Karyotype of Zea luxurians and Z. mays subsp. mays using FISH/DAPI, and analysis of meiotic behavior of hybridsIn memoriam of Dr. Carlos A. Naranjo.

Abstract

The karyotypes of Zea luxurians and a race of maize from northwestern Argentina are described and compared using 4′,6-diamidino-2-phenylindole (DAPI) banding and fluorescent in situ hybridization (FISH) to localize the 180 bp knobs. The meiotic behavior of the F1 artificial hybrids Z. luxurians × maize is also analyzed to determine the genomic relationships between both species. Neocentromere activity at knobs in the meiosis of the hybrids is particularly discussed. The meiotic behavior and the high pollen sterility of the hybrid revealed genetical and (or) chromosomal divergences, leading to postzygotic reproductive isolation among their parents. Here, we propose that maize shows lower genomic affinity to Z. luxurians than to other species of the genus with 2n = 20.