Pachytene Karyotypes in the Genus Crotalaria L. (Leguminosce)

Abstract

Karyotypes were prepared using pachytene chromosomes in 11 species of Crotalaria (Leguminosae). This was done in view of the realization that minor difference in chromosome morphology, which can not be detected in mitotic metaphase chromosomes, would be resolved in pachytene bivalents.
Karyotype asymmetry was found to be of a low order. The eleven karyotypes were placed in three categories (IA, IB and 2B) of the 12 categories recognized by Stebbins (1971). It is concluded that if C. incana (2n=14) is derived from other species with 2n=16, as suggested on the basis of morphology, a secondarily derived trend from asymmetry to symmetry will have to be assumed.