Submitted to: Plant Genetic Resources
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/11/2013
Publication Date: 3/20/2013
Publication URL: http://handle.nal.usda.gov/10113/58024
Citation: Jaradat, A.A. 2013. Perceptual distinctiveness in Native American maize (Zea mays L.) landraces has practical implications. Plant Genetic Resources: Characterization and Utilization. 11(3):266-278.
Interpretive Summary: Native American farmers identify and manage a wide range of variation in corn largely based on kernel color. They developed and selected corn for kernel color traits that allowed them to distinguish between and maintain large diversity for various traditional uses. A 2-year field experiment was conducted to study a collection of Northern flint corn. The corn was managed by Native American farmers and obtained from the White Earth Recovery Project in northern Minnesota. The kernel physical, chemical, and color characteristics were used to identify relationships between color and nutrients. The names used in this study, such as Purple Mountain Purple and Pink Lady, reflect a long-established Native American tradition. Farmers usually refer to corn by the most prominent color of its kernels. Occasionally, corn was referred to by its use or source, such as Bear Island and Dakota Black popcorn. Kernel colors were digitally measured on random kernels from a large collection of Native American corn. Variation in kernel color was found to be associated with variation in quality traits; it may be used to select for certain quality attributes in corn kernels. A visual selection procedure was developed to identify corn with colors that are associated with high levels of quality traits. This procedure can be used to identify closely related varieties and to maintain large variation of corn in farmers’ fields.
Technical Abstract: The large variation in the multifactorial and seemingly non-adaptive kernel color trait displayed by Native American maize landraces is an evidence of recurring selection for perceptual distinctiveness. Native American farmers selected for color traits that allowed them to distinguish between and maintain large diversity within maize landraces for various traditional uses. Multivariate statistical procedures were employed to quantify variation and interrelationships between physical traits, carbon:nitrogen ratio, protein content, micro- and macro-nutrient concentrations measured on random kernel samples of Northern flint maize landraces grown for two years in a common-garden experiment. The color space descriptors (L*, a*, and b* indicating dark-light, red-green, and yellow-blue color continuum, respectively) were digitally quantified on 10 random kernels from each of 28 accessions in 10 landraces. Accessions within landraces exhibited the largest variation for all three color descriptors. Variation in the L*a*b*, L*a* and L*b* combinations explained significant variances in 35, 15, and 37% of 120 landrace-trait combinations, respectively; the remaining 13% were explained by L*, a*, or b*. On average, 37.5% of variation in protein content (range 19.2 to 64.5%) and 36.6% of variation in C:N ratio (range 15.7-65.0%) were explained by combinations of color descriptors in different landraces. Larger amounts of average variation in potassium (43.7%), sulfur (43.0%), iron (42.2%), and phosphorus (40.8%) were accounted for by color descriptors. A joint and hierarchical clustering procedure of landraces and traits was developed to facilitate the identification of large variation and selection of single or multiple traits based on kernel color descriptors with reasonable certainty.