RESISTANCE OF WATERMELON (CITRULLUS LANATUS VAR. CITROIDES) GERMPLASM FOR RESISTANCE TO ROOT-KNOT NEMATODES

Root-knot nematodes (Meloidogyne incognita, M. arenaria, and M. javanica) cause severe damage to watermelon and resistance has not been identified in any watermelon cultivar. In greenhouse tests, we evaluated 265 U.S. plant introductions (PIs) for nematode resistance (based on root galling and nematode reproduction), and identified 22 PIs of Citrullus lanatus var. citroides as moderately resistant to M. arenaria race 1. In subsequent tests, these 22 PIs exhibited low to moderate resistance to M. incognita race 3 and M. arenaria race 2. Three watermelon (C. lanatus var. lanatus) cultivars (Charleston Gray, Crimson Sweet, and Dixie Lee), three C. colocynthis PIs, and four C. lanatus var. citroides PIs, all previously shown to be susceptible to M. arenaria race 1, were susceptible to M. incognita race 3 and M. arenaria race 2. The C. lanatus var. citroides PIs that are most resistant to both M. incognita and M. arenaria should be useful sources of resistance for developing root-knot nematode resistant watermelon cultivars.

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Characterization of Watermelon (Citrullus lanatus var. citroides) Germplasm for Resistance to Root-knot Nematodes

HortScience ◽

10.21273/hortsci.42.7.1530 ◽

2007 ◽

Vol 42 (7) ◽

pp. 1530-1533 ◽

Cited By ~ 25

Author(s):

Judy A. Thies ◽

Amnon Levi

Keyword(s):

Root System ◽

Citrullus Lanatus ◽

Sources Of Resistance ◽

Root Knot Nematodes ◽

Plant Introductions ◽

Race 1 ◽

Race 2 ◽

Moderate Resistance ◽

Moderately Resistant

Root-knot nematodes (Meloidogyne spp.) cause extensive damage to watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai var. lanatus], and resistance to root-knot nematodes has not been identified in any watermelon cultivar. Twenty-six U.S. Plant Introductions (PIs) of Citrullus lanatus (Thunb.) Matsum. & Nakai var. citroides (L. H. Bailey) Mansf., one PI of C. lanatus var. lanatus, and three PIs of Citrullus colocynthis (L.) Schrad. were evaluated in greenhouse tests for resistances to Meloidogyne incognita (Kofoid & White) Chitwood race 3 and Meloidogyne arenaria (Neal) Chitwood race 2. Twenty-three of the C. lanatus var. citroides PIs and the C. lanatus var. lanatus PIs were previously identified as moderately resistant to M. arenaria race 1. Overall, the C. lanatus var. citroides PIs exhibited low to moderate resistance, and the C. lanatus var. lanatus and C. colocynthis PIs were susceptible to both M. incognita race 3 and M. arenaria race 2. The C. lanatus var. citroides PI 482303 was the most resistant PI with gall index (GI) = 2.88 and reproductive index (RI) = 0.34 for M. incognita race 3 and GI = 3.46 and RI = 0.38 for M. arenaria race 2 (1 = no galling; 5 = 26% to 38% root system galled; 9 = 81% to 100% root system galled). These results demonstrate that there is significant genetic variability within C. lanatus var. citroides for reaction to M. incognita and M. arenaria race 2, and several C. lanatus var. citroides PIs may provide sources of resistance to root-knot nematodes.

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Sources of Resistance in U.S. Plant Introductions to Watermelon Vine Decline Caused by Squash Vein Yellowing Virus

HortScience ◽

10.21273/hortsci.44.2.256 ◽

2009 ◽

Vol 44 (2) ◽

pp. 256-262 ◽

Cited By ~ 17

Author(s):

Chandrasekar S. Kousik ◽

Scott Adkins ◽

William W. Turechek ◽

Pamela D. Roberts

Keyword(s):

