Microsporogenesis and reduced fertility in Algerian populations of <i>Hordeum bulbosum</i> L. (Poaceae)

This report focuses on the meiotic process during microsporogenesis in wild populations of Hordeum bulbosum L. (Poaceae), which were sampled in Algeria. This species is known for its natural vegetative propagation via bulbs. Pollen mother cells (PMCs) at various stages were treated with basic fuchsin to study meiotic behavior, and mature pollen was stained with a aniline blue dye to assess viability. The analyzed samples were confirmed to be diploid (2n=2x=14, based on x=7) and exhibited regular-looking meiosis with seven bivalents at metaphase and four microspores at the end of division. The pollen was also found to be relatively viable (85.55% and 89.7%). The presence of univalents in some pollen mother cells (0.58% and 0.31%) may indicate a genetic isolation mechanism in the species. Conversely, the presence of tetravalents (0.17% and 4.81%) suggests heterozygosity for a reciprocal translocation. The analyses revealed several abnormalities at low frequencies (with cumulative rates ranging from 5.71 to 6.63%). These abnormalities included laggards, chromatin bridges, micronuclei, unoriented bivalents, asynchronous divisions, syncytia, triads, and cytomixis. However, these cytogenetic findings alone do not appear to explain the species’ low caryopsis production (ranging from 46.62 to 49.3%) or its reliance on asexual reproduction through bulbs. The report discusses other potential biological mechanisms that may contribute to this reduced fertility.