Chromosomal heteromorphy in the karyotypes of three local cultivars of Hippeastrum vittatum (Amaryllidaceae)

Cytological studies of three cultivars viz., `Apple Blossom`, Cardinal and `Minerva` of H. vittatum were undertaken for the evaluation of Karyomorphological variations. On the basis of length, the chromosomes were classified in to three groups viz., large, medium and small. Within each group, chromosomes were arranged in the ascending order of heterobrachy. Basic Karyotype observed was composed of 2 metacentric, 2 submetacentric, 4 subacrocentric 3 acrocentric chromosomes. Chromosomes exhibited heteromorphism for size due to loss of parts of long or short arms in one of the members in varying degrees. Pronounced difference in length was regarded as mismatching and lesser degree of variation betwiin counterpart membrs as heteromorphy. In diploid plants, chromosomes VII and XI exhibited variation, which was regarded as mismatching. Three cultivars could not be differentiated on the basis of chromosomal morphology. In tetraploid plants chromosomes were arranged in to eleven linkage group of four members each. In general, the morphology of chromosomes was similar to that of diploid cultivars. Among the Karyotypes of tetraploid cva. Cardinal and `Minerva` there was no set with mismatched chromosomes, however, in cv. `Apple Blossom` mismatched chromosomes were observed in linkage group IV and XI. Heteromorphy of varying degree was found in several chromosomes of diploid and tetraploid plants.