Characterization of New Sources of Resistance in Cowpea to the 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 to the Peanut Root-Knot Nematode (Meloidogyne arenaria) in Arachis hypogaea1

Peanut Science ◽

10.3146/i0095-3679-19-1-9 ◽

1992 ◽

Vol 19 (1) ◽

pp. 35-37 ◽

Cited By ~ 23

Author(s):

C. Corley Holbrook ◽

James P. Noe

Keyword(s):

Egg Production ◽

Economic Losses ◽

Egg Mass ◽

Root Weight ◽

Meloidogyne Arenaria ◽

Root Knot Nematode ◽

Sources Of Resistance ◽

Plant Introductions ◽

Nematode Eggs ◽

Fresh Root

Abstract The peanut root-knot nematode [Meloidogyne arenaria (Neal) Chitwood race 1] causes significant economic losses throughout the peanut (Arachis hypogaea L.) production area of the southern United States. Chemicals for control of this pest are becoming increasingly limited, and there are no known sources of resistance within the U. S. A. hypogaea collection. The objectives of this research were to screen 1,321 plant introductions for resistance or hypersusceptibility based on egg-mass ratings in greenhouse tests and to conduct more intensive greenhouse studies of selected genotypes to evaluate this method for identifying resistance to the peanut root-knot nematode. Twenty-seven genotypes with low and eight genotypes with high egg-mass ratings were selected and reevaluated in a more intensive greenhouse experiment. Seventeen of the low selections supported fewer (P≤0.05) egg masses, and seven supported less egg production per gram of fresh root weight than Florunner. Three selections for high egg-mass ratings supported more nematode eggs per plant than the cultivar Florunner and had a greater host efficiency. One of these genotypes supported more nematode eggs per gram of fresh root weight than Florunner. These results show that resistance to M. arenaria exists in the cultivated peanut species and can be selected by rating egg-mass production on greenhouse-grown plants.

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(259) TigerPaw-NR, a Root-knot Nematode Resistant, Habanero-type Pepper

HortScience ◽

10.21273/hortsci.41.4.1073d ◽

2006 ◽

Vol 41 (4) ◽

pp. 1073D-1073

Author(s):

Richard L. Fery ◽

Judy A. Thies

Keyword(s):

Dominant Gene ◽

Nematode Resistance ◽

Field Studies ◽

The United States ◽

Root Knot Nematode ◽

Nematode Resistance Gene ◽

Plant Grown ◽

Variety Protection ◽

High Level ◽

Southern Root Knot Nematode

The USDA–ARS has released a new Habanero-type pepper cultivar named TigerPaw-NR. The new cultivar is the product of a conventional recurrent backcross breeding procedure to transfer a dominant root-knot nematode resistance gene from the Scotch Bonnet accession PA-426 into the Habanero-type accession PA-350. TigerPaw-NR was derived from a single F3BC4 plant grown in 2002. TigerPaw-NR is homozygous for a dominant gene conditioning a high level of resistance to the southern root-knot nematode, the peanut root-knot nematode, and the tropical root-knot nematode. TigerPaw-NR has a compact plant habit and produces attractive lantern-shaped, orange-colored fruit. The results of three replicated field studies conducted at Charleston, S.C., indicate that the fruit and yield characteristics of TigerPaw-NR are comparable to those of currently available Habanero-type cultivars. A typical fruit weighs 7.8 g, is 2.7 cm wide × 4.4 cm long, and is extremely pungent (348,634 Scoville heat units). Root-knot nematodes are major pests of peppers in the United States, and all Habanero-type cultivars currently available to commercial growers and home gardeners are susceptible. The root-knot nematode resistant TigerPaw-NR is recommended for use by both commercial growers and home gardeners. Protection for TigerPaw-NR is being sought under the Plant Variety Protection Act.

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

HortScience ◽

10.21273/hortsci.41.3.520a ◽

2006 ◽

Vol 41 (3) ◽

pp. 520A-520

Author(s):

J. A. Thies ◽

A. Levi

Keyword(s):

Citrullus Lanatus ◽

Nematode Resistance ◽

Root Knot Nematode ◽

Sources Of Resistance ◽

Root Knot Nematodes ◽

Nematode Reproduction ◽

Plant Introductions ◽

Race 1 ◽

Race 2 ◽

Moderate Resistance

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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