@article{guner_strange_wehner_pesic-vanesbroeck_2002, title={Methods for screening watermelon for resistance to papaya ringspot virus type-W}, volume={94}, ISSN={["1879-1018"]}, DOI={10.1016/S0304-4238(02)00007-9}, abstractNote={Papaya ringspot virus-watermelon strain (PRSV-W) affects all agriculturally important species of the Cucurbitaceae, and is of economic interest because of its destructiveness. The objective of this study was to develop a consistent and reliable method to screen watermelon for resistance to PRSV-W. PRSV-W isolates 1637, 1870, 2030, 2038, 2040, 2052, 2169, 2201, 2207, and W-1A were maintained in ‘Gray Zucchini’ squash, and were used in the inoculations. Three experiments were run, a preliminary experiment to determine the important factors involved in disease development, a main experiment to quantify the effects of those factors, and a retest of three cultigens to determine test variability. The experiment was a split-plot treatment arrangement in a randomized complete block design with four replications. Whole plots were growth stage (cotyledon, first true leaf), subplots were pot size (55 or 100 mm), and sub-subplots were the 10 isolates. Plants were rated on a scale of 0–9 for each of three traits: leaf necrosis, mosaic symptoms, and leaf deformation. We found the best method for a screening of the watermelon germplasm collection for resistance to PRSV-W is to grow the seedlings in square, 100 mm diameter pots (or 55 mm diameter pots if uniform germination is expected) and inoculate plants at the first true leaf stage using PRSV-W isolate 2052 and the rub method. Significant differences were obtained (with LSD values of 0.6–1.5) using four replications of five plants per plot, but fewer replicates and plants may be adequate for a large germplasm screening experiment. The method can be used by researchers interested in screening for PRSV-W resistance in watermelon, verifying that resistance, studying its inheritance, and transferring it to elite cultivars.}, number={3-4}, journal={SCIENTIA HORTICULTURAE}, author={Guner, N and Strange, EB and Wehner, TC and Pesic-VanEsbroeck, Z}, year={2002}, month={Jun}, pages={297–307} }
 @article{strange_guner_pesic-vanesbroeck_wehner_2002, title={Screening the watermelon germplasm collection for resistance to papaya ringspot virus type-W}, volume={42}, ISSN={["0011-183X"]}, DOI={10.2135/cropsci2002.1324}, abstractNote={Papaya ringspot virus watermelon strain (PRSV-W), formerly watermelon mosaic virus-1, is a major disease of watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai]. The objectives of this study were (i) to screen the USDA watermelon germplasm collection for PRSV-W resistance, (ii) to verify the disease rating for the most resistant and most susceptible accessions, (iii) to determine the number of escapes on the basis of the retest of the germplasm screening test. The experiment was a randomized complete block with five replications and 1275 accessions. 'Charleston Gray' susceptible checks were used to verify that the PRSV-W inoculum was virulent. Enzyme-linked immunosorbent assay (ELISA) was performed after the last rating to determine whether the virus was in the plant tissue. The PI accessions with the highest resistance to PRSV-W that also had resistance to other watermelon viruses (ZYMV, zucchini yellow mosaic virus or WMV, watermelon mosaic virus, formerly watermelon mosaic virus-2) were PI 244018, PI 244019, PI 255137, and PI 482299. The first retest of the most resistant 21 PI accessions showed that there were some escapes that were not resistant to PRSV-W. Of the 21 PI accessions in the retest, seven PI accessions were identified for further testing. Of the 60 resistant PI accessions in the final retest, eight had resistance with a rating of 3.6 or less for the best, average, and maximum ratings: PI 244017 (best over all tests), PI 244019, PI 482342, PI 482318, PI 485583, PI 482379, PI 595203, and PI 244018.}, number={4}, journal={CROP SCIENCE}, author={Strange, EB and Guner, N and Pesic-VanEsbroeck, Z and Wehner, TC}, year={2002}, pages={1324–1330} }