ABSTRACT Discocactus zehntneri subsp. petr-halfari, an endangered taxon, is represented by a single population in an anthropized area of Bahia, Brazil, where it is suffering due to extreme extractivism. Thus, information about this cactus, such as its reproductive patterns, is urgently needed to support conservation strategies. A population genetics approach was used to determine if this subspecies has a preferential pattern of reproduction. We sampled 18 individuals, both with and without connection to parental plants, from five clumps and assessed their diversity and genetic structure using five ISSR markers. The results revealed two clumps that are genetically supported by the presence of genetically equal individuals. The other three groups presented individuals that are genetically different and similar to individuals in other clumps. These findings suggest that this subspecies has sexual and clonal reproduction and that its environmental distribution might be shaped by events of dispersion. In addition, a possible hybrid origin may explain its rates of genetic diversity. Despite all these factors, this taxon is in danger and so the development of conservation strategies to preserve its population are urgently needed, including in situ and ex situ actions such as the micropropagation in vitro, living collections and cryopreservation.

RESUMO O estudo objetivou caracterizar morfoagronomicamente acessos de capim buffel do Banco de Germoplasma de Cenchrus (BGC) da Embrapa Semiárido, verificando a variabilidade e eficiência dos descritores nos acessos em dois cortes consecutivos. Foram utilizados 25 acessos e cinco cultivares de capim buffel em delineamento em blocos casualizados completos com três repetições. As avaliações foram realizadas após dois cortes consecutivos, cada avaliação foi realizada 90 dias após cada corte. A caracterização foi realizada com base em 15 descritores morfoagronômicos quantitativos e qualitativos. Os descritores quantitativos foram submetidos a análise de variância univariada individual e conjunta e, em seguida, aplicado o teste de Scott-Knott a 5% de significância. Os descritores qualitativos foram submetidos a análise descritiva. Para as análises de divergência tanto descritores quantitativos quanto qualitativos foram agrupados com base no algoritmo de Gower. Foi estabelecido também um dendrograma e calculada a importância relativa dos caracteres para a divergência. Na análise conjunta, os efeitos de genótipo e corte foram significativos para quase todas os descritores. Esse resultado indica variabilidade genética entre os genótipos e quanto ao corte indica, principalmente, diferenças na velocidade de crescimento de cada genótipo em cada época de corte. Os genótipos foram separados em três grupos demonstrando boa variabilidade entre os genótipos. O número de perfilhos por touceira, seguida por quantidade de inflorescência e cor das sementes foram os caracteres de maior relevância na separação dos genótipos.

ABSTRACT This study aimed to characterize buffel grass accessions of the Cenchrus Germplasm Active Bank (CGAB) from Embrapa Semi-Arid in a morphoagronomic way, checking the descriptors variability and efficiency in accessions on two consecutive cuts. Twenty-five accessions and five buffel grass cultivars were used in randomized complete block design with three replications. Evaluations were conducted after two consecutive cuts, each evaluation performed 90 days after each cut. Characterization was based on 15 quantitative and qualitative morphoagronomic descriptors. Quantitative descriptors were subjected to individual and joint univariate analysis of variance, followed by the Scott-Knott’s test at 5% significance. Yet qualitative descriptors were submitted to descriptive analysis. Both quantitative and qualitative descriptors were grouped based on the Gower algorithm for divergence analysis. A dendrogram and calculations of the characters relative importance for divergence were established. Genotype and cutting effects were significant for almost all descriptors in the joint analysis. This result indicates a genetic variability between genotypes and, regarding the cut, it indicates mainly differences in growth rate of each genotype in each cutting season. Genotypes were separated into three groups, which showed good genotype variation. The number of tillers per clump, followed by number of inflorescence and color of seeds, were the most relevant characters in genotype separation.

