Plant Breeding (1999) 118, 549-554

Birgit Jensen, S. Vaerbak, L. Munk and S.B. Andersen (1999)
Characterization and inheritance of partial resistance to downy mildew, Peronospora parasitica, in breeding material of broccoli, Brassica oleracea convar. botrytis var. italica
Plant Breeding 118 (6), 549-554
Abstract: Twenty doubled haploid broccoli lines from breeding material were evaluated for resistance to Peronospora parasitica at the seedling stage. All lines supported sporulation of the pathogen, but to varying extents and intensities. Partial resistance of the more resistant lines, 'br8' and 'br9', reduced conidia production on cotyledons by 50–70% compared with the most susceptible lines. Inoculation of the two most resistant lines with 13 isolates of different geographical origins revealed that 'br9' showed a rather uniform level of resistance to all isolates while 'br8' showed some isolate specificity. Partial resistance was evaluated in six of the broccoli lines in a half diallel set of crosses. Disease assessment of seedlings showed that additive genetic effects explained 45.8% and 31.8% of the total variation of sporulation score and conidia production, respectively. This suggests that recurrent selection for partial resistance to P. parasitica in early generation inbreds or in populations of broccoli will be efficient to obtain cotyledon resistance.
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Link to article at publishers website
Database assignments for author(s): Birgit Jensen, Sven Bode Andersen

Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Hyaloperonospora parasitica	Cabbage (Brassica oleracea)
	Hyaloperonospora brassicae	Cabbage (Brassica oleracea)