Question

Why breeding for disease resistance not feasible for all types of plant diseases?

Answer 1

Resistance to nearly all pathogens occurs abundantly inour crops. Much of the resistance exploited by breedersis of the major gene type. Polygenic resistance, although used much less, is even more abundantly available. Many types of resistance are highly elusive, the pathogen apparently adapting very easily them. Other types of resistance, the so-called durable resistance, remain effective much longer. The elusive resistance is invariably of the monogenic type and usually of the hypersensitive type directed against specialised pathogens.Race-specificity is not the causeof elusive resistance but the consequence of it. Understanding acquired resistance may open interesting approaches to control pathogens. This is even truer for molecular techniques, which already represent an enourmously wide range of possibilities. Resistance obtained through transformation is often of the quantitative type and may be durable in most cases.Key words:types of resistance; genetics of resistance; acquired resistance.