Study On SSR Appraisal Of Seed Purity Test Of F1 Hybrid Of Watermelon

Nowdays, the new watermelon hybrid generation has been widely used in production. While doing seed-fabrication process in artificial system, however, female inbred lines or other leaves, such as fake hybrid seeds, are unexpectedly mixed together due to lax isolation, imperfect or incomplete or out-of-time male germs picking-up and cause agricultural production losses. Therefore, the hybrids have to pass various purity tests before being packed or saled.The study identified the hybrid seed purity of F1 watermelon (XY-1), using SSR molecular markers and got the following conclusions:1) The method of CTAB-DNA isolation was used to extract genomic DNA from the fully expand cotyledons of watermelon and melon. DNA samples with high purity,high yield and long fragments could be gained by this method, and were good enough for the use of SSR analysis.2) The optimum PCR-systems factors and their quantities were fixed in this study, including dNTPs,primers,Mg2+,TaqDNA and so on.The SSR-PCR application systems with good repeatability and fine definition were also established by choosing the best timing for DNA denaturation, anneal and elongation; the temperature for DNA anneal;and the best replication cycleinde.3) After several attempts, the study found that all those factors, such as the temperature, the last time for silver nitrate staining and for resinning and development after dyeing, the condition of the treated glass plates, the quantity of PCR product, the rank of the voltage, could cause great impact on the results. After improvement of all of the above parameters, the polyacrylamide electrophoresis bands are complete, clear, accurate and easy for recording instead of being bend, with deep background, or interferenced with each other, or causing error and an inaccurate result for SSR analysis.4) 20 pairs of primers were taken as SSR markers for F1 of watermelon hybrid strains (XY-1), and one pair suitable for the identification of seed purity was picked out of the primers. The pair of primer was used for the purity identification of 100 grains of F1 seeds and the result showed out 97 percent purity.