Abstract

JARAMILLO VILLEGAS, Sonia  and  BOTERO HERRERA, Juan Manuel. RESPONSE OF DIFFERENT POPULATIONS OF Spongospora subterranea f .sp. subterranea TO ROTATION OF TWO POTATO CULTIVARS (Solanum tuberosum ssp. andigena). Rev. Fac. Nac. Agron. Medellín [online]. 2007, vol.60, n.2, pp.3859-3876. ISSN 0304-2847.

In Antioquia Colombia were realized three experiments with potatoes, to know the behavior of the ICA Puracé cultivar, considered by agricultures as powder scab resistant, and the Diacol Capiro cultivar, which is highly susceptible. It is pretended to evaluate if there is a rotation effect, of the two varieties and different populations of Spongospora subterranea f. sp. subterranea on the powder scab. Cistosori (spore balls) was extracted from 23 populations of S. subterranea extracted from pustules in tubers surface or galls in roots from different varieties, from potato regions of Colombia . The incidence and severity degree of these populations was evaluated under the process of the ICA Puracé-Diacol Capiro rotation and viceversa, in three successive harvests, under the mesh house conditions. It was observed that the different pathogen populations did not affect the weight, neither caused powder scab symptoms in the tubers, although presented different severity levels on the roots of two varieties) with unpredictable tendency during the different harvests, with low level (> 0 to 2), medium (>2 to 6) and high (>6) symptoms, being more susceptible the Diacol Capiro, which apparently incremented the infection in the soil. The ICA Puracé was low level affected by few population (7/23) with the powder scab, during the first cycle and possibly presented a suppressive effect over the powdery scab for the Diacol Capiro rotation in the second harvest, and then, a rising in the galls of both varieties during the third harvest, in the pots where originally planted, because of a possible increasing of cistosori in the soil. The initial rotation reduces the powder scab symptoms (second harvest) in Diacol Capiro, but the ICA Puracé cultivar is more affected trough the generations where Diacol Capiro was growing.

Keywords : Disease; powdery scab; susceptibility; Diacol Capiro; ICA Puracé; pathogenicity; rotation.

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