Resistance of Cucumber to the Root-knot Nematode, Meloidogyne hapla

admin

Cucurbit Genetics Cooperative Report 13:10-11 (article 4) 1990

S. Alan Walters and Todd C. Wehner
Department of Horticultural Science, North Carolina State University, Raleigh NC 27695-7609

Kenneth R. Barker
Department of Plant Pathology, North Carolina State University, Raleigh NC 27695-7616

Cucumber (Cucumis sativus L.) is one of the most susceptible crops to root-knot nematode (Meloidogyne spp.) (2). There are four major pathogenic species of root-knot nematodes, M. incognita, M. arenaria, M. javanica and M. hapla. In North Carolina, cucumbers were reported to be resistant to M. hapla (5). However, others have reported that some cultivars of cucumber were susceptible to M. hapla (3,6,7). The objective of this study was to screen the cucumber germplasm collection for resistance to M. hapla to determine which cultigens had the most resistance.

Methods. Nine hundred cultigens of Cucumis sativus (728 accessions, 36 breeding lines and 136 cultivars), and 24 cultigens of Cucumis metuliferus (24 accessions) were evaluated in a greenhouse study for resistance to the root-knot nematode, M. hapla. Plants were grown from seed, with one plant per 150-mm-diameter clay pot. One replication of 924 plants was grown. (The experiment was not repeated since all cultigens were found to be resistant.)

‘Rutgers’ tomato was used to grow root-knot nematodes for inoculum. Three plants were grown in 150-mm-diameter pots, and inoculated at the seven-leaf stage with 5000 eggs of M. hapla. The same inoculum was used the same day to inoculate the 924 cultigens of Cucumis. These three plants were grown as checks for both temperature and inoculum.

Two weeks after planting each pot was inoculated with 5000 eggs of M. hapla using the technique developed by Hussey and Barker (4). Eleven weeks after planting (9 weeks after inoculation) plants were rated using the gall index system. This system determines the percentage of a given root system that is galled by a root-knot nematode. The gall index system ranges from 0 to 100, indicating percentage of roots injured (1).

Results. The 3 tomato plants that were grown as checks had an average gall index of 65. We were worried that high temperatures in the greenhouse would reduce the amount of gall development. However, the high GI for ‘Rutgers’ indicated that temperature was not a problem, and that the inoculum of M. hapla was virulent.

All cultigens evaluated were resistant to M. hapla, indicating that cucumber was a poor host. That conclusion supports the findings of Winstead and Sasser (5). Most cultigens (82.4%) had a gall index below 2 (Table 1). Cultigens that had a gall index of 0 included ‘Marketmore 76’ and Wisconsin SMR 18. The least resistant cultigen was ‘Armstrong Early Cluster’. No susceptibility to M. hapla was found in the 870 Cucumis cultigens evaluated.

Table 1. Cucumber resistance (gall index) to Meloidogyne hapla.z

Gall index

Example Cultigens

No. of Cultigens

% of Cultigens
0 Gy 4, ‘Poinsett’, ‘Sumter’ 308 33.3
1 ‘Coolgreen’, ‘Magnolia’ 453 49.1
2 ‘Chipper’, ‘Cubit’, PI 321006 95 10.3
3 ‘Dual’, PI 220860, PI 222986 10 1.1
4 ‘Sieger’ 1 0.1
5 PI 267746 1 0.1
6 – 0 0.0
7 PI 432856 1 0.1
8 ‘Armstrong Early Cluster’ 1 0.1
65 ‘Rutgers’ tomato – –
Missing – 54 5.8
Total – 924 100.0

z Data are means of 1 replication of 1 plant each. Gall index represents percentage of root system damaged by nematode galls.

Literature Cited

  1. Barker, K. R. 1978. Determining nematode population responses to control agents. In (E. I. Zehr, ed.) Methods for evaluating plant fungicides, nematicides and bactericides. Amer. Phytopathol. Soc., St. Paul, Minnesota, pp. 114-125.
  2. Fassuliotis, G. 1979. Plant breeding for root-knot nematode resistance. In (F. Lamberti and C. E. Taylor, eds.) Root-knot nematodes (Meloidogyne spp.): Systematics, Biology and Control. Academic Press, New York, pp. 425-453.
  3. Gaskin, T. A. and H. W. Crittenden. 1956. Studies of the host range of Meloidogyne hapla. Plant Dis. Rptr. 265-270.
  4. Hussey, R. S. and K. R. Barker. 1973. A comparison of methods of collecting inocula of Meloidogyne spp., including a new technique. Plant Dis. Rptr. 12:1025-1028.
  5. Winstead, N. N. and J. N. Sasser. 1956. Reaction of cucumber varieties to five root-knot nematodes (Meloidogyne spp.). Plant Dis. Rptr. 40:272-275.
  6. Thomason, I. J. and H. E. McKinney. 1959. Reaction of some Cucurbitaceae to root-knot nematodes (Meloidogyne spp.). Plant Dis. Rptr. 43(4):448-450.
  7. Zimmer, R. C. and C. Walkof. 1968. Occurrence of the northern root-knot nematode, Meloidogyne hapla, on field grown cucumber in Manitoba. Can. Plant Dis. Surv. 48:154.