Resumo A savana brasileira, também conhecida como Cerrado, é caracterizada por sua grande diversidade de fitofisionomias e detém a maior diversidade de espécies e nível de endemismo entre as savanas mundiais. Contudo, devido principalmente às atividades agropecuárias essa vasta vegetação está entre as mais degradadas, apresentando elevadas taxas de extinção. Entre as espécies atualmente presentes na “lista vermelha” encontra-se a endêmica Gymnopogon doellii, uma gramínea cuja distribuição é extremamente restrita a algumas poucas áreas. No Distrito Federal e arredores apenas uma população é conhecida, localizada dentro dos limites do Parque Nacional de Brasília. Neste estudo levantamos informações relevantes relacionadas a biologia dessa população de G. doellii, como sua área de distribuição, variabilidade genética e características de germinação. Mudas a partir de suas cariopses foram produzidas em casa de vegetação, plantadas em diferentes fisionomias do Cerrado, incluindo áreas degradadas, e suas taxas de sobrevivência e desempenho fisiológico acompanhados por quase quatro anos. A população apresenta baixa variabilidade genética. As mudas apresentaram altas taxas de sobrevivência (> 25%), padrões de crescimento similar aos indivíduos selvagens e produziram cariopses viáveis. Recomendamos o plantio de indivíduos de G. doellii tanto para sua conservação in situ como para recuperação de áreas degradadas do Cerrado.

Abstract The Brazilian savanna, regionally known as Cerrado, is characterized by a great diversity of physiognomies and holds the highest species diversity and level of endemism among world savannas. However, due mainly to agribusiness, this vegetation is among the most threatened ones, currently presenting alarming rates of extinction. Among the species present in the “red list” we find the endemic Gymnopogon doellii, a grass whose distribution is restricted to a few sites. In the Federal District and surroundings, for example, only one population, with scattered subpopulations, is known, within the limits of the Brasilia National Park. By this study we raised information related to the biology of G. doellii, as population size and distribution, genetic variability and germination characteristics. Besides, we produced seedlings in greenhouse, planted in different physiognomies of the Cerrado and followed them for almost four years to check for their survival, growth and fruiting under natural conditions. Seedlings transplanted to the field presented high rates of recruitment (> 25%), growth patterns similar to wild plants and produced viable caryopses. We recommend transplanting of individuals of G. doellii for both in situ conservation as well as for the revegetation of degraded areas of the Cerrado.

Abstract Peanut is a crop of the Kayabi tribe, inhabiting the Xingu Indigenous Park, Brazil. Morphological analysis of Xingu accessions showed variation exceeding that described for cultivated peanuts. This raised questions as to the origin of the Xingu accessions: are they derived from different species, or is their diversity a result of different evolutionary and selection processes? To answer these questions, cytogenetic and genotyping analyses were conducted. The karyotypes of Xingu accessions analyzed are very similar to each other, to an A. hypogaea subsp. fastigiata accession and to the wild allotetraploid A. monticola. The accessions share the number and general morphology of the chromosomes; DAPI+ bands; 5S and 45S rDNA loci distribution and a high genomic affinity with A. duranensis and A. ipaënsis genomic probes. However, the number of CMA3+ bands differs from those determined for A. hypogaea and A. monticola, which are also different from each other. SNP genotyping grouped all Arachis allotetraploids into four taxonomic groups: Xingu accessions were closer to A. monticola and A. hypogaea subsp. hypogaea. Our data suggests that the morphological diversity within these accessions is not associated with a different origin and can be attributed to morphological plasticity and different selection by the Indian tribes.

