Genome size variation in Peruvian Andean maize landraces

Maize (Zea mays ssp. mays) showed intraspecific variability in DNA content. This variation ranges from 40% to 58%, and negative correlations between genome size and cultivation altitude have been detected in Andean landraces from Northwest Argentina and Bolivia. These variations have been attributed to variability in the percentage of heterochromatin and the presence of B chromosomes. In order to investigate if variation in DNA content is also observed in landraces from the secondary center of the diversification of maize, genome size was estimated in nine Andean landraces from Cuzco and Abancay, Peru, which are cultivated between 2450 m.a.s.l. and 3483 m.a.s.l. Inter- and intraracial variations in DNA content were observed, although with a lower percentage of variation (13.21%) than that reported by other authors. The mean 2C value was 5.14 ± 0.42 pg, with a range from 4.54 ± 0.05 pg estimated in the landrace Kculli to 5.44 ± 0.14 pg found in the landrace Confite Morocho. No correlation between genome size and cultivation altitude was found. The fact that we observed much smaller genome size variation values than those previously reported, as well as the lack of correlation with cultivation altitude, could be due to the narrow altitudinal cline sampled. Future studies will be conducted expanding the altitudinal range. The variation in genome size found here will be discussed in reference to the variability in heterochromatin content and B chromosomes that these Peruvian landraces possess.