Comparison of carrot cultivars for resistance and susceptibility to carrot root
rot caused by Fusarium
M.T. Tesfaendrias and M.R. McDonald
Department of Plant Agriculture, University of Guelph, ON, N1G 2W1
Root rot and crown rot caused by
Fusarium coeruleum Lib. ex Sacc. has been
identified on carrots in the field in the Holland Marsh, Ontario in 2008. Field and
controlled environment trials were conducted to evaluate the response of carrot cultivars to
Fusarium infection. In the field trial 7 cultivars and in the controlled environment
28 cultivars were evaluated. The filed trial was conducted at a commercial carrot field in
the Holland Marsh, Ontario, with a history of fusarium root rot of carrots. The controlled
environment trial was conducted by artificially inoculating healthy carrot roots. A
randomized complete block arrangement with four replicates per treatment was used. In the
field trial, each experimental unit consisted of 5 m long row., a random sample of 25 and
100 carrots from field plots was collected on 22 August and 19 October, 2012 respectively.
On 29 August and 20 December, carrots were visually assessed for fusarium root rot lesions
and sorted into classes. There were no significant differences among the cultivars at either
assessment periods. Of all the carrots assessed during the August evaluation, only three
were infected with
Fusarium. At the second assessment (collected on 19 October),
24-41% of the carrots were infected with
Fusarium and had developed the
characteristic symptoms of carrot root rot. Although not statistically significant, the
percentage of healthy carrots was 70% or more for carrot cultivars Fontana, Cellobunch and
Olympus. The artificially inoculated carrots were evaluated by measuring the lesion size.
Lesion sizes of the carrots were significantly different among the cultivars with a lesion
size ranging from 7 to 29 mm. Cultivars Fontana, Envy, Belgrado and 55-205 had less than 10
mm lesion size.
Last updated
Friday, 02-Aug-2013 12:12:54 CDT
