Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: 2/14/2005
Publication Date: 6/1/2005
Citation: Roberts, B.W., Fish, W.W., Bruton, B.D., Popham, T.W., Taylor, M.J. 2005. Effects of watermelon grafting on fruit yield and quality [abstract]. HortScience. 40(3):871.
Technical Abstract: Grafted cucurbits are commonly grown in various Asian and European countries, but only rarely in North America. Disease control in fields where crop rotation cannot be practiced is a common justification for grafting cucurbits. In the present study, grafting is being examined as a methyl bromide alternative, which may allow cucurbits to be grown in fields where heavy disease pressure would make production of non-grafted cultivars impractical. A study with watermelons (Citrullus lanatus) grafted onto rootstocks of squash and gourd was conducted at Lane, Oklahoma in 2004. Treatments consisted of watermelon cultivars SF 800, SS 5244, SS 7167, SS 7177, and SS 7187 from Abbot & Cobb Seed Co., grown on their own roots, or grafted onto rootstocks of RS1330, RS1332, RS1420, or RS 1421. Controls consisted of non-grafted cultivars Sangria, Royal Sweet, Jubilee, and Jamboree. Two fields were planted, with three replications per field. Plants were grown on 1 m centers, with rows 3 m apart. Yields of grafted plants were generally equal to or greater than the non-grafted plants. Sugar content, measured as soluble solids, was affected minimally, if any, by grafting. Lycopene content of fruit from grafted plants was equal to, or marginally better than, fruit from non-grafted plants. Fruit firmness, as measured by a penetrometer, was significantly greater in the grafted fruit than in the non-grafted fruit. The firmest fruit occurred with SS 7167 scions, grafted onto RS 1420 rootstock, which had a value of about 2.0 x 10**5 Pascals. The non-grafted plants had values of about 1.0 x 10**5 Pascals, or less. Matching of scions with appropriate rootstocks was important, as interactions did occur. Certain combinations were significantly superior to other combinations. We estimate that the cost to purchase a grafted seedling plant from a seedling supplier would be $0.75- $1.00, which would include the cost of the seed and the grafting operation. This cost would compare favorably with the cost of applying methyl bromide to the soil and then planting non-grafted seeds or transplants. Higher plant survival due to disease resistance along with planting fewer plants per hectare is anticipated with grafted plants. The high values in fruit firmness in grafted fruit should be of particular interest to the fresh-cut industry.