Cytological studies of the genus Rosa with special reference to the section Caninae

Abstract

The Caninae type meiosis in the genus Rosa is demonstrated in a hexaploid, Rosa jundzillii Bess. (2n = 42). A probable hybrid plant which is taxonomically identical with the jundzillii hexaploid was found to be heptaploid (2n = 49) with irregular contraction of chromosomes in the late prophase, prometaphase and metaphase. Multivalent‐like configurations were also observed. This is a common feature in other Rosa hybrids, but expressed in different degrees. Of particular interest in the meiosis of Rosa are (1) the diffuse stage, (2) the irregularities in the condensation of chromosomes and the formation of multivalents and (3) the appearance and disappearance of nucleoli and nucleolus‐like bodies. © 1974 Mendelian Society of Lund