Interactions between water and triacylglycerols may explain faster aging rates in stored germplasm at low temperatures

The purpose of this research is to explore the extent and significance of possible interacting factors on the viability of stored germplasm. Our work begins with characterizing the kinetics of TAG and water phase changes in peanut (Arachis hypogaea) and Papaya (Carica papaya) seeds equilibrated to different water contents and stored at temperatures between -5 and -80°C. Water and TAG phase was measured using a Perkin Elmer Differential Scanning Calorimeter. Cytoplasm ultra-structure was visualized without chemical fixatives using low temperature scanning electron microscopy (cryo-SEM) performed with a Zeiss DSN 960 scanning microscope equipped with a Cryotrans CT-1500 cold plate (Oxford, UK).

Potencial de fitorremediação de diferentes plantas em solo contaminado por 14C-tebuthiuron

Este trabalho teve como objetivo avaliar a tolerância e a capacidade de fitorremediação de crotalária (Crotalaria spectabilis), sorgo (Sorghum bicolor), nabo forrageiro (Raphanus sativus), amendoim (Arachis hypogaea) e alfafa (Mendicago sativa) a solos contaminados por tebuthiuron. Para determinar a tolerância das plantas ao herbicida estas foram submetidas a 5 diferentes doses (300, 600, 1200, 2400 e 4800 gramas de ingrediente ativo por hectare gi.a. ha-1) e comparadas com uma testemunha que não recebeu aplicação do herbicida. Crotalária, Nabo forrageiro e alfafa se mostraram sensíveis ao herbicida, mesmo na menor dose de aplicação, enquanto sorgo se mostrou tolerante ao herbicida até a dose de 600 gi.a. ha-1 tendo apresentado fitointoxicação de 80% na dose de 1200 gi.a. ha-1 e amendoim foi tolerante até a dose de 4800 gi.a. ha-1 para a qual apresentou apenas 40% de fitointoxicação. Plantas de amendoim e sorgo foram submetidas a dose de contaminação de 600 gi.a. ha-1 aplicada por meio de uma solução de trabalho contendo 17,47kBq (Quilobecquerels) de 14C-tebuthiuron. As duas plantas foram capazes de remediar o solo, no entanto amendoim se mostrou mais eficiente reduzindo a contaminação em 75,8% enquanto sorgo retirou do solo 44,49% do herbicida contaminante

Study of the genetic variability and similarity among and within Arachis villosulicarpa, A-pietrarellii and A-hypogaea through isoenzyme analysis

Arachis villosulicarpa is a perennial species cultivated for its soft and tasty seeds by indigenous inhabitants of the Mate Grosso State, Brazil. Besides A. hypogaea, this species is considered as the only species of Arachis which represents a valuable food source for human consumption. Due to the lack of knowledge concerning the genetic diversity of A. villosulicarpa, this study was conducted to evaluate the genetic variability of the accessions from the Germplasm Collection of CENARGEN/EMBRAPA (Brasilia, DF, Brazil) and Institute Agronomico (IAC, Campinas, SP, Brazil). In addition, the genetic similarity between A. villosulicarpa, the related wild species A. pietrarellii, and the cultivated peanut A. hypogaea cv. Tatu was evaluated. From the entire sample analyzed of A. villosulicarpa, the accession from Institute Agronomico showed the highest indices of diversity for both enzymatic systems analyzed, pointing this accession as a promising source of genetic variability that must be preserved in the Germplasm Bank. A high level of genetic similarity was observed between A. pietrarellii and A. villosulicarpa, supporting previous suggestions that A. pietrarellii could be the ancestral progenitor species of A. villosulicarpa or that both species originated from a common ancestor.

