Combinations of Rootstocks and Scions to Increase the Fruit Quality in Watermelon

Grafted plants have been a useful tool in the control of soil-borne diseases. However, some studies indicate that the combination of some rootstock-scion could change the quality of the fruits, and therefore the selection of the rootstock and the scion is fundamental. The aim of this study was to evaluate the variability of quality parameters, such as firmness, soluble solid content and lycopene concentration in fruits of two types of seedless watermelon scions (cv Mielheart and Ocelott) grafted onto four commercial rootstock (Cucurbita maxima x Cucurbita moschata cv. “TZ-148” and “RS-841”, Cucurbita maxima cv. “53004” and Cucurbita moschata cv. “Super Shintoza”). Non-grafted “Mielheart” and “Ocelott” were used as control. Plants were growing in open field conditions under commercial system production in Colima, Mexico. The field was arranged in a split-plot design with three repetitions. Lycopene concentration ranged up to 50% depending on the watermelon scions. Lycopene concentration could increase in grafted plant fruits by 19 to 28% compared with the non-grafted fruits. There was a difference of more than 10% in the Total Soluble Solid content between the two watermelon scions used, however, there was no difference between the grafted and non-grafted fruits. Grafted fruits had superior firmness compared to non-grafted fruits; in this case there was no difference between the two watermelon scions. Lycopene, Total Soluble Solid and firmness may vary depending on the combination of scion and rootstock used. The use of grafted plants could be a useful tool to increase the fruit quality.