Lack of mycorrhizal autoregulation and phytohormonal changes in the supernodulating soybean mutant nts1007

Autoregulatory mechanisms have been reported in the rhizobial and the mycorrhizal symbiosis. Autoregulation means that already existing nodules or an existing root colonization by an arbuscular mycorrhizal fungus systemically suppress subsequent nodule formation/root colonization in other parts of the root system. Mutants of some legumes lost their ability to autoregulate the nodule number and thus display a supernodulating phenotype. On studying the effect of pre-inoculation of one side of a split-root system with an arbuscular mycorrhizal fungus on subsequent mycorrhization in the second side of the split-root system of a wild-type soybean (Glycine max L.) cv. Bragg and its supernodulating mutant nts1007, we observed a clear suppressional effect in the wild-type, whereas further root colonization in the split-root system of the mutant nts1007 was not suppressed. These data strongly indicate that the mechanisms involved in supernodulation also affect mycorrhization and support the hypothesis that the autoregulation in the rhizobial and the mycorrhizal symbiosis is controlled in a similar manner. The accumulation patterns of the plant hormones IAA, ABA and Jasmonic acid (JA) in non-inoculated control plants and split-root systems of inoculated plants with one mycorrhizal side of the split-root system and one non-mycorrhizal side, indicate an involvement of IAA in the autoregulation of mycorrhization. Mycorrhizal colonization of soybeans also resulted in a strong induction of ABA and JA levels, but on the basis of our data the role of these two phytohormones in mycorrhizal autoregulation is questionable.

Adaptive responses of wild mungbean (Vigna radiata ssp sublobata) to photo-thermal environment. I. Phenology

The phenology of 11 diverse accessions of wild mungbean was observed under natural and artificial photoperiod - temperature conditions, in order to examine whether genotypic differences might be attributed to adaptive responses to photo-thermal conditions. There was large variation in phenological response among accessions and across environments, much of which was due to differences in the duration of the pre-flowering phase. Accessions that flowered earlier tended to flower for longer, apart from 2 earlier flowering, inland Australian lines that were also earlier maturing. The patterns of response in time from sowing to flowering over environment were consistent with quantitative short-day photoperiodic adaptation, a conclusion supported by the effects of artificial day-length extension and by 'goodness of fit' of the observed responses to standard models relating rate of development to photoperiod and temperature. The fitted models indicated that rate of development towards flowering was hastened by warmer temperatures, and delayed by longer day lengths, with differential sensitivity between accessions to both factors. The models also suggested that photoperiod was more important for accessions collected closer to the equator, which were generally later flowering as a consequence. Conversely, temperature was relatively more important in lines from higher latitudes. Modelling also suggested that the period from first flowering to maturity was sensitive to photoperiod and temperature. Again, longer days appeared to prolong growth and delay maturity. However, cooler temperatures accelerated rather than slowed maturity, by suppressing further vegetative growth. The variation observed indicated that there is considerable scope for using the wild population to broaden the adaptation of cultivated mungbean. In particular, the unusual response of a late-flowering, photoperiod-insensitive accession warrants further study to establish whether the wild population contains a unique 'long juvenile' trait analogous to that being used for improving phenological adaptation in soybean.

Fungicidas protetores no manejo da ferrugem da soja, processos fisiológicos e produtividade da cultura

