Karyotyping of Spondias L. (Anacardiaceae) Using Fluorescent Microscope

The genus Spondias L. belongs to the Anacardiaceae family and includes 18 species with at least nine Neotropical species [1]. Spondias is native to tropical America and Asia, and Madagascar. Spondias has been used as far as 6500 B.C., in the Tehuacán Valley of Mexico [2]. S. mombin L. (Cajá), S. tuberosa Arruda Câmara (Umbu) and S. purpurea (Serigüela) are the most economically important species in the genus for agro-industrial applications. Chromosomal data are a valuable resource for cytogeneticists and breeders as they provide better insights into taxonomic and phylogenetic relationships among the species [3,4]. Cytogenetic studies addressing the genus Spondias are rather limited. Previous studies showed that studied Spondias species were diploids with somatic chromosome number of 2n= 32. The only cytogenetic data available are the chromosome numbers (2n = 32) of three species: S. pinnata [5-7], S. mombin [8], and S. tuberosa [9]. Recently, De Souza Alemdia et al. [10] studied the karyotype differentiation among five Spondias species and the putative hybrid Umbucajá. All the studied species and hybrid presented the same chromosome number (2n=32) and morphology. Previous studies did not include all Spondias species and chromosome numbers of the different Spondias species are questionable because inefficient chromosome counting protocols were employed [11]. These protocols are hampered by the small sized chromosomes of Spondias species and a few cell divisions were visible in a single root tip [11]. The aim of this study was to develop more effective method to resolve the chromosome numbers in Spondias species using fluorescent microscope and provide more insight into understanding the cytogenetic and phylogeny of the genus Spondias.