Citrullus Lanatus ◽

Field Trials ◽

Limiting Factor ◽

Sources Of Resistance ◽

Central Florida ◽

Plant Introductions ◽

Disease Progress ◽

Vine Decline ◽

Moderate Resistance ◽

Yellowing Virus

Watermelon vine decline (WVD) is a new and emerging disease caused by the whitefly-transmitted squash vein yellowing virus (SqVYV). The disease has become a major limiting factor in watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] production in southwest and west–central Florida and is estimated to have caused more than $60 million in losses. Symptoms of WVD typically occur at or just before harvest and are manifested as sudden decline of the vines, often with a reduction in fruit quality. In this study, we present results of greenhouse and field evaluations of U.S. plant introductions (PIs) for resistance to SqVYV. Of the 218 PIs we evaluated for resistance to SqVYV, none were completely immune, but several showed varying levels of resistance and these were further evaluated in two greenhouse and field trials. Disease progress was significantly slower on the selected PIs compared with disease progress on susceptible watermelon cultivars Mickey Lee and Crimson Sweet. Moderate resistance was observed in two C. colocynthis (PI 386015 and PI 386024), a Praecitrullus fistulosus (PI 381749), and two C. lanatus var. lanatus PIs (PI 482266 and PI 392291). Variability in the resistant reaction to SqVYV within most PIs was observed. The identification of potential sources of partial resistance to SqVYV suggests that watermelon germplasm with moderate resistance can be developed by careful screening and selection of individual resistant plants within these PIs for use in breeding programs.

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Development and Genetic Characterization of Peanut Advanced Backcross Lines That Incorporate Root-Knot Nematode Resistance From Arachis stenosperma

Frontiers in Plant Science ◽

10.3389/fpls.2021.785358 ◽

2022 ◽

Vol 12 ◽

Author(s):

Carolina Ballén-Taborda ◽

Ye Chu ◽

Peggy Ozias-Akins ◽

C. Corley Holbrook ◽

Patricia Timper ◽

...

Keyword(s):

Seed Size ◽

Crop Improvement ◽

Flower Color ◽

Nematode Resistance ◽

Wild Relative ◽

Root Knot Nematode ◽

Sources Of Resistance ◽

Phenotypic Data ◽

Nematode Reproduction ◽

Advanced Backcross

Crop wild species are increasingly important for crop improvement. Peanut (Arachis hypogaea L.) wild relatives comprise a diverse genetic pool that is being used to broaden its narrow genetic base. Peanut is an allotetraploid species extremely susceptible to peanut root-knot nematode (PRKN) Meloidogyne arenaria. Current resistant cultivars rely on a single introgression for PRKN resistance incorporated from the wild relative Arachis cardenasii, which could be overcome as a result of the emergence of virulent nematode populations. Therefore, new sources of resistance may be needed. Near-immunity has been found in the peanut wild relative Arachis stenosperma. The two loci controlling the resistance, present on chromosomes A02 and A09, have been validated in tetraploid lines and have been shown to reduce nematode reproduction by up to 98%. To incorporate these new resistance QTL into cultivated peanut, we used a marker-assisted backcrossing approach, using PRKN A. stenosperma-derived resistant lines as donor parents. Four cycles of backcrossing were completed, and SNP assays linked to the QTL were used for foreground selection. In each backcross generation seed weight, length, and width were measured, and based on a statistical analysis we observed that only one generation of backcrossing was required to recover the elite peanut’s seed size. A populating of 271 BC3F1 lines was genome-wide genotyped to characterize the introgressions across the genome. Phenotypic information for leaf spot incidence and domestication traits (seed size, fertility, plant architecture, and flower color) were recorded. Correlations between the wild introgressions in different chromosomes and the phenotypic data allowed us to identify candidate regions controlling these domestication traits. Finally, PRKN resistance was validated in BC3F3 lines. We observed that the QTL in A02 and/or large introgression in A09 are needed for resistance. This present work represents an important step toward the development of new high-yielding and nematode-resistant peanut cultivars.

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Greenhouse and field resistance in cucumber to root-knot nematodes

Nematology ◽

10.1163/156854199508270 ◽

1999 ◽

Vol 1 (3) ◽

pp. 279-284 ◽

Cited By ~ 5

Author(s):

S. Alan Walters ◽

Todd C. Wehner ◽

Kenneth R. Barker

Keyword(s):