Currently, the management recommendations for asian soybean rust (ASR) has been based on the application of protective fungicides mixed with triazoles and stronilurins. Thus, this study aimed at assessing whether the increased productivity provided by the application of protective fungicides is due solely to the fungicidal action of the product or some physiological changes in the plant and which the latter would be. The experiment was conducted from March to July 2015 at the experimental station of Udi Research and Development in Uberlândia-MG, with the cultivar 97Y07 RR. The experimental design chosen for this study was comprised of a randomized block with four replications and 16 treatments: check, fluxapyroxad + pyraclostrobin (116.55 + 58.45 g ha-1), azoxystrobin + benzovindiflupir (90 + 45 g ha-1), trifloxystrobin + prothioconazole (60 + 70 g ha-1), tebuconazole + picoxystrobin (100 + 60 g ha-1), picoxystrobin + cyproconazole (60 + 24 g ha-1), mancozeb (1125 g ha-1), azoxistrobina + tebuconazole + difenoconazole (60 + 75 + 120 g ha-1), azoxystrobin + tebuconazole + difenoconazole + chlorothalonil ( 60 + 120 + 75 + 1440 g ha-1), and mistures fluxapyroxad + pyraclostrobin + mancozeb, azoxystrobin + benzovindiflupir + mancozeb, trifloxystrobin + prothioconazole + mancozeb, tebuconazole + picoxystrobin + mancozeb, picoxystrobin + cyproconazole + mancozeb, azoxystrobin + tebuconazole + difenoconazole + mancozeb, and azoxystrobin + benzovindiflupir + chlorothalonil, from the aforesaid doses. The first application of the treatments occurred in R1, in the absence of symptoms. The number of applications, intervals and the use of adjuvants were performed according to the recommendations by manufacturers. The variables analyzed were: disease severity, concentration of chlorophylls and carotenoids, photosynthetic rate (A), transpiration rate (E), stomatal conductance (gs), internal carbon concentration (Ci), instantaneous efficiency in water use (A/E), intrinsic water use efficiency (A/gs), and carboxylation efficiency (A/C). With these data collected, this study set to date the progress curve of each variable (AUPC). At the end of the crop cycle, the average of pods per plant was quantified, grain per pod, productivity and weight of 1,000 grains. It was concluded that: the addition of mancozeb to fluxapyroxad + pyraclostrobin, azoxystrobin + benzovindiflupir, trifloxystrobin + prothioconazole and tebuconazole + picoxystrobin potentiated the ASR control; adding mancozebe to the mixture azoxystrobin + benzovindiflupir provided better control of the disease compared to the addition of chlorothalonil; mancozeb amounts to AUPC concentration of photosynthetic pigments and when added to axozystrobin + tebuconazole + difenoconazole, increases the AUPC for total chlorophyll concentration, as well as when chlorothalonil was added; mancozeb added to the mix fluxapyroxad + pyraclostrobin raised the AUPC for A/Ci and A/gs, increasing the W1,000G and crop productivity; the addition of protectors similarly reflected on the productivity of culture.

Analyses of the community compositions of root rot pathogenic fungi in the soybean rhizosphere soil

Soybean ( Glycine max [L.] Merr.) root rot is an important disease of soybean under continuous cropping, and root rot is widely distributed throughout the world. This disease is extremely harmful, and it is difficult to prevent and control. The study aimed to elucidate the composition of root rot pathogenic fungal communities in the continuous cropping of soybean. In this study, we employed PCRDGGE technology to analyze the communities of root rot pathogenic fungi in soybean rhizosphere soil subjected to continuous cropping during a season with a high incidence of root rot in Heilongjiang province, China, the main soybean producing area in China. The results of 13 DGGE bands were analyzed by phylogenetic revealed that the predominant root rot pathogenic fungi in rhizosphere soil in the test area were Pythium ultimum and Fusarium species. The results of cluster analysis showed that the duration of continuous cropping, the soybean variety and the plant growth stage all had significant effects on the diversity of root rot pathogenic fungi in rhizosphere soil.

A pigeonpea gene confers resistance to Asian soybean rust in soybean.

Asian soybean rust (ASR), caused by the fungus Phakopsora pachyrhizi, is one of the most economically important crop diseases, but is only treatable with fungicides, which are becoming less effective owing to the emergence of fungicide resistance. There are no commercial soybean cultivars with durable resistance to P. pachyrhizi, and although soybean resistance loci have been mapped, no resistance genes have been cloned. We report the cloning of a P. pachyrhizi resistance gene CcRpp1 (Cajanus cajan Resistance against Phakopsora pachyrhizi 1) from pigeonpea (Cajanus cajan) and show that CcRpp1 confers full resistance to P. pachyrhizi in soybean. Our findings show that legume species related to soybean such as pigeonpea, cowpea, common bean and others could provide a valuable and diverse pool of resistance traits for crop improvement.

Agriculture and forest: A sustainable strategy in the Brazilian Amazon.

