A new disease caused by Phoma andina var crystallyniformis has been reported by Loerakker, et al.(1985). The fungus causes yield reductions of around 67% when the plants exhibit medium grade of disease (rating 3) and more than 98% when they exhibit high grade (rating 5). Resistance to the disease has been found at seedling stage (Lobo et al., 1984), but the resistance does not hold to maturity. A collection of different species of tomato was tested in a field with high level of inoculum of the fungus in the soil. Resistance was found in three accessions of L. hirsutum as well as in three accessions of L. parviflorum and one each of L. peruvianum and L. chimielewski. Previously near-inmumty was found in L. hirsutum (PI 251305). The hybrid PI 251305 x 'Licatol' (susceptible parent) was resistant to the disease. Currently, a wider collection is being tested to find the best resistance source and to conduct inheritance studies. The results obtained with some of the tested genotypes are included in Table 1.
Literature cited:
Lobo, M., R. Navarro, B.N. Quintero, and A.M. Jaramillo. Phoma resistance in tomato seedlings. Tomato Genetics Coop. 34:12. 1984.
Loerakker, W.M., R. Navarro, M. Lobo, and L.J. Turkesteen. Phoma andina var crystallyniformis var. nav un patogeno nuevo del tomate y la papa en los Andes (in press).
Table 1. Phoma andina var crystllyniformis resistance in accessions of different tomato species.
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Rating of the disease (1)
Genotype Species days after transplanting
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23 44 50 57 62
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LA 375 L. pimpinellifolium 1.5 3.0 3.0 4.0 4.5
LA 373 L. pimpinellifolium 2.0 3.0 3.0 3.5 4.0
LA 369 L. pimpinellifolium 2.0 3.5 3.5 4.0 4.5
LA 121 L. pimpinellifolium 1.5 2.5 3.0 4.0 5.0
LA 100 L. pimpinellifolium 1.0 2.5 3.0 4.0 5.0
LA 2113 L. parviflorum 0.0 0.0 0.0 0.0 0.0
LA 2325 L. parviflorum 0.0 0.0 0.0 0.0 0.0
LA 2113 L. parviflorum 1.0 1.0 1.0 1.0 1.0
LA 247 L. parviflorum 0.0 1.0 1.0 2.0 2.0
LA 1306 L. chmielewski 0.0 0.0 0.0 0.0 0.0
PI 126448 L. peruvianum 0.0 0.0 0.0 0.0 0.0
PI 129445 L. hirsutum 0.0 0.0 0.0 0.0 0.0
PI 134417 L. hirsutum 0.0 0.0 0.0 0.0 0.0
PI 129157 L. hirsutum 0.0 0.0 1.0 1.0 1.0
PI 251304 L. hirsutum 0.0 0.0 1.0 2.0 2.0
LA 1622 L. esc. v. cerasiforme 2.0 3.0 4.0 4.5 5.0
LA 1461 L. esc. v. cerasiforme 2.5 3.0 3.5 4.5 5.0
LA 1468 L. esc. v. cerasiforme 2.0 3.0 3.5 4.5 4.5
Licato (2) L. esculentum 3.0 4.0 5.0 5.5 6.0
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(1) 0: No symptoms
7: plants dead
(2) Susceptible control.