The pointed shape of kernels is controlled by a single gene within a complex of genes on chromosome 4 that is important in separating the ears of teosinte and maize (P. C. Mangelsdorf and W. C. Galinat, 1963, MNL 37:30-31). Pointed kernels will fit snugly into either an elongate fruit case, as in Guatemalan teosinte, or a pod corn enclosure. Pointed kernels also have a higher embryo/endosperm ratio. Because corn oil is extracted chiefly from the embryo, the pointed kernel trait may be economically important in breeding for increased oil content. The longer embryos may have evolved in annuals (e.g., Palomero Toluqueho maize) as an adaptation to cool climates requiring a head start by rapid germination and early leaf display.
Walton C. Galinat
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