EVALUATION METHOD OF FEMALE FLOWER BEARING ABILITY IN WATERMELON USING SILVER THIOSULFATE (STS)

Watermelon cultivars with high female flower bearing ability bore the first female flower at a lower node than those with low female flower bearing ability, when sprayed with silver thiosulfate, STS, at the cot yledonary stage or at the first true leaf stage. Also, watermelon seed lings sprayed with STS produced more female flowers than did the unspr ayed control plants. Correlation between the number of female flowers in the F-2 population sprayed with 6 mM STS and the node order of the first female flowers is high. In a progeny selected from the F-2 popul ation, the female flower was borne at a lower node order of the main s tem, whereas in another, the first female flower differentiated at a h igher node order; the former had more female flowers than had the latt er. These results indicate that we are efficiently able to select the plants with high female flower bearing ability by STS treatment before transplanting.