Submitted to: International Symposium of Molecular Breeding of Forage Turf
Publication Type: Proceedings
Publication Acceptance Date: 2/15/2005
Publication Date: 7/3/2005
Citation: Vogel, K.P., Lee, D.J., Caha, C.A. 2005. Rflp analysis of chloroplast dna of the crested wheatgrasses. p.270. In M.O. Humphreys (ed.) Proc. Int. Symp. of Molecular Breeding of Forages and Turf, 4th, Aberystwyth, Wales. 3-6 July 2005. Wageningen Academic Publishers, Wageningen, The Netherlands. Interpretive Summary: The crested wheatgrasses (Agropyron species) are widely distributed in eastern Europe and Asia and have been used to re-vegetate millions of acres of land in the northern plains and intermountain areas of North America. The genus consists of about 10 species that are based on the same set of chromosomes, the 'P' genome. The complex includes species with 2, 4, and 6 sets of chromosomes. The two main agronomic species are the standard and fairway type crested wheatgrasses. In addition to the nuclear DNA that exists in the chromosomes of plants, DNA also is found in the cytoplasm of plant cells in the chloroplasts. The objective of this study was to determine if chloroplast DNA variation exists among strains of the two main crested wheatgrass species. Molecular markers were used to assay for genetic variation. No chloroplast DNA variation was detected in the ten crested wheatgrasses stains that were analyzed. The strains represented all combinations of chromosome numbers that exist in the two species. The chloroplast DNA of the crested wheatgrasses appears to relatively uniform. The primary genetic variation in the crested wheatgrasses appears to be due to nuclear DNA variation including variation in chromosome numbers.
Technical Abstract: The crested wheatgrasses (Agropyron spp.) are widely distributed Eurasian grasses that have been used to re-vegetate millions of hectares of land in the northern plains and intermountain areas of North America. The genus consists of about 10 species that are based on the 'P' genome and includes diploids (2n = 14), tetraploids (2n = 28), and octaploids (2n = 42). The two main species agronomic species are A. cristatum (L.) Gaertner and A. desertorum (Fischer ex Link) Schultes. The objective of this study was to determine if chloroplast DNA polymorphisms occur within and among ploidy levels of these two main species of the complex. Restriction fragment length polymorphisms (RFLP) procedures were used to assay for chloroplast DNA polymorhphism using four restriction enzymes and twenty chloroplast DNA probes. No chloroplast DNA polymorphisms were detected in the ten crested wheatgrasses stains that were analyzed which included both species and diploids, tetraploids, and octaploids. The chloroplast DNA of the Agropyron complex appears to relatively uniform and suggests that the cytoplasmic DNA of the genus is conserved. Primary genetic variation in the genus appears to be due to nuclear DNA variation including polyploidy.