scholarly journals Accessions of Citrullus lanatus var. citroides Are Valuable Rootstocks for Grafted Watermelon in Fields Infested with Root-knot Nematodes

HortScience ◽  
2015 ◽  
Vol 50 (1) ◽  
pp. 4-8 ◽  
Author(s):  
Judy A. Thies ◽  
Jennifer J. Ariss ◽  
Richard L. Hassell ◽  
Sharon Buckner ◽  
Amnon Levi

Root-knot nematode-resistant rootstock lines (designated RKVL for Root-Knot Vegetable Laboratory) derived from wild watermelon (Citrullus lanatus var. citroides) were compared with wild tinda (Praecitrullus fistulosus) lines and commercial cucurbit rootstock cultivars for grafting of seedless triploid watermelon ‘Tri-X 313’ (C. lanatus var. lanatus) in a field infested with the southern root-knot nematode (RKN) (Meloidogyne incognita) in Charleston, SC, during 2009 and 2010. In both years, RKN infection was severe in ‘Emphasis’ bottle gourd, ‘Strong Tosa’ hybrid squash, and wild tinda rootstocks with galling of the root system ranging from 86% to 100%. In 2009, the RKVL wild watermelon rootstocks exhibited lower (P < 0.05) percentages of root galling (range 9% to 16%) than non-grafted ‘Tri-X 313’ (41%), ‘Emphasis’, ‘Strong Tosa’, and the wild tinda rootstocks. The grafted wild watermelon rootstock RKVL 318 produced more (P ≤ 0.05) fruit (12 per plot) than all other entries (mean = five per plot), and it produced a heavier (P ≤ 0.05) fruit yield (29.5 kg per plot) than all entries except self-grafted ‘Tri-X 313’ (21.5 kg per plot). In 2010, soil in half of the plots was treated with methyl bromide (50%):chloropicrin (50%) (392 kg·ha–1) before planting. The RKVL wild watermelon rootstocks exhibited resistance to RKN with percentages of root system galled ranging from 11% for RKVL 316 to 56% for RKVL 301 in the untreated control plots. Fruit yields in the untreated plots were 21.9, 25.6, and 19.9 kg/plot for RKVL 301, RKVL 316, and RKVL 318, respectively. Yields were greater (P ≤ 0.05) for the three RKVL rootstocks than for ‘Strong Tosa’ (3.0 kg) and ‘Ojakkyo’ wild watermelon rootstock (2.8 kg) in the untreated plots. Yields of watermelon grafted on ‘Strong Tosa’ were nearly seven times greater (P ≤ 0.05) in the methyl bromide-treated plots than in the untreated plots. In contrast, yields of RKVL 316 and RKVL 318 were similar in both treatments and the yield of RKVL 301 was less (P ≤ 0.05) in the methyl bromide-treated plots than in the untreated plots. The three RKVL wild watermelon rootstock lines exhibited resistance to RKN. RKVL 316 had low root galling and produced the heaviest fruit yield and greatest numbers of fruit of any rootstock evaluated in 2010. The RKVL lines should be useful sources of RKN resistance for rootstocks for grafted watermelon.

Plant Disease ◽  
2019 ◽  
Vol 103 (6) ◽  
pp. 1383-1390 ◽  
Author(s):  
Anthony P. Keinath ◽  
W. Patrick Wechter ◽  
William B. Rutter ◽  
Paula A. Agudelo

Interspecific hybrid squash (Cucurbita maxima × Cucurbita moschata) rootstocks used to graft watermelon (Citrullus lanatus var. lanatus) are resistant to Fusarium oxysporum f. sp. niveum, the fungus that causes Fusarium wilt of watermelon, but they are susceptible to Meloidogyne incognita, the southern root knot nematode. A new citron (Citrullus amarus) rootstock cultivar Carolina Strongback is resistant to F. oxysporum f. sp. niveum and M. incognita. The objective of this study was to determine if an interaction between M. incognita and F. oxysporum f. sp. niveum race 2 occurred on grafted or nongrafted triploid watermelon susceptible to F. oxysporum f. sp. niveum race 2. In 2016 and 2018, plants of nongrafted cultivar Fascination and Fascination grafted onto Carolina Strongback and interspecific hybrid squash cultivar Carnivor were inoculated or not inoculated with M. incognita before transplanting into field plots infested or not infested with F. oxysporum f. sp. niveum race 2. Incidence of Fusarium wilt and area under the disease progress curve did not differ when hosts were inoculated with F. oxysporum f. sp. niveum alone or F. oxysporum f. sp. niveum and M. incognita together. Fusarium wilt was greater on nongrafted watermelon (78% mean incidence) than on both grafted rootstocks and lower on Carnivor (1% incidence) than on Carolina Strongback (12% incidence; P ≤ 0.01). Plants not inoculated with F. oxysporum f. sp. niveum did not wilt. At the end of the season, Carnivor had a greater percentage of the root system galled than the other two hosts, whereas galling did not differ on Fascination and Carolina Strongback. F. oxysporum f. sp. niveum reduced marketable weight of nongrafted Fascination with and without coinoculation with M. incognita. M. incognita reduced marketable weight of Fascination grafted onto Carnivor compared with noninoculated, nongrafted Fascination. In conclusion, cucurbit rootstocks that are susceptible and resistant to M. incognita retain resistance to F. oxysporum f. sp. niveum when they are coinfected with M. incognita.


