Tissue Culture And Somaclonal Variation Of3Cultivars Of Watermelon

Plant tissue culture is widely used in agricultural production, it is also one of the most important technologies that improve crop qualities.3cultivars of watermelon(Citrullus vulgaris),"S320","S56-1-1" and "SS7-1", was studied in this research in order to find the suitable regeneration system. Morphology and molecular tools were used to detected the somaclonal variations in regenerated plants. The results showed:1. The genetype, origin and physiological status of explants affected the regeneration rate mostly.3-day cotyledons for S320and25-day immature cotyledons for S56-1-1could reach the highest differentiation rate on MS+0.68mg/L6-BA+0.53mg/L IAA;3-day cotyledons for SS7-1could reach the highest differentiation rate on MS+1.00mg/L6-BA+10%coconut water. MS+0.23mg/L BA was the suitable shoot elongation medium and MS+1.11mg/L IBA was the premium rooting medium for all cultivars.2. Although the regenerations were diversity among cultivars, the younger explants owned stronger regeneration ability, no matter cotyledon or immature cotyledon. Also, light green cotyledons could be induced more buds than other states.6-BA was the most suitable regulator for callus and buds induction, and shoot elongation. Media containing lower concentration of6-BA showed higher regeneration rate for all cultivars.3. Part of regenerated plants showed variations, including chromosome copies, leaf shapes, fruits forms, flower forms and stoma forms. S320regenerated plants appeared morphologically abnormal on leaves and staminate flowers, and tetraploid plant was detected in S56-1-1. No variations were observed in SS7-1.4. Regenerated plantlets were detected by60RAPD random primers, the results showed that all cultivars existed variation. S320, S56-1-1and SS7-1showed polymorphism under1,4and14primers respectively.We builted the regeneration system for the3cultivars, and proved that somaclonal variations happened during tissue culture. Relevant RAPD primers were found to analysis the regenerated plants. This may provide assistance for the breeding careers.