Search Results

You are looking at 1 - 10 of 42 items for :

  • " C. colocynthis " x
  • Refine by Access: All x
Clear All
Free access

Judy A. Thies and Amnon Levi

Root-knot nematodes [Meloidogyne arenaria (Neal) Chitwood, Meloidogyne incognita (Kofoid & White) Chitwood, and Meloidogyne javanica (Treub) Chitwood] are serious pests of watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai var. lanatus] in the southern United States and worldwide. Watermelon cultivars with resistance to any of these nematode pests are not available. Therefore, we evaluated all accessions of Citrullus colocynthis (L.) Schrad.(21) and Citrullus lanatus (Thunb.) Matsum. & Nakai var. citroides (L.H. Bailey) Mansf.(88), and about 10% of C. lanatus var. lanatus (156) accessions from the U.S. Plant Introduction (PI) Citrullus germplasm collection for resistance to M. arenaria race 1 in greenhouse tests. Only one C. lanatus var. lanatus accession exhibited very low resistance [root gall index (GI) = 4.9] and 155 C. lanatus var. lanatus accessions were susceptible (GI ranged from 5.0 to 9.0, where 1 = no galls and 9 = ≥81% root system covered with galls). All C. colocynthis accessions were highly susceptible (GI range = 8.5 to 9.0). However, 20 of 88 C. lanatus var. citroides accessions were moderately resistant with a GI range of 3.1 to 4.0; overall GI range for the C. lanatus var. citroides accessions was 3.1 to 9.0. Resistance to M. arenaria race 1 identified in the C. lanatus var. citroides accessions was confirmed on a subset of accessions in a replicated greenhouse test. The results of our evaluations demonstrated that there is significant genetic variability within the U.S. PI Citrullus germplasm collection for resistance to M. arenaria race 1 and also identified C. lanatus var. citroides accessions as potential sources of resistance.

Free access

Kelechi Ogbuji, Gloria S. McCutcheon, Alvin M. Simmons, Maurice E. Snook, Howard F. Harrison, and Amnon Levi

shows a wide phenotypic and genetic diversity ( Levi et al., 2001b ). The genus Citrullus includes several species or subspecies. Among them is the bitter watermelon C. colocynthis (L.) Schrad that thrives in the deserts of North Africa, the Middle

Free access

John L. Coffey, Alvin M. Simmons, B. Merle Shepard, Yaakov Tadmor, and Amnon Levi

genus Citrullus , including C. colocynthis (L.) Schrad, C. rehmii De Winter, and C. ecirrhosus Cogniaux, hold potential sources of resistance to whiteflies. Citrullus colocynthis is a perennial melon species that exists in the deserts of

Free access

Amnon Levi, John Coffey, Laura Massey, Nihat Guner, Elad Oren, Yaakov Tadmor, and Kai-shu Ling

resistance in PIs representing the perennial bitter watermelon ( C. colocynthis ) that exists in the deserts of northern Africa, the Middle East, southwest Asia, and India. In a previous study, PIs of C. colocynthis exhibited wide genetic diversity compared

Free access

R. Provvidenti

A high level of resistance to zucchini yellow mosaic virus (ZYMV) was found in four landraces of Citrullus lanatus (Thunb.) MatSum. & Nakai (PI 482322, PI 482299, PI 482261, and PI 482308) originally collected in Zimbabwe. This resistance is specific to the Florida strain of the virus (ZYMV-FL), which prevails in the United States. Inheritance studies were conducted by using a single-plant selection (PP261-I) of PI 48226I and the ZYMV-susceptible watermelon cultivar New Hampshire Midget. In F1, F2, and reciprocal backcross populations, resistance was conferred by a single recessive gene to which the symbol zym is assigned. There was no linkage between zym and one of the three homodimer bands of the isozyme phosphoglucoisomerase (Pgi-2b), which was found in PP261-1, and in other ZYMV-FL resistant plants.

Free access

Judy A. Thies and Amnon Levi

material. Twenty-six accessions of C. lanatus var. citroides , one accession of C. lanatus var. lanatus , and three accessions of C . colocynthis from the U.S. PI Citrullus germplasm collection were evaluated for resistance to M. incognita

Free access

Angela R. Davis, Amnon Levi, Antonia Tetteh, Todd Wehner, Vincent Russo, and Michel Pitrat

NPGS at the Southern Regional Plant Introduction Station, USDA-ARS, Griffin, GA, were evaluated. The accessions represent 75 countries of origin and five species, belonging to C. lanatus var. lanatus , C. lanatus var. citroides , C. colocynthis

Free access

Chandrasekar S. Kousik, Scott Adkins, William W. Turechek, and Pamela D. Roberts

Sweet’ had typical symptoms of WVD. In comparison, the seven PIs had significantly less fruits with symptoms of WVD ( Table 7 ). Almost none of the fruits of the C. colocynthis PI had symptoms of WVD. Although foliar symptoms on the C. lanatus var

Free access

Howard F. Harrison Jr., W. Patrick Wechter, and Chandrasekar S. Kousik

of watermelon and the related species C. colocynthis . Materials and Methods Testa tissue preparation. The genotypes included in this experiment were the watermelon cultivar, Charleston Gray, the U.S. Vegetable Laboratory experimental watermelon line

Free access

Haiying Zhang, Jianguang Fan, Shaogui Guo, Yi Ren, Guoyi Gong, Jie Zhang, Yiqun Weng, Angela Davis, and Yong Xu

status of species, subspecies, and varieties in this genus is evolving. Previously, Citrullus included four species including C . lanatus (Thunb.) Matsum. Et Nakai, C . colocynthis (L.) Schrad., C . eccirrhosus Cogn., and C . rehmii de