2010 ◽  
Vol 16 (2) ◽  
Author(s):  
Z. Mándoki

Newly bred resistant bell pepper varieties and those grafted onto resistant rootstock s were tested in soil severely infested with southern root-knot nematode [Meloidogy11e incognita (Kofoid and White) Chitwood] in unheated plastic house and compared to varieties on their own roots, in order to evaluate the efficiency of this environmentally friendly control method. 'Cinema F I ' carrying the N gene yielded significantly more than the two susceptible varieties. Varieties grafted onto resistant rootstocks outyielded those on their own roots although to different extent, which was not always significant. At the end of the vegetat ion period the roots of the rootstocks were undamaged and the roots of some resistant varieties were slightly infected. whereas the roots of susceptible varieties were severely damaged. According to our result  . both the use of resistant varieties and grafted plants offer an effective and environmentally safe way of controlling M. incognita.


HortScience ◽  
2008 ◽  
Vol 43 (1) ◽  
pp. 188-190 ◽  
Author(s):  
Judy A. Thies ◽  
Don W. Dickson ◽  
Richard L. Fery

Two root-knot nematode-resistant bell pepper cultivars, ‘Charleston Belle’ and ‘Carolina Wonder’ (Capsicum annuum L. var. annuum], and their susceptible parents, ‘Keystone Resistant Giant’ and ‘Yolo Wonder B’, were compared for managing the southern root-knot nematode [Meloidogyne incognita (Chitwood) Kofoid and White] in fall and spring tests at Citra, FL. In the fall test, ‘Charleston Belle’ and ‘Carolina Wonder’ exhibited minimal root galling and nematode reproduction, and ‘Keystone Resistant Giant’ and ‘Yolo Wonder B’ exhibited severe root galling and high nematode reproduction. Fruit yield of ‘Charleston Belle’ was 97% greater than yields of the two susceptible cultivars (P ≤ 0.006). In the spring test, one-half of the plots were treated with methyl bromide/chloropicrin before planting the same four bell pepper cultivars. ‘Keystone Resistant Giant’ and ‘Yolo Wonder B’ grown in untreated control plots exhibited severe root galling and high nematode reproduction, but the other six cultivar × methyl bromide combinations exhibited minimal root galling and nematode reproduction. Although soil temperatures (10-cm depth) were greater than 30 °C on 78 days and 57 days during the Fall 2002 and Spring 2003 trials, respectively, resistance did not break in ‘Charleston Belle’ and ‘Carolina Wonder’ in either test. These results demonstrate that root-knot nematode-resistant cultivars such as Charleston Belle and Carolina Wonder are viable alternatives to methyl bromide for managing southern root-knot nematode in bell pepper in sub-tropical environments.


2016 ◽  
Vol 48 (1) ◽  
pp. 14-19 ◽  
Author(s):  
JUDY A. THIES ◽  
JENNIFER J. ARISS ◽  
CHANDRASEKAR S. KOUSIK ◽  
RICHARD L. HASSELL ◽  
AMNON LEVI

Plant Disease ◽  
2010 ◽  
Vol 94 (10) ◽  
pp. 1195-1199 ◽  
Author(s):  
Judy A. Thies ◽  
Jennifer J. Ariss ◽  
Richard L. Hassell ◽  
Steve Olson ◽  
Chandrasekar S. Kousik ◽  
...  

