Genome size evolution and chromosome numbers of species of the cryptanthoid complex (Bromelioideae, Bromeliaceae) in a phylogenetic framework

We describe the chromosome numbers and genome sizes of species of the cryptanthoid complex of Bromeliaceae in a phylogenetic framework and their relationship with habitat preferences. The 2C DNA contents varied 2.13-fold among species, ranging from 0.76 to 1.66 pg. A significant difference in DNA content was found among Cryptanthus, Hoplocryptanthus and Rokautskyia. Moreover, species from campos rupestres and the Atlantic Forest had lower and higher genome size values, respectively. The smaller genome sizes of Hoplocryptanthus spp. from campos rupestres may be related with the large genome constraint. The species show a highly conserved ploidy (with 2n = 32 and 34), although the genome sizes varied considerably. The observed variation in chromosome numbers seems to be influenced by dysploidy, but additional investigations are needed. Our study demonstrates that the genome size variation in the cryptanthoid complex species is not strictly related to the phylogenetic relationships and has probably been influenced by different evolutionary processes.