|BRANHAM, SANDRA - Clemson University|
|Wechter, William - Pat|
|ZHAO, GUANGWEI - Chinese Academy Of Agricultural Sciences|
|GUNER, NIHAT - Sakata Seed America, Inc|
|BELLO, MARCO - Sakata Seed America, Inc|
|KABELKA, EILEEN - Sakata Seed America, Inc|
|FEI, ZHANGJUN - Cornell University|
Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2019
Publication Date: 12/10/2019
Citation: Branham, S., Wechter, W.P., Ling, K., Chanda, B., Massey, L.M., Zhao, G., Guner, N., Bello, M., Kabelka, E., Fei, Z., Levi, A. 2019. QTL mapping of resistance to Fusarium oxysporum f. sp. niveum race 2 and Papaya ringspot virus in Citrullus amarus. Theoretical and Applied Genetics. 133:677-687. https://doi.org/10.1007/s00122-019-03500-3.
Interpretive Summary: Watermelon is an important crop in the USA and throughout the world. Fusarium wilt (FW) is a major disease of watermelon. Also, Papaya ring-spot virus (PRSV) is an important pathogen causing serious damage to the watermelon crop. There is great interest by seed companies and growers in development of watermelon varieties resistant to these two major diseases. In this study, ARS scientists in collaboration with scientists from Clemson University, Cornell University, the Chinese Academy of Agricultural Sciences, and Sakata Seed America conducted genetic mapping analyses using advanced genomic technologies and were able to identify gene loci conferring resistance to these two major diseases of watermelon. The results of this study should be useful for watermelon breeders and scientists interested in accelerating the breeding process to develop elite watermelon varieties resistant to FW and PRSV.
Technical Abstract: Multiple disease screens of the USDA Citrullus spp. germplasm collection have highlighted the value of Citrullus amarus (citron melon or wild watermelon) as a resource for enhancing modern watermelon cultivars (Citrullus lanatus) with resistance to a broad range of fungal, bacterial and viral diseases of watermelon. We have generated a genetic population of C. amarus segregating for resistance to two important watermelon diseases, Fusarium wilt (caused by the fungus Fusarium oxysporum f. sp. niveum; Fon race 2) and papaya ringspot virus-watermelon strain (PRSV-W). QTL mapping of Fon race 2 resistance identified seven significant QTLs, with the major QTL representing a novel genetic source of resistance and an opportunity for gene pyramiding. A single QTL was associated with resistance to PRSV-W, which adhered to expectations of a prior study indicating a single gene recessive inheritance in watermelon. The resistance loci identified here provide valuable genetic resources for introgression into cultivated watermelon for improvement of disease resistance.