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ARS Home » Southeast Area » Charleston, South Carolina » Vegetable Research » Research » Research Project #432663

Research Project: Biology, Etiology and Host Resistance in Vegetable Crops to Diseases and Nematodes

Location: Vegetable Research

2019 Annual Report

4. Accomplishments
1. Development and release of a root-knot nematode resistant cherry pepper line. Development and release of a root-knot nematodes (RKN) are serious yield limiting pests of pepper production in the U.S. as well as the rest of the world. Incorporating RKN resistance genes into agronomically and commercially favorable pepper varieties can increase yield and reduce the need for nematicide applications. ARS scientists at Charleston, South Carolina, have released a new sweet cherry-type pepper line ‘PA-593’containing the ‘N’ resistance gene for RKN resistance. This new RKN resistant line will provide a valuable resource for stakeholders looking for new RKN resistant varieties, and for breeders looking to quickly incorporate this resistance into their cherry-type pepper breeding programs.

2. Identification of guava root-knot nematode in South Carolina. The guava root-knot nematode (GRKN, Meloidogyne enterolobii) is a hyper-virulent and invasive species in the southeastern U.S. where it causes serious damage on a wide range of historically RKN resistant crops. Through survey efforts, ARS scientists at Charleston, South Carolina, found GRKN for the first time in the state, where it was infecting the normally RKN resistant sweetpotato cultivar Covington. The identification of this invasive nematode in South Carolina has helped to initiated a collaborative multistate effort between researchers in four southeastern states to find, study, and manage GRKN in the field. This effort will help stakeholders to understand the threat posed by GRKN, slow the spread of this nematode to new areas, and provide resources to help farmers manage GRKN in their operations.

3. Development and release of powdery mildew resistant cucurbit germplasm lines. Watermelon is an important vegetable crop grown in 44 states in the U.S. Many diseases and pests attack watermelon seedlings and plants and reduce their yield resulting in monetary loss for growers. One such disease, known as powdery mildew can infest watermelon seedlings and can cause reduced vigor or death of seedlings and also result in yield reduction in the field. Growers generally spray expensive pesticides to manage this disease. ARS scientists in Charleston, South Carolina, have developed four watermelon germplasm lines (USVL608-PMR, USVL313-PMR, USVL255-PMR and USVL585-PMR) with resistance to powdery mildew. Similarly, two bottle gourd lines (USVL351-PMR and USVL482-PMR) with resistance to powdery mildew were released in 2018. These resistant germplasm lines can be used by private and public sector plant breeders to develop watermelon or gourd varieties and breeding lines with resistance to powdery mildew. Development of varieties with resistance to powdery mildew will help reduce pesticide use and allow growers to produce a healthy crop. Private plant breeders and plant pathologists at vegetable seed companies, university researchers and extension agents can use these lines in their programs. Seeds of these powdery mildew resistant lines were provided to various national and international seed companies upon request including Sakata Seeds, Bayer, VNR and Enza Zaden. These lines are being used in their breeding and powdery mildew evaluation programs.

Review Publications
Pogorelko, G., Juvale, P., Rutter, W.B., Hutten, M., Maier, T., Hewezi, T., Paulus, J., Van Der Hoorn, R., Grundler, F., Siddique, S., Lionetti, V., Zabotina, O., Baum, T. 2019. Retargeting of a plant defense protease by a cyst nematode effector. Plant Journal.
Rutter, W.B., Kousik, C.S., Thies, J.A., Farnham, M.W., Fery, R.L. 2018. PA-593: A root-knot nematode resistant sweet cherry-type pepper. Horticultural Science. 53(12):1922-1923.
Wu, S., Wang, X., Reddy, U., Sun, H., Bao, K., Patel, T., Oritz, C., Abburi, L., Nimmakayala, P., Branham, S., Wechter, W.P., Massey, L.M., Ling, K., Kousik, C.S., Hammar, S.A., Tadmor, Y., Portnoy, V., Gur, A., Katzir, N., Guner, N., Davis, A., Hernandez, A.G., Wright, C.L., McGregor, C., Jarret, R.L., Xu, Y., Zhang, X., Wehner, T.C., Grumet, R., Levi, A., Fei, Z. 2019. Genome of ‘Charleston Gray’, the principal American watermelon cultivar, and genetic characterization of 1,365 accessions in the U.S. National Plant Germplasm System watermelon collection. Plant Biotechnology Journal.
Kousik, C.S., Ikerd, J.L., Mandal, M., Adkins, S.T., Webster, C.G., Turechek, W. 2018. Powdery mildew resistant bottle gourd germplasm lines: USVL351-PMR and USVL482-PMR. HortScience. 53(8):1224-1227.
Kousik, C.S., Ikerd, J.L., Mandal, M., Adkins, S.T., Turechek, W. 2018. Watermelon germplasm lines: USVL608-PMR, USVL255-PMR, USVL313-PMR and USVL585-PMR with broad resistance to powdery mildew. HortScience. 53(8):1212-1217.
Keinath, A.P., Gabriel, R., Kousik, C.S. 2018. First report of resistance to boscalid in podosphaera xanthii, cucurbit powdery mildew, in South Carolina. Plant Health Progress. 19:220-221.
Keinath, A.P., Ling, K., Adkins, S.T., Hasegawa, D.K., Simmons, A.M., Hoak, S., Mellinger, C., Kousik, C.S. 2018. First report of cucurbit leaf crumple virus infecting three cucurbit crops in South Carolina. Plant Health Progress. 19:322-323.
Hajihassani, A., Rutter, W.B., Luo, X. 2019. Resistant pepper carrying N, Me1, and Me3 have different effects on penetration and reproduction of four major meloidogyne species. Journal of Nematology. 51:1-9.
Keinath, A.P., Wechter, W.P., Rutter, W.B., Agudelo, P.A. 2019. Cucurbit rootstocks resistant to fusarium oxysporumf.sp. niveum remain resistant when co-infected by <i>Meloidogyne incognita in the field. Plant Disease. 103(6):1383-1390.
Rutter, W.B., Skantar, A.M., Handoo, Z.A., Mueller, J., Aultman, S.P., Agudelo, P. 2019. Identification of Meloidogyne enterolobii infecting root-knot nematode resistant sweetpotato (Ipomoea batatas) in South Carolina. Plant Disease. 103(4):11.