Genetic diversity in Parkia platycephala Benth.: a pathway for conservation and optimization of germplasm bank

Parkia platycephala Benth., a tree native to Brazil North and Northeast, faces a threat due to the intense use of its fruit in animal nutrition. This research aimed to characterize the genetic diversity and structure within provenances and progeny of P. platycephala using the molecular marker ISSR (Inter Simple Sequence Repeat) to inform germplasm bank establishment for species genetic conservation. Thirteen ISSR primers were amplified in 87 loci with 100% polymorphism. The primers demonstrated the highest efficiency in polymorphism detection based on their average values for polymorphic information content (PIC = 0.43), marker index (MI = 2.88), and resolving power (RP = 3.85). Nei’s genetic diversity (H) showed an average of 0.31, while the Shannon index (I) had an average of 0.47, with the highest diversity observed in progenies from Bom Jesus. The analysis of the genetic structure indicated a greater degree of genetic variation within populations (82.74%). The value of Φst (0.172) suggested a moderate genetic structure between provenances. The unweighted pair group method with arithmetic mean (UPGMA) clustering and Bayesian analysis (K = 4) identified the formation of distinct genetic groups. The mating system is primarily allogamous, with a significant presence of progenies formed by crosses between relatives. These results highlight the importance of maintaining ex-situ conservation of P. platycephala, utilizing promising individuals for the production and propagation of quality seeds, as well as genetic improvement.