Maize is blessed with relatively large reproductive cells, and an exceptional cytology. It is thus a powerful experimental model to analyze chromatin dynamics during reproduction at high resolution, in a stage-specific manner, using a combination of methylome analysis, and hyper-resolution microscopy. We have developed efficient protocols to study DNA methylation using bisulfite sequencing in isolated reproductive cells, in both wild type plants and mutants affected in DNA methyl-transferase activity. We have generated a temporal series of methylomes covering individual stages of male meiosis, including prophase I (leptotene, pachytene, dyakinesis), metaphase I, dyades, metaphase II, tetrads and young spores. The data shows that DNA methylation during meiosis is dynamic, and significantly different from the patterns observed in somatic cells. We further looked at the dynamic of methylation in developing embryos. We uncovered a rapid process of hyper-methylation specifically in the CHH context, which is strictly dependent on RNA-directed DNA methylation. DNA methyltranferase mutants in maize display a number of developmental deffects, including strict embryo lethality for CG methyltransferases, but also distinctive effects on meiosis, gametogenesis and embryogenesis for mutants affecting CHG and CHH methylation. We are currently analyzing the functional bases of these phenotypes using both classical cytology, bisulfite sequencing and hyper-resolution microscopy. The data shows that Zmet5, a maize homologue of Arabidopsis CMTs, is a key player of meiocyte methylation at non-CG sites. The mutant shows high degrees of sterility, linked to clear meiotic abnormalities. Altogether, the data indicates that maize represents a remarkable model to establish causal relationships between DNA methylation patterns and reproductive functions.