Cytomorphological studies on American and European 
Phleum commutatum Gaud. (Poaceae)

Adam Kula1, Barbara Dudziak4, Elwira Sliwinska2, Aleksandra Grabowska-Joachimiak1, Alan Stewart3, Hieronim Golczyk4 and Andrzej J. Joachimiak4*

1Cytogenetics Group in the Department of Plant Breeding and Seed Science, The Agricultural University of Cracow, Łobzowska 24, 31-140 Kraków, Poland
2 Laboratory of Molecular Biology and Cytometry, Department of Genetics and Plant Breeding, University of Technology and Agriculture, 85-796 Bydgoszcz, Poland
3 Ceres Research Centre, PO Box 3100, Christchurch 8015, New Zealand
4Department of Plant Cytology and Embryology, Institute of Botany, Jagiellonian University, 
ul. Grodzka 52, 31-044 Kraków, Poland

*corresponding author, email: a.joachimiak@iphils.uj.edu.pl

Received March 25, 2006; revision accepted May 10, 2006

The morphology, karyotype structure and nuclear DNA amount of European and American representatives of alpine cat’s tail Phleum commutatum Gaud. were analysed. The evolutionary relationships within this group of taxa are discussed.
It was shown that the American and European tetraploids are both morphologically and karyologically similar to each other and to the diploid race of this species from the Polish Carpathians.
Diploid relatives of tetraploid P. commutatum i.e., P. commutatum (2x) and P. rhaeticum (Humphries) Rauschert, showed intra- and interspecific differences in nuclear 2C DNA values, whereas tetraploids (of both European and American origin) showed highly uniform nuclear DNA amounts. The 2C DNA uniformity and the greater mean size of the basal chromosome set in tetraploid P. commutatum as compared with its diploid relatives suggest that the change in genome size occurred during early evolution of the tetraploid race of P. commutatum, before its migration to America.

Key words: Phleum commutatum, P. alpinum, P. rhaeticum, morphology, chromosomes, karyotype, C-banding, heterochromatin, flow cytometry, nuclear genome size.