Grafting Extends Field Storage Life of Seedless Watermelon, Cucerbitaceae 2014 Proceedings, RichArd hAssell* Coastal REC, Clemson University, Charleston, SC 29414, USA, PeneloPe Perkins-veAZie, Plants for Human Health Institute, Department of Horticultural Sciences, North Carolina State University, Kannapolis, NC 28081, USA, lisA deAn, USDA-ARS, Market Quality and Handling Research, Raleigh, NC 27695, USA
AbstrAct. Quality of watermelon fruit is a combination of firmness, full red color, sweetness, and perceived shelf life in
field and market; fresh cut watermelon must also have low drip loss. Watermelon grafting is widely used outside of the
US to avoid soil borne pathogens and abiotic stresses. Commonly used rootstocks and seedless watermelon scions were
used to determine best fruit productivity and marketable yield in the southeastern US relative to non-grafted plants.
In 2012, fruit identified as ripe were left in the field on the vine 0 to 2 weeks to test the relative holding life, then used
for fresh cut studies (held an additional 14 days at 3 °C) to determine firmness, drip loss, and composition. Depending
on scion and rootstock cultivar, lycopene content increased slightly (up to 10%) with grafting while citrulline content
decreased 10 to 30%. Holding grafted fruit in the field for 1 week increased citrulline content by 20%. Firmness was
increased 10 to 40% by grafting. Percentage drip loss of fresh cut product was reduced to one third or one half using
grafted watermelons regardless of fruit holding time in field. Grafted watermelons harvested at 0 or 1 week field holding
resulted in acceptable fresh cut product after 14 days cold storage. Our results indicate that grafted watermelon can
improve firmness and reduce drip loss in fresh cut watermelon without loss of sugars or lycopene, and that grafting
extends field shelf life an extra week compared to non-grafted watermelons.