RFLP analysis of genetic variation in species of section Arachis, genus Arachis (Leguminosae)

Four A-genome species of the genus Arachis ( A. cardenasii, A. correntina, A. duranensis, A. kempff-mercadoi), three B genomes species ( A. batizocoi, A. ipaensis and A. magna), the AABB allotetraploid A. hypogaea (cultivated peanut) and introgression lines resulting from a cross between A. hypogaea and A. cardenasii were analyzed by RFLP. The A genome species (cytologically characterized by the presence of a small chromosome pair 'A') were closely similar to each other and shared a large number of restriction fragments. In contrast, the B genome species differed more from one another and shared few fragments. The results of this study indicate that the absence of the small chromosome pair is not a good criterion for grouping species of section Arachis as B genome species, since their genome might be quite distinct from the B genome of A. hypogaea. The lowest genetic variation was detected within accessions of A. duranensis (17 accessions), followed by A. batizocoi (4 accessions) and A. cardenasii (9 plants of accession GKP 10017). The high level of genetic variation found in A. cardenasii might indicate that not all accessions of wild species of Arachis are autogamous, as reported for A. hypogaea.

Application of C-banding in two Arachis wild species, Arachis pintoi Krapov. and W.C. Gregory and A-villosulicarpa Hoehne to mitotic chromosome analyses

Two wild diploid (2n = 20 chromosomes) and self-pollinating Arachis species, Arachis Pintoi Krapov and W.C.Gregory and A. villosulicarpa Hoehne were submmited to C-band technique to karyotype analyses. Root tips were employed in the analyses. Morphometric data chose that chromosome lengths varied from 3.12 in A. villosulicarpa to 1.45 in A. Pintoi. Karyotype formula obtained was 10sm to A. Pintoi and 9sm + 1m to A. villosulicarpa. There was a predominance of pericentromeric C-band in all mitotic metaphasic chromosomes in both species. Besides C-band values, both species still did not differ in respect to chromosome absolute and relative lengths, centromeric index, symmetry index and total karyotype haploid length. C-band and morphometric data did not show strong or significant differences which could separate these two species of peanut which belong to evolutive different sections.

Heterologous microsatellite primer pairs informative for the whole genus Arachis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Genetic variation within and among species of genus Arachis, section Rhizomatosae

The genus Arachis is endemic to South America and comprises 80 species, 69 of which have already been described and eleven not yet published. The genus includes the cultivated peanut ( A. hypogaea) and several forage species, the most important ones being A. glabrata and A. pintoi. Accessions of section Rhizomatosae, including three tetraploid species 2n = 4x = 40 (A. glabrata, A. pseudovillosa and A. nitida nom. nud.) and one diploid species 2n = 2x = 20 (A. burkartii), were evaluated using RAPD markers to assay genetic variability within and among species. The ten random primers used yielded a total of 113 polymorphic bands. The data were scored as the presence or absence of each band in each sample. A distance matrix and dendrogram were obtained using Link's coefficient and the neighbor-joining method. Most accessions analyzed grouped into two major clusters: the first comprised most accessions of A. glabrata and accessions of A. nitida, and the second cluster comprised accessions of A. burkartii. Arachis pseudovillosa and a few accessions of A. glabrata and A. nitida were placed between these major clusters. The diploid and tetraploid species were grouped quite separately, suggesting that the tetraploids did not originate from the diploid species analyzed.

Occurrence of Enneothrips flavens moulton and Stegasta bosquella (chambers) and its effects on agronomic traits of wild Arachis accessions

Some wild species of the genus Arachis have demonstrated potential for improvement of peanuts. This work was performed to evaluate the occurrence and symptoms of Enneothrips flavens and Stegasta bosquella and its effects on agronomic traits of wild Arachis accessions. Nine accessions of wild Arachis species and a commercial A. hypogaea variety were studied in a split plot statistical scheme with a completely randomized block design and four replications. The main plots consisted of plants sprayed or not sprayed for insect control, while the subplots comprised the peanut accessions. Accessions GKP10017 (A. cardenasii) and V7639 (A. kuhlmannii) showed the lowest percentages of leaflets with E. flavens and S. bosquella. Accessions V9912, V7639 and V8979 (all three A. kuhlmannii) and V13250 (A. kempff-mercadoi) showed the lowest responses to insecticide application among the various plant traits evaluated. These accessions are of interest for further studies to identify mechanisms of resistance, to be used in breeding programs for resistance to these insects.

