Comparison Of ISSR And SSR Markers For Seed Genuineness And Purity Identification In Soybean, Rape And Watermelon

Identification of seed genuineness and variety purity is important for seed quality control. The DNA markers are powerful tool for seed genuineness and variety purity identification testing due to its high efficiency, low time-consuming and high veracity. The comparison of ISSR and SSR markers for seed genuineness and variety purity identification in soybean, rape and watermelon, whose cultivars were mainly planted in Zhejiang Province, was conductued in the present research. The main results achieved were as follows.Uniform design was applied to optimize PCR reaction system in soybean, rape and watermelon, and the optimal reaction systems for ISSR and SSR markers were established, respectively. The results showed that variations of Mg2+, dNTPs, primer and Taq polymerase concentrations changed the fingerprinting patterns significantly. The smearing or dispersion of the amplified bands may be due to the high concentration of Mg2+ or Taq polymerase.Total 48 cultivars of soybean, rape and watermelon were identified with ISSR and SSR markers, respectively. The 4 ISSR primers or 5 pairs of SSR primers succesessfully identified all the 15 soybean cultivars,2 ISSR primers or 6 pairs of SSR primers succesessfully identified all the 15 rape cultivars,2 ISSR primers or 5 pairs of SSR primers succesessfully identified 18 watermelon cultivars by combining analyses.The maker utility of ISSR and SSR markers for seed genuineness identification in soybean, rape and watermelon was compared. SSR marker showed a higher level of percentage of ploymorphic band, average band informativeness and marker index, however with a lower level of average band number and efective multiplex ratio comparing to ISSR marker. The results indicated that SSR marker was more suitable for seed genuineness identification among a large number of cultivars, with less but more specific locis detected and higher marker efficiency.The regression relationships respectively in soybean and rape between the variety purity results tested by SSR marker and the results by field test were also built. The equations obtained can be used to predict the variety purity in the field.