Searching a Gene Bank: The Case of Wheat

This paper presents theoretical and empirical results on the optimal search for genetic traits within a crop gene bank. Three specific questions are posed and answered, using data on the distributions of resistance genes and on the costs and benefits of search. First, we ask what is the optimal size of search for a trait of economic value? Second, what is the value of specialized knowledge about likely sources of resistance? Third, how should search resources be allocated across different types of genetic resources? Results demonstrate that for some traits, large searches are justified. In other cases, the costs and time lags associated with conventional prebreeding techniques may make it efficient to ignore certain categories of genetic resources. In general, the infrequency of searches does not imply that additional accessions are valueless; low utilization of the gene bank by breeders does not imply that banks are “seed morgues.” * Douglas Gollin is Assistant Professor of Economics at Williams College and Affiliate Scientist, CIMMYT Economics Program. Melinda Smale is CIMMYT economist, and Bent Skovmand is the Head of Wheat Genetic Resources, CIMMYT. Among those who have contributed helpful comments and suggestions are: Norman Borlaug, Cheryl Doss, Jesse Dubin, Bob Evenson, Paul Heisey, Lucy Gilchrist, Michael T. Jackson, Stephane Lemarié, Sanjaya Rajaram, Matthew Reynolds, Greg Traxler, and Maarten van Ginkel. Harold Bockelman, director of the U.S. Department of Agriculture’s National Small Grains Collection, made available part of the GRIN data base. Will Chang provided research assistance. The views represented here are those of the