A jabuticabeira é uma planta nativa da América do Sul e tem sofrido grande erosão genética devido à expansão da agricultura e desmatamento. Neste trabalho buscou-se investigar: a) o sistema reprodutivo de quatro espécies de Myrciaria spp. (Myrciaria cauliflora, M. jaboticaba, M. coronata e M. trunciflora); b) a compatibilidade de cruzamentos, utilizando tratamentos de polinização cruzada interespecíficos entre M. trunciflora x M. cauliflora e M. jaboticaba x M. coronata visando identificação de possíveis mecanismos de isolamento reprodutivos pós-zigóticos e c) relacionar a distância genética destas espécies e outros 14 táxons conservados ex situ, através de marcadores moleculares tipo RAPD. Os tratamentos reprodutivos mostraram que as jabuticabeiras são espécies autocompatíveis e não se observa apomixia. Os cruzamentos bidirecionais de polinização entre M. trunciflora x M. cauliflora e entre M. jaboticaba x M. coronata, produziram taxa de obtenção de frutos de 22 a 27% cujas sementes produziram plântulas normais evidenciando a falta de barreiras genéticas entre as espécies testadas, além de frutos abortados precocemente. Esta compatibilidade de intercruzamentos pode ser explorada no melhoramento genético, visando a transferência de caracteres de interesse em genótipos agronomicamente superiores. Foi encontrada pouca diferenciação genética entre os diferentes táxons, sugerindo que a similaridade genética observada não é compatível com a similaridade morfológica e os principais caracteres de valor taxonômico são polimórficos dentro do gênero.

The jabuticaba tree is a native plant from South America and has undergone genetic erosion due to agricultural expansion and deforestation. The present study aimed to investigate: a) the reproductive system of four species of Myrciaria spp. (Myrciaria cauliflora, M. jaboticaba, M. coronata and M. trunciflora); b) the compatibility of cross breeding using interspecific cross-pollination treatments between M. trunciflora x M. cauliflora and M. jaboticaba x M. coronata in order to identify possible postzygotic reproductive isolation mechanisms, and c) relate the genetic distance of these species and 14 other taxa preserved ex situ, by RAPD molecular markers. The reproductive treatments showed that jaboticaba are self-compatible species and no apomixis was found in these species. The bi-directional cross-pollinations between M. trunciflora x M. cauliflora, and between M. jaboticaba x M. coronata, generated fruit production that ranged from 22 to 27%, and their seeds produced healthy plants, demonstrating the lack of genetic barriers between these species, as well as immature fruit dropping. Such compatibility of interbreeding can be explored in genetic improvements aimed at the transfer of traits of interest in agronomically superior genotypes. A low degree of genetic differentiation was found among the different taxa, suggesting that the genetic similarity observed is not compatible with the morphological similarity and the main taxonomic characters are polymorphic within the genus.

Dentre as espécies cultivadas no semiárido baiano, as abóboras são uma excelente alternativa de produção. Nessa região onde são encontrados os mais baixos Índices de Desenvolvimento Humano (IDH) do Brasil e populações com alta incidência de hipovitaminose A, materiais promissores de abóboras, fontes de carotenoides, podem ser inseridos no agronegócio irrigado. O objetivo do trabalho foi identificar acessos de abóboras do Banco Ativo de Germoplasma (BAG) de Cucurbitáceas da Embrapa Semiárido com altos teores de carotenoides totais e vitamina A. Os teores de carotenoides totais (CT), expressos em termos de β-caroteno, variaram de 14,93µg g-1 (A4) até 290,62µg g-1 (A43) entre os diferentes acessos (A). Dos carotenoides encontrados nos acessos com maiores teores de CT, 60-70% foram quantificados como α- e β-caroteno, representando um valor total de vitamina A de 1.182,39 gRAE 100g-1 (A40) e 1.828,84 gRAE 100g-1 (A43). Esses resultados demonstram que os 48 acessos de abóboras do BAG estudados apresentam grande variação quanto ao teor de carotenoides totais, e os selecionados representam alta fonte de vitamina A.

Among the species of short cycle crops, with great potential to be increased within the agribusiness of the Semi-Arid Bahia, the pumpkins are an excellent alternative for production. In this region where are found the lowest HDI of Brazil, and populations with high incidence of hypovitaminosis A, promising materials of pumpkins with high amounts of carotenoids have a chance to be good accepted and inserted into the irrigated agribusiness. The aim of this research was to identify accessions of pumpkins from the Active Germplasm Bank (BAG) of Cucurbitáceas from Embrapa Semi-arid with high amounts of total carotenoids and vitamin A. The amount of total carotenoids found by UV-vis spectrophotometry (445nm) in different accessions (A) ranged from 14.93mg g-1 (A4) to 290.62mg g-1 (A43), with average value of 366.60 31.21µg g-1. In the access with higher amounts of total carotenoids a percentage between 60-70 % were quantified as α- and β-carotene showing a total value of vitamin A of 1,182.39 gRAE 100g-1 (A40) and 1,828.84 gRAE 100g-1 (A43). These results demonstrate that the 48 accessions of pumpkins BAG studied show a big variation in the content of total carotenoids, and may represent some high source of vitamin A, which really increase the importance of identifying genotypes for production in large scale of lines segregant of vitamin A.