Selection of Tetraploid of a Yellow Flesh Mini-Watermelon Using Oryzalin

Abstract

In order to provide parent material for small-type triploid watermelon, this study has been carried out to induce high-quality tetraploid watermelon. We induced tetraploid plants of watermelon by treating the growing points of seedlings of a small-type yellow flesh diploid watermelon with 40, 60 and 100ml/L Oryzalin for different treating time. The autotetraploid plants were selected and identified basing on morphology, determination of the number of chloroplasts in stomatal guard cells, flow cytometry analysis and hybridization. Then we observed a stable autotetraploid material. The results showed that tetraploid watermelons could be obtained under different treatments. The most effective way was extirpating the interior leaves at the 8th day after sowing, then treating the growing points of seedlings with 100mg/L Oryzalin for 6d. The treated seedlings could all survive and the induction frequency of the tetraploid watermelon was 33.33%.

A comparative study of morphological characteristics in diploid and tetraploid (auto and allotetraploids) Citrullus genotypes

“…Consistent with our results, an increase in the number of chloroplasts per guard cell has been reported in tetraploid watermelons (Şimşek et al, 2013;Zhang et al, 2014). A similar increase in the chloroplast number in guard cells from 7.6-8.1 chloroplast/stoma to 17.7-18.8 chloroplast/stoma was also reported by Oh et al (2015a) in watermelon.…”

“…Flow cytometry allows polyploid plants to be analysed at an early stage, saving space and time (Väinölä, 2000). Zhang et al (2014Zhang et al ( , 2019 reported that the fluorescence intensity of the main peak of the diploid E46 watermelon genotype is 203.46 pg/2C, and the fluorescence intensity of the main peak of the tetraploid E46 watermelon genotype is about 371.07 pg/2C, which means that the DNA content of cells of tetraploid plants is about twice that of diploid plants. This result is in consensus with our fluorescence intensity results.…”

Efficient Characterization of Tetraploid Watermelon

“…The material is homologous diploid (E46, 2n) and tetraploid (yE46, 4n) watermelon. Tetraploid watermelon is induced by homologous diploid watermelon by colchicine (Sigma Chemical Company, MO, USA) [36], the diploid drying seeds were soaked in warm water at 50 °C for 30 min, soaked in 0.5% KMnO 4 (Sinopharm Chemical Reagent Company, Shanghai, China) for 30 min, then washed with water and soaked in water for 6 h. Germination at 28 °C for 24–36 h. Seeded in a 72-well format tray (Grass soil:Perlite = 3:1), 25 °C. When the cotyledons of the seedlings were flattened, the new leaves of the growing point were removed, and the growth point was treated with a 0.3% colchicine, which was treated twice every day at 8:00 and 18:00 for 7 days.…”