Meiotic irregularities in larix

Meiotic irregularities occured during microsporogenesis in four different larch species were investigated as the first step to determine factors affecting seed yield in Larix. The major abnormalities observed in the materials examined were chromosomal stickiness, degeneration of PMCs(pollen mother cell), acentric chromosomes, unequal distribution of chromosomes, lagging chromosomes, and aberrant microspore formation. Among them degeneration of PMCs, acentric chromosomes at metaphase 1, and aberrant microspore formation were the most common irregularities in all species investigated. Conclusively, meiosis of the larch PMCs was disrupted with total frequencies ranging from 28.3% to 52%, depending on the species. The results obtained in this study indicate that pollen quality might be responsible for seed loss in Larix.