Resumo Apresenta-se um estudo taxônomico do gênero Paspalum (Poaceae) no Parque Ecológico Bernardo Sayão (PEBS). Paspalum possui mais de 350 espécies neotropicais, com centro de diversidade no Brasil Central. O PEBS está inserido na matriz urbana de Brasília, engloba nascentes e é coberto, principalmente, por cerrado sentido restrito e campo sujo, que são as fitofisionomias mais abrangentes do bioma Cerrado e as mais ameaçadas pela agricultura e pecuária, em decorrência da facilidade de mecanização. O estudo foi baseado em um ano de coletas quinzenais na área e ampla revisão de herbários. O gênero está representado no PEBS por 24 espécies, o que corresponde a 34% do total de espécies registradas no Distrito Federal. O presente artigo traz uma chave de identificação, descrições, comentários taxonômicos pertinentes ao reconhecimento dos táxons, época de coleta em floração, particularidades ambientais e ilustrações de alguns caracteres diagnósticos, auxiliando na identificação das espécies.

Abstract A taxonomic study of the genus Paspalum (Poaceae) in the Bernardo Sayão Ecological Park (PEBS) is presented. Paspalum has more than 350 neotropical species, with the center of diversity in Central Brazil. The PEBS is part of the urban matrix of Brasília. It holds springs and is mainly covered by cerrado sentido restrito and campo sujo, which are the most extensive phytophysiognomies of the Cerrado biome and those most threatened by conversion to agriculture and livestock, due to the ease of mechanization. The study was based on a year of biweekly collections in the area and extensive herbarium review. The genus is represented in the PEBS by 24 species, which correspond to 34% of the total species of this genus registered in the Federal District. The present article presents a key for the identification, species descriptions, taxonomic comments pertinent to the recognition of the taxa, phenological data stressing the flowering periods, environmental peculiarities and illustrations of some diagnostic characters, helping in the identification of the species.

ABSTRACT Peanut or groundnut (Arachis hypogaea L.) is a globally important oilseed crop, with important nutritional qualities, and a rich source of amino acids and protein. Another 80 species have been described in the genus Arachis, 64 of which are found in Brazil, and even though their morphology and agronomic traits remain largely unknown, they have been cultivated for forage and for landscaping and have great potential for breeding with cultivated peanut. Thus, the morphological characterization of wild Arachis species is essential for their conservation and use. In this study, we present a morphological and agronomic characterization of 29 diploid accessions of eleven wild Arachis species and one of the tetraploid A. monticola (section Arachis) with A and B genomes and determine their intra- and interspecific variability in greenhouse and field conditions. In total, 35 morphological descriptors were developed a priori from greenhouse accessions in the first crop year and used in field accessions in the second crop year. Significant differences in descriptors compiled in the greenhouse and the field support the use of different descriptors for different experimental conditions. PCA analysis showed that the distribution of accessions accorded with the taxonomy of species. The ten morphological descriptors that were important in differentiating section Arachis accessions were seed length, lateral branch length, right apical leaflet length, right apical leaflet width, height and diameter of main stem, branch color, standard petal base color, number of flowers, and presence of bristles on rachis.

ABSTRACT Grama-tio-pedro (Paspalum oteroi Swallen) is a rare stoloniferous grass of the Plicatula group of Paspalum, well adapted to continuous grazing in areas subject to seasonal flooding in the Pantanal region, in central western Brazil. The species is a facultative apomictic (asexual reproduction by seed) tetraploid, sporadically cultivated on Pantanal farms, propagated either by cuttings or seed. Due to its potential for extensive cultivation and forage quality, Grama-tio-pedro appears as a candidate for genetic improvement within the Plicatula group through plant breeding. We used a colchicine-induced sexual autotetraploid genotype of P. plicatulum Michx. to obtain interspecific hybrids using the apomictic species, P. oteroi, as pollen donor. The very similar meiotic chromosome behavior observed in both parents, with main quadrivalent and bivalent associations, suggested that P. oteroi is a natural autotetraploid. The hybrids showed less irregular meiotic behavior with fewer quadrivalents and more bivalents than either parent. Fertility among interspecific hybrids varied from complete sterility in some of them to seed productions in others that were approximately twice as much as for either parent. The great variability of seed set performance may well be a drastic genetic consequence of joining two homologous chromosome sets of P. plicatulum together with two homologous sets of P. oteroi that, in turn, have some homeology between them. Most hybrids reproduce by sexual means, thus, they could be used as female parents in backcrosses and in crosses with other species of the Plicatula group for interspecific gene transferring in breeding programs.