Four bottle gourd (Lagenaria siceraria) cultivars, one squash (Cucurbita moschata × C. maxima) hybrid, five wild watermelon (Citrullus lanatus var. citroides) germplasm lines, and one commercial wild watermelon (C. lanatus var. citroides) cultivar were evaluated as rootstocks for cultivated watermelon (C. lanatus var. lanatus) in fields infested with the southern root-knot nematode (Meloidogyne incognita) in Charleston, SC in 2007 and 2008, and in Quincy, FL in 2008. Commercial watermelon ‘Fiesta’ (diploid seeded) and ‘Tri-X 313’ (triploid seedless) scions were grafted onto the rootstocks in 2007 and 2008, respectively. In 2007, the plants grafted on rootstock from the wild watermelon germplasm line RKVL 318 had significantly less (P < 0.05) root galling than nongrafted ‘Fiesta’ watermelon or plants with the squash hybrid or bottle gourd rootstocks. In 2008, ‘Fiesta’ plants with rootstocks from all five wild watermelon germplasm lines and the commercial watermelon rootstock had significantly less (P < 0.05) root galling than plants with the squash hybrid or bottle gourd rootstocks. Root galling of the squash hybrid and bottle gourd rootstocks was severe (78 to 99%) in both years. Root galling for nongrafted ‘Fiesta’ and ‘Tri-X 313’ watermelon was 36 and 50%, respectively. Root galling for the wild watermelon germplasm lines ranged from 11 to 34% and 36 to 44% in 2007 and 2008, respectively. Wild watermelon germplasm lines derived from C. lanatus var. citroides were identified that may be useful as resistant rootstocks for managing root-knot nematodes in watermelon.


2010 ◽  
Vol 50 (3) ◽  
pp. 321-325 ◽  
Author(s):  
Ishola Odeyemi ◽  
Steve Afolami ◽  
Olufemi Sosanya

Effect of Glomus Mosseae (Arbuscular Mycorrhizal Fungus) On Host - Parasite Relationship of Meloidogyne Incognita (Southern Root-Knot Nematode) on Four Improved Cowpea VarietiesTwo pot experiments and a field study were conducted in a Randomized Complete Block Design (RCBD). The experiments were conducted to determine the effect ofGlomus mosseae, a mycorrhiza fungus, on the reaction of four improved cowpea varieties toMeloidogyne incognita.Cowpea plants were inoculated with a single or a combination of 5 000 eggs ofM. incognitaand 50 g ofG. mosseaeinoculum containing 5 spores/g of soil. The standardized method of screening and reporting resistance of crop germplasm to root-knot nematodes at 60 days after planting, and the modified version of including yield for resistance rating at harvest were used for this study. Root galling due toM. incognitainfection was significantly lower on all the cowpea varieties treated withG. mosseaeand more significantly on IT90K-277-2 and IT89KD-288 in the screenhouse.G. mosseae, suppressed root-knot nematode reproduction on all the varieties compared to cowpea plants infected only byM. incognitaboth in the screenhouse and field experiments. Also,G. mosseaemitigated the damage attributable to the root-knot nematode on all these varieties. Using Gall Index (GI), reproduction factor and yield,G. mosseaewas effective in improving the resistance of the cowpea varieties toM. incognita.IT90K-76 cowpea variety was consistently resistant to the root-knot nematode, while IT90K-277-2 was tolerant withM. incognitainfection but resistant withG. mosseaetreatment. IT90K-941-1 variety was resistant in the screenhouse. The results of this study also confirmedG. mosseaeas a potential bio-control agent forM. incognitaon these cowpea varieties.


2008 ◽  
Vol 9 (1) ◽  
pp. 11 ◽  
Author(s):  
K. L. Bowen ◽  
A. K. Hagan ◽  
H. L. Campbell ◽  
S. Nightengale

In Alabama and other southeastern states, corn is frequently planted in rotation with cotton and peanut in order to minimize soil-borne pest problems. Even in areas where peanut is not grown, corn is increasingly being planted in rotation with cotton. However, one root-knot nematode, Meloidogyne incognita race 3, causes damage to both cotton and corn. In this study, we determined levels of corn grain loss when southern root-knot nematodes are present in soil. Losses were 3.8 to 11.4% based on preceding years' counts and 2.2 to 7.0% with current years' counts for every 100 2nd-stage juvenile root-knot nematodes in 100 cm ≥ of soil. Knowledge of the percent loss in corn grain due to southern rootknot nematode populations can provide additional guidance for use of risk thresholds when growers are making management decisions. Accepted for publication 21 June 2008. Published 10 September 2008.


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