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

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. namaquanum and p rosulatum ' horombense' for the first time. A significant variation in nuclear DNA amount was recorded at interspecific level. The somatic chromosome number 2n=18 was recorded in all the species. The 4C DNA amount varied with 8.425 pg in P. lamerei, to 10.918 pg in P. rosulatum 'horombense' and 11.928 pg in P namaquanum The correlation coefficient studies showed that the 4C DNA content and genomic chromosome volume were interdependent. 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.