Identification of rust physiolocical races (Uromyces phaseoli typica Arth.) on beans (Phaseolus vulgaris L.) in two physiographical regions of Rio Grande Do Sul, Brazil

Abstract

In 1965 and 1966 a survey was made of physiologi cal races of rust (Uromyces phaseoli var. typica Arth.) of beans (Phaseolus vulgaris L.) from samples collec ted on the Encosta do Sudeste in the counties of Pelotas and São Lourenço and on the Serra do Su deste in the counties of Piratini and Ganguçu of Rio Grande do Sul, Brazil. Fifteen races were identified by use of the reaction of six differential varieties adopted by Harter and Zaumeyer (1941) following the scale of reading of reaction of the varieties adopted by Harter and Dongo and Crispin (1962). The races of greatest frequency were B₁ and B₂ du ring 1965 and 1966. Races B₂, B₃, B₅ and B₁₀ increased in 1966; whereas races B₁, B₄, B₆, B₇, B₈ and B₁₁ decreased. Race B15 remained constant. Races B12 and B14 were isolated only in 1965 and B12 only in 1966.