Primary Technology Of Ornamental And Adaptable Clematis Genus Plants Crossbreeding In Shanghai Area

Based on the comprehensive evaluation of stress resistance and ornamental value for 20 cultivars of Clematis,6 cultivars suitable for planting in Shanghai are selected as crossing parents.The germination rate and morphological characteristics of pollen in 6 cultivars was measured and observed to determine collecting time of pollen.The effects of drying time and temperature on the pollen germination rate were studied,meanwhile,the morphological characteristics of F1 generation hybrid seeds and breeding system of Clematis were also observed.The results were shown as follows:(1)According to the ornamental value and adaptability characteristics of 20 Clematis cultivars,a comprehensive assessment model by Allalytic Hierarchy Process(AHP)was developed,and the weight coefficient and synthesis scores were calculated.The result showed that sepal characteristics was the most important index(the weight coefficient was 0.30),the second was the resistant to wilt disease(the weight coefficient was 0.24).Selected five early large-flowered cultivars and one lately large-flowered cultivar of Clematis as the materials for pollen preservation and crossbreeding based on synthesis scores and feasibility of crossbreeding.(2)Took C.‘Henryi' and C.‘Hagley Hybrid' for examples,the total value of OCI was 3.Stigma had receptivity since 2 days before flowering to the 4 days after flowering.The seed setting rate showed that its breeding system can be determined as a mixed-mating system dominated by outcrossing mechanisms.Which was partial self-incompatibility and cross-compatibility.(3)Identified of wilt pathogenic bacteria.Observed diseased plants.After cultured diseased tissues,separated and purificated of bacterial strain by tissue isolation,observed morphological characteristics and defined it was Alternaria alternate.After PCR amplification of ITS sequence and similarity retrieval on NCBI,confirmed Alternaria alternate is the pathogenic bacterium of wilt,belonging to the genus of Alternaria.(4)Pollen morphological characteristics were observed by using SEM,the results showed that pollen grains were separated from each other,isopolar,pantoporate,and spinous on surface.There were no significant difference among cultivars.(5)Pollen germination rate showed the trend of first increasing and then decreasing but C.‘Fujinami' showed increasing,in the third day it was the highest(30.1%),all 6 cultivars' pollen diameter were increasing in the first 3 day after flowering.(6)Compared with fresh pollen,C.‘The First Lady',C.‘Asao' and C.‘Fujinami' were suitable for preserving at 4? after drying 12 h,24 h and 48 h respectively,the relative survival rate was 87.86%,71.27% and67.24%.Pollen of C.‘Madame le Coultre',C.‘Henryi' and C.‘Hagley Hybrid' preserved in LN after drying 24 h retained high relative survival rate(59.65%,78.74% and 69.33%,respectively).Pollen relative survival rate was only 0 to 56.85% after preserving at-20?.(7)After pollinated with pollen preserved in 4? and LN,the mean fruit setting rate was 83.33%.(8)Morphological characteristics of hybrid seeds were observed and result showed that were tawny to black,styles persistent and there were tomentum on surface,the thousand seed weight was 15.40 g,these characteristics could help them to dispersal with wind or animals.Water content is 7.59% and suitable for preserving.The vitality was 72.67% by using TTC method and guaranteed specie contimuation of Clematis.