Due to its efficacy grafting watermelon (Citrullus lanatus) onto resistant rootstock has emerged as a promising biological management strategy against biotic and abiotic stressors in many regions of the world. However, grafted transplants are expensive due in part to the grafting methods that are commonly used for this crop, the one-cotyledon and hole insertion methods. In order to reduce cost and expand utilization on a large scale in the U.S., the grafting process needs to become more efficient. To accomplish these goals, the studies were designed to advance the splice-grafting method where both cotyledons are removed from the rootstock as it exhibits great potential to reduce time and labor for watermelon grafting. The first study evaluated the efficacy of sucrose with antitranspirant applied to rootstock seedlings before grafting and found that survival of splice-grafted plants was 91% for plants that received sucrose solution + antitranspirant compared to 25% for plants that received only water. In addition, a follow-up field study found that fruit yield and quality attributes were similar for watermelon grafted with splice and one-cotyledon methods and for nongrafted watermelon plants. Another greenhouse study was conducted to determine if external applications of auxin in combination with sucrose and antitranspirant solutions to rootstock seedlings before grafting can increase the survival of splice-grafted watermelon transplants, but did not show any difference in the survival with and without auxin. Additionally, this study tested if cutting the roots from rootstock seedlings prior to grafting and rerooting the grafted plants could increase the survival of splice-grafted watermelon seedlings. However, survival decreased by 11% compared to root-intact plants. The third study was a 2-year field study to evaluate the combination of four different rootstocks and two types of plastic mulch (black and clear) on date of watermelon first flowering, fruit ripening, yield and fruit quality when plants were exposed to Verticillium dahliae. Rootstocks reduced verticillium wilt severity and increased fruit yield whereas mulch had no effects, and 5 V. dahliae cfu.g-1 of soil may be the minimum level for impact on watermelon fruit yield
