Caracterização morfoagronômica, molecular e citogenética de yacon (Smallanthus sonchifolius (Poepp. & Endl.) H. Rob.)

Abstract

Yacon (Smallanthus sonchifolius [Poepp.] H. Rob., Asteraceae), is a plant originally from Andes, rich in nutraceutical properties, with beneficial effects on the organism, due to high concentrations of fructooligosaccharides (FOS), a natural sweetener capable of reducing blood lipid and glucose levels, helping to prevent chronic diseases such as diabetes. The growing global interest in its beneficial properties to human health promotes the advancement and expansion of its commercial cultivation beyond its natural Andean frontier of production, original site, and thus, different adaptive challenges. Therefore, this work aimed to evaluate the genetic diversity among the different yacon accessions, cultivated in states of southeastern Brazil. The results showed a low genetic diversity among the materials cultivated in southeastern Brazil, a situation that can be common throughout the country because materials cultivated in other Brazil regions have a common origin in the southeast. The phenotypic analysis revealed differences between the materials for characteristics related to agronomic and commercial interest, highlighting the possibility of ecotype formation. In all genotypes, the nuclear DNA content is 2C = 6.39 pg, with genome 1C = 3,124,710 Mpb. All with 2n = 58 chromosomes, with a karyotype characterized by the occurrence of 29 pairs of chromosomes, thirteen submetacentric (1–5, 7 – 12, 14, 20), and sixteen metacentrics (6, 13, 1–19, 21-29). Their sizes varied from 3.64 to 1.67 µm, and secondary construction in the pair of chromosomes 21. All this information contributes to the increase the genetic knowledge on yacon, relevant for its conservation, evolution, and diversification, reflecting, consequently, on the agricultural cultivation capacity outside the Andean borders.