36th International Carrot Conference Abstract

Carrot cavity spot incidence and severity as affected by pigmentation

¹K. Vander Kooi, ¹M.R. McDonald, and ²P.W. Simon

1Dept. of Plant Agriculture, University of Guelph, Guelph, Ontario, Canada N1G 2W1

2USDA, ARS and University of Wisconsin, Madison WI 53706 USA

Cavity spot of carrot, caused by several species of Pythium, is an important soil borne disease of carrots grown in organic and mineral soils in Canada. From 2002 to 2012, field trials have been conducted in the Holland/Bradford Marsh region of Ontario to determine the effect of carrot pigmentation on cavity spot incidence and severity using various white, yellow, red, orange and purple commercial carrot cultivars as well as breeding lines from the USDA breeding program at the University of Wisconsin. Carrots were seeded in organic soil in late May, harvested in late October and assessed for cavity spot in early December. Disease incidence and severity varies from year to year, when years are grouped, similarities in disease incidence and severity have been observed in carrots with similar colours. In 2011 & 2012, cavity spot was highest in carrot cultivars with red and white pigmentation (94 to 86%), while purple pigmented carrots had the lowest incidence (29 to 21%) suggesting that pigment influences disease. However, purple breeding line 665-1 had a cavity spot incidence of 90% in both 2011 and 2012, suggesting that pigment may not be directly involved in cavity spot resistance.

Last updated Thursday, 25-Jul-2013 11:52:33 CDT