In the Footsteps of Vavilov: Plant Diversity Then and Now

N.I. Vavilov’s theories direct present-day global activities in plant science, breeding, and conservation. His expeditions around the world located centers of diversity of crop evolution. Vavilov was one of the earliest scientists to realize that wild genetic diversity could be lost, through genetic erosion, reducing the possibilities for future crop improvement. To measure genetic erosion, Gary Nabhan and colleagues traveled in 11 countries following routes that Vavilov had taken more than half a century before. The detailed notes concerning the vegetation and flora that Vavilov observed could be used as a baseline in contrast with Nabhan’s plant and cultivar inventories to observe changes in plant diversity at specific sites. The objective of this manuscript is to summarize potential genetic erosion at three case study locations, the Pamiri Highlands of Tajikistan, the Ethiopian Highlands, and the Colorado Plateau of Southwestern North America. At these localities Vavilov’s notes can be compared with the agricultural activities of themodern day. In each case, significant climatic, environmental, and human-caused changes have affected the local agriculture during the intervening years. Localities that have retained diversity have suffered the least. Reduction of diversity is associated with decreased agricultural stability and productivity. Programs encouraging farmers to manage diversity and promote involvement of local youth in agriculture may reduce or moderate the effect of genetic erosion.