UBC Theses and Dissertations
Comparative karyotype analysis of four Douglas-fir Pseudotsuga menziesii (Mirb.) Franco provenances De-Vescovi, Maria Adela
A comparative karyotype study was made of chromosomes in root-tip meristematic cells of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco germinants obtained from three Coastal (#1,3,22,) and one Interior (#28) sources distributed through 8°04" latitude. The somatic chromosome number in all provenances was 2n=26 or x=13. The morphological index was found to be the most useful criterion for separating the five metacentric, six submetacentric and two subtelocentric chromosomes of the basic set. A clinal increase from south to north in chromosome width (1.3), and volume (1.6), was noted among the chromosomes of the three Coastal provenances. The haploid chromosome complement of the Coastal provenance (#22) had 1.5 times more volume than the corresponding Interior one (#28), substantiating previous results as far as variation in nuclear volume and DNA contents are concerned. Gasguet (#3) provenance showed more dissimilarities regarding the length of the chromosome arms and secondary constrictions than the chromosomes of the other three provenances .