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Preliminary study on genetic relationships of Melocactus Link & Otto of the family Cactaceae revealed through karyotype, DNA content and RAPD analysis

2008; University of Florence; Volume: 61; Issue: 1 Linguagem: Inglês

10.1080/00087114.2008.10589604

2165-5391

Anath Bandhu Das, S. Mohanty,

Plant and animal studies

Abstract The genetic relationships of 10 species of Melocactus was determined using karyotype, Interphase Nuclear Volume (INV), 4C DNA content and RAPD markers. Somatic chromosome number varied from 2n = 22 to 2n = 44. Detailed karyotype analysis showed interspecific variation along with structural alteration of chromosomes. Significant variation in INV and nuclear DNA content were noted among the species. DNA content per chromosome varied from 0.812pg in M. ernestii (2n = 44) to 1.13pg. in M. bahiensis (2n = 22). Interspecific RAPD polymorphism varied from 42.85% in between M. bahiensis and M. ernestii to 75.60% in between M. zehntneri and M. ernestii ssp ernestii. Phylogenetic tree obtained from RAPD markers revealed M. curvispinus as an original species of the group with a wide assemblage of M. peruvianus, M. bahiensis ssp bahiensis f. acispinosus and M. zehntneri. M. bahiensis ssp bahiensis f. acispinosus claimed as separate species and separated out from M. oreas group as well as M. zehntneri from M. violaceus group. Close genetic homology among M. ernestii ssp ernestii, M. ernestii, and M. matanzanus confirmed the right placement of these species in M. oreas group where M. ernestii ssp ernestii could be considered as a species. Distant affinity of M. bahaensis with M. ernestii under a same group confirmed its right position in M. oreas group. M. concinnus with the M. ernestii and M. bahiensis forming a separate distinct branch of the tree confirm its origin from a same ancestor and disagree with its placement in M. violaceus.