This study considered the effects of three continuous growth temperatures (14, 21, and 28 °C) on apparent genomic structure, apparent chromosome arm ratio, pollen abortion, and meiotic nonreduction in full-sib genotypes of Festuca mairei × F. arundinacea var. glaucescens. Ten genotypes were sampled for meiosis and 20 for pollen. The metaphase I (MI) data for each sampled combination of genotype, temperature, and replication were subjected to a bootstrap algorithm that calculated 95% confidence limits for each class of meiotic figure and for the ratio of ring bivalents to total bivalents, the total number of chromosomes in multivalents per cell, and the mean arm-binding frequency. These confidence limits permitted an evaluation of the significance of differences among genotypes, temperatures, and replications. The MI data were also subjected to two types of numerical models to investigate apparent genomic structure and mean effective chromosome arm ratio, i.e., pairing regulation and extent of chiasma interference across the centromere. The hybrids overall exhibited a 2:2 (AABB) genomic structure, but there were significant differences among genotypes in arm-binding frequency and frequencies of univalents, rod bivalents, and ring bivalents. Except for desynapsis and impaired chromosome contraction in one genotype at 28 °C, temperature had little effect; optimized genomic structure was slightly more 2:1:1 (like AABC) at 14 °C and chiasma interference increased slightly at 28 °C. One genotype was monosomic but meiotically normal. Pollen stainability was significantly depressed at 14 °C, while microspore micronuclei were more numerous. Pollen diameter was least at 21 °C regardless of degree of abortion.Key words: meiosis, meiotic modeling, temperature, pollen fertility, Festuca.