progeny,the orange-red,yellow,red,pink single plant accounted for a large proportion,for 22.4%,16.2%,16.2% and 13.7%respectively,accounting for 68.5% of the four colors;The heredity of flower color is more maternal heredity.The field phenotypic traits of the progenies of 869 individual plants were observed and counted,and 12 main ornamental quality traits were comprehensively evaluated including plant height,crown width,crown height ratio,number of main branches,number of flowers per plant from colonization stage to coloration stage,number of flowers per plant,color of flowers,number of lingulate flowers,diameter of inflorescence,number of days of flowering stage,plant shape and branch intensity,and applicated of expert consultation method,analytic hierarchy process(AHP),and K-Means clustering method to establish evaluation system.The results showed: the weight values of plant height,lodging resistance,crown height ratio,plant shape,crown width and main branch number were the highest,which had the greatest influence on the comprehensive evaluation.The weight of lingulate flower number,flower color and inflorescence diameter in the evaluation system is low,and the influence on the comprehensive evaluation of garden chrysanthemum hybrid offspring is relatively small.The comprehensive evaluation results of single plant in F1 generation were as follows: there were 115 excellent grades,accounting for 13%;There are 240 good grades,accounting for 28%;There are 307 intermediate grades,accounting for 36%;There are 196 poor grades,accounting for 23%.