Variação cromossômica e tamanho de genoma em variação cromossômica e tamanho de genoma em Vanilla variação cromossômica e tamanho de genoma em (Orchidaceae)

Abstract

Vanilla plays a crucial role in the food and fragrance industries, emphasizing the need for sustainable practices. However, cytogenetic research on the genus remains limited, with only 13% of the species having their chromosome numbers documented. This study aimed to conduct comprehensive karyomorphological analyses, evaluate numerical chromosomal variation, perform chromosome banding with CMA and DAPI fluorochromes, and quantify genome size in different Brazilian species of the genus Vanilla. In the first chapter, we identified that V. chamissonis and V. cribbiana exhibit 2n = 32, with moderately asymmetrical karyotypes. Chromosome size variation ranged from 2.93 µm to 1.36 µm in V. chamissonis and from 3.15 µm to 0.82 µm in V. cribbiana. In the second chapter, we confirmed the chromosome numbers of seven species as 2n = 32, while an unidentified species exhibited 2n = 64. Genome sizes varied significantly from 1C = 2.73 pg in V. phaeantha to 1C = 7.32 pg in V. chamissonis. New genome size records were registered for V. cf. bahiana, V. cribbiana, V. palmarum, and an unidentified tetraploid. Additionally, we identified three distinct types of chromosomal bands, highlighting their applicability in identifying homologous and heteromorphic chromosomes. Cytogenetic information clarified the taxonomic relationship between V. cf. bahiana and V. phaeantha as distinct species. These results accentuate the importance of the genus Vanilla for the development of programs aimed at producing more productive and commercially valued varieties.