Figure - uploaded by Judy Ann Thies
Content may be subject to copyright.
Response of nine Citrullus spp. accessions and cultivars to Meloidogyne incognita in a field test with and without nematicide treatment, Charleston, SC, 2007.
Source publication
Southern root-knot nematode (RKN, Meloidogyne incognita) is a serious pest of cultivated watermelon (Citrullus lanatus var. lanatus) in southern regions of the United States and no resistance is known to exist in commercial watermelon cultivars. Wild watermelon relatives (Citrullus lanatus var. citroides) have been shown in greenhouse studies to po...
Similar publications
This study aims to examine the potential reasons for the current prevalence of the fusarium wilt in the oriental melon. Twenty-seven Fusarium isolates obtained from oriental melon greenhouses in 2010–2011 were identified morphologically and by analysis of elongation factor-1 alpha gene (EF-1α) and internal transcribed spacer (ITS) rDNA sequences as...
The aim of this study was to evaluate the performance of progenies from Citrullus lanatus var. lanatus (cultivated watermelons) when crossed with progenies from C. lanatus var. citroides (fodder watermelon with a historic of resistance to the nematode Meloidogyne enterolobii). The parents and their F1s were evaluated for resistance to this nematode...
This study aimed to evaluate the efficacy of different concentrations of abamectin, in combination with thiabendazole and thiamethoxam, on seed physiological quality and on the control of Meloidogyne javanica in watermelon plants. To this purpose watermelon seeds of the Crimson Sweet variety were employed in the study. The treatment of the seeds co...
Citations
... Among the available alternative techniques to methyl bromide, plant resistance is one of the most investigated techniques in PPN management (Onkendi et al. 2014). Most crops lack resistant genotypes to Meloidogyne species as observed in four commercial genera of Cucumis, Citrullus, Cucurbita and Lagenaria within the Cucurbitaceae family (Liu et al. 2016;Thies et al. 2016;Verdejo-Lucas and Talavera 2019;Singh and Patel 2015). Cucumis africanus is highly resistant to Meloidogyne species (Pofu et al. 2012); however, the mechanism of nematode resistance in this crop has not been established. ...
Using nematode resistant varieties is one of effective and environmental sound strategies being adopted in the management of economically important Meloidogyne species. Wild cucumber (Cucumis africanus) has been reported to possess resistance to Meloidogyne species. Two mechanism of nematode resistance, pre-and post-penetration resistance, had been identified, with post-penetration mechanism being used in plant breeding programs and crop rotation systems. The objective of this study was to determine the mechanism of nematode resistance in C. africanus to M. incognita and M. javanica. 6 weeks old C. africanus seedlings were separately inoculated with 100 s-stage juveniles (J2) of M. incognita and M. javanica. For 30 days, five seedlings were harvested from both M. incognita and M. javanica experiments every other day. Seedlings' roots were examined for necrotic spots, rootlet interferences, giant cells and root gall numbers as indicators of successful or unsuccessful nematode penetration. Harvesting times were highly significant (P ≤ 0.01) on necrotic spot, rootlet interference and root gall numbers in both C. africanus-M. incognita and-M. javanica relations, but were not significant for giant cell number in C. africanus-M. incognita. The results suggested that C. africanus have post-penetration nematode resistance to both Meloidogyne species.
... Citron melons are grown worldwide mainly for animal feed and fruit preserves. Resistance to nematodes, expressed as less galling than that of Cucurbita hybrids and bottle gourd rootstocks (Thies et al. 2016), and Fusarium wilt (Patrick Wechter et al. 2012) has been reported in some citron melon accessions, suggesting that this group is a promising alternative source of rootstock for managing root-knot nematodes (RKNs) and Fusarium wilt in watermelon. It has been reported by different researchers that the use of citron rootstock in the production of grafted watermelon can be an interesting alternative to the currently used commercial rootstock (Edelstein et al. 2014;Levi et al. 2014;Fredes et al. 2016). ...
