Rootstock potential of auto and Allotetraploid Citron [Citrullus lanatus var. citroides (L. H. Bailey) Mansf.] for Watermelon [Citrullus lanatus var lanatus (Thunb.) Matsum. & Nakai] under hydroponic conditions: plant growth and some physiological characteristics

The emergence of some physiological and fruit quality problems due to the common squash rootstocks used in watermelon has led researchers to search for alternative rootstocks sources. Exploitation of novel Citrullus germplasm such as citronmelon (Citrullus lanatus var. citroides) is an alternative to avoid these problems. In this study, rootstocks potential of auto and allotetraploid citrullus genotypes for watermelon were investigated as regard to plant growth and some physiological parameters under hyroponic conditions. Plant length was significantly affected by rootstock genotype and the longest plant stem was measured in watermelon plants grafted on N7-4T tetraploid rootstock (62.67 cm) while the shortest stem was measured in grafted plants onto autotetraploid Calhounn Gray with 14.33 cm. Among the graft combinations, N7-4T/CT (93.33 g) and CN7-5T/CT 95.00 g) graft combination produced the highest shoot fresh and dry weight. As in shoot fresh weight, the exploitationted on to tetraploid rootstock produced higher root fresh and dry weight than the plants grafted on diploid rootstocks and commercial rootstock. The highest root fresh and dry weight were determined in the plants grafted on to autotetraploid N5-4T and allotetraploid CN7-5T. Root characteristics were significantly affected by rootstock genotypes. The N, P, K and Ca contents of the leaves of the CT watermelon cultivar grafted on different rootstocks were significantly affected by the rootstocks. This study showed that citrullus tetraploid genotypes (auto and allo) to be produced by polyploidy method can be an important alternative rootstock source for watermelon.