Cucumis Sativus ◽

Multiple Root ◽

Nematode Species ◽

Nematode Resistance ◽

Field Resistance ◽

Field Conditions ◽

Meloidogyne Arenaria ◽

Root Knot Nematode ◽

Root Knot Nematodes ◽

Race 2

Abstract Ten cultigens were evaluated for resistance to Meloidogyne arenaria races 1 and 2, and M. javanica under greenhouse and field conditions. Resistance to M. arenaria races 1 and 2, and M. javanica was verified in Cucumis sativus var. hardwickii line LJ 90430 and to M. arenaria race 2 in C. sativus var. sativus Southern Pickler and Mincu in a greenhouse test. Another cultigen of C. sativus var. hardwickii (PI 215589) was found to be resistant to M. arenaria race 2 but not to other root-knot nematode species tested. LJ 90430 is the cultigen of choice to develop root-knot nematode resistant cucumbers, since it has multiple root-knot nematode resistance and is cross-compatible with cucumber. Greenhouse and field data were positively correlated (r = 0.74) over both years. Experiment repeatabilities were calculated from the cultigens infected with root-knot nematodes under both greenhouse and field conditions. Four environments (greenhouse and field over 2 years) were used in the analysis. Repeatabilities were high in all instances (ranging from 0.83-0.99) and indicated that the environment (field or greenhouse) was not an important factor in assessing root-knot nematode resistance for the cultigens evaluated. Resistenz von Gurkengegen Wurzelgallennematoden im Gewachshaus undim Freiland - Unter Gewachshausund Freilandbedingungen wurden zehn Cultigene auf ihre Resistenz gegen Meloidogyne arenaria Rassen 1 und 2 und gegen M. javanica gepruft. Bei Cucumis sativus var. hardwickii Linie LJ 90430 wurde im Gewachshausversuch Resistenz gegen M. arenaria Rassen 1 und 2 sowie gegen M. javanica nachgewiesen, und in C. sativus var. sativus "Southern Pickler" und "Mincu" Resistenz gegen M. arenaria Rasse 2. Cultigen C. sativus var. hardwickii (PI 215589) war resistent gegen M. arenaria Rasse 2 aber nicht gegen die anderen gepruften Arten von Wurzelgallennematoden. LJ 90430 ist das Cultigen der Wahl bei der Entwicklung von Gurken, die gegen Wurzelgallennematoden resistent sind, da es multiple Resistenzen gegen Wurzelgallennematoden besitzt und kreuzungsvertraglich mit Gurke ist. Die Ergebnisse der Gewachshaus- und Feldversuche waren uber beide Versuchsjahre hin positiv korreliert (r = 0,74). Ausgehend von den Cultigenen, die im Gewachshaus und im Freiland mit Wurzelgallennematoden infiziert waren, wurden die Wiederholbarkeiten der Versuche berechnet. Dabei wurden vier verschiedene Umweltbedingungen (Gewachshaus und Freiland uber zwei Jahre) verwendet. Die Wiederholbarkeiten waren in allen Fallen hoch (0,83-0,99) und zeigten an, dass die Umwelt (Freiland oder Gewachshaus) kein wichtiger Faktor bei der Bestimmung der Resistenz gegen Wurzelgallennematoden bei den gepruften Cultigenen war.

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Identification and Evaluation of Additional Sources of Resistance to Peanut Root-knot Nematode in Arachis hypogaea L.1

Peanut Science ◽

10.3146/i0095-3679-23-2-5 ◽

1996 ◽

Vol 23 (2) ◽

pp. 91-94 ◽

Cited By ~ 7

Author(s):

C. Corley Holbrook ◽

James P. Noe ◽

Michael G. Stephenson ◽

William F. Anderson

Keyword(s):

Arachis Hypogaea ◽

Field Experiments ◽

Germplasm Collection ◽

Economic Losses ◽

Egg Mass ◽

Root Knot Nematode ◽

Sources Of Resistance ◽

Nematode Reproduction ◽

Plant Introductions ◽

Production Areas

Abstract The root-knot nematode (Meloidogyne arenaria race 1) causes significant economic losses throughout the peanut (Arachis hypogaea) production areas of the southern U.S. Chemicals for control of this pest are becoming increasingly limited, and there are no peanut cultivars with resistance. Seven moderately resistant plant introductions have been identified; however, less than 25% of the germplasm collection has been examined for resistance based on nematode reproduction. The objectives of this work were to examine an additional 1000 plant introductions for resistance to the peanut root-knot nematode and to compare the most resistant introductions to previously reported sources of resistance. Preliminary greenhouse screening trials were conducted to rate severity of root galling and amount of egg mass production. Seventeen accessions were selected based on a mean egg mass rating of less than or equal to three. These selections were reevaluated in additional greenhouse and field experiments to quantify levels of resistance and to directly compare these sources of resistance to those previously reported. Eight accessions had a significantly higher level of resistance (lower egg mass rating) than Florunner; however, none had a significantly higher level of resistance than those previously reported. Results of this study identified additional sources of resistance which may provide unique genes for resistance. In addition, two of these new sources of resistance (PI 298848 and PI 311265) exhibited significantly higher yield than those previously identified when grown in soil heavily infested with M. arenaria.

