MEIOTIC BEHAVIOR AND DNA, CONTENT IN ALLOPLASMIC LINES OF MAIZE

The cytoplasm of Zea mays ssp. mexicana (teosinte) affects several inh erited traits when combined with genotypes of maize (Zea mays ssp. may s). The meiotic behavior and the total DNA content of four lines of ma ize with teosinte cytoplasm were compared with those of the parental l ines. The results obtained suggest that the cytoplasm of teosinte prom otes an increase in total nuclear DNA content, perhaps through an incr ease of highly repetitive DNA in the knob zones. The analysis of meiot ic behavior indicates that the cytoplasm of teosinte can alter the spa tial distribution of the genomes, since two groups of five bivalents e ach were observed at a high frequency. During prophase I - anaphase I, each group of five bivalents behaves in a slightly asynchronous way w ith respect to the other group and, moreover, two nucleoli were observ ed in 10% of the cells. These results suggest that the cytoplasm of te osinte could induce changes affecting genomic structure and function i n some maize genotypes. These changes are of potential importance for breeding programs and evolutionary studies.