Caracteres estruturais e dimensão fractal da folha de espécies de Arachis e sua relação com a cercosporiose

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Investigação de efeitos alelopáticos de espécies do gênero Arachis

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Forage peanut (Arachis spp.) genetic evaluation and selection.

Forage peanut improvement for use in grass?legume mixtures is expected to have a great impact on the sustainability of Brazilian livestock production. Eighteen cloned Arachis spp. ecotypes were evaluated under clipping in a Brazilian Cerrado region and results analysed using a mixed model methodology. The objective was to estimate genetic and phenotypic parameters and to select the best ecotypes based on selection index applied on their predicted genotypic value. The traits of total dry-matter (DM) and leaf DM yield presented moderate (0_30 < h2g < 0_50) to high (>0_50) broad-sense heritability, in contrast to the low genetic variability in nutritional quality-associated traits. Ecotypes of Arachis spp. contained average crude protein concentrations of 224 g kg _1 DM in leaves and 138 g kg _1 DM in stems, supporting the potential role of these species to overcome the low protein content in Cerrado pastures. The correlations between yield traits and traits associated with low nutritional value in leaves were consistently significant and positive. Genetic correlations among all the yield traits evaluated during the rainy or dry seasons were significant and positive. The ecotypes were ranked based on selection index. The next step is to validate long-term selection of grass?Arachis in combination with pastures under competition and adjusted grazing in the Cerrado region.

Arachis spp. com diferentes níveis de sintomas de virose no Acre, Brasil.

Em 1998, Peanut mottle virus - PeMoV foi relatado em A. pintoi na Região de Cerrado, no Brasil. Plantas anormais com clorose, mosaico e mosqueado foram observadas em amendoim forrageiro (Arachis spp.) cultivado no campo, no Acre. Para entender a causa dessa anormalidade realizou-se um trabalho epidemiológico com diagnóstico e avaliação da reação de plantas em campo.

Occurrence Of Isoflavonoids In Brazilian Common Bean Germplasm (phaseolus Vulgaris L.).

Common bean (Phaseolus vulgaris) is present in the daily diet of various countries and, as for other legumes, has been investigated for its nutraceutical potential. Thus, 16 genotypes from different gene pools, representing seven types of seed coats and different responses to pathogens and pests, were selected to verify their isoflavone contents. The isoflavonoids daidzein and genistein and the flavonols kaempferol, myricetin, and quercetin were found. Grains of the black type showed the highest concentrations of isoflavonoids and were the only ones to exhibit daidzein. IAC Formoso, with high protein content and source of resistance to anthracnose, showed the greatest concentration of genistein, representing around 11% of the content present in soybean, as well as high levels of kaempferol. Arc 1, Raz 55, and IAC Una genotypes showed high content of coumestrol. The results suggest the use of IAC Formoso to increase the nutraceutical characteristics in common bean.

Influence Of The Stage Of Ripeness On The Composition Of Iridoids And Phenolic Compounds In Genipap (genipa Americana L.).

Genipap fruits, native to the Amazon region, were classified in relation to their stage of ripeness according to firmness and peel color. The influence of the part of the genipap fruit and ripeness stage on the iridoid and phenolic compound profiles was evaluated by HPLC-DAD-MS(n), and a total of 17 compounds were identified. Geniposide was the major compound in both parts of the unripe genipap fruits, representing >70% of the total iridoids, whereas 5-caffeoylquinic acid was the major phenolic compound. In ripe fruits, genipin gentiobioside was the major compound in the endocarp (38%) and no phenolic compounds were detected. During ripening, the total iridoid content decreased by >90%, which could explain the absence of blue pigment formation in the ripe fruits after their injury. This is the first time that the phenolic compound composition and iridoid contents of genipap fruits have been reported in the literature.