Polyloidy Breeding Of Chrysanthemum Lavandulifolium And Breeding Of Ground-cover Chrysanthemum (Chrysanthemum Morifolium)

Ground-cover chrysanthemum (Chrysanthemum morifolium) has been widely used in garden for its strong stress resistance, richness of flowers and colors, lowness of plant height. But absence or less of fragrance and late florescence which is mainly in autumn are their disadvantages. So breeding new types of ground-cover chrysanthemum with earlier florescence and aroma is objective of study. In this study, germplasm resources was collected from Beijing, Inner Mongolia, Yunnan, Sichuan and Xinjiang province, while collecting the fine ground-cover chrysanthemum cultivars. Selected with fragrant early flowering of wild chrysanthemum species, as well as excellent ground-cover chrysanthemum varieties as parents carried out a cross-breeding. In order to overcome incompatibility in breeding, tetraploid Chrysanthemum lavandulifolium was induced.Main results are as follow:1)13 kinds of species or varieties and 60 varieties of ground-cover chrysanthemum were collected, from Beijing, Inner Mongolia, Yunnan, Sichuan and Xinjiang province. germplasm resources were evaluated, selected 4 kinds of fragrant resources:Chrysanthemum lavandulifolium, C. indicum var. aromaticum, Opisthopappus taihangensis, O. longilobus; 7 kinds of early flowering of germplasm resources:Chrysanthemum morifolium'Qiyuetaohua', C.'Mibaizao', C.'Fanbailu', C 'Dandandehuang', C.'Hongchenzao', C.'Qipao', C.'Lianghuangzao',2) The effects of 7 kinds of colchicines concentration and 4 kinds of treatment time duration on the seeds of C. lavandulifolium were studied and the results showed that method for polyploidy induction was soaking seeds in 500mg/L colchicum for about 12h and the induction ratio was about 23% which shows significant difference. Only one tetraploidy plant was obtained with the chromosome number of 2n=4x=36. The tetraploidy plant exhibited some morphological and cytological variations, including the larger guard cells size of stomata, more chloroplasts in stomata guard cell, smaller leaves, bigger flower diameter, less number of ray flower and more number of tubular flower.3) Parents with aroma or earlier florescence were chosen to form 16 cross combinations. 8637seedlings were achieved, of which more than 100 new strains of ground-cover chrysanthemum.2 aroma strains and 1 earlier strain has been obtained.11 strains has applied for protection of new varieties, namely, C. morifolium'Zhaoyanghong', C. morifolium'Jiaoyanghong', C. morifolium 'Liuguangyicai', C. morifolium'Nongfenzhaoxia', etc.This study provides new germplasm resources for fragrant flower breeding, get a new ground-cover chrysanthemum varieties which has very broad application prospects...