JAN 2 6 1998
University of Florida
UTILITY OF MIGENE RESISTANCE IN TOMATO
TO MANAGE JAVANESE ROOT-KNOT NEMATODES
IN NORTH FLORIDA.
J. R. Rich, S. M. Olson, and S. K. Barber
NFREC Research Report 97: 11
North Florida Research and Education Center
University of Florida
Route 3 Box 4370
Quincy, FL 32351
Supported by a grant from the Gadsden Tomato Growers, Quincy, FL.
Use of plant resistance is an effective and efficient integrated nematode
management technique. Resistance to one or more root-knot nematodes is currently
available in crops such as soybean, tobacco, and bell pepper (Roberts 1992). In
tomato,'Migene' resistance to major root-knot nematode pests has been available for
over 35 years (Smith, 1944, Roberts 1992). The gene has been incorporated into many
commercially available tomato varieties and used extensively as a root-knot nematode
management technique in home gardens and processing tomato production (Roberts and
Thomason, 1989). While this resistance has some limitations, it is generally effective in
combination with other management techniques such as rotation and sanitation. Until
recently, however, root-knot nematode resistance has not been incorporated into
tomato varieties nor tested in stake tomato production systems in Florida. Reasonably,
the extensive use of methyl bromide over the past 30 + years precluded the need for
varieties with this resistance. With impending loss of methyl bromide, however, this
resistance could become an important nematode management technique in Florida stake
These present tests were conducted to determine potential effectiveness of
Migene resistance in stake tomatoes to manage the Javanese root-knot nematode
(Meloidogyne javanica) in north Florida.
MATERIALS AND METHODS
The test site was located at the University of Florida North Florida Research and
Education Center, Quincy, FL. Soil was an Orangeburg loamy fine sand and was
moldboard plowed and double-disced in early March, 1997. Fertilizer was applied
broadcast at the rate of 175-54-175 ofN-PzOs-K20 and disc-incorporated. Prior to
experiment initiation, methyl bromide (98%) was applied at a broadcast equivalent rate
of 400 Ibs./A. Application was made to 8 inches deep with a single row bed press
through 3 chisels spaced 12 inches apart on a 3 ft. wide raised bed. Black polyethylene
mulch (1.25-mil) and drip tubing were laid concurrently with methyl bromide
application. On 12 April, 0 or 500 Javanese root-knot nematode eggs or juveniles/100
cm3 soil were applied through the drip tube to 18 main plots each. Quantity of inoculum
was calculated to represent a soil volume equal to plots 10 ft. long, 1 ft. wide and 6
inches deep. Two days later, two transplants of the resistant Peto PSR 8991994 (Sanibel
sister line) tomato breeding line and two of the susceptible cv. Colonial were planted
into each main plot.
Tomato was irrigated and sprayed as needed to promote good plant growth. Fruit
was harvested on 20 June and 8 July. Root gall ratings were conducted on plants in each
plot on 11 July. Additionally, five soil cores to 8" deep were collected separately around
roots of resistant and susceptible plants in each plot. Soil was processed with the
modified centrifugation-flotation technique and root-knot nematode juveniles counted.
A second test for Fall tomato production was conducted on the site of the Spring
test. The previously placed drip tubing and plastic mulch were removed. Fertilizer (117-
36-117 of N-P205-K20/A ) was then manually applied and incorporated by rototilling to
8 inches deep. Bed pressing and shaping were conducted in the same operation. White
polyethylene mulch (1.25-mil) and drip tubing was placed over the formed beds. The
tomato varieties Agriset (susceptible) and Sanibel (resistant) were alternately planted on
22 August in each plot represented in the Spring trial. Total tomato fruit, regardless of
size, were harvested and weighed on 14 November. On 17 November, root galling was
estimated on a 0-10 scale where 0 = no root galling and 10 = 100% of the root system
In addition to the above experiment station tests, a Spring observational planting
of PSR 8991994 was made on the Murray Brothers Farm in Decatur County, GA.
Tomato was transplanted into a strip-tilled bahiagrass tomato production site that had
not been treated with nematicidal materials. A small area infested with root-knot
nematodes was located previously in the three acre site by soil sampling, and the PSR
8991994 was transplanted to approximately 100 feet of row. Rows on either side were
transplanted to Florida 47 tomato on the same day, 1 April 1997. Plants were grown and
harvested according to standard grower practices. On 23 July, 12 randomly selected
plants of the PSR 8991994 and 12 in adjacent row of Florida 47 were rated for root
galling as described above.