Peanut (Arachis hypogaea) is the fifth most produced oil crop worldwide. Besides lack of water, fungal diseases are the most limiting factors for the crop. Several species of Arachis are resistant to certain pests and diseases. This study aimed to successfully cross the A-genome with B-K-A genome wild species previously selected for fungal disease resistance, but that are still untested. We also aimed to polyplodize the amphihaploid chromosomes; cross the synthetic amphidiploids and A. hypogaea to introgress disease resistance genes into the cultivated peanut; and analyze pollen viability and morphological descriptors for all progenies and their parents. We selected 12 A-genome accessions as male parents and three B-genome species, one K-genome species, and one A-genome species as female parents. Of the 26 distinct cross combinations, 13 different interspecific AB-genome and three AA-genome hybrids were obtained. These sterile hybrids were polyploidized and five combinations produced tetraploid flowers. Next, 16 combinations were crossed between A. hypogaea and the synthetic amphidiploids, resulting in 11 different hybrid combinations. Our results confirm that it is possible to introgress resistance genes from wild species into the peanut using artificial hybridization, and that more species than previously reported can be used, thus enhancing the genetic variability in peanut genetic improvement programs.

Números cromossômicos são reportados para trinta e quatro acessos, representando cinco espécies de Paspalum, grupo Caespitosa. Todos são múltiplos do número básico x=10. Confirmou-se o número diploide 2n=20 para P. chacoense e P. indecorum como, também, a sexualidade para P. indecorum. As contagens cromossômicas são inéditas para P. ligulare (2n=20 e 40), P. pleostachyum (2n=20, 30 e 40) e P. redondense (2n=20 e 40). A meiose foi regular nos diploides, com pareamento em bivalentes na diacinese e metáfase I, enquanto irregularidades, tais como univalentes, trivalentes e quadrivalentes, foram comuns nos poliploides. Acessos diploides de P. pleostachyum e P. ligulare mostraram um único saco embrionário meiótico em cada óvulo, indicando reprodução sexual. O acesso triploide e um dos tetraploides de P. pleostachyum evidenciaram sacos apospóricos e alguns sacos meióticos, sugerindo apomixia facultativa. A identificação dos novos acessos diploides poderá se mostrar bastante útil para o estudo filogenético do gênero, assim como para programas de melhoramento genético focados no potencial forrageiro das espécies do grupo Caespitosa.

Somatic chromosome numbers are reported for thirty four germplasm accessions of Paspalum, Caespitosa group, representing five different species. All five species have shown x=10 as the basic chromosome number. The diploid 2n=20 chromosome number was confirmed for P. chacoense and P. indecorum, as well as sexuality for the latter. This is the first report of the chromosome number and cytological behavior for P. ligulare (2n=20 and 40), P. pleostachyum (2n=20, 30 and 40) and P. redondense (2n=20 and 40). The present results document regular meiosis in diploid accessions, with primarily bivalent pairing at diakinesis and metaphase I. Polyploids of these species had irregular meiosis, with univalent, trivalent, and quadrivalent chromosome associations. Diploid accessions of P. pleostachyum and P. ligulare have shown a single meiotic embryo-sac, indicating sexual reproduction, while the triploid and one of the tetraploid accessions of P. pleostachyum have shown aposporic embryo-sacs of nucelar origin, and a few meiotic sacs, suggesting facultative apomixis. Identification of the new diploid accessions may prove useful for phylogenetic studies of Paspalum, as well as for breeding programs focusing on the forage potential of species of the Caespitosa group.