A hydroponic experiment was conducted to assess whether grafting with citroides rootstocks could improve the salt tolerance of cucumber. One cucumber cultivar (Mercur F1) was grafted onto six diploid and tetraploid (auto and allo) citroides genotypes and the commercial rootstocks Argentario and RS841. Plants were grown in hydroponic culture at two electrical conductivity (EC) levels (control at 1.5 dS m⁻¹ and salt at 6.0 dS m⁻¹). Hydroponic salt stress led to a significant reduction in biomass growth of both grafted and nongrafted cucumbers. However, the plants least affected by salt stress were those grafted onto tetraploid citroides rootstocks. The leaf nutrient uptake of cucumber plants was significantly (p < 0.001) affected by salt, graft combination, and the salt × graft interaction. Ion leakage was significantly increased by salt application, and rootstock genotypic variation was significant. While the highest amount of proline was measured in plants grafted onto RS841 and N7T, the lowest amount of proline was determined in nongrafted control plants. Antioxidative enzyme activities were significantly affected by rootstocks under both control and salt-stress conditions. In this study, all graft combinations showed increased superoxide dismutase, catalase, and peroxidase activities with salt application, which differed according to rootstock genotypes. Tetraploid citroides cultivars have high rootstock potential for cucumber and their significant contribution to salt tolerance was closely associated with inducing physiological and biochemical responses of scions. These traits could be useful for the selection and breeding of salt-tolerant rootstocks for sustainable agriculture in the future.
... No commercially available watermelon cultivars are resistant to RKN and yield losses have been predicted to reach approximately 20% in situations with high RKN populations [23,28,29]. Additionally, the interspecific hybrid squash and bottle gourd rootstocks used in grafted watermelons against FON are susceptible to RKN [30]. Recent reports indicate variable responses in terms of incidence and severity of wilt symptoms during FON and RKN interactions in watermelon [8,[31][32][33], further investigation is warranted to identify other factors that govern differential responses against FON and RKN. ...
The soil-borne pathogens, particularly Fusarium oxysporum f. sp. niveum (FON) and southern root-knot nematode (RKN, Meloidogyne incognita) are the major threat to watermelon production in the south-eastern United States. The role of soil micronutrients on induced resistance (IR) to plant diseases is well-documented in soil-based mediums. However, soil-based mediums limit the determination of the role(s) of individual micronutrients in IR. In this manuscript, we utilized hydroponics to assess the effect of controlled application of micronutrient, including iron (Fe), manganese (Mn), and zinc (Zn) on the expression of some IR genes (PR1, PR5, and NPR1 from salicylic acid (SA) pathway, and VSP, PDF, and LOX genes from jasmonic acid (JA) pathway) in watermelon seedlings upon inoculation with either FON or RKN or both. Plants were treated with higher (3X) or lower (0.5X) concentrations of micronutrients in Steiner solution (X= standard dose of micronutrient) for 7 days in a hydroponics system under greenhouse conditions. A subset of micronutrient-treated plants was inoculated (on the 8th day of micronutrient application) with FON and RKN (single and mixed). The expression of the IR genes in treated and control samples were evaluated using qRT-PCR. Although, significant phenotypic differences were not observed with respect to the severity of wilt symptoms or RKN galling with any of the micro-nutrient treatments within the 30 day-experimental-period, differences in the induction of IR genes were observed. However, the level of gene expression varied with sampling period, type and concentration of micro-nutrients ap-plied, and pathogen-inoculation. In the absence of pathogens, no significant changes were observed in the expression level of IR genes on 7th day of micronutrient treatment. However, pathogen inoculation affected the expression levels of the IR genes at 3-day post-inoculation. In FON inoculated plants, PDF was upregulated in high Fe treatment, whereas in RKN inoculated plants, low Mn treatment resulted in up-regulation of VSP. In the case of mixed inoculation with FON and RKN, the plants with low Zn treatment resulted in the upregulation of PR1. These observations suggest that the type and concentration of micronutrients in watermelon may potentially induce systemic resistance against FON and RKN through SA and JA pathways.
... Vegetable grafting is extensively used in agricultural production to control soil-borne pathogens (Yetisir et al., 2003;Thies et al., 2016), and to improve tolerance to salinity (Yang et al., 2013), suboptimal temperatures (Li et al., 2014;Yang et al., 2016), and mineral deficiency (Nawaz et al., 2017). Commercial vegetable grafting is mainly practiced in Cucurbitaceae and Solanaceae species, with watermelon having the highest grafting proportion. ...
