The concept of durable resistance was introduced by Dr Roy Johnson about 40 years ago, following a breakdown in the slow rusting or adult plant resistance of several English winter wheats to stripe rust, including Joss Cambier, and continued effectiveness of resistance in several other cultivars including Cappelle Desprez and Hybrid de Bersee. The resistance in the latter was referred to as durable, and durable resistance defined as “resistance that remains effective when a cultivar is grown widely in environments favouring disease development”. Durable resistance is a descriptive term; it does not provide any explanation of the causes underlying long lasting resistance. It does, however, contain two conceptual elements, one being that there may be any of several underlying causes for durable resistance and the other that resistance that has remained effective for a long period of widespread use may not necessarily continue to do so in the future. This paper will discuss the role of durable resistance in achieving sustained control of cereal rust diseases. In view of the complexity of host : pathogen interactions, genetic diversity must be seen as a key ingredient in large scale sustained control of plant diseases. It has been argued that even where specific or major resistance genes are used, genetic diversity can be used as insurance against lack of durability and hence as a means of reducing genetic vulnerability. Above all, responsible use of resistance genes depends upon an understanding of the resistance genes present in cultivars and breeding populations, and monitoring pathogen populations with respect to deployed resistances, are crucial in ensuring that the genetic bases of resistances are not narrowed.
Durable rust resistance: From gene to paddock, continent and beyond
Poster or Plenary?: