Sofikon, Greece, 1969 - Threshing wheat. Threshing machines of this sort travel through Greek villages, except in the most isolated areas. In each village, the entire grain harvest is gathered in one place to await the thresher's arrival. Lead caption: In July 1969, Erna Bennett, Genetic Conservation and Information Specialist from the Crop Ecology and Genetic Resources Branch of the Food and Agriculture Organization of the United Nations (FAO), carried out a mission in Greece searching for and collecting primitive wheat varieties native to the mountains and valleys of that country. These primitive wheat races are one of the world's richest storehouses of the genetic characteristics that plant breeders require. They will build desirable characteristics from crops as old as agricultural man, like building blocks, into new high-yielding varieties. But old races are being swamped by the spread of modern varieties, and in certain areas - and in the case of certain crops - emergency measures are necessary to collect these old races before they disappear completely. FAO and other leading international crop improvement organizations are increasingly concerned with the conservation of primitive crop races, in whose amazing diversity hides the promise of better crops to come.