Novel watermelon rootstock knocks out disease and pests

Novel watermelon rootstock knocks out disease and pests
Carolina Strongback ripe fruit with seeds. Credit: Agricultural Research Service

A new watermelon line, developed by Agricultural Research Service (ARS) and Clemson University scientists, gets to the root of the problem of a major disease and pest of watermelon crops in the southern United States.

Carolina Strongback is a that is resistant to Fusarium wilt and the southern root-knot , according to William "Pat" Wechter, plant pathologist with the ARS U.S. Vegetable Research Laboratory (USVL) in Charleston, South Carolina. Fusarium wilt, a soilborne disease that threatens vegetable crops, can stay in the soil for 30 years or longer, and fumigants used to control it are no longer available, he added. In addition, watermelon is extremely susceptible to nematodes, which are especially brutal on crops in the Southeast.

Susceptible watermelons can be grafted onto resistant rootstocks of other vegetables such as squash and pumpkin to control certain pathogens, Wechter said. Grafting, which has been used in other countries for years, is a new concept in the United States. Some watermelons grafted to squash rootstock have shown to be resistant to Fusarium wilt, but they were susceptible to southern root-knot nematode.

When tested in highly infested soils with fusarium and nematodes, Carolina Strongback performed well and maintained a high production level of harvested fruit, according to Wechter.

To develop this watermelon line, Wechter worked with two wild citron watermelon (Citrullus amarus) lines that possessed resistance to Fusarium wilt and nematodes. Working with USVL geneticist Amnon Levi, Wechter crossed the Citrullus amarus lines, and then made selections for numerous generations to produce the best plants. Wechter partnered with Clemson University horticulture scientist Richard Hassell, an expert at grafting rootstock, to test the plants. They continued to make more selections to produce the final resistant line—Carolina Strongback.

Selected for its grafting qualities and , Carolina Strongback material can be used by seed companies, grafting companies and watermelon growers as a rootstock for growing susceptible watermelon cultivars in soils infested by the watermelon Fusarium wilt pathogen and root-knot nematodes.

Citation: Novel watermelon rootstock knocks out disease and pests (2019, June 26) retrieved 1 October 2023 from
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.

Explore further

Watermelon cultivar wards off soil-borne diseases


Feedback to editors