Submitted to: North American Alfalfa Improvement Conference
Publication Type: Abstract Only
Publication Acceptance Date: 7/27/2002
Publication Date: N/A
Technical Abstract: The combined techniques of chromosome C-banding, image analysis, and cluster analysis were utilized to compare the four historically distinct non-dormant alfalfa germplasm sources of tetraploid alfalfa (Medicago sativa ssp. sativa). Cytogenetic analyses revealed polymorphisms for heterochromatic DNA in all the plants observed. Abundant variability in the number, intensity and location of constitutive heterochromatic DNA was noted; however, this variability was not sufficient to preclude recognition of homologous chromosomes. Karyotypes of Peruvian and Indian populations were developed and compared to the reference African population. In general, there is little distinction between the number of heterochromatic DNA bands of African, Chilean and Peruvian, however, Indian has fewer heterochromatic bands than the other three. Cluster analysis and multiple correspondence analysis based on all eight alfalfa genome chromosomes yielded no clear separation of the non-dormant alfalfa populations. Thus, the inability to differentiate between the four non-dormant types of alfalfa could be due to similar genetic backgrounds of the initial introductions, intercrossing of the different sources, and/or genetic drift during maintenance, or common genetic backgrounds of the initial parental germplasm sources. Based upon this study and others, we recommend that for future studies of the nine historically recognized alfalfa germplasm sources the original parental germplasm sources should be used.