1. © ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Significance of cultivar resistance (tolerance) in the integrated pest management of winter wheat MODULE C12

2. © ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Background Yield losses from wheat diseases are significant (5-25 dt/ha) Use of resistant cultivars: important control measure against diseases Great potential for reducing dependence on fungicides © Jean-Marie Bossennec, INRA Distribution of yield loss in 108 trials in 2005 for three classes of resistance to foliar diseases

3. © ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Resistance-susceptibility Resistant Overcome the effect of a pathogen, no yield loss Tolerant Endure infection of a pathogen without severe yield loss Susceptible React with severe symptoms and yield loss to a pathogen degree

4. © ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Important wheat diseases in Europe DiseaseScientific nameYield loss 2003- 2007 (%) Septoria leaf blochMycosphaerella graminicola/Septoria tritici 10-70 Brown rustPuccinia recondita5-60 Take-allGaeumannomyces graminis var. tritici difficult to estimate Fusarium head blightFusarium graminearum, F. culmorum 1-7 Yellow rustPuccinia striiformis1-10 Powdery mildewBlumeria graminis f.sp. tritici2-20 Tan spotPyrenophora tritici-repentis/ Drechslera tritici-repentis1-20 EyespotTapesia yallundae, T. acuformis1-6

5. © ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Symptoms of significant diseases

6. © ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY pathogen host plant environment EPIDEMICS Factors that affect epidemics

7. © ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Estimate disease development Disease pressure must be balanced against field resistance Disease pressure = disease inoculum + weather and region Field resistance = varieties + crop management

8. © ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY DON risk assessment grid on wheat by ARVALIS 2008 Role of host susceptibility in risk assessment

9. © ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Breeding for resistance Effective resistance genes in new cultivars Types of genetic resistance: Specific 100 % protection Not durable Non- specific Less than 100 % protection Durable easy to breed difficult to breed

10. © ENDURE, February 2007 FOOD QUALITY AND SAFETY © ENDURE, February 2007 FOOD QUALITY AND SAFETY Resistance ratings of top 10 UK cultivars (9= fully resistant) Resistance of cultivars