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SUMMARY:Within-field diversity and the effectiveness of crop mixtures at r
 educing pathogen damage - Joe Helps
DTSTART:20120503T150000Z
DTEND:20120503T153000Z
UID:TALK36683@talks.cam.ac.uk
CONTACT:Suzy Stoodley
DESCRIPTION:Major gene resistance and the application of fungicides have t
 ogether formed the main arsenal against pathogens through the latter half 
 of the 20th century. However both major gene resistance and fungicides oft
 en have an effective lifespan from deployment of around a decade or less b
 efore new pathogens strains render them ineffective [1]. Both partial resi
 stance and cultivar mixtures have been suggested as durable methods of res
 istance\, and have several other advantages over monocultures of a single 
 cultivar with a single resistance gene [2].\nSeveral authors have investig
 ated the mixture effect achieved by mixtures of cultivars with major gene 
 (absolute) resistance. However\, little is known about whether growing mor
 e than one partially resistant cultivar in a mixture could provide the sam
 e benefit found in mixtures of cultivars with major-gene resistance. Using
  a variety of modelling approaches we have examined this question\, by com
 bining host types with different resistance parameters and determining the
  severity and velocity of a new pathogen in such a mixture. Beneficial mix
 ture effects were found to arise under certain mixtures\, but it is equall
 y likely that mixtures of this sort could increase the pathogen severity o
 ver what might be expected.\n\nReal quantitative resistance parameters fro
 m published data were then used to parameterise the above models for leaf 
 stripe rust on barley under realistic host landscapes\, and the results pr
 oduced so far suggest that\, while the benefits predicted can occur in rea
 l situations\, quantitatively the benefits accrued are relatively small.\n
 \nReferences:\n\n1.	Parlevliet\, J.E.\, Durability of resistance against f
 ungal\, bacterial and viral pathogens\; present situation. Euphytica\, 200
 2. 124(2): p. 147-156.\n\n2.	Mundt\, C.C.\, Use of multiline cultivars and
  cultivar mixtures for disease management. Annual Review of Phytopathology
 \, 2002. 40: p. 381-410.\n\n\n
LOCATION:Department of Plant Sciences\, Large Lecture Theatre
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