Characterization and variability of morpho-genetic traits of commercial importance in achiote collection

The achiote or annatto ( Bixa orellana L.) is a tropical plant displaying high morphological variation associated with variable bixin content, which is a valuable commercial natural pigment. This study assesses the morphological and genetic variation of 58 domesticated individuals of achiote. The analysis involved 16 morphological traits, 23 SSR markers, and SNPs of the lycopene β-cyclase 1 (Boβ-LCY1) gene. The individuals analyzed showed variation in morphological traits. A two-step cluster analysis revealed three clusters of morphological traits; among them, one group stood out with important agronomic traits considered desirable for the crop. Some individuals exhibited agronomic traits of interest, such as a higher number of seeds per fruit (43 ± 4.7), indehiscent fruits, and a bixin production of 42.6 mg·g –1 (dry weight). The achiote individuals showed genetic diversity covering 2.1 effective alleles, a Shannon-Weaver of 0.75, and an observed and expected heterozygosity of 0.58 and 0.48, respectively. The individuals displaying higher levels of bixin were associated with polymorphisms of Boβ-LCY1 gene; thus, this may be considered a promising marker to be included in the selection profile of elite plants in genetic improvement programs for this cultivar.