Preliminary search for sources of resistance to T. solanivora in the Colombian Potato Collection

Abstract

In Colombia, Guatemalan moth Tecia solanivora (Povolny) (Lepidoptera: Gelechiidae) is one of the most limiting pests in potato production. Its management has been directed towards the intensive use of chemical insecticides with consequences such as pest resistance and the negative effect on the environment and human health. An alternative is varietal resistance as a sustainable strategy for control of single-denogent T.. This work focused on taking advantage of the genetic diversity of the Colombian Potato Collection (CCC) to seek sources of resistance to pest insect. 132 CCC admissions were evaluated in experiments of non-choice in laboratory and free choice in storage at CI Tibaitatá. Five genotypes were selected that consistently showed pest resistance characteristics. These materials were evaluated in field conditions to determine their response to the damage of single-infested T. with natural infestation in a producing municipality with high incidence of moth. Significant differences were found between the evaluated materials (p-0.0001, F=10,54, gl=7). The 1815 and 2384 genotypes had less damage and less susceptibility, the commercial varieties Pearl Black and Parda Pastusa showed susceptibility to the insect. Spearman's correlation test showed a relationship between moth incidence and the intensity and primary flower color (Rho=0.7882, p=0.0325; Rho=-0.2479, p=0.0117). In terms of performance, the 1815 material presented the highest values. In conclusion, materials 1815 and 2384 are highlighted as promising for varieties or as valuable parents in an improvement program.

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