Assertion: Resistance of the host plant is the ability to prevent the pathogen from causing disease and is determined by the genetic constitution of the host plant.
Reason:Brown rust of wheat disease is caused by virus .

Assertion (A) is true but Reason (R) is not correct.

The correct answer is Option (3)-Assertion (A) is true but Reason (R) is not correct.

A wide range of fungal, bacterial and viral pathogens, affect the yield of cultivated crop species, especially in tropical climates. Crop losses can often be significant, up to 20-30 per cent, or sometimes even total. In this situation, breeding and development of cultivars resistant to disease enhances food production. This also helps reduce the dependence on use of fungicides and bacteriocides. Resistance of the host plant is the ability to prevent the pathogen from causing disease and is determined by the genetic constitution of the host plant. Before breeding is undertaken, it is important to know about the causative organism and the mode of transmission. Some of the diseases caused by fungi are rusts, e.g., brown rust of wheat, red rot of sugarcane and late blight of potato; by bacteria – black rot of crucifers; and by viruses – tobacco mosaic, turnip mosaic, etc.