In the Spring trial, no differences in tomato fruit weight, number of fruit or
weight/fruit were found between the noninoculated PSR 8991994 or Colonial
tomato (Table 1). In spite of methyl bromide treatment, however, small residual
populations of the Javanese root-knot nematodes were present in this uninoculated
control treatment. The resistant PSR 8991994 showed significantly less root galling and
nematode numbers as compared to the Colonial. In plots where nematodes were added,
the resistant PSR 8991994 significantly increased fruit weight, number of fruit and
weight/fruit, and reduced root galling and nematode populations compared toColonial.
In the Fall test, significant differences in total fruit weight were not found
between the Sanibel and Agriset where no nematodes were added in the Spring trial
(Table 2). The Sanibel exhibited significantly lower root galling than the Agriset. In the
previously nematode-inoculated plots, Agriset, even when showing high root galling,
yielded significantly better than Sanibel. Root galling, however, was significantly
reduced in Sanibel. Similarly at the on-farm observational site, large differences in root-
galling were recorded between the PSR 8991994 and Florida 47. The Florida 47 averaged
a root gall rating of 7.4 while the PSR 8991994 averaged a rating of 0.25.
The PSR 8991994 and Sanibel exhibited excellent resistance to the Javanese root-
knot nematode in the Spring and Fall trials as well as at the on-farm site. While
preliminary, these data suggest that the Migene may be useful as a nematode
management technique in north Florida stake tomato production. Experience from other
tomato production systems indicate this resistance is effective in reducing root-knot
nematode damage in tomato, but it must be utilized in an IPM context to maintain
effectiveness. Continuous use has resulted in resistant breaking biotypes of root-knot
nematodes. Thus, alternating susceptible and resistance cultivars in field production or
utilizing good rotation systems has proven important to maintain usefulness.
Additionally, the resistance tends to lose effectiveness as the soil temperatures increase
above 80-85 F. Further tests are needed since this may limit use of the resistance at
higher soil temperatures inherent in the Fall tomato crop in north Florida. Other work
is necessary to determine the stability of this resistance to native populations of all three
of the root-knot nematode species, southern, peanut, and Javanese, present in north
Variable yield data, particularly as shown in the Fall test, indicates the need to
include resistance in high-yielding and adapted varieties such as Agriset.
Roberts, P.A., and I. J. Thomason. 1989. A review of variability in four Meloidogyne
spp. measured by reproduction on several hosts including Lycopersicon. Agricultural
Zoology Reviews 3: 225-252.
Smith, P.G. 1944. Embryo culture of a tomato species hybrid. Proceedings of the
American Society for Horticulture Science 44: 413-416.
Roberts, P. A. 1992. Current status of the availability, development, and use of host
plant resistance to nematodes. Journal of Nematology 24: 213-227.
Table 1. Yield, root galling and nematode numbers in a field trial comparing the response of a
resistant and susceptible stake tomato to the Javanese root-knot nematode, Spring 1997.
Fruit No. Weight/ Root Nematodes/
Cultivar/line Nematodes1 weight2 fruit fruit galling3 100 cm3 soil
PSR 8991994 17.5 44 0.40 0.0 5
Colonial 18.7 49 0.39 0.8 163
LSD (P< 0.05) 4.3 12 0.02 0.5 111
PSR 8991994 + 23.1 56 0.42 0.1 132
Colonial + 15.6 40 0.39 7.0 4523
LSD (P < 0.05) 4.0 9.3 0.02 0.8 2810
1Javanese root-knot nematode eggs and juveniles were applied at the rate of 0 (-) or 500 (+)/100
2Fruit was harvested twice and graded to eliminate culls.
3Root galling was based on a 0-10 scale where 0 = no galling and 10 = 100% of the root system
Table 2. Total fruit yield and galling on root-knot nematode resistant Sanibel and susceptible
Agriset stake tomato, Fall 1997.
Cultivar Nematodes' Fruit weight2 Root galling3
Agriset -10.9 4.2
Sanibel -9.3 0.4
LSD (P < 0.05) 3.8 1.8
Agriset + 15.9 7.1
Sanibel + 9.7 0.7
LSD (P < 0.05) 2.6 1.0
'Following a spring crop inoculated with Javanese root-knot nematodes.
2Transplanted on 22 August, all fruit harvested on 14 November.
3Root galling was based on a 0 10 scale where 0 = no galling and 10 = 100% of the root system