Genetic Fine Structure Analysis of the AMYLOSE-EXTENDER Locus in ZEA MAYS L.

On the basis of interallelic recombination frequencies measured in diallelic crosses of the 5 amylose-extender alleles in maize, ae, B1, B3, M2 and i1, it was possible to construct a unique linear genetic map ordering all 5 alleles within the locus. The reciprocal diallelic crosses each gave comparable frequency estimates. The relative order is ae, i1, B3, B1, M2 or the reverse. Even though F1 endosperms resulting from all possible diallelic crosses were phenotypically mutant, therefore non-complementing, no decision as to whether or not these alleles exhibit functional complementation should be made without biochemical characterization of the starches from the various heteroallelic genotypes.