Chromosomal Polymorphism as Detected by C‐Banding Patterns in Chilean Alfalfa Germplasm ¹

Abstract

A cytogenetic investigation was conducted on the tetraploid alfalfa [Medicago sativa subsp. sativa (L.) L. & L.] Chilean germplasm source PI 536534 using the combined techniques of C‐banding and image analysis. Cluster and multiple correspondence analyses were utilized to compare the C‐banding patterns of the Chilean germplasm source and the previously published African germplasm source. Cytogenetic analyses revealed polymorphisms for heterochromatic DNA in the 19 plants observed in detail. 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. Five out of the 50 plants studied were aneuploids (2n = 4x + 1 = 33 or 2n = 4x − 1 = 31) because of the presence or absence of a chromosome with a satellite. The Chilean karyotype resembled the reference tetraploid African alfalfa karyotype; however, a reduction in the total amount of heterochromatic DNA was observed. Cluster analysis and multiple correspondence analysis based on all eight alfalfa genome chromosomes yielded no clear separation of Chilean and African germplasms. However, the analysis of C‐banding patterns of Homolog 1 of Chromosome 8 in Chilean and African germplasms was effective in separating the two germplasm sources with the exception of two individuals from each germplasm source which clustered together.

Orcein, C- and NOR-banding on mitotic chromosomes of some wild diploid coffee species (CoffeaL.)

“…This trend can also be observed among the four coffee species studied. C-banding is considered a useful technique for demonstrating heterochromatin in chromosomes (Hoshi et al 1998) and a reliable chromosome marker, along with karyomorphometric data in comparative studies, allowing for improved characterization of species, populations and germplasms (Bauchan et al 2002;Dong et al 2011). Despite the small size of coffee chromosomes, it was possible to obtain C-bands.…”

Karyological Observations in Medicago Section Dendrotelis (Fabaceae)

“…Cytogenetic studies in Medicago have reported useful data to i) identify parental chromosomes in hybrids (Bauchan and Hossain 1997); ii) to discriminate germplasm sources from cultivated species (Bauchan et al 2002); and iii) to contribute towards the integration of molecular, genetic and cytogenetic maps (Kulikova et al 2001).…”

Comparative Chromosome Banding Studies of Nondormant Alfalfa Germplasm

“…Several cytogenetic studies have been conducted to karyotype the somatic chromosomes of tetraploid alfalfa (Agarwal and Gupta, 1983; Falistocco, 1987; Schlarbaum et al, 1988; Falistocco et al, 1995; Bauchan and Hossain, 2001a,b; Bauchan et al, 2002). The alfalfa karyotype consists of one set of homologous chromosomes with a satellite (chromosome 8), four sets of submetacentric chromosomes (chromosome 1–4) and three sets of metacentric chromosomes (chromosomes 5–7).…”

“…The alfalfa karyotype consists of one set of homologous chromosomes with a satellite (chromosome 8), four sets of submetacentric chromosomes (chromosome 1–4) and three sets of metacentric chromosomes (chromosomes 5–7). Chromosome banding studies have identified individual chromosomes of M. sativa subspecies, including coerulea, falcata (Bauchan and Hossain, 1997, 1998a, 1999a,b,c) and sativa (Falistocco et al, 1995; Bauchan and Hossain, 2001a,b; Bauchan et al, 2002). Bauchan and Hossain (2001b) evaluated the African tetraploid population and concluded it resembled the C‐banding pattern of diploid M. sativa subsp.…”

“…coerulea (Bauchan and Hossain, 1997). The African germplasm source revealed the most heterochromatic DNA of the nine alfalfa germplasm sources (Bauchan and Hossain, 1998b) and its C‐banded karyotype was used as the reference karyotype for characterizing the Chilean population (Bauchan et al, 2002).…”