Grafting is an effective way to increase watermelon's tolerances to biotic and abiotic stresses. However, the survival of grafted seedlings largely depends on successful graft formation. Therefore, understanding the graft formation process, particularly vascular reconnection, is of critical importance. This study found that lignin in watermelon stem showed strong auto-fluorescence under blue-light excitation. Consequently, blue-light excited fluorescent tracers (FTs) such as 5(6)-carboxy fluorescein diacetate (CFDA) were unsuitable for assaying vascular connectivity in watermelon. In contrast, UV-light excited esculin and red-light excited acid fuchsin proved to be efficient FTs for monitoring phloem and xylem connectivity, respectively, in self-grafted watermelon. Furthermore, combining esculin application to the scion cotyledon and acid fuchsin to the rootstock root enabled simultaneous monitoring of both phloem and xylem connectivity in individual self-grafted watermelon seedlings. Based on this assay, we found that phloem and xylem reconnections occurred simutaneously in self-grafted watermelon. Moreover, low temperature and removal of the rootstock cotyledons both delayed vascular reconnection in the self-grafted watermelon. In conclusion, this new method provided a convenient, accurate and rapid way to analyze vascular connectivity in watermelon.
... Even though the crop is drought-tolerant, when cultivated as a low input crop, the productivity of the crop is substantially low due to an assortment of challenges, which include the availability of nutrient elements such as phosphorus and the incidence of high population densities of root-knot (Meloidogyne species) nematodes. Generally, Meloidogyne species are a serious threat in crop production systems, with crops without nematode resistance to the genus suffering losses from as high as 50% to total crop failure (Thies et al., 2016). Fortunately, certain cowpea cultivars/landraces with resistance to Meloidogyne species had been identified (Ononuju and Nzenwa, 2011;Ruanpanun and Somta, 2015). ...
Cowpea [( Vigna unguiculata (L.) Walp)] is highly susceptible to the emerging guava root-knot nematode, Meloidogyne enterolobii , with available management options being limited due to the withdrawal of effective fumigant nematicides from the agrochemical markets. Filamentous fungi, available as Biocult (a.i. Glomus species + Trichoderma asperellum Lieckf and Nirenberg) and Nemafric-BL phytonematicide (a.i. cucurbitacin B) each improves plant growth and suppresses nematode population densities. However, when filamentous fungi like Biocult are combined with other biocontrol agents, the combined effects either have synergestic or antagonistic effects on the test variables. The combined effects of Biocult and cucurbitacin phytonematicides on plant growth and nematode suppression remain undocumented. The objective of this study was therefore to determine the combined effects of Biocult and Nemafric-BL phytonematicide on growth of cowpea var. Eureka and suppression of M. enterolobii population densities. Eureka was subjected to the effects of the two products in a 2 × 2 factorial experiment on a field infested with M. enterolobii . At harvest, the interaction of Biocult and Nemafric-BL phytonematicide was highly significant ( P ≤ 0.01) on plant and nematode variables, with a two-way table used to assess the findings. Relative to untreated control, Biocult alone increased plant growth variables from 15 to 74%. Similarly, NemafricBL phytonematicide increased plant variables from 14 to 61%, whereas the combined effects significantly increased dry shoot mass (19%) and dry harvestable leaf mass (21%), but did not have significant effects on plant height and stem diameter. Relative to untreated control, Biocult alone reduced nematode eggs in root (80%), J2 in root (84%) and J2 in soil (53%), whereas the combined relative effects of the two products did not have significant effects on nematode population densities. In conclusion, Biocult and Nemafric-BL phytonematicide had antagonistic effects on growth of cowpea and suppression of M. enterolobii population densities and therefore, should be used separately in cowpea production.
... Another accession (PI 299379) from South Africa was reported to be resistant to anthracnose disease of the races 1 and 2 (Levi et al. 2001). Also, semi-wild accessions PI 244018 and PI 244019 were found to be resistant to watermelon virus disease (Levi et al. 2001), while PI 244018 conferred resistance to rootknot nematodes (Thies et al. 2016). Typically, the white-fleshed fruit from semi-wild citron watermelon is not suitable as fruit salad due to poor eating quality and presence of undesirable carotenoids. ...
