Study on Mutugenesis of Tetraploid Watermelon by Using Oryzalin

In order to provide breeding high-quality parent material for seedless watermelon,taking small-type diploid watermelon line A8as material,tetraploid plants of watermelon were induced by treating the growing points of seedlings with different concentration Oryzalin and lasting different treating time.Autotetraploid plants were selected and identified basing on morphology,flow cytometry,hybridization and characterization.Then observed a stable tetraploid material after three quarters' continuous cultivation,observation and filtering.The results showed that different treatments could obtain tetraploid watermelons by processing with Oryzalin.The most effective way was extirpating interiorleaf at the 8th day after sowing,then treating the growing points of seedlings with 100mg/L Oryzalin for 6d.The treatmented seedlings could all survival and the induction frequency of tetraploid watermelon was 30.59%.