The occurrence and severity of rust diseases of winter rye in Estonian climatic conditions.

This paper presents a six-year study (2000-2005) of rusts on 11 winter rye varieties in Estonian conditions. Environmental factors may b e related to occurrence of different pathogens causing rye diseases. The aim of the stud y was to analyse the influence of environmental factors on the occurrence of rust dis eases on rye. Visual assessments of Puccinia recondita at inflorescence emergence (GS 50) and Puccinia graminis at milk ripening stage (GS 75) under natural infection conditions were carried out. As to average of the years, trial results demonstrated quite moderate infection level in the field conditions at the Jogeva Plant Breeding Institute (PBI). The year's climatic conditions had significant influence on the occurrence of stem rust . The impact of year to leaf rust was insignificant. Genotype had an insignificant effect on stem and leaf rust. Stem rust correlated highly with year and variety - R 2 = 70.3%, p < 0.001. Neither year nor variety had any impact on the occu rrence of leaf rust ( R≤ = 40.6%).