Bottle gourd (Lagenaria siceraria (Molina) Standl.] and citron watermelon (Citrullus lanatus var. citroides (L. H. Bailey) Mansf. ex Greb.) are amongst the widely grown yet under-researched cucurbits genetic resources in sub-Saharan Africa (SSA). Fresh immature leaves, fruit and seed are used for food and medicinal purposes in the region. Furthermore, both species are used as rootstock and donors of novel genes for commercial production and breeding of sweet dessert watermelon cultivars. Despite their economic value and contribution to food and nutrition security in the region, bottle gourd and citron watermelon genetic resources remain under-utilized and largely un-explored for commercial product development. The objective of this review was to document the unique values of bottle gourd and citron watermelon for genetic improvement and development of value-added food and non-food products, and to highlight regional and global efforts on conservation , production, processing, commercialization and various enterprise development of these important indigenous species. The review discussed on the value of both crops as a rootstock to improve fruit yield and quality of cultivated watermelon. This is followed by important summaries on phenotypic and genetic variation of bottle gourd and citron watermelon genetic resources and implications for new cultivar design. Finally, the review highlighted value-added non-food and food-based products developed based on indigenous knowledge systems in SSA and availability and access to genetic resources of bottle gourd and citron watermelon for breeding, product design and deployment.
... About 40%of watermelon plants are grafted in China, and over 95% of commercial watermelon seedlings are grafted in Japan, Korea, Greece, Israel, and Turkey [3][4][5]. The main purposes of watermelon grafting are to solve fusarium wilt and root-knot nematode problems [6,7], to increase nutrient use efficiency [8], tolerance to salinity [9], cold, and drought [10,11], and to increase fruit yield [12]. Huang et al. [12] reported that the productivity of grafted watermelon can be 13%-25% higher than nongrafted plants. ...
Grafting is a widely used technique in watermelon (Citrullus lanatus) production. However, cost of grafted seedlings is generally high as a result of intensive labor inputs for propagation using traditional grafting methods such as the manual removal of rootstock regrowth. This study developed a new grafting tool to physically remove the epidermis of pumpkin (C. maxima × C. moschata) and bottle gourd (Lagenaria siceraria) rootstock cotyledon base during grafting; we called this a new grafting method. Compared with the traditional grafting, the new grafting method significantly decreased the pumpkin rootstock regrowth rate from 100% to 8% in hole insertion and 2% in one cotyledon grafting, respectively. These attenuated rates for bottle gourd rootstock regrowth were 23% and 9% in hole insertion and one cotyledon grafting, respectively. The scion dry weights of new hole insertion and one cotyledon grafting were increased by 78% and 74% when pumpkin was used as rootstock as compared with traditional grafting without regrown rootstock removal, while the respective values were 33% and 17% in bottle gourd rootstock grafted plants. In addition, the time used for the new hole insertion grafting method to physically remove the epidermis of pumpkin rootstock cotyledon base was significantly shorter than the time required to remove the rootstock regrowth manually three times in the traditional grafting (4.2 s/plant vs. 9.3 s/plant). Similar results were also observed in the new one cotyledon grafting (4.2 s/plant vs. 8.8 s/plant). Taken together, this study presents a new method in watermelon grafting to reduce rootstock regrowth, therefore benefiting both scion growth and plant management, thus the development of this new method is clearly useful in watermelon production.
... Vegetable grafting is extensively used in agricultural production to control soil-borne pathogens (Yetisir et al., 2003;Thies et al., 2016), and to improve tolerance to salinity (Yang et al., 2013), suboptimal temperatures (Li et al., 2014;Yang et al., 2016), and mineral deficiency (Nawaz et al., 2017). Commercial vegetable grafting is mainly practiced in Cucurbitaceae and Solanaceae species, with watermelon having the highest grafting proportion. ...
