Study a Collection of Watermelons for a Mutation Affecting Male Sterility

Systems favoring cross-pollination such as male sterility and female flowering type are of great importance in the development of new hybrid cultivars and their seed production. The advantages of male sterility are expressed in production of cheaper and competitive seeds. The presence of this characteristic in watermelon is not common, and in some cases, it is accompanied by negative manifestations. The aim of this study was to search for a genetic source of male sterility in a col-lection of watermelon. A collection of 150 watermelon genotypes was tested at the Maritsa Vege-table Crops Research Institute, Bulgaria over the past nine years. The results show that two mutations were found. The first mutation was found in a plant of the Asar variety, which formed completely degenerated structures in place of male and female flowers and could not reproduce. The other, a mutation affecting male flowers, female flowers and leaf shape was observed in one genotype. Male flowers produce a small amount of pollen. Female flowers are formed but they are sterile and abort at an early stage. The genotype can be propagated by pollination of the normal plants, which in the next generation derivate into mutant 25% and normal 75%. The gene source is phenotyped according to the main characteristics of the fruits and the vegetation period. The mutation found cannot be directly used in breeding program, but it is of interest for studying this important trait. The success of detecting sterility flowers depends on the volume of watermelon plants, which for the conditions of the experiment amounted to a minimum of 4492 plants at a probability of P3 – 0.95.