On a long winter's night, no treat seems simpler than a big bowl of popcornuntil you start to trace the connections between traditional races of popping corns and modern commercial varieties of popcorn.
Plant geneticist Amalio Santacruz Varelathen a graduate student at Iowa State University and currently a professor and researcher at el Colegio de Postgraduados in Mexicoteamed up with Mark Widrlechner to assemble some popcorn pedigrees. Widrlechner is a plant geneticist with the Agricultural Research Service (ARS), working at the agency's North Central Regional Plant Introduction Station (NCRPIS) in Ames, Iowa.
They focused on 56 maize (Zea mays L.) varieties from the United States and Latin Americaemphasizing popcornsand measured 29 morphological traits based on heritable qualities and popping characteristics. They also obtained genetic data from DNA markers and from variations in proteins called enzymes.
Statistical programs were used to analyze these data and estimate the probability of close genetic relationships among the maize varieties. Drawing on the results, the team proposed classifying the majority of U.S. popcorn varieties into three main groups.
Most of the common U.S. commercial varieties belong to the North American Yellow Pearl Popcorns group. This type of popcorn may have its origins in a Chilean popcorn variety adapted to growing conditions similar to conditions in typical U.S. production areas.
The second group, North American Pointed Rice Popcorns, has two subgroups. One contains genetically similar, white popcorns with pointed kernels from the United States, and another represents the major pointed popcorn races from Latin America.
A third group, North American Early Popcorns, appears to be closely related to Northern Flint varieties, which in turn originated from Mexican maize progenitors. Northern Flint varieties have contributed significantly to the development of other important U. S. corn varieties, including Corn Belt Dentsthe yellow field corn grown on millions of acres in the United States and other nationsand many sweet corn types.
Plant breeders can use this information about the origin and genetic relationships of U. S. popcorns to develop even better varieties of popcorn for snacking enthusiasts.
ARS is the U.S. Department of Agriculture's chief scientific research agency.