India: Local and Introduced Crops [and Discussion]

The oldest agriculture so far demonstrated archaeologically in India is that of the Harappan civilization, beginning in approximately 2500 B.C.; the Harappans had an advanced farming technology and a range of crops. The earliest archaeological records are of species of west Asian origin, found in northwest India and Pakistan; locally domesticated species followed and cereal crops of African origin occurred remarkably early. Southeast Asian crops leave no archaeological evidence, but there are biological indications of substantial antiquity in India; crops of American origin are recent acquisitions. Indian crops provide material for a study of the rate of genetic change under domestication. Native species, long domesticated and in contact with their wild relatives, are compared with domesticates introduced from outside, and separated from their parent species at different points in time. Seed propagated species are compared with vegetatively propagated crops and, among the latter, evolutionary change is demonstrated in spite of greatly restricted sexual reproduction.