title: Controlling elements in a tribal maize from Colombia: fcu , a two-unit system.
abstract: The genetic basis for a striking aleurone color variegation of a maize population from Colombia is described. The variegation is the result of the interaction of a particular r allele, designated r-cu , and a specific factor, Fcu (Factor Cuna), that collectively compose a controlling element system. In the absence of Fcu, a variable dilute (nonvariegated) pigmentation is expressed in the aleurone. The degree of variegation is determined by differences in the dosage of the Fcu element; differences in variegation between kernels with one r-cu vs. two r-cu's cannot be detected. Because of the specificity of the interaction, Fcu is different from the three other well-known controlling elements, Dt, Ac and En(=Spm), and therefore represents a fourth controlling element system in maize. In addition to Fcu, the Cuna tribal maize contains two other controlling elements, Dt and a very weak En. The prevalence of controlling elements in natural maize populations is discussed.
authors.affiliation: Department of Agronomy, Iowa State University, Ames, Iowa 50011.
authors.forename: J A
authors.initials: JA
authors.lastname: Gonella
authors.forename: P A
authors.initials: PA
authors.lastname: Peterson