Resistance to Root‐Knot Nematode in Control of Root‐Knot Nematode‐Fusarium Wilt Disease Complex in Cotton
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Eight cotton cultivars, with and without aldicarb treatment, were evaluated for their effect on the severity of the root-knot nematode-Fusarium wilt disease complex in cotton. A randomized complete block design with a split-plot arrangement of treatments was used with cotton cultivars as the main plots and nematicide treatments as the subplots. Results in 1994 and 1995 were similar. Yield of lint, boll weight, and wilt and root-gall ratings were different among cultivars and between nematicide treatments both years. Increased lint yield and boll weight, and reduced root-gall and wilt ratings were associated with application of aldicarb. Increased lint percentage was associated with application of aldicarb in 1994, but not in 1995. Fiber micronaire, elongation, uniformity, and strength were different among cultivars, but not between nematicide treatments. Fiber length (UHM; Upper-Half Mean) was different among cultivars and was higher in the aldicarb-treated plots in both years. Numbers of Meloidogyne incognita second stage juveniles and eggs extracted from soil samples were lower in the aldicarb-treated plots in July, but not at harvest, both years. Population densities of M. incognita were not different among cultivars, except the mid-season sample in 1995.

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Effect of Planting Date and Host Genotype on the Root-Knot Nematode-Fusarium Wilt Disease Complex of Cotton

Phytopathology ◽

10.1094/phyto-83-645 ◽

1993 ◽

Vol 83 (6) ◽

pp. 645 ◽

Cited By ~ 10

Author(s):

D. P. Jeffers

Keyword(s):

Fusarium Wilt ◽

Planting Date ◽

Wilt Disease ◽

Root Knot Nematode ◽

Host Genotype ◽

Disease Complex ◽

Fusarium Wilt Disease

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A Fusarium Wilt Resistance Gene in Gossypium barbadense and Its Effect on Root-Knot Nematode-Wilt Disease Complex

Phytopathology ◽

10.1094/phyto-96-0727 ◽

2006 ◽

Vol 96 (7) ◽

pp. 727-734 ◽

Cited By ~ 33

Author(s):

C. Wang ◽

P. A. Roberts

Keyword(s):

Fusarium Wilt ◽

Nematode Resistance ◽

Wilt Disease ◽

Root Knot Nematode ◽

Root Knot Nematodes ◽

Wilt Resistance ◽

Minor Genes ◽

Disease Complex ◽

Allele Dosage ◽

Race 1

Fusarium wilt, caused by the soilborne pathogen Fusarium oxysporum f. sp. vasinfectum race 1, is a vascular disease in cotton (Gossypium spp.), and is a component of a disease complex with root-knot nematodes (Meloidogyne incognita). Genetic analysis of two interspecific crosses (G. barbadense Pima S-7 × G. hirsutum Acala NemX and Pima S-7 × Acala SJ-2) showed that one major gene (designated Fov1) with allele dosage effect conferred resistance to F. oxysporum f. sp. vasinfectum race 1 in Pima S-7. Two amplified fragment length polymorphism (AFLP) markers were linked to Fov1 in Pima S-7, with genetic distance from the gene of 9.3 and 14.6 centimorgans. Less severe wilt symptoms in Acala NemX than Acala SJ-2 indicated that Acala NemX possesses one or more minor genes contributing to delay of wilt symptoms. Highly resistant plants in F2 and F3 (Pima S-7 × NemX) families indicated transgressive segregation effects of minor genes in Acala NemX combined with Fov1 from Pima S-7. The effects of wilt and nematode resistance on the nematode-wilt disease complex were assayed with two inoculation methods. In the presence of both pathogens, wilt damage measured as shoot and root weight reductions was greatest on wilt- and nematode-susceptible Acala SJ-2 and least in root-knot nematode-resistant and wilt-susceptible Acala NemX. Intermediate damage occurred in wilt-resistant and root-knot nematode-susceptible Pima S-7. The results indicated that nematode resistance was more effective than wilt resistance in suppressing wilt symptoms when either resistance was present alone. Nematode resistance combined with intermediate wilt resistance, as in the F1 (Pima S-7 × NemX), was highly effective in protecting plants from root-knot nematodes and race 1 of Fusarium wilt as a disease complex.

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