| Cucurbit vegetable production contributes significantly to vegetable supply in China. As the development of society and production, the requirement of new cultivar was enhancing and complex, the relying solely on cultivated varieties was obviously not enough, especially in breeding of disease resistance and adversity resistance, it was urgent need to introduce wild germplasm resources. In addition, the development of distant hybridization, somatic hybridization and gene engineering in modern breeding, the scope of the interspecific gene-exchange was further expanded, which maked the utilization of wild germplasm resources more prominent. Wild plants in the harsh natural conditions to the long-time choice, disease resistance and adversity resistance of which was better than cultured varieties, or it had some valuable characteristics which cultured crops had lacked. Wild germplasm resources of cucurbit are important genetic resources for cucurbit breeding. It has important significance to protect and innovate cucurbit germplasm resources and cucurbit breeding, which for promoting native germplasm resources collection, morphological and biological characters, disease-resistant characteristics, cytology characteristics and genetic relationships were discussed in this study. The germplasm resource of cucurbit were identified and assessed systematically in morphology, biology, disease resistant, cytology and molecular marker. The results showed as follows:The morphological and biology characteristics for four materials of wild cucurbit were investigated. The result indicated that the No.9, No.10, No.11and No.12wild cucurbit were wild Ivy gourd, wild melon (wild bisexual cucumis), wild snakegourd, wild watermelon (wild red-seed using watermelon), respectively. The experimental four wild cucurbit were different in morphology. Some of the experimental materials can’t be used directly because of their poor-fruit quality, but they showed the exuberant vitality, and three of them showed higher resistance. Meanwhile, their resistance to diseases can be used in the cucurbit breeding.Fusarium wilt resistance and powdery mildew resistance identification of four materials of wild cucurbit. The result indicated that the disease-incident and disease-index of the No.9, No.11, No.12wild cucurbit were lower than contrasts, these three materials of wild cucurbit were high resistant accessions of the two diseases, which could be used in cucurbit disease resistant breeding of fusarium wilt and powdery mildew. The No.10wild cucurbit was susceptible accession. The analysis of the chromosome number and karyotype for four materials of wild cucurbit were dyed with DAPI to make the plate for observation. The result indicated that the chromosome numbers of the No.9, No.10, No.11and No.12wild cucurbit were2n=24,2n=24,2n=22,2n=22, respectively. The karyotype formula of No.9was2n=2x=24=24m, and the karyotype multiple was "1A" type. The karyotype formula of No.10was2n=2x=24=18m+4sm+2sm (SAT), the10th chromosome had satellites, and the karyotype multiple was "2A" type. The karyotype formula of No.11was2n=2x=22=18m+4sm, and the karyotype multiple was "2A" type. The karyotype formula of No.12was2n=2x=22=22m, and the karyotype multiple was "1A" type. This study was the first report for karyotype analysis of snakegourd, which had provided cytology basis for the study on snakegourd genera plants.The genetic relationships were analyzed by SSR markers for four materials of wild cucurbit. The result indicated that15pairs of SSR primer selected from130pairs of primer generated total of271bands,124(45.8%) of which were polymorphic through the analysis of the investigated accessions. The genetic similarity coefficient among four materials of wild cucurbit and four kinds of cultivated cucurbit accessions including melon, cucumber, watermelon and pumpkin ranged from0.62to0.99. The Winboot software showed that the No.9, No.10, No.11and No.12wild cucurbit had narrow genetic relationship with cucumber, melon, pumpkin and watermelon, respectively. |
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