Horizontal resistance laboratory measurements

horizontal resistance can be measured in the laboratory using plant growth chambers. But these measurements are expensive and difficult, and they do not necessarily correspond to field performance. They are not recommended for amateur breeders . Horizontal resistance, opposition to

The scientific opposition to horizontal resistance during the twentieth century was apparently due to the fact that plant breeding was dominated by Mendelian breeders who (1) disliked working with polygenes and population breeding methods, and (2) favoured work with single-gene resistances, in spite of the ephemeral nature of vertical resistance. This attitude, which still endures, has led to a serious vertifolia effect in many crops, and it does much to explain why we now use crop protection chemicals in such enormous quantities. See also: Mindset. Horizontal resistance, relative measurements horizontal resistance is difficult to measure and it has no exact scale of measurement comparable, say, to the Celsius scale of temperature measurement. In practice, the only feasible measurements of horizontal resistance are field measurements that are also relative measurements. That is, a cultivar is described as being either more or less resistant to a specified parasite, than another cultivar of known performance.

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