Characterization of Phytophthora infestans Isolates from Two Potato Varieties in the Highlands Agro-Ecological Zone of Cameroon

Background: Late blight caused by Oomycete Phytophthora infestans remains a huge problem in potato production and one of the most severe crop diseases worldwide. In Cameroon, the populations characterization of this pathogen remain very little known.

Aims: This study aims to characterize isolates of P. infestans collected in twelve localities of Highlands zone of Cameroon.

Study Design: Twelve localities in three main potato production areas of the Highlands agro-ecological zone (HAZ) in Cameroon were selected for sample collection. The phenotypic parameters of sporangia were measured. The presence of mating types and pathogenicity tests on detached leaflets of two potato varieties (MANATE and CIPIRA) were assessed.

Results: A total of 36 isolates were collected. Height (08) Sporangia shape of P. infestans were obtain and 02 new different shape were pip form and oval to ellipsoid. Sporangia length/width ratio ranged from 1.62 to 2.18. Mating types A1 and A2 were present in the studied areas. Pathogenicity test on detached potato leaflets was positive with all the 36 isolates. The isolate HPBT02 from Tsela locality was more aggressive (P<0.05). MANATE variety was more susceptible.

Conclusion: The study shows that mating types A1 and A2 of P. infestans exit in Cameroon and the morphology of sporangia varies according to the localities. Molecular characterization is needed.