title: Evaluation of Watermelon Germplasm for Resistance to Phytophthora Blight Caused by Phytophthora capsici.
abstract: This study was conducted to determine the Phytophthora rot resistance of 514 accessions of watermelon germplasm, Citrullus lanatus var lanatus. About 46% of the 514 accessions tested were collections from Uzbekistan, Turkey, China, U.S.A., and Ukraine. Phytophthora capsici was inoculated to 45-day-old watermelon seedlings by drenching with 5 ml of sporangial suspension (10(6) sporangia/ml). At 7 days after inoculation, 21 accessions showed no disease symptoms while 291 accessions of susceptible watermelon germplasm showed more than 60.1% disease severity. A total of 510 accessions of watermelon germplasm showed significant disease symptoms and were rated as susceptible to highly susceptible 35 days after inoculation. The highly susceptible watermelon germplasm exhibited white fungal hyphae on the lesion or damping off with water-soaked and browning symptoms. One accession (IT032840) showed moderate resistance and two accessions (IT185446 and IT187904) were resistant to P. capsici. Results suggest that these two resistant germplasm can be used as a rootstock and as a source of resistance in breeding resistant watermelon varieties against Phytophthora.
authors.affiliation: Organic Agriculture Division, National Academy of Agricultural Science, Suwon 441-707, Korea.
authors.forename: Min-Jeong
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: Organic Agriculture Division, National Academy of Agricultural Science, Suwon 441-707, Korea.
authors.forename: Chang-Ki
authors.initials: CK
authors.lastname: Shim
authors.affiliation: Organic Agriculture Division, National Academy of Agricultural Science, Suwon 441-707, Korea.
authors.forename: Yong-Ki
authors.initials: YK
authors.lastname: Kim
authors.affiliation: Organic Agriculture Division, National Academy of Agricultural Science, Suwon 441-707, Korea.
authors.forename: Hyeong-Jin
authors.initials: HJ
authors.lastname: Jee
authors.affiliation: Organic Agriculture Division, National Academy of Agricultural Science, Suwon 441-707, Korea.
authors.forename: Sung-Jun
authors.initials: SJ
authors.lastname: Hong
authors.affiliation: Organic Agriculture Division, National Academy of Agricultural Science, Suwon 441-707, Korea.
authors.forename: Jong-Ho
authors.initials: JH
authors.lastname: Park
authors.affiliation: Organic Agriculture Division, National Academy of Agricultural Science, Suwon 441-707, Korea.
authors.forename: Eun-Jung
authors.initials: EJ
authors.lastname: Han
keywords: Citrullus lanatus var lanatus; Phytophthora resistance; sporangia