Grafting is an effective way to increase watermelon tolerance to biotic and abiotic stresses. However, the survival of grafted seedlings largely depends on successful graft formation. Therefore, understanding the graft formation process, particularly the vascular reconnection process is of critical importance. This study found that lignin in watermelon stem shows strong auto-fluorescence under blue-light excitation which makes blue-light excited fluorescent tracers (FTs) such as 5(6)-carboxy fluorescein diacetate (CFDA) become unsuitable for assaying vascular connectivity in watermelon. In contrast, UV-light excited esculin and red-light excited acid fuchsin were proved to be efficient FTs for monitoring the phloem and xylem connectivity, respectively, in self-grafted watermelon. Furthermore, a combined application of esculin to the scion cotyledon and acid fuchsin to the rootstock root enabled simultaneous monitoring of the phloem and xylem connectivity in individual self-grafted watermelon seedlings. In addition, this method is also applicable in investigating the phloem and xylem reconnections in self-grafted melon and cucumber, and heterograft of watermelon, melon and cucumber onto pumpkin rootstock. Based on this established method, we found that phloem and xylem reconnections are not timely separated in self-grafted watermelon. Furthermore, low temperature and removal of the rootstock cotyledons both delayed the vascular reconnection process in watermelon. In conclusion, this new method provides a convenient, accurate and rapid way to analyze the vascular connectivity not only in watermelon, but also in other cucurbit crops.
... Also, citron watermelon is currently valued as a suitable rootstock for improving fruit yield and quality of grafted sweet dessert watermelon (Kombo & Sari, 2019;Yan et al., 2018;Yavuz et al., 2020;Zhong et al., 2018). Other production attributes of the crop included abiotic (i.e., heat and drought stress) (Mo et al., 2016;Yavuz et al., 2020) and biotic stress tolerance Thies et al., 2016). Therefore, citron watermelon is a useful genetic resource for breeding and cultivar development of C. lanatus var. ...
The present study estimated variance components, heritability and genetic advance of phenotypic traits in citron watermelon to guide selection of superior genotypes for direct production and breeding. Thirty-six citron watermelon landrace accessions were evaluated across two seasons using a 6 × 6 alpha lattice design with three replications. High broad-sense heritability and genetic advance as per cent of the mean were recorded for fruit length at 83.86% and 4730.45%, seed length (77.73% and 1731.27%), hundred seed weight (73.73% and 4027.36%), fruit diameter (70.44% and 2949.64%) and fruit weight (70.39% and 8490.05%), respectively. Step-wise regression analysis revealed marketable fruit yield (Myld) and total number of fruits per plant (TNFr) explained 89% (R2 = .89) of total variation for total fruit yield per plant (TFYld), whereas number of seed per fruit (NSPFr) and hundred seed weight (HSW) explained 92% (R2 = .92) of total variation for seed yield per fruit (SYPFr). Citron watermelon landrace accessions WWM03, WWM14, WWM16, WWM39, WWM65, WWM67 and WWM79 with high TFYld and SYPFr were selected for production or breeding.
... Watermelon is an important horticultural crop and grafting is widely used in its production [3,4]. The main purpose of watermelon grafting is to solve fusarium wilt and root-knot nematode problems [5,6], to increase nutrient use efficiency [7], tolerance to salinity [8], cold and drought [9,10], and to increase fruit yield [11]. Zhao [11] reported that the productivity of grafted watermelon can be 13-25% higher than nongrafted plants. ...
Grafting is an effective way to increase plant tolerance to biotic and abiotic stressors, it is widely used in watermelon production. However, grafting is labor intensive due to the additional time is required, such as the management of rootstock regrowth. This study used a new grafting tool to destroy (remove) the epidermis of pumpkin and bottle gourd rootstock cotyledon base during grafting, we called this a new grafting method. Compared with the traditional grafting (100%), the new grafting method had significantly lower rate of rootstock regrowth (2-23%), higher watermelon scion dry weight and leaf area. In addition, the time used for the new hole insertion and one cotyledon grafting method to destroy (remove) the epidermis of rootstock cotyledon base (4.2 s/plant, 4.2 s/plant) is significantly shorter than the time required to remove the rootstock regrowth manually in the traditional grafting (9.3 s/plant, 8.8 s/plant). Thus, this study developed a new grafting method for watermelon to inhibit rootstock regrowth and enhance scion growth, and this new method is cost-effective for grafted watermelon seedlings.
