Single-kernel Analysis for the Presence of the sugary enhancer (se) Gene in Sweet Corn

Abstract

Abstract This paper presents the methodology for the extraction and quantitative analysis of the sugars from single kernels of maize (Zea mays L. var. saccharata Bailey). Concentrations of sorbitol, fructose, glucose, sucrose, and maltose were determined for individual kernels of sweet corn inbreds homozygous for the endosperm carbohydrate mutants sugary (su) and sugary enhancer (se) by gas chromatographic analysis. The extraction procedure was efficient and precise. Single-seed sugar analysis of kernels from the inbreds IL451b (su) and IL677a (su se) revealed that genetic differences between the inbreds was the primary source of phenotypic variation in kernel sugar content. Differences between ears of the same inbred was also a significant source of variation, whereas, in most instances, kernel-to-kernel variation on ears was not. Fifty-eight percent of the variation in the predominant corn sugar, sucrose, was attributed to genetic differences between the two inbreds. Analysis of the observed and predicted distribution in a mature-dry F2 kernel population for sucrose content indicated that single-kernel analysis can isolate the action of the se gene in segregating populations. This procedure can be used to simplify the incorporation of se into elite inbreds, map its chromosomal location, and uncover other potentially useful alleles that modify corn endosperm carbohydrate metabolism.