CHARACTERIZATION OF NATURAL POPULATIONS OF Amburana cearensis (ALLEMÃO) A.C.SM.: IMPLICATIONS FOR SEED COLLECTION AND in situ CONSERVATION
Endangered species, dry forests, forest seeds, genetic conservation, forest restauration.
Amburana cearensis (Allemão) A.C.Sm. (Fabaceae) is a native species of the endangered Caatinga. Thus, studying the remaining natural populations is imperative to assist in their conservation. Thus, it aimed to characterize natural populations of A. cearensis to support in situ conservation strategies and seed collection of this species in the Caatinga biome. Three populations were selected for the study, one in the state of Paraíba (Soledade) and two in Rio Grande do Norte (Caicó and Assu). The quality of the seeds produced by the trees of the population of Soledade were analyzed with the perspective of selecting matrix trees for seed collection and the three populations were genetically characterized to support in situ conservation strategies and seed collection. A total of 17 trees (100%) of the population of Soledade presented potential for seed production, as they presented satisfactory values for physiological quality. By analyzing the amplification profile of 30 ISSR (Inter Simple Sequence Repeat) molecular primers, it was found that only twelve of them revealed loci with good resolution, reproducible and with high polymorphism (83-100%). This set of primers revealed 89 loci with 98.8% polymorphism, this amount being sufficient to detect genetic polymorphism based on the resampling technique. The evaluated genetic diversity indices were polymorphism percentage (%PL), polymorphic information content value (PIC), Nei genetic diversity index (He), Shannon index (I), total heterozygosity (Ht), genetic differentiation (GST) and gene flow. Informative and satisfactory values were found for genetic diversity indices for trees in the Caicó population (%PL = 69.3; He = 0.152; I =0.232), Soledade (%PL = 80.8; He = 0.225; I = 0.338) and Assú (%PL = 73.7; He = 0.240; I = 0.350). However, for Nei genetic diversity (He = 0.364), Shannon Index (I = 0.539) Total heterozygosity (Ht = 0.371), genetic differentiation (GST = 0.447), only among populations these values were moderately satisfactory. Gene flow was low (Nm = 0.620), indicating isolation or fragmentation of populations. For morphometric characterization of Caicó, Soledade and Assu, there was a significant difference only for height, in which taller tree classes were observed, indicating advanced ontogenetic stage of the trees. Therefore, from the results obtained, it was possible to characterize all populations of A. cearensis as potential seed producers and satisfactory genetic diversity for seed collection and in situ conservation of the species.