Efficiency of grafting watermelon scions on resistant rootstocks for controlling Fusarium wilt under greenhouse and field conditions was evaluated. Two grafting methods, i.e. tongue approach graft and hole insertion graft, were evaluated for grafting three watermelon scions, i.e. Aswan hybrid and cv. Giza 1, on four rootstocks, i.e. Wild watermelon, Bottle Gourd, Strong Tosa and Ferro. Results indicated that the most effective method is tongue approach graft with Aswan hybrid and cv. Giza 1 which recorded 92.0 to 96.0% survived plants except cv. Giza 1 that was grafted on Bottle Gourd. Grafting of Aswan hybrid and cv. Giza 1 on Bottle Gourd, Strong Tosa and Ferro rootstocks significantly reduced the wilt disease incidence. Complete protection of Fusarium wilt was obtained with both cultivars grafted on Bottle Gourd and Strong Tosa. Grafting of both cultivars on Ferro rootstock resulted in reducing disease incidence by 95.2% for Giza 1 and Aswan hybrid. Also, the highest increase in enzyme activities was obtained with both cultivars grafted on all the tested rootstocks. Grafting increased peroxidase, chitinase and µ-1,3-glucanase activities as compared with un-grafted plants. Moreover, under field conditions grafting of two watermelon scion, i.e. Aswan hybrid and cv. Giza 1, on three rootstocks, i.e. Bottle Gourd, Strong Tosa and Ferro, to study the effect of grafting on Fusarium wilt incidence and fruit yield. Results revealed that all treatments reduced the wilt incidence during the two growing seasons. Complete protection of Fusarium disease was obtained with both scions grafted on all rootstocks. The highest increase in watermelon yield was obtained with Aswan hybrid grafted on each of Bottle Gourd, Strong Tosa and Ferro which increased fruit yield by 175.3, 166.3, 165.2%, respectively as compared with un-grafted cultivars. |