The cytogenetic characterization of Arachis species is useful for assessing the genomes present in this genus, for establishing the relationship among their representatives and for understanding the variability in the available germplasm. In this study, we used fluorescence in situ hybridization (FISH) to examine the distribution patterns of heterochromatin and rDNA genes in 12 Brazilian accessions of five species of the taxonomic section Arachis. The heterochromatic pattern varied considerably among the species: complements with centromeric bands in all of the chromosomes (A. hoehnei) and complements completely devoid of heterochromatin (A. gregoryi, A. magna) were observed. The number of 45S rDNA loci ranged from two (A. gregoryi) to eight (A. glandulifera), while the number of 5S rDNA loci was more conserved and varied from two (in most species) to four (A. hoehnei). In some species one pair of 5S rDNA loci was observed adjacent to 45S rDNA loci. The chromosomal markers revealed polymorphism in the three species with more than one accession (A. gregoryi, A. magna and A. valida) that were tested. The previous genome assignment for each of the species studied was confirmed, except for A. hoehnei. The intraspecific variability observed here suggests that an exhaustive cytogenetic and taxonomic analysis is still needed for some Arachis species.

In this study, the phenotypic diversity of five accessions of giant missionary grass (Axonopus jesuiticus × A. scoparius) was evaluated by using morphophysiological traits. Accessions V 14337, V 14403, V 14404, V 14405 and V 14406 are hybrids derived from spontaneous crossing that occurred in Vale do Itajaí, Santa Catarina, Brazil. Plants were cultivated in greenhouse and evaluated at 60, 90, 120, 150, 180, 210 and 240 days of growth. Variation was observed for dry matter production, phenology and morphological traits, showing the possibility of selection. Flowering started at 210 days of growth and only in accessions V 14337 and V 14404. The Mahalanobis distance among accessions ranged from 35.64 (V 14403 and V 14405) to 183.38 (V 14337 and V 14405), and three groups were formed, based on 17 vegetative morphophysiological traits evaluated in plants with 180 days of growth: G1 (V 14403, V 14405), G2 (V 14406) and G3 (V 14337, V 14404). Group I presented the greatest dry matter production of stolon and aboveground, which were the traits with the largest relative contribution to genetic divergence, 38.67% and 38.31%, respectively. Accessions V 14403 and V 14405 are the most promising for agronomic evaluations that address their records as forage cultivars.

Duas espécies novas de Paspalum L., grupo informal Plicatula, são descritas e ilustradas. Paspalum laurentii L., do Rio Grande do Sul, é reconhecida, principalmente, pelos tricomas longos na margem da ráquis e do pedicelo. Paspalum longipedicellatum L., do Mato Grosso do Sul, possui base flabelada, rizomas curtos com catáfilos velutinos, cobertos por tricomas amarelados, e pedicelos das espiguetas longos, especialmente na porção proximal do racemo.

Two new species of Paspalum L. belonging to the informal group Plicatula are described and illustrated. Paspalum laurentii L., from Rio Grande do Sul, southern Brazil, is mainly recognized by the long trichomes on the margins of the rachis and pedicel. Paspalum longipedicellatum L., from Mato Grosso do Sul, west-central Brazil, is flabellate at the base, with short rhizomes covered by velvety cataphylls, the trichomes yellowish, and it has long spikelet pedicels, specially in the proximal portion of each raceme.

O amendoim (Arachis hypogaea) possui genoma AB e é uma das mais importantes culturas oleaginosas em todo o mundo. Os principais problemas da cultura no Brasil são as doenças fúngicas. Várias espécies do gênero Arachis são resistentes a pragas e doenças. Este trabalho visou a identificar espécies silvestres pertencentes à seção Arachis associadas aos genomas A ou B (ou " não-A" ) do amendoim que são resistentes à mancha castanha (Cercospora arachidicola), mancha preta (Cercosporidium personatum) e ferrugem (Puccinia arachidis). Para a identificação de genótipos resistentes a doenças fúngicas, bioensaios utilizando folhas destacadas foram realizados em condições de laboratório, com inoculação artificial, temperatura controlada de 25ºC e fotoperíodo de 10h luz/14h escuro, por 20-42 dias, de acordo com a espécie fúngica. A maioria dos acessos das espécies silvestres foram mais resistentes que os acessos de A. hypogaea para uma, duas ou todas as espécies fúngicas estudadas. Arachis monticola, considerada como o possível ancestral tetraplóide ou como um derivativo de A. hypogaea, também mostrou-se mais suscetível a Cercosporidium personatum e Puccinia arachidis, quando comparado à maioria das espécies silvestres. Portanto, acessos de germoplasma silvestre com genoma A ou B estão disponíveis para serem utilizados na introgressão de genes de resistência a doenças fúngicas no amendoim.

