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ABSTRACT. Poincianella pyramidalis (Tul.) L.P. Queiroz is an endemic Caatinga (Brazilian savannah biome) species that has been exploited for different purposes, although information is necessary about still existing natural populations. The objective of this study was to evaluate the genetic diversity among 20 P. pyramidalis individuals occurring in a population localized in the Caatinga biome of Paraíba State, aiming at seed collection, using RAPD markers. For the DNA extraction, young shoots of the individuals were used, and amplification was carried out using 20 primers. The obtained markers were converted to a binary matrix, from which a genetic dissimilarity matrix was built using the arithmetic complement of Jaccard's coefficient, and the dendrogram was built by the UPGMA analysis. No amplified fragment was monomorphic, resulting in 100% polymorphism of the analyzed population. The mean genetic diversity among the matrices was 63.28%, ranging from 30.9 to 97.7%. Individuals 09 and 17 showed relevant genetic proximity, and thus planting their seedlings at close sites would not be indicated. The population evaluated in this study showed high genetic diversity, originating twelve groups from the UPGMA hierarchical cluster analysis. Based on the results, individuals 09 and 17 can provide plant material for the evaluation of the physiological performance of P. pyramidalis seeds, and the set of individuals of this population has a high genetic diversity that characterizes them as adequate matrices for projects of restoration and conservation of the seed species.

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Studies on genetic diversity of cacti are important to elucidate evolutionary events and ecological characteristics of populations vulnerable to genetic erosion. The objective of this study was to evaluate the genetic diversity among individuals of Pilosocereus catingicola subsp. salvadorensis occurring in three populations located in the Caatinga do Agreste region of Paraiba, using RAPD markers. For the extraction of DNA, tissues of the parenchyma and cladodium of the stem of the individuals were used by the 2% CTAB method and amplified using 05 primers. The obtained marks were converted into a binary matrix, from which the matrix of genetic dissimilarity was constructed using the arithmetic complement of the Jaccard coefficient and the construction of the dendrogram, by the UPGMA method. All markers tested amplified, being 82.4% polymorphic locus and 10.6% monomorphic for the Arara population; 84.4% polymorphic and 15.6% monomorphic for the Areial population, the Boa Vista population did not show monomorphism, resulting in 100% polymorphism. The averages of heterosigose observed (0.372, 0.492 and 0.135) show that there are genetic divergences within the populations. The primers used were effective in identifying polymorphism in the species. The populations evaluated in this study showed high genetic diversity, both within and between the population, originating fifteen groups among the 120 individuals from the UPGMA hierarchical grouping analysis, and it was possible to discriminate the populations.

ABSTRACT. Brazil has a great diversity of Capsicum peppers that can be used in breeding programs. The objective of this study was to evaluate genetic variation in traits related to the physiological quality of seeds of Capsicum annuum L. in a segregating F 2 population and its parents. A total of 250 seeds produced by selfing in the F 1 generation resulting from crosses between UFPB 77.3 and UFPB 76 were used, with 100 seeds of both parents used as additional controls, totaling 252 genotypes. The seeds were germinated in gerboxes containing substrate blotting paper moistened with distilled water. Germination and the following vigor tests were evaluated: first count, germination velocity index, and root and shoot lengths. Data were subjected to analysis of variance, and means were compared by Scott and Knott's method at 1% probability. Tocher's clustering based on Mahalanobis distance and canonical variable analysis with graphic dispersion of genotypes were performed, and genetic parameters were estimated. All variables were found to be significant by the F test (P ≤ 0.01) and showed high heritability and a CVg/CVe ratio higher than 1.0, indicating genetic differences among genotypes. Parents (genotypes 1 and 2) formed distinct groups in all clustering methods. Genotypes 3, 104, 153, and 232 were found to be the most divergent according to Tocher's 12480 A.M.S. Pessoa et al. ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 14 (4): 12479-12488 (2015) clustering method, and this was mainly due to early germination, which was observed on day 14, and would therefore be selected. Understanding the phenotypic variability among these 252 genotypes will serve as a basis for continuing the breeding program within this family.