Screening for resistance toFusarium dry rot in progenies of cultivars ofS. tuberosum ssp.andigena with resistance toErwinia chrysanthemi

Tubers from open pollinated progenies of 15 cultivars ofS. tuberosum ssp.andigena were evaluated separately for their reactions toFusarium andErwinia. The materials inoculated withF. oxysporum (Fo) showed a range of 8 to 29% (mean= 18.6%) of genotypes with no rotting symptoms. In inoculations withF. solani(Fs), the range was from 6 to 41% (mean=24.3%). High levels of resistance toE. chrysanthemi (Ech) soft rot were observed in 7 out of the 15 progenies evaluated. A range from 5 to 19% (mean=10.1%) of genotypes with cylindrical rot of less than 1.9 mm was observed. A total of 115 out of 512 genotypes combined resistances to both Fo and Fs. Moreover, 59 genotypes that combine resistance toErwinia andFusarium were also identified. Seven of these were resistant to Fo and Ech, 25 to Fs and Ech, and more important, there were 27 genotypes resistant to Fo, Fs, and Ech.