Structural Differences of Chromosomes in Diploid Agave

Abstract

Cytological studies have been carried out on five different species of Agave, collected from different parts of India. All of them revealed diploidy having 2n=60 chromosomes. A distinct bimodal karyotype with very long and very short chromosomes in a definite proportion of 5:25 ratio is the most significant characteristic of this genus. However, the karyotype formulae, as brought out in the present study differ quite distinctly amongst the species in-vestigated. Such variations principally involve the nucleolar chromosomes of both long and short types. The total chromosome lengths and volumes also differ at the interspecific level. Structural alterations along with differential degrees of coiling of chromosomes are the suggested factors principally responsible for such variations.