Cytomorphological Studies in some species of Chrysanthemum L. (Asteraceae)

Abstract

Meiotic studies, chromosome pairing and chiasma frequency were performed on 12 species of Chrysanthemum (Asteraceae). All the species studied are based on x=9, the commonest base number of the genus. The present record of 2n=36 for C. maximum is a new tetraploid cytotype for the species. C. koreanum (2n=54) and C. paludosum (2n=18) are the two species studied cytologically for the first time. Chromosomal counts on Indian accessions of species viz. C. coccineum, C. indicum, C. multicaule, C. pyrethrum and C. segetum are made for the first time. Chiasma frequency ranges from 1.80-1.99 per bivalent in diploids, 2.47-3.01 per bivalent in tetraploids and 1.37 in hexaploid. Multivalents are noticed in both diploids and tetraploids.