Twenty-seven tomato lines were evaluated for resistance to the foliar blight phase of bacterial canker (Clavibacter michiganensis) in a field study at Fletcher, NC in 1988. Plants were inoculated 32 days after planting 5-week-old seedlings by spraying foliage with a nutrient broth suspension containing 10^10^-10^12^ colony forming units per ml of the bacterium (Tipton isolate). Inoculum was applied with a Solo backpack mistblower. The field was irrigated by over-head sprinklers immediately before and after inoculation.
Ratings of marginal leaf burn and associated blighting caused by bacterial canker were made 40 days after inoculation. Independent ratings by two individuals are presented below. NC 409-1-1, selected in earlier studies for resistance to the leaf blight and fruit spot phase of the disease, had very low ratings as did several sources of resistance from other breeding programs. Lines from a collection screened in Florida for bacterial wilt resistance varied from resistant to highly susceptible. Additional testing is planned in 1989 with the most promising lines.
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Foliage blight**
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Line Seed Source* Rating 1 Rating 2
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NC 409-1-1 1 1.25 1.50
Okitsu Sozai #1 2 2.25 1.75
Cordeok 2 2.00 2.00
Porense 2 1.75 2.50
HAR 84, 372-2 3 2.50 1.75
HAR 84, 372-1 3 2.50 1.75
IRAT-L3 2 2.50 2.00
84 BWR 120565B 4 2.50 2.00
GA 1565-2-4 BWT (PI263722) 4 2.25 2.50
HAR 86, 189-2 3 2.75 2.25
GA 1405-1-2 BWT (PI251323) 4 2.25 2.75
Hawaii 7998 4 2.75 2.25
NC 710-1W 1 3.00 2.25
HAR 85, 300-2 3 3.00 2.25
Hawaii 7997 4 2.50 2.75
CRA 66 4 3.00 2.50
HAR 85,305-3 3 3.00 2.75
IHR 663-12-3 4 3.50 2.75
HAR 86, 200 3 3.00 3.25
HAR 86, 338-2 3 3.50 3.00
Heinz 2990 3.25 3.25
HAR 86,195-3 3 3.50 3.50
Flora-Dade 1 4.00 3.25
Mountain Pride 1 4.00 3.75
GA 1095-1-4 BWT (PI196298) 4 4.00 4.00
PI 126408 4 4.00 4.50
GA 219-1-2 BWT (PI126408) 4 4.25 5.00
LSD (.05) 0.66 0.98
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*1 = R. G. Gardner, Fletcher, NC;
2 = H. Laterrot, Montfavet, France;
3 = V. Poysa, Harrow, Ontario;
4 = J. W. Scott, Bradenton, FL
**0 = none, 1 = trace, 2 = light, 3 = moderate,
4 = heavy, and 5 = severe
marginal burn and blighting; each value is the mean of
4, 6-plant plots. No ratings of <1 were recorded.