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ARS Home » Southeast Area » Charleston, South Carolina » Vegetable Research » Research » Publications at this Location » Publication #431582
Research Project: Genomics and Genetic Improvement of Disease Resistance and Horticultural Characteristics of Watermelon, Broccoli, and Leafy Brassicas

Location: Vegetable Research

Title: Assessing grafted triploid watermelon and yellow nutsedge growth in saline agro-ecosystems

Author
item BAZZLE, JOSEPH - Clemson University
item WAD, BRIAN - Clemson University
item BRANHAM, SANDRA - Clemson University
item HORRY, MATTHEW - Clemson University
item BRIDGES, WILLIAM - Clemson University
item Levi, Amnon
item CUTULLE, MATTHEW - Clemson University

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/14/2026
Publication Date: 4/8/2026
Citation: Bazzle, J., Wad, B., Branham, S., Horry, M., Bridges, W., Levi, A., Cutulle, M. 2026. Assessing grafted triploid watermelon and yellow nutsedge growth in saline agro-ecosystems. HortScience. https://doi.org/10.21273/HORTSCI19245-25.
DOI: https://doi.org/10.21273/HORTSCI19245-25

Interpretive Summary: Rising salinity levels in soils present a growing threat for crop production around the world. As a result, availability of salt-free land for growing crops could be considerably reduced in the future. Watermelon plants are highly sensitive to salt at most growth stages, particularly during seedling establishment and at the early plant growing stages. This unfavorable conditions is driving the watermelon community to find agricultural solutions and/or identify and utilize germplasm resources useful for increasing salinity stress tolerance. In this study, ARS and Clemson scientists collaborated on a field study to evaluate response to salt treatment of a seedless watermelon variety grafted on a rootstock derived from a wild watermelon versus a non-grafted watermelon treatment. Also, the scientists assessed the density of the "yellow nutsedge" weed in a field with saline versus a field with non-saline conditions. The results of the study indicate high sensitivity of the grafted watermelon plants to salinity conditions. The saline conditions also favored higher weed growth and density around watermelon plants. These results indicate the need to find agro-technique solutions to overcome or reduce salinity soil condition. At the same time, evaluate the whole watermelon germplasm (genetic material maintained by USDA; https://www.ars-grin.gov/) for salt tolerance and identify genetic source useful for improving salt tolerance in watermelon cultivars.

Technical Abstract: Rising salinity levels in soils present a growing threat for food production around the world. While there is research focused on reducing the impacts of high salinity on crops, these studies are typically conducted in the greenhouse due to the difficulty of setting up field trials and the long-term negative impacts of soil salinization. The objective of this study was to assess the response of grafted watermelons to saline irrigation water in a field experiment. Two common rootstocks were selected to assess the use of grafting in saline conditions: ‘Carolina Strongback’, a Citrullus amarus variety, and ‘Carnivor’, a Cucurbita maxima x Cucurbita moschata hybrid. Citrullus amarus varieties (a type of wild watermelon/citron melon) have been used for the control of many biotic stressors, and Cucurbita maxima hybrids can be used for their rapid growth and resistance to colder ground temperatures. ‘Melody’, a popular seedless watermelon variety, was used as the scion for all plots. To simulate a water source inundated with salt water, sea water was collected directly from the Atlantic Ocean at a nearby boat landing and was mixed with fresh water to obtain target treatment levels of <1, 4, 8, and 12 mS cm-1. There was a significant decline in crop health at every treatment level compared to the control, with visual assessments being an average of 30% lower at the highest salinity treatment. The endemic population of Cyperus esculentus, commonly referred to as yellow nutsedge, was also assessed during this trial to observe any potential competition with the watermelon crop. Weed populations were significantly higher in areas with saline irrigation during the early season, while there was no difference between treatments at the end of the season. This demonstrates a potential increase in weed competition for areas exposed to rising salinity levels.