New report on chromosome number, karyotype and 4C DNA content in three species of Pachypodium Lindley

Extensive karyotype analysis including determination of somatic chromosome number, total chromosome length and volume and estimation of 4C DNA content were carried out on three species of Pachypodium namely P. lamerei; P. nam aquanum and P. rosulatum 'horombense' for the first time. A significant var iation in nuclear DNA amount was recorded at interspecific level. The somat ic chromosome number 2n=18 was recorded in all the species. The 4C DNA amou nt varied with 8.425 pg in P. lamerei, to 10.918 pg in P. rosulatum 'horomb ense' and 11.928 pg in P. namaquanum. The correlation coefficient studies s howed that the 4C DNA content and genomic chromosome volume were interdepen dent. The structural alteration of chromosomes as well as loss or addition of highly repetitive sequences in the genome showed a variation in the DNA amount at species level indicated a close relationship between them.