Report of the Tomato Genetics Cooperative Number 58

RESEARCH REPORTS TGC REPORT 58, 2008
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523), BC1 (NE-1x(NE-1xECU-523)), BC2 ((NE-1xECU-523)xECU-523) and F2 (NE-1xECU-523).
Forty-four plants of NE-1, 25 of ECU-523, 30 of the F1, 145 of the BC1, 100 of the BC2 and 101 of
the F2 were tested.
Results and discussion
Yellow spots were observed at 15 DPI in the inoculated leaves of the controls NE-1 and
Fortuna-C. At 30-45 DPI, bronzing and curling of the leaflets were observed in the newly developed
leaves. Throughout the assay the symptoms became more acute, particularly bronzing, and all
susceptible control plants became systemically infected (Table 1).
All plants from the accession Uco Plata showed systemic infection (Table 1). Nevertheless, at
60 DPI, only 31.6% of the Uco Plata plants were systemically infected. Viral accumulation in these
materials, measured by the maximum absorbance, was 48% of the accumulation of the susceptible
control NE-1. In line UPV-32, 16.7% of the plants were not infected. Systemically infected plants of
this accession showed 86% of the NE-1 viral accumulation. Accessions PI-126944 and PI-126935
showed 10% and 20% of resistant plants, respectively. Susceptible plants of these accessions
showed similar viral accumulations than the susceptible control Fortuna-C. At 15 DPI, ECU-523
showed 40% of systemically infected plants. Nevertheless, at 30 DPI these plants recovered and did
not show systemic infection and no symptom, similarly to what was reported by Soler et al. (1998) in
S. habrochaites.
In the genetic control assay, all NE-1 plants were susceptible (Table 2). ECU-523 showed the
same performance that in previous assay. Although, at 15 DPI some plant showed systemic infection,
subsequently, these plants recovered and did not present symptoms. All F1 plants became infected
at 15 DPI. Nevertheless, at 60 DPI, only 26.7 % of the plant showed systemic infection, and no plant
had symptoms. In 32 plants (31.7%) of the F2, a susceptible reaction to mechanical inoculation was
observed. The other plants did not show systemic infection (resistant), or recovered at the end of the
assay. These data, taken together, indicate that the ECU-523 resistance is monogenic and dominant.
The results in BC1 and BC2 (Table 2) confirm this suggested genetic control for the resistance in this
accession of S. habrochaites.
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