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Expression of Nematode Resistance in Plant Introductions of Arachis hypogaea

Peanut Science ◽

10.3146/i0095-3679-27-2-8 ◽

2000 ◽

Vol 27 (2) ◽

pp. 78-82 ◽

Cited By ~ 5

Author(s):

P. Timper ◽

C. C. Holbrook ◽

H. Q. Xue

Keyword(s):

Arachis Hypogaea ◽

Nematode Resistance ◽

Root Knot Nematode ◽

Feeding Site ◽

Plant Introductions ◽

Arachis Hypogaea L ◽

Cultivated Peanut ◽

Race 1 ◽

Moderately Resistant ◽

Resistant Genotypes

Abstract The peanut root-knot nematode (Meloidogyne arenaria, race 1) is a world-wide pest of peanut (Arachis hypogaea L.). Several moderately resistant genotypes have been identified in the cultivated peanut species. Our objective was to determine the expression of resistance for six of these genotypes. We examined four potential expressions of resistance—(a) fewer second-stage juveniles (J2) penetrate the roots, (b) fewer J2 establish functional feeding sites, (c) slower maturation, and (d) reduced fecundity (eggs per female). Seedlings of the susceptible cultivar Florunner and the resistant genotypes were inoculated with J2 of M. arenaria, and transplanted 3 d later to synchronize nematode development. Penetration was assessed at 3 and 10 d; development at 10 (or 12), 17, 22, and 27 d; and fecundity at 60 d after inoculation. The experiments were conducted in a greenhouse or growth chamber. The number of J2 within the roots was similar in resistant and susceptible peanut after 3 d; however, numbers were lower in two of the resistant genotypes than in Florunner after 10 d. A greater percentage of J2 failed to develop in all of the resistant genotypes (72 to 79%) than in Florunner (50%) after 17 d. Of the J2 that did begin to develop, the rate of maturation and fecundity was similar in resistant and susceptible genotypes. A lack of development indicates that the J2 failed to establish a feeding site. Therefore, the primary expression of resistance in the six peanut genotypes appears to be a reduction in the percentage of J2 that establish a functional feeding site. The decline in J2 after infection may be related to the failure to establish a feeding site.

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Root-knot Nematode Resistance in Capsicum chinense: Development of Resistant Habanero-type Cultivars

HortScience ◽

10.21273/hortsci.39.4.766b ◽

2004 ◽

Vol 39 (4) ◽

pp. 766B-766 ◽

Cited By ~ 1

Author(s):

Richard L. Fery* ◽

Judy A. Thies

Keyword(s):

United States ◽

Dominant Gene ◽

Nematode Resistance ◽

The United States ◽

High Yield ◽

Root Knot Nematode ◽

Root Knot Nematodes ◽

Nematode Resistance Gene ◽

Race 1 ◽

Southern Root Knot Nematode

Root-knot nematodes (Meloidogyne spp.) are major pests of pepper (Capsicum spp.) in the United States, and parasitism of susceptible plants can result in severe yield losses. Although cultivars belonging to the species C. annuum account for most of the peppers grown in the United States. Habanero-type cultivars belonging to the species C. chinense are becoming increasingly popular. Unfortunately, all commercial Habanero-type cultivars are susceptible to root-knot nematodes. In 1997, the USDA released three C. chinense germplasm lines that exhibit high levels of resistance to root-knot nematodes. The resistance in these lines is conditioned by a single dominant gene, and this gene conditions resistance to the southern root-knot nematode (M. incognita), the peanut root-knot nematode (M. arenaria race 1), and the tropical root-knot nematode (M. javanica). A recurrent backcross breeding procedure has been used to transfer the C. chinense root-knot nematode resistance gene in Habanero-type germplasm. Several root-knot nematode resistant, Habanero-type candidate cultivars have been developed. Each of these Habanero-type candidate cultivars has a compact plant habit and produces a high yield of orange-colored, lantern-shaped fruit.

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Characterization of Resistance Conferred by the N gene to Meloidogyne arenaria Races 1 and 2, M. hapla, and M. javanica in Two Sets of Isogenic Lines of Capsicum annuum L.

