CHROMOSOME NUMBERS IN SOME TRIFOLIUM SPECIES WITH A KARYOTYPE FOR T. PHYSODES

Abstract

Chromosome numbers for 8 Trifolium spp. were determined. These represented first counts for T. philisticum Zoh. and T. strepens Crantz. and confirmation for T. amabile H.B.K., T. badium Schreb., T. megalanthum Steud., T. virginicum Small., T. aureum Poll. and T. physodes Stev. ex M.B. Six of the 8 spp. had 2n = 16 chromosomes. T. megalanthum, T. badium, T. aureum and T. strepens have 2n = 32, 2n = 14, 2n = 16, and 2n = 16 chromosomes, respectively. T. strepens and T. aureum have the same chromosome number and morphology; they are the same species under the name of T. aureum. Karyotypic analysis of T. physodes revealed 2 basic types of chromosomes with nearly median and nearly submedian centromeres. Chromosome mean percentage lengths for T. physodes were 16.24-10.18 and the arm ratios were 1.14-1.68.