Issued 1999                                                                       PDF Version

Columbia Root-Knot Nematode Resistance
Meloidogyne chitwoodi (race 2)

J.L. Kugler and H. Mojtahedi

PLANT CULTURE 

Greenhouse

Container……........ Pot or Cone (4cm dia. X 21 cm long)
Media.................... Steam-sterilized sandy loam soil mixture
Seed Prep……....... Scarify, surface sterilize or treat with fungicide
Temp/Light……...... 20 - 25° C, 16 hr photoperiod, w/ supple-mental light during winter
No. of Plants…...... 100 plants minimum. (10 plants/pot; or 2 plants/ cone ( 5 cones per rep)
No. of Reps…........ 10+
Other…………....... Promote good growth; use proper insect control.

INOCULUM SOURCE

Source………......... Greenhouse cultured winter wheat; eggs obtained by NaOCl method (2).
Storage………........ Egg in sterile or deionized water at 0-5° C, maximum 10 days.

INOCULATION PROCEDURE

Plant age……........ 3-4 weeks.
Inoc. Type….......... 500 eggs per plant in suspension adjusted to 100 eggs/ml.
Method………........ Apply egg suspension in 3 holes 2 cm deep next to seedling; cover; water.

INCUBATION

Location…….......... Greenhouse bench.
Duration…….......... 55 days.

RATING

Rating (RF) is on a per-plant basis from root extractions by the NaOCl method (2). One ml aliquots of the sample egg suspensions are counted using a stereoscope.

Reproductive Factor where RF = final egg count (Pf) / initial inoculum (Pi , 500) per plant

Non-host……………..……RF < 0.1
Poor host……………........0.1< RF <1
Good host………………….RF > 1

CHECK VARIETIES

  Approximate Expected Reaction

Acceptable Range of Reaction
Poor host
Nev. Syn XX RF < 1 RF = 0-1
Good host
Lahontan RF > 20 RF > 10

DISTRIBUTION of Meloidogyne chitwoodi Race 2

 

Columbia root-knot nematode, Meloidogyne chitwoodi (race 2) Golden et.al.

SOURCE OF INOCULUM

Name…................. H. Mojtahedi
Address…............. Washington State University
IAREC
2410 Bunn Road
Prosser, WA 99350
Phone……............. 509-786-9286
Email.................... mojtahed@tricity.wsu.edu

SCIENTISTS WITH EXPERTISE

Name…................. G.S. Santo
Address…............. Washington State University
IAREC
2410 Bunn Road
Prosser, WA 99350
Phone................... 509-786-9256
Email.................... gsanto@tricity.wsu.edu

 
Name…................. S.L. Hafez
Address................ R. & E. Center Univ. of Idaho
29603 U of I Lane
Parma, ID 83660
Phone................... 208-722-6701
Email.................... shafez@uidaho.edu

 
Name…................. R.E. Ingham
Address................. Dept. Botany & Plant Pathology 
Oregon State University
Corvallis, OR 97331
Phone................... 541-737-5255
E-mail................... inghamr@bcc.orst.edu

 
Name…................. J.L. Kugler
Address................. W-L Research, Inc 
21029 Rd. 6 S.E. 
Warden, WA 98857
Phone................... 509-349-8864
Email.................... johnkugler@abtmail.com

RACES

M. chitwoodi consists of race 1, which does not parasitize alfalfa, and race 2 that do. The latter is composed of two pathotypes with different RF values on Solanum bulbocastarum that carries a resistant Rcm1 gene.

HELPFUL INFORMATION

M. chitwoodi race 2 may not cause galls on alfalfa, and therefore gall count may not reveal the host-parasite relationship. Also, egg mass count is less desirable, because some nematodes may reach maturity on a resistant plant, but produce a gelatinous matrix with very few eggs deposited. Thus, the Reproductive Factor (RF) value is the most reliable measure to evaluate the host status of alfalfa cultivars and breeding lines. Wheat as increase host is preferred over tomato which is a host for M. hapla, the Northern root-knot nematode that occasionally contaminates tomato cultures.

REFERENCES

  1. Griffin, G.D., R.N Peaden and W.J. Knipe. 1995. Root-Knot Nematode Resistance. Pp.N-2. In Standard Tests to Characterize Alfalfa Cultivars. Third Ed. NAAIC.
  2. Hussey, R.S., and K.R. Barker. 1973.Comparison of methods of collecting inocula of Meloidogyne sp. including a new technique. Plant Dis. Rep. 57:1025-1028.
  3. Mojtahedi, H., J.N. Pinkerton, and G.S.Santo. 1989. Host status of alfalfa cultivars and germplasms to Meloidogyne chitwoodi race 2 and reactions of selected cultivars to M. chitwoodi and M. hapla infection. Plant Dis. 73:391-394.
  4. Mojtahedi, H., J.G. Van der Beek, G.S. Santo and C.R. Brown. 1998. Re-assessment of host race concept for Columbia root-knot nematode, Meloidogyne chitwoodi. J.of Nematology. Abstracts. 30:507.
  5. Walters, S.A. and K.R. Barker. 1994. Current distribution of five major Meloidogyne species in the United States. 1994. Plant Dis. 78:772-774.

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