Cytological studies in the genus Rosa. II. Meiotic analysis of ten species.

Abstract

Male meiosis was studied in 6 diploid, 3 tetraploid and I pentaploid Rosa species. Chromosome associations at diakinesis and irregularities at anaphase and telophase were scored. Pollen fertility was also determined. The diploids and one tetraploid, R. s. pimpinellifolia showed regular meiosis and high pollen fertility. The tetraploid hybrid species, R. macrantha showed fairly irregular meiosis with only about one third of pollen fertile. Highly irregular meiosis, with 6-7 bivalents and remaining univalents, was observed both in the tetraploid R. glauca and, pentaploid R. canina. Additionally these had a very high frequency of laggards resulting in formation of more than four pollen grains per PMC thereby drastically reducing the pollen fertility.