Abstract
The Annonaceae includes 107 genera (Guo & al., 2017), with 2400 species, many of which occur in Amazonia (Maas & al., 2015; Guo & al., 2017). Within the family, the genus Annona L. stands out for the many species with edible fruit, such as A. mucosa Jacq. (Larranaga & al., 2019; Araujo & al., 2021). The monophyly of the genus Annona depended on the inclusion of the genus Rollinia A.St.-Hil. (Rainer, 2007; Chatrou & al., 2009), whose flowers differ from the other species of Annona (Maas & al., 1992).
The genus Annona has a basic chromosome number of x = 7 (Morawetz, 1986). Annona mucosa has two ploidy levels: 2n = 4x = 28 in probably wild populations in Peru (Maas & al., 1992) and 2n = 6x = 42 in domesticated populations in Brazil (Morawetz, 1986; Lorenzoni, 2016). The species also appears to be variable in genome size (2C = 4.77, 5.42 and 6.00 pg) (Soares & al., 2014; Lorenzoni, 2016; Leitch & al., 2019). Recent studies identified wild populations of A. mucosa in Mexico (Segura & al., 2018; Escobedo-López & al., 2019).
We expected wild populations to present lower ploidy than cultivated populations. However, our results show that this Mexican population is hexaploid. The chromosome numbers were determined for the first time for this species in Mexico and suggest that this population may once have been cultivated.