Description
Chromosomes of two diploid (2n=2x=16) subspecies of Medicago sativa, ssp. caerulea and ssp. falcata, their hybrid and tetraploid (2n=4x=32) cultivated alfalfa (M. sativa, ssp. sativa) were studied. Feulgen’s staining, C- and N-banding techniques and an image analysis system were used. The chromosomes of ssp. falcata have only centromeric bands, however, a multitude of bands were observed in both the C- and N-banding pattern of ssp. caerulea and ssp. sativa enabling the precise identification of each of the eight sets of chromosomes and development of a karyotype. The differences in banding patterns between the diploid subspecies makes it possible to identify hybrids between these subspecies. Karyotypic analysis of tetraploid alfalfa revealed that alfalfa has four nearly identical sets of chromosomes based on their identical chromosome morphology and C-banding patterns, thus providing support that alfalfa is an autotetraploid.
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Identification of Alfalfa Chromosomes Using Giemas Banding and Image Analysis Techniques
Chromosomes of two diploid (2n=2x=16) subspecies of Medicago sativa, ssp. caerulea and ssp. falcata, their hybrid and tetraploid (2n=4x=32) cultivated alfalfa (M. sativa, ssp. sativa) were studied. Feulgen’s staining, C- and N-banding techniques and an image analysis system were used. The chromosomes of ssp. falcata have only centromeric bands, however, a multitude of bands were observed in both the C- and N-banding pattern of ssp. caerulea and ssp. sativa enabling the precise identification of each of the eight sets of chromosomes and development of a karyotype. The differences in banding patterns between the diploid subspecies makes it possible to identify hybrids between these subspecies. Karyotypic analysis of tetraploid alfalfa revealed that alfalfa has four nearly identical sets of chromosomes based on their identical chromosome morphology and C-banding patterns, thus providing support that alfalfa is an autotetraploid.