Groundnut (Arachis hypogaea) has an AB genome and is one of the most important oil crops in the world. The main constraints of crop management in Brazil are fungal diseases. Several species of the genus Arachis are resistant to pests and diseases. The objective of our experiments was to identify wild species belonging to the taxonomic section Arachis with either A or B (or " non-A" ) genomes that are resistant to early leaf spot (Cercospora arachidicola), late leaf spot (Cercosporidium personatum) and rust (Puccinia arachidis). For the identification of genotypes resistant to fungal diseases, bioassays with detached leaves were done in laboratory conditions, with artificial inoculation, a controlled temperature of 25ºC and a photoperiod of 10 h light/14 h dark, for 20-42 days, depending on the fungi species. Most of the accessions of wild species were more resistant than accessions of A. hypogaea for one, two or all three fungi species studied. Arachis monticola, considered to be a possible tetraploid ancestor or a derivative of A. hypogaea, was also more susceptible to Cercosporidium personatum and Puccinia arachidis, as compared to most of the wild species. Therefore, wild germplasm accessions of both genome types are available to be used for the introgression of resistance genes against three fungal diseases of peanut.

Trata-se do primeiro levantamento florístico das espécies de Poaceae da Estação Ecológica do Seridó. A família apresenta grande valor econômico e ecológico. A região denominada Seridó apresenta uma Caatinga aberta com estrato herbáceo contínuo, onde os representantes da família constituem um dos principais componentes, principalmente na estação chuvosa. Foi registrada a ocorrência de 57 espécies distribuídas em 34 gêneros, das quais 41 são nativas e 16 exóticas. O trabalho consta de chaves analíticas para tribos, gêneros e espécies, descrições, discussão sobre a delimitação de algumas espécies, distribuição dos táxons na Estação e ilustrações botânicas. Eragrostis cilianensis (Bellardi) Vignolo ex Janch., Mesosetum annuum Swallen e Cenchrus ciliaris L. são citadas pela primeira vez para o Rio Grande do Norte.

This is the first floristic survey of grass species undertaken in Rio Grande do Norte. The family has great economic and ecological value. In the Seridó area, where the "caatinga vegetation" is open and shows a continuous herbaceous stratum, representatives of the family constitute the main component of the vegetation in the raining season. We documented the occurrence of 57 species of Poaceae, distributed in 34 genera, in the Seridó Ecological Station. Of those species, 41 are native to the area and 16 are exotic. The paper includes analytical keys for the grass tribes genera and species descriptions, a discussion about the delimitation of some species, the distribution of the species in the Station, and botanical illustrations. Eragrostis cilianensis (Bellardi) Vignolo ex Janch., Mesosetum annuum Swallen and Cenchrus ciliaris L. are recorded for the first time for the Flora of Rio Grande do Norte.

O número cromossômico foi determinado para 126 novos acessos de 50 espécies de Paspalum do Brasil, Argentina, Paraguai e Bolívia. Foram verificados os números somáticos 2n=12, 20, 24, 30, 40, 50, 60 e 80. Estas são as primeiras contagens para P. arenarium (2n=20), P. barretoi (2n=20), P. aff. ceresia (2n=40), P. corcovadense (2n=20), P. crispulum (2n=20), P. flaccidum (2n=40), P. nummularium (2n=20), P. scalare (2n=20), P. vescum (2n=20) e P. rectum (2n=20). O nível diplóide (2n=20) é reportado pela primeira vez para P. malacophyllum. Os dados confirmam a predominância de acessos tetraplóides (43,6%) no gênero e mostram um número incomumente elevado de espécies (44%) e acessos diplóides (35,7%). Estes resultados trazem novas perspectivas para programas de melhoramento, para estudos filogenéticos e para pesquisa orientada ao controle da apomixia, já que em Paspalum as plantas diplóides são tipicamente sexuais.

