Response of Cucurbit Rootstocks for Grafted Melon to Root-knot Nematodes Judy A. Thies 1, Jennifer J. Ariss 1, Richard L. Hassell 2, and Amnon Levi 1 1 U.S. Vegetable Laboratory, USDA, ARS, Charleston, SC; 2 Clemson Coastal Res. & Education Center, Charleston, SC
Introduction Southern root-knot nematode (RKN) causes severe damage Significantly reduces fruit yields Interacts with Fusarium wilt No resistance available in cultivated melon Pre-plant fumigation is primary control
Introduction Grafting melon on cucurbit rootstocks used in Asia since the 1920 s for control of soil-borne diseases and increased yield Cucurbit rootstocks commonly used for grafted melon are highly susceptible to root-knot nematode (RKN) Nematode resistant rootstocks are greatly needed for managing RKN in melon
Response of Athena Melon to Southern Root-knot Nematode Methyl bromide treatment (left) untreated (right)
Objective Compare responses of 23 commercial cucurbit rootstocks and cucurbit Plant Introductions (PI) to Meloidogyne incognita in the greenhouse.
Experimental design Randomized complete block design with 23 cucurbit rootstocks x 6 replicates (5 plants per replicate) 23 cucurbit rootstocks Cucumis metulifer (African horned cucumber) Cucurbita maxima x C. moschata (squash hybrid) Cucurbita moschata Cucumis melo (melon)
WR-15006 Dinero 53009 AQ TZ148 BS1 Carnivor Kazado No. 1 Shintosa Camel RS1330 Jing Xin No. 4 TI-140 Jing Xin No. 2 Strong Tosa Tetsukabuto Jing Xin No. 3 TI-151 CM 123 CM 101 CM155 CM111 CM134 5 4 3 2 1 Greenhouse Rootstock Study Cucumis metulifer Cucurbita maxima x C. moschata Cucurbita moschata Cucumis melo Gall index
Jing Xin No. 3 squash hybrid
Dinero melon rootstock
Carnivor squash hybrid
Cucumis metulifer
Summary PIs of Cucumis metulifer (African horned cucumber) exhibited the least galling (P<0.05) among the 4 cucurbit taxa with GI ranging from 2.6 to 3.3. Cucumis melo (melon) rootstocks Dinero and WR-15006 were highly susceptible with GI = 4.9 and 4.7, respectively. All 12 Cucurbita moschata x C. maxima hybrids were highly susceptible to RKN (GI range 4.2 to 5.0).
Objective Compare responses of commercial cucurbit rootstocks and cucurbit Plant Introductions (PI) grafted with the scion Athena melon to Meloidogyne incognita in field tests, Charleston, SC.
Experimental design Randomized complete block design: cucurbit rootstocks grafted with scion Athena melon x 6 replicates x 6 plants per replicate Cucumis metulifer (African horned cucumber) Cucurbita maxima Cucurbita moschata C. maxima x C. moschata (squash hybrid) Cucumis melo (melon) Cucurbita ficifolia Benincasa hispida Cucurbita argyrosperma
Methods Athena melon scions were grafted on different cucurbit rootstocks and evaluated in two fields highly infested with Meloidogyne incognita in Charleston, SC.
Summary Benincasa hispida, Strong Tosa Cucurbita maxima x C. moschata hybrid squash, Cucurbita argyrosperma, Cucumis melo, C. maxima, and C. ficifolia were highly susceptible to RKN (range: 250 eggs for C. melo Dinero to 3,500 eggs per gram fresh root for C. argyrosperma). Cucumis metulifer exhibited moderate resistance (mean = approx. 100 eggs per gram fresh root).
Strong Tosa squash hybrid in RKN-infested field, Charleston, SC
Grafted Melon Study: Fruit Numbers
Summary Strong Tosa (Cucurbita maxima x C. moschata hybrid), Benincasa hispida, Cucumis melo, and Cucumis metulifer, produced the most fruit. Cucurbita argyrosperma, C. maxima, and C. ficifolia produced the fewest fruit.
Conclusions African horned cucumber (Cucumis metulifer) germplasm holds promise as a candidate rootstock for managing root-knot nematodes in melon. All other cucurbit rootstocks evaluated are highly susceptible to RKN and are not suitable for use in fields infested with root-knot nematodes.
Future Research We are currently evaluating Cucumis metulifer PIs and selecting lines with desirable traits for melon rootstocks. Our goal is to develop resistant, vigorous and compatible rootstocks for managing RKN in grafted melon.
Acknowledgements Sharon Buckner, Zach Stansell, Tim Ave, M.K. Ruddy, Louise Cauthen, Aposia Singleton, Freddy Carruth, Matt Horry Funded by USDA, SARE, 2010-2013
Cucumis metulifer USVL rootstock selection