Meiotic behavior during microsporogenesis, responsible for male sterility in some species of Salvia sect. Aethiopis in Iran

The genus Salvia L. (Lamiaceae: tribe Mentheae) contains about 1000 species. Section Aethiopis in this genus has a distribution in the Mediterranean and central Asia and contains about 34 species in Iran. This study aimed to investigate the chromosome number and meiotic behavior in five species of Salvia sect. Aethiopis. To this end, pollen mother cells were used, and the squash method was employed. The results showed that S. persepolitana and S. spinosa had a chromosome number of 2n=2x=20, while S. sclarea, S. hypoleuca, and S. limbata had a chromosome number of 2n=2x=22. The study of meiotic behavior revealed the presence of abnormalities such as chromosome stickiness, cytomixis, non-synchronous segregation, chromosome bridges, laggard chromosomes, formation of micronuclei in tetrad cells, formation of tripolar cells, and pentapolar with different frequencies in the studied species. The meiotic index was reported as the highest in S. persepolitana and the lowest in S. hypoleuca. Pollen fertility was also affected by meiotic abnormalities, showing a decreasing trend from S. persepolitana to S. spinose. Meiotic abnormalities may have played a role in the evolution of aneuploidy and polyploidy in the Salvia genus.