Evaluation of different grafting methods and rootstocks in watermelon grown in Egypt

• Higher plant growth and yield were associated with TAG than SIG and HIG methods.
• Female flowers no. and sex ratio non-significantly differed in all grafting types.
• Grafting onto ‘Nun 6001F1’ using HIG gave the lowest male flowers and sex ratio.
• The lowest number of female flowers was found in non-grafted plants.
• Tongue approach (TAG) seems to be the best grafting technique for watermelon.

Grafting is an alternative approach to reduce crop damage resulting from soil-borne pathogens and increase plant abiotic stress tolerance, which in turn increases crop production. The purpose of this study was to determine the effect of three grafting methods [Tongue approach (TAG), Hole insertion (HIG) and Side grafting (SIG)] on plant growth and fruit yield of watermelon (Citrullus lanatus) ‘Aswan F1’ that was grafted onto three rootstocks (‘Nun 6001 F1’, ‘Strongtosa F1’ and ‘Tetsukabuto F1’) which are hybrids between Cucurbita maxima and Cucurbita moschata. TAG had significant higher main stem length, number of lateral stems, number of male flowers per plant, fruit yield per plant and fruit weight comparing to other grafting methods (SIG and HIG). However, number of leaves, number of female flowers per plant and sex ratio were not significantly different in all grafting types. Vegetative growth and fruit yield showed highest values when the ‘Nun 6001 F1’ rootstock and TAG were used. The lowest number of male flowers and sex ratio were found when the ‘Nun 6001 F1’ rootstock and HIG method were used. However, the lowest number of female flowers was found in non-grafted plants. Among the 3 grafting methods tested, TAG seems to be the best grafting technique for watermelon. However an interaction between the grafting method and the used rootstock also seems to exist.