<Ul> <Li> The Irish potato blight of 1846 was a major factor in the deaths of one million people and the emigration of about two million . It was the result of planting only two potato varieties, both vulnerable to the blight, Phytophthora infestans, which arrived in 1845 </Li> <Li> When rice grassy stunt virus struck rice fields from Indonesia to India in the 1970s, 6,273 varieties were tested for resistance . Only one was resistant, an Indian variety and known to science only since 1966 . This variety formed a hybrid with other varieties and is now widely grown . </Li> <Li> Coffee rust attacked coffee plantations in Sri Lanka, Brazil and Central America in 1970 . A resistant variety was found in Ethiopia . The diseases are themselves a form of biodiversity . </Li> </Ul> <Li> The Irish potato blight of 1846 was a major factor in the deaths of one million people and the emigration of about two million . It was the result of planting only two potato varieties, both vulnerable to the blight, Phytophthora infestans, which arrived in 1845 </Li> <Li> When rice grassy stunt virus struck rice fields from Indonesia to India in the 1970s, 6,273 varieties were tested for resistance . Only one was resistant, an Indian variety and known to science only since 1966 . This variety formed a hybrid with other varieties and is now widely grown . </Li> <Li> Coffee rust attacked coffee plantations in Sri Lanka, Brazil and Central America in 1970 . A resistant variety was found in Ethiopia . The diseases are themselves a form of biodiversity . </Li>

1. give an account of biodiversity in india