QUANTITATIVE VARIATION IN DNA AS RELATED TO PLOIDY LEVEL AND SPECIES IN SOME WILD ROSES

Abstract

Relative DNA content and chromosome number and behaviour were studied in Manitoba wild roses. The hexaploid, Rosa acicularis, contained the largest amount of DNA, about three times that of the diploid, R. woodsii. Another diploid species, R. blanda, contained less DNA than R. woodsii. One specimen, identified as R. blanda with some introgression from R. woodsii, had the same amount of DNA as the latter species. R. × dulcissima, a hybrid between R. blanda and R. woodsii, had DNA contents similar to R. woodsii. The origin of a tetraploid, with DNA contents intermediate between diploid and hexaploid species, and 14 bivalents in diakinesis, was suggested to be hybridization between R. acicularis and a diploid rose. Chromosome behaviour in meiosis and DNA content were used in a discussion of interspecific relationships.