The Influence of Rootstock Selection on Fruit Quality Attributes of Watermelon

Grafting watermelon (Citrullus lanatus) to control Fusarium wilt has been practiced in Europe, the Middle East, and the Far East for decades. Until recently, grafting watermelon has not been practiced in the United States due to labor costs and land availability. There is some disagreement in the literature as to the effects that grafting has on watermelon fruit quality. This study was designed to determine the effects of grafted watermelon on fruit firmness, lycopene content, and total soluble solids (TSS) using five different rootstocks. When using Cucurbita ficifolia or Cucurbita maxima x Cucurbita moschata hybrid as the rootstock, watermelon fruit consistently had higher fruit firmness values. Other C. maxima x C. moschata hybrids or Lagenaria siceraria rootstocks generally produced lower or more varied fruit firmness values. Grafting increased fruit firmness by as much as 25% in some cases, but field and year effects were observed. In addition, grafting had no effect on lycopene content or TSS. Furthermore, no off-flavors were detected in fruit from grafted plants, but there was a 5to 7 day delay in fruit maturity compared to their non-grafted counterpart. Although environment can have a major influence on fruit quality attributes, rootstock selection may be equally important in achieving the desired outcome.