Obtaining tetraploid lines that is aimed for developing seedless watermelon (Citrullus lanatus (Thunb.) Matsum and Nakai) varieties

Production of seedless watermelon, which constitutes approximately 5 % of watermelon yields in Turkey, is envisaged to increase considerably in the upcoming years. 100 % of seedless watermelon seeds are imported to Turkey. There is no seedless watermelon variety developed in Turkey. This study has been carried out to develop tetraploid lines which forms the base of seedless watermelons. In the study, different doses of colchicine (0.0 %, 0.2 %, 0.3 %, 0.4 % and 0.5 %) and oryzalin chemicals (0 µM, 20 µM, 35 µM and 50 µM) have been studied on four watermelon genotypes (AB-54, AB-267, Crimson Sweet and Sugar Baby) under in vivo conditions during the seedling period.At the end of the study, it has been determined that tetraploid watermelon lines could be developed by applying both colchicine and oryzalin chemicals. In vivo chemical application suggests that success rate of generating tetraploid plant is ranging from 0.69 % to 2.08 %. The study also indicates that in comparison to oryzalin, colchicine chemical increases the success rate of creating tetraploid plants. There is also an interaction between genotype, chemical and the dose and a pre-study on these increases the achievement rate of producing tetraploid plants. İt has been revealed that there are morphological and cytological differences between diploid and tetraploid watermelon plants. The distinction of diploid and tetraploid plants could be drawn by means of morphological and cytological evaluations.At the end or the studies 12 tetraploid watermelon lines have been developed and 3, 3, 5 and 1 tetraploid lines at a time have been obtained from AB-54 and AB-267, Crimson Sweet and Sugar Baby genotypes, respectively.