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.125.1.71 ◽

2000 ◽

Vol 125 (1) ◽

pp. 71-75 ◽

Cited By ~ 26

Author(s):

Judy A. Thies ◽

Richard L. Fery

Keyword(s):

Capsicum Annuum ◽

Nematode Resistance ◽

N Gene ◽

Recurrent Parent ◽

Resistance Locus ◽

Meloidogyne Arenaria ◽

Meloidogyne Hapla ◽

Root Knot Nematode ◽

Race 1 ◽

Race 2

Two isogenic sets of bell pepper (Capsicum annuum L.) lines (differing at the N root-knot nematode resistance locus) were characterized for resistance to Meloidogyne arenaria (Neal) Chitwood races 1 and 2, M. hapla Chitwood, and M. javanica (Treub) Chitwood in greenhouse and growth chamber tests. The isogenic sets of C. annuum were `Charleston Belle' (NN) and `Keystone Resistant Giant' (nn-recurrent parent), and `Carolina Wonder' (NN) and `Yolo Wonder B' (nn-recurrent parent). Meloidogyne arenaria race 1 is pathogenic to C. annuum. `Charleston Belle' and `Carolina Wonder' exhibited high resistance to M. arenaria race 1. Their respective recurrent backcross parents, `Keystone Resistant Giant' and `Yolo Wonder B', were susceptible to M. arenaria. Meloidogyne arenaria race 2 and M. javanica are not highly pathogenic to pepper. However, `Charleston Belle' and `Carolina Wonder' both exhibited higher (P≤0.05) resistance to M. arenaria race 2 and M. javanica than `Keystone Resistant Giant' and `Yolo Wonder B'. Meloidogyne hapla is pathogenic to pepper. Both `Charleston Belle' and `Carolina Wonder' and their respective recurrent parents, `Keystone Resistant Giant' and `Yolo Wonder B', were susceptible to M. hapla. We concluded that the N gene confers resistance to M. arenaria races 1 and 2, and M. javanica in C. annuum, but the N gene does not condition resistance to M. hapla.

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Characterization of New Sources of Resistance in Cowpea to the Southern Root-knot Nematode

HortScience ◽

10.21273/hortsci.29.6.678 ◽

1994 ◽

Vol 29 (6) ◽

pp. 678-679 ◽

Cited By ~ 8

Author(s):

Richard L. Fery ◽

Philip D. Dukes ◽

Judy A. Thies

Keyword(s):

Egg Production ◽

Nematode Resistance ◽

Field Studies ◽

Egg Mass ◽

Root Knot Nematode ◽

Sources Of Resistance ◽

Dominant Type ◽

Plant Introductions ◽

Nematode Resistance Gene ◽

Southern Root Knot Nematode

A series of greenhouse and field studies was conducted over 9 years to characterize three new sources of resistance in cowpea [Vigna unguiculata (L.) Walp.] to the southern root-knot nematode [Meloidogyne incognita (Kofoid & White) Chitwood] and to determine if the resistances are conditioned by genes allelic to the Rk root-knot nematode resistance gene in `Mississippi Silver'. Three plant introductions (PI), PI 441917, PI 441920, and PI 468104, were evaluated for reaction to M. incognita in four greenhouse tests, and in every test each PI exhibited less galling, egg mass formation, or egg production than `Mississippi Silver'. F2 populations of the crosses between `Mississippi Silver' and each of the three resistant PIs were also evaluated for root-knot nematode resistance in a greenhouse test. None of the F2 populations segregated for resistance, indicating that PI 441917, PI 441920, and PI 468104 each has a gene conditioning resistance that is allelic to the Rk gene in `Mississippi Silver'. Our observations on the superior levels of resistances exhibited by PI 441917, PI 441920, and PI 468104 suggest that the allele at the Rk locus in these lines may not be the Rk allele, but one or more alleles that condition a superior, dominant-type resistance. The availability of additional dominant alleles would broaden the genetic base for root-knot nematode resistance in cowpea.

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Resistance of Watermelon Germplasm to the Peanut Root-knot Nematode

HortScience ◽

10.21273/hortsci.38.7.1417 ◽

2003 ◽

Vol 38 (7) ◽

pp. 1417-1421 ◽

Cited By ~ 19

Author(s):

Judy A. Thies ◽

Amnon Levi

Keyword(s):

Citrullus Lanatus ◽

Germplasm Collection ◽

Plant Introduction ◽

Root Knot Nematode ◽

Sources Of Resistance ◽

Race 1 ◽

Gall Index ◽

Moderately Resistant ◽

The U.S ◽

Greenhouse Tests

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.

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