C-banding of alfalfa chromosomes: standard karyotype and analysis of a somaclonal variant
1991
Masoud, S.A. | Gill, B.S. | Johnson, L.B.
C-banding was used to identify diploid alfalfa (Medicago sativa L. cv. CADL; 2n = 2x = 16) somatic chromosomes and to construct a karyogram. CADL is "cultivated alfalfa at the diploid level" and was derived from cultivated tetraploids. All chromosomes were differentially C-banded and were identified individually based on position, number, and/or staining intensity of bands. All chromosomes showed centromeric band(s). Six of eight chromosomes-1, 2, 4, 5, 6, and 8-had telomeric bands but differed in number (0-2) and position of intercalary bands. Chromosomes 3 and 7, which lacked telomeric bands, were also distinguishable. Chromosome 3 exhibited an intercalary band, whereas chromosome 7 was smaller and possessed only a centromeric band. C-banding polymorphism was observed for CADL within some homologous chromosome pairs. The usefulness and reproducibility of the C-banding technique was demonstrated by the analysis of a plant regenerated from tissue culture. Chromosomal rearrangements were documented, including an apparent deletion and an isochromosome derived from chromosome 8. It should now be feasible to use C-banding to gain basic cytogenetic information and to monitor chromosome transfers from other Medicago species into alfalfa.
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