Somatic karyotype, heterochromatin distribution and chromosome differentiation in six wheat genotypes (Triticum aestivum L.)

Somatic karyotype, heterochromatin distribution and chromosome differentiat ion of six wheat genotypes, viz. Aghrani (Ag), Akbar (Ak), Ananda (An), Kan chan (Kan), FM-32 and FM-139 were studied by acetocarmine-stained and N-ban ded chromosomes. Since some of the chromosome pairs in all the genotypes ha ve shown the identical distribution of heterochromatin bands, the number of banding patterns became reduced to 9 in An, 10 in Ag and ii in Ak, Kan, FM -32 and FM-139. From this, it was assumed that the later genotypes were der ived from a more advanced progenitor compared to that of the former two. Th e highly heterochromatic and mostly polymorphic but nearly identical bandin g patterns of B genome chromosomes corresponded individually in all the gen otypes. Only in the D genome, 1D in FM-139, 3D in Ag and FR1-32, 4D in An, 5D in Ag and An, and 7D in Ak and Kan were not found to be banded, although their positions in idiograms were determined on the basis of probabilistic inferences. However, 6D chromosome was almost identical in all the genotyp es. Few A genome chromosomes showed certain morphological changes in additi on to differential heterochromatinization among the same chromosome of diff erent genotypes. It might be accounted for genomic and genic diversity of t he studied materials.