Meiotic behavior of hybrids involving Rosa laevigata

Abstract

Meiotic chromosome configuration frequencies at diakinesis and metaphase I were tabulated in diploid and induced tetraploid Rosa laevigata Michx., diploid R. roxburghii Tratt., and tetraploid amphidiploids of R. laevigata with R. roxburghii and R. banksiae Ait. Numerical analysis of configuration frequencies suggests up to two-fold length variation between short and long chromosome arms in the diploids, and incomplete independence of chromosome arms during pairing and chiasma formation in the tetraploids. Since the sampled genomes pair homeologously in intersubgeneric amphidiploids, they are relatively closely related. The meiotic data collectively suggest that R. roxburghii should be classified in subgenus Rosa.