Survey and Race Analysis of Puccinia triticina Eriks. Causing Leaf Rust Disease in Wheat; Evidence for Secondary Foci of Infection in Puccinia Path

Survey and Race Analysis of Puccinia triticina Eriks. Causing Leaf Rust Disease in Wheat; Evidence for Secondary Foci of Infection in Puccinia Path

A survey was carried out on leaf rust of wheat in kharif and rabi season during 2010-11 and 2011-12 in Karnataka. Survey in the districts Chikmagaluru and Chitradurga during kharif season of both the years revealed the absence of wheat cultivation in these areas. Survey (roving survey) during rabi, 2010-11 and 2011-12 revealed the difference in disease severity and incidence of leaf rust in different districts. Among seven districts; Belgaum, Bhagalkot, Bijapur, Dharwad, Gadag, Gulbarga and Yadgiri disease was observed only in three potential wheat growing districts viz., Belgaum, Dharwad and Gadag with severity ranges of 10MS-100S, 20MS-100S and 60S-80S, respectively during rabi, 2010-11 and 10MS-100S, 20MS-100S and 5S-100S respectively during rabi, 2011-12. The bread wheat variety DWR162 grown in large area (>50%) showed the highest disease severity and infection type in all surveyed districts. The pathotype 121R63-1 (77-5) was dominant and distributed in 35.71 per cent and 58.90 per cent during rabi 2010-11 and rabi 2011-12, respectively. Occurrence of a diverse population of pathotypes, some of which (12,104,162 group of pathotypes) do not occur in Nilgiri hills reveal that the surveyed areas form a different focus of infection..