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Components of resistance to diseases in winter oilseed rape cultivars - LK0956

Description
Components of Resistance to Diseases in Winter Oilseed Rape Cultivars
Background and purpose. Resistance to stem canker (Leptosphaeria maculans) and light leaf spot (Pyrenopeziza brassicae), the main diseases of winter oilseed rape in the UK, is complex and operates at different stages in epidemics between sowing (autumn) and harvest (summer). Resistance ratings to these diseases, which are major components of the merit rating for selection of cultivars for the HGCA Recommended List, are currently based on visual disease assessments. The performance of cultivars shows variation between sites, which is not understood. Disease resistance ratings can be improved by quantifying components of resistance. Recently developed molecular techniques to detect both pathogens within infected host tissue offer new techniques to quantify pathogen biomass within the plant. In this LINK project, disease assessments will be made at different stages, including real time PCR assessments during symptomless stages, to dissect resistance into its components.
Objectives. (1) To test if measuring components of resistance to stem canker (especially to symptomless spread of L. maculans from leaf to stem) will improve selection of resistant cultivars. (2) To test if measuring components of resistance to light leaf spot (especially to symptomless growth of P. brassicae in leaves in autumn) will improve selection of resistant cultivars. (3) To produce new methods to rate cultivar resistance to stem canker and light leaf spot in winter oilseed rape cultivar selection and evaluation trials.

Benefits to industry, science and environment. (1) Novel real time PCR-based methods to identify components of resistance stem canker (monocyclic) and light leaf spot (polycyclic) will improve understanding of the basis of resistance to diseases of winter-sown arable crops. (2) More reliable methods for assessing resistance to stem canker and light leaf spot to decrease costs of identifying resistant cultivars will benefit Defra/SEERAD, HGCA (better data from NL and RL trials) and plant breeders (better selection of resistant breeding lines) (estimated benefits £0.5M per season). (3) Benefits to growers include increased gross outputs from improved cultivar recommendations through more reliable resistance ratings for RL cultivars; optimised fungicide use from better disease risk assessments; decreased management time (estimated benefits £10/ha on 500000 ha = £5M per season). (4) Ultimately the public and environment will also benefit, as exploitation of improved knowledge of disease resistance will decrease reliance on chemical control in winter oilseed rape.
Programme of work
Cultivar selection. Breeders, HGCA and RL/NL contractors will select 20 cultivars with a diverse range in susceptibility /resistance to stem canker and light leaf spot.
Experiments. These cultivars will be used in replicated field plot experiments taken to yield, unsprayed breeders' disease nurseries and pot experiments. These will complement RL trials in England and Scotland. Disease assessment. To identify components of resistance, recent knowledge on epidemic development for both diseases will be used to define stages in epidemic and crop development for assessments to be made. For stem canker, stages considered will be: 1. Infection to leaf spot; 2. Symptomless spead from leaf to stem; 3. Development in stems; 4. Disease severity/yield loss. For light leaf spot, stages will be: 1. Leaf infection to meristem infection (symptomless); 2. Meristem infection (symptomless) to leaf symptoms; 3. Leaf to pod symptoms; 4. Disease severity/yield loss. Visual assessment results will be compared with those from real time PCR-based methods to quantify fungal biomass in symptomless infected tissues.
Data analysis. These data on components of resistance to stem canker and light leaf spot will be compared with results obtained in NL/RL trials using current visual resistance rating protocols.
New methods for rating resistance of winter oilseed rape cultivars to the stem canker and light leaf spot pathogens will be delivered to breeders and NL/RL contractors.
Exploitation. The new methods developed will be tested and exploited directly by breeders and RL and NL contractors (e.g. NIAB, SAC) during the course of the project. New scientific information about components of resistance to stem canker (monocyclic) and light leaf spot (polycyclic) will be published in refereed scientific journals. New data on cultivar - disease relationships will be incorporated into models in Phase 3 of the PASSWORD DSS project for delivery to growers. HGCA will be directly involved in transfer of information about improvements in rating of cultivar resistance to growers.
Objective
11 Objective(s)
Scientific objective(s)
(1) To test if measuring components of resistance to stem canker (especially to symptomless spread of L. maculans from leaf to stem) will improve selection of resistant cultivars.
(2) To test if measuring components of resistance to light leaf spot (especially to symptomless growth of P. brassicae in leaves in autumn) will improve selection of resistant cultivars.
(3) To produce new methods to rate cultivar resistance to stem canker and light leaf spot in winter oilseed rape cultivar selection and evaluation trials.


11.2 Interdependence of objectives
Objective 3 is dependent on achieving objectives 1 and 2.
Project Documents
• ABS - Abstract : Components of Resistance to Diseases in Winter Oilseed Rape Cultivars   (11k)
Time-Scale and Cost
From: 2004

To: 2008

Cost: £455,226
Contractor / Funded Organisations
Home Grown Cereals Authority, Nickerson UK Ltd, Syngenta Crop Protection UK Ltd, Saaten-Union Ltd, Monsanto UK Ltd, ADAS UK Ltd., Elsoms Seeds Ltd, National Institute of Agricultural Botany, Rothamsted Research (BBSRC), University - Scottish Agricultural College, CPB Twyford Ltd
Keywords
Arable Farming              
Breeding              
Crop Diseases              
Crops              
Farming              
LINK Programme              
Oilseed Rape              
Pathogens              
Plant Pests and Diseases              
Resistance              
Sustainable Farming and Food              
Sustainable Production              
Fields of Study
Arable Crops