The use of multivariate analysis of karyotypesto determine relationships between species of Opuntia (Cactaceae)

Abstract

Somatic chromosomes were studied from roots from seven species and two varieties of the genus Opuntia collected from different localities in Eastern India. 2n = 22 chromosomes were observed in four, 2n = 44 in two and 2n = 55 chromosomes in one population. The total chromosome length is maximum in O. Ficus-indica (2n = 55) and minimum in O. microdasys var. lutea (2n = 22). The karyotypes show a similarity in basic number x = 11, except for the horticultural variety, O. monocantha variegata with 2n = 34. The chromosome sizes range from very small (0.97 mm) to medium (3.46 mm); the primary constriction varies from nearly submedian to median and the numbers of chromosomes with secondary constrictions are from four to six. Numerical analysis of data indicates a general similarity of the karyotypes, with O. Ficus-indica occupying a separate position. © 2000 Taylor & Francis Group, LLC.