Chromosome studies in the genus Jatropha L

The inflorescences of ten species of the genus Jatropha were fixed in Cornoy’s fluid (6:3:1). Acetocarmine stain (2%) was used for staining the pollen mother cells. Seven species exhibited 11 bivalents and 2n =22 and x=11. But the two other species, J.villosa var. villosa and J.villosa var. ramnadensis showed only 10 bivalents and 2n number of 20 chromosomes and x=10. The study concluded the occurrence of two kinds of haploid chromosome numbers of n =10 and n =11. Except Jatropha tanjorensis, cytological investigation in all species exhibited normal and complete pairing and bivalent formation in metaphase I and equal separation of chromosome in anaphase and indicated that the course of meiosis was normal. Jatropha tanjorensis did not exhibit normal course of meiosis and no proper count of chromosomes could be made. Present chromosomal studies in Jatropha revealed the existence of two basic chromosomes numbers x = 5 and x = 6.