Chromosome numbers were counted in 126 new accessions of 50 Paspalum species from Brazil, Argentina, Paraguay and Bolivia. The chromosome numbers 2n=12, 20, 24, 30, 40, 50, 60, 80 were confirmed. Chromosome numbers for P. arenarium (2n=20), P. barretoi (2n=20), P. aff. ceresia (2n=40), P. corcovadense (2n=20), P. crispulum (2n=20), P. flaccidum (2n=40), P. nummularium (2n=20), P. scalare (2n=20), P. vescum (2n=20) and P. rectum (2n=20) and a diploid cytotype of P. malacophyllum are reported for the first time. The predominance of tetraploid accessions (43.6%) was confirmed, but an unusually high number of diploid species (44%) and accessions (35.7%) was found. These results open new perspectives for breeding programs, phylogenetic studies, and for research on apomixis control, since diploids of Paspalum are typically sexual.

Propõe-se a sinonimização de quinze nomes referentes a espécies de Paspalum, grupo informal Plicatula: P. paludosum Swallen e P. validum Swallen em P. atratum Swallen, P. guaricense Swallen em P. centrale Chase, P. plicatulum Michx. var. villosissimum Pilg. em P. geminiflorum Steud., P. goyanum Swallen e P. plicatulum var. rigidum Döll em P. glaucescens Hack., P. gracile J. Le Conte e P. nicorae Parodi em P. lepton Schult., P. limbatum Henrard, P. formosum Swallen e P. pontanale Swallen em P. lenticulare Kunth, P. olivaceum Hitchc. & Chase em P. riparium Nees, P. plicatulum var. cinereum Döll, P. macedoi Swallen e P. kempffii Killeen em P. rojasii Hack. e P. telmatum Swallen em P. wrightii Hitchc. & Chase. Relata-se pela primeira vez a ocorrência de P. lepton no estado brasileiro do Mato Grosso do Sul.

We propose fifteen synonyms for Paspalumspecies belonging to the informal Plicatula group: P. paludosum Swallen and P. validum Swallen to P. atratum Swallen, P. guaricense Swallen to P. centrale Chase, P. plicatulum Michx. var. villosissimum Pilg. to P. geminiflorum Steud., P. goyanum Swallen and P. plicatulum var. rigidum Döll to P. glaucescens Hack., P. gracile J. Le Conte and P. nicorae Parodi to P. lepton Schult., P. limbatum Henrard, P. formosum Swallen and P. pontanale Swallen to P. lenticulare Kunth, P. olivaceum Hitchc. & Chase to P. riparium Nees, P. plicatulum var. cinereum Döll, P. macedoi Swallen and P. kempffii Killeen to P. rojasii Hack., and P. telmatum Swallen to P. wrightii Hitchc. & Chase. Paspalum lepton is a new record for the Brazilian state of Mato Grosso do Sul.

O objetivo deste trabalho foi avaliar a influência de diferentes substratos e pré-tratamentos in vitro, na aclimatização de plantas in vitro de Arachis retusa. As plantas foram transferidas para Plantmax ou areia e adubadas com solução de Hoagland. Plantas mantidas em areia, com adubação ou sem adubação, apresentaram maiores taxas de sobrevivência. Para avaliação da influência de pré-tratamentos in vitro, segmentos de caule foram cultivados em meio MS suplementado com diferentes concentrações de sacarose. As maiores taxas de sobrevivência e desenvolvimento foram observadas em plantas cultivadas em sacarose a 1,5% e 3%. Depois de cinco meses, foram observadas a floração e a produção de frutos.

The objective of this work was to evaluate the influence of substrate and preconditioning treatments on the acclimatization of in vitro plants of Arachis retusa. Plants were transferred to Plantmax or sand, and fertilized with Hoagland's nutrient solution. Plants maintained in sand, with or without fertilizer, showed the highest survival rates. In order to evaluate the influence of in vitro preconditioning treatments, stem segments were cultured on MS medium supplemented with different sucrose concentrations. The highest survival and developmental rates were observed in plants from two accessions cultured on MS supplemented with 1.5% and 3% sucrose. Flowering and fruit production were observed after five months.