When aleurone color is intensified by a thicker and/or multiple-celled aleurone, it may be used to facilitate transfer of this trait by reducing the tedious task of sectioning hundreds of kernels. We selected a recessive pale blue aleurone color that will serve this purpose. This is important to us because we are attempting to recombine the two-celled pericarp, derived from teosinte, with a thick multiple-celled aleurone, from the race Coroico of South America, in an acceptable sweet corn background. The teosinte-type pericarp is lethal in a typical maize background with a single-celled aleurone. The pericarps split in the early milk stage and the kernels are soon destroyed by mold. But the teosinte pericarp is coadaptive with the thick aleurone, which substitutes for it in terms of containing turgor pressure from the endosperm.

Typical North American corn has a pericarp from 7 to 20 cells thick, although in certain extra tender sweet corn (Hayes White) it may be only 5 or 6 cells thick, or in high expansion popcorn 30 or 40 cells thick. But in the wild ancestor of corn the pericarp is only two cells thick because it has reinforcement from the superstructure of a fruit case. In Coroico of Bolivia and Peru, the thick aleurone apparently evolved when an early domesticate from teosinte, still with a thin pericarp, started down an independent pathway of a system allowing kernel expansion. Coroico has a pericarp often 3 or 4 cells thick with an aleurone of equal or greater thickness.

Walton C. Galinat, Josephine Starbuck and Chandra V. Pasupuleti

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