RESUMO -Fava d'anta (Dimorphandra mollis Benth) é uma planta nativa do Cerrado brasileiro utilizada na extração da rutina, quercetina e ramnose, produtos usados nas indústrias farmacêuticas e de cosméticos. O norte do Estado de Minas Gerais produz cerca de 23% da rutina nacional. A obtenção dessa espécie tem sido de forma predatória pelos extrativistas, e estudos da variabilidade genética dessas populações podem fornecer subsídios para estratégias de conservação e manutenção da espécie. O objetivo deste trabalho foi analisar a diversidade genética dessa planta por meio da técnica de RAPD. Para isso, foram coletadas folhas jovens de fava d'anta em sete localidades diferentes (Januária, Patis, Mirabela, Lontra, CAA, Jequitaí e Morro Alto) da região Norte de Minas Gerais. Nessa análise, testaram-se 43 primers. A análise de variância molecular (AMOVA) indicou que 10,3% e 89,7% da variação genética foi distribuída entre e dentro das populações, respectivamente. A diversidade genética de Nei ( e ) variou de 0,1736 (população de Morro Alto) a 0,2867 (população de Mirabela). Já a análise genética permitiu a construção de um dendrograma com formação de grupos distintos, cujas informações poderão ser utilizadas na criação de um banco de germoplasma e contribuir para a preservação da espécie.Palavras-chave: Fava d'anta, variabilidade genética e RAPD. GENETIC VARIABILITY OF FAVA D'ANTA (Dimorphandra mollis) POPULATIONS INE NORTHERN MINAS GERAIS

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Cupuassu (Theobroma grandiflorum [Willd. ex Spreng.] Schum) is a species of high economic importance in Brazil with great potential at international level due to the multiple uses of both its seeds and pulp in the industry of sweets and cosmetics. For this reason, the cupuassu breeding program focused on the selection of genotypes with high pulp and seed quality—selection associated with the understanding of the mechanisms involved in fruit formation. Gene expression is one of the most used approaches related to such understanding. In this sense, quantitative real-time PCR (qPCR) is a powerful tool, since it rapidly and reliably quantifies gene expression levels across different experimental conditions. The analysis by qPCR and the correct interpretation of data depend on signal normalization using reference genes, i.e. genes presenting a uniform pattern of expression in the analyzed samples. Here, we selected and analyzed the expression of five genes from cupuassu (ACP, ACT, GAPDH, MDH, TUB) to be used as candidates for reference genes on pulp and seed of young, maturing and mature cupuassu fruits. The evaluation of the gene expression stability was obtained using the NormFinder, geNorm and BestKeeper programs. In general, our results indicated that the GAPDH and MDH genes constituted the best combination as reference genes to analyze the expression of cupuassu samples. To our knowledge, this is the first report of reference gene definition in cupuassu, and these results will support subsequent analysis related to gene expression studies in cupuassu plants subjected to different biotic or abiotic conditions as well as serve as a tool for diversity analysis based on pulp and seed quality.

ABSTRACT. The objectives of this study were to identify the population structure and to assess the genetic diversity of maize inbreds. We genotyped 81 microsatellite loci of 90 maize inbreds that were derived from tropical hybrids and populations. The population structure analysis was based on a Bayesian approach. Each subpopulation was characterized for the effective number of alleles, gene diversity, and number of private alleles. We also performed an analysis of molecular variance and computed a measure of population differentiation (F ST ). The genetic distances were computed from the similarity index of Lynch and the dissimilarity measures proposed by Smouse and Peakall. The cluster analyses were based on the unweighted pair-group method using arithmetic averages and Tocher method. The clustering efficiency was assessed by the error rate of the discriminant analysis. We also performed a principal coordinates analysis. The population structure analysis revealed three tropical heterotic pools, which have been used by worldwide and Brazilian maize seed companies. The degree of genetic differentiation and of intra-and inter-population genetic diversity for these tropical heterotic pools are comparable to that observed for temperate and subtropical heterotic pools. The higher allelic frequency variation within each tropical heterotic pool and the high genetic diversity between the inbreds were evidence of heterotic groups within the main tropical heterotic pools.

Modern cultivated Citrus species and varieties result from interspecific hybridization between four ancestral taxa. Among them, Citrus maxima and Citrus reticulata, closely associated with the pummelo and mandarin horticultural groups, respectively, were particularly important as the progenitors of sour and sweet oranges (Citrus aurantium and Citrus sinensis), grapefruits (Citrus paradisi), and hybrid types resulting from modern breeding programs (tangors, tangelos, and orangelos). The differentiation between the four ancestral taxa and the phylogenomic structure of modern varieties widely drive the phenotypic diversity’s organization. In particular, strong phenotypic differences exist in the coloration and sweetness and represent important criteria for breeders. In this context, focusing on the genes of the sugar, carotenoid, and chlorophyll biosynthesis pathways, the aim of this work was to develop a set of diagnostic single-nucleotide polymorphism (SNP) markers to distinguish the ancestral haplotypes of C. maxima and C. reticulata and to provide information at the intraspecific diversity level (within C. reticulata or C. maxima). In silico analysis allowed the identification of 3,347 SNPs from selected genes. Among them, 1,024 were detected as potential differentiation markers between C. reticulata and C. maxima. A total of 115 SNPs were successfully developed using a competitive PCR technology. Their transferability among all Citrus species and the true citrus genera was very good, with only 0.87% of missing data. The ancestral alleles of the SNPs were identified, and we validated the usefulness of the developed markers for tracing the ancestral haplotype in large germplasm collections and sexually recombined progeny issued from the C. reticulata/C. maxima admixture gene pool. These markers will pave the way for targeted association studies based on ancestral haplotypes.