Identification Of Watermelon Cultivars Based On SSR Markers

Watermelon is a fruit and vegetable crop which has high demand of market and wide area of cultivation.For the development of watermelon seed industry,it is particularly important to construct varieties fingerprints and identification of seed purity.In this study,core SSR markers were used to construct varieties fingerprints of 11 watermelon cultivars that planted mainly in Hunan region,subsequently,the genetic diversity of above watermelon materials was analyzed.The 23 pairs of core primers were screened,and 2 pairs of primers with specificity can identify accurately and reliably purity of ‘Xue Long No.3'.The main results are as follows:1.The extraction site of watermelon DNA was studied.The DNA was extracted from the real leaves,cotyledons,buds and seeds of watermelon using Plant DNA extraction kit.The results showed that the concentrations and qualities of extracted DNA were sorted as follow:leaves>cotyledons>buds>seeds.The SSR-PCR amplification analysis was performed using DNA templates which extracted from various materials,the above 4 sets of DNA templates were able to amplify clear and visible bands which had slightly different effects,but it did not affect the read of stripes.2.The SSR-PCR reaction system of watermelon was optimized and established.Through screening 23 pairs of core SSR primers,finally,8 pairs of polymorphism primers were screened to construct fingerprints of 11 watermelon varieties which come from Hunan region including ‘Xin No.1',‘Xin No.2',‘Xue long No.1',‘Xue long No.3',‘Hong xiao-yu',‘Huang xiao-yu',‘Zao jia',‘Zao mi',‘Xi nong No.9',‘Cui jin' and ‘Hei mei-niang'.What's more,the results of cluster analysis showed that above 11 experimental watermelon varieties can be divided into four categories at the genetic distance of 0.66.3.Using 'Xue long No.3' with high resistance to Fusarium wilt disease and its parents as experimental materials,2 pairs of primers(BVWS02048 and BVWS00106)which had different amplification bands between ‘Xue long No.3' hybrid and its parents were screened,above 2 pairs of specific primers were used to identify the seed purity of ‘Xue long No.3',and verified its accuracy by morphological markers.Results showed that 99 % of the SSR molecular markers identification results matched the field planting results.