Karyotype determination of three Tigridia species (Aspargales, Iridaceae)

Abstract

Studies of the genus Tigridia Jussieu show that there is inadequate cytological information, and variable basic numbers and karyotype features have been reported. To have more accurate karyotypic information within the genus, the chromosome number, morphology of chromosomes, karyotype formula, total length of the genome (TLG), chromosomal symmetry, and asymmetry index (TF %) was determined in Tigridia pavonia var. Sandra, Tigridia multiflora, and Tigridia alpestris subsp. obtusa. All three species have a chromosome number of 2n = 2x = 28, showing a bimodal karyotype consisting of four large chromosomes and 24 small ones. Tigridia pavonia var. Sandra has a karyotypic formula of 28 m with secondary constrictions on three small chromosomes; this species has a more symmetrical karyotype than the others. T. multi ora showed a karyotypic formula of 24 m + 4st, while T. alpestris subsp. obtusa exhibited a karyotypic formula of 22 m + 2sm + 4st. For these two species, this is the first report of the number and chromosome structure. In both, the LGT and TF% values were contrasting compared to the values found in T. pavonia var. Sandra.