Large-scale agriculture is increasing in anthropogenically modified areas in the Amazon Basin. Crops such as soybean, maize, oil palm, and others are being introduced to supply the world demand for food and energy. However, the current challenge is to enhance the sustainability of these areas by increasing efficiency of production chains and to improve environmental services. The Amazon Basin has experienced a paradigm shift away from the traditional slash-and-burn agricultural practices, which offers decision makers the opportunity to make innovative interventions to enhance the productivity in previously degraded areas by using trees to ecological advantage. This study describes a successful experiment integrating the production of soybean and paricá (Glycine max L. and Schizolobium amazonicum) based on previous research that indicated potential topoclimatic zones for planting paricá in the Brazilian state of Pará. This paper shows that a no-tillage system reduces the effects of drought compared to conventional tillage still used by many farmers in the region. The integrated system was implemented during the 2014/2015 season in 234.6 ha in the high-potential zone in the municipality of Ulianópolis, Pará. Both soybean and paricá were planted simultaneously. Paricá was planted in 5 m x 2 m inter-tree spacing totaling 228x103 trees per hectare and soybean, in 4 m x 100 m spacing, distributed in nine rows with a 0.45 m inter-row distance, occupying 80% of the area. The harvested soybean production was 3.4 t ha-1, higher than other soybean monocultures in eastern Pará. Paricá benefited from soybean fertilization in the first year: It exhibited rapid development in height (3.26 m) and average diameter (3.85 cm). Trees and crop rotation over the following years is six years for forest species and one year for each crop. Our results confirm there are alternatives to the current production systems able to diminish negative impacts resulting from monoculture. In addition, the system provided environmental services such as reduced soil erosion and increased carbon stock by soil cover with no-tillage soybean cultivation. The soybean cover contributes to increased paricá thermal regulation and lower forestry costs. We concluded that innovative interventions are important to show local farmers that it is possible to adapt an agroforest system to large-scale production, thus changing the Amazon.

Controle do caruncho-do-feijoeiro Zabrotes subfasciatus com óleos vegetais, munha, materiais inertes e malathion

Na busca de alternativas ao controle químico do caruncho Zabrotes subfasciatus (Coleoptera:Bruchidae), avaliou-se, em feijoeiro (Phaseolus vulgaris L.), o efeito de três genótipos, cv. Carioca e duas linhagens contendo a proteína arcelina (Arc1 e Arc3), e da adição nos grãos armazenados de óleo de soja (Glycine max Merrill); óleo de nim (Azadirachta indica A. Juss.), munha (resíduo de trilha da colheita), calcário dolomítico e terra de formigueiro, comparativamente aos grãos não tratados e ao controle químico com malathion 500 CE. O experimento foi realizado no laboratório da Embrapa-Centro Nacional de Pesquisa de Arroz e Feijão, localizado no Município de Santo Antônio de Goiás, GO, em condições não controladas. Na linhagem Arc1, constatou-se maior proteção aos danos do caruncho, observando-se redução do número de ovos e de adultos emergidos e da porcentagem de sementes danificadas em relação à Arc3 e à cv. Carioca. Quando os grãos foram tratados com malathion, óleo de nim e óleo de soja, observou-se menor número de ovos e de adultos emergidos e redução de danos, e não houve diferença na porcentagem de sementes danificadas entre o malathion e o óleo de nim. A mistura das sementes com terra de formigueiro conferiu baixa proteção ao caruncho, enquanto os tratamentos com munha e calcário dolomítico não apresentaram eficiência na redução da progênie e dos danos de Z. subfasciatus.

Acao antioxidante de extratos de alecrim (Rosmarinus officinalis L.) em files de peixes da especie pacu (Piaractus mesopotamicus Holmberg)

The antioxidant effect of plant extract has been an interesting issue for many researchers in past few years. Spices have been identified as products with large amounts of antioxidants, and rosemary is one the most studied spice. Studies have shown evidences that population with high intake of these substances have less incidence of coronary heart disease. The objective of this work was verify the antioxidant action of the commercial rosemary oleoresin Herbalox® (used to feed the pacu (Piaractus mesopotamicus) fish. The juveniles pacu were fed with isocaloric and isoproteic diets, for two groups the lipid source was soybean oil and for the another it was corn oil. For each group of the different lipid sources, rosemary extract Herbalox® (were added in one lot and on the other which was used as control. The results showed that the addition of rosemary extracts to the ration protected them against peroxidation, when compared with the control, the lipid source also have influence on these protection.

Tocopherol content and fatty acid profile in soybean oil supplemented with salvia extract (Salvia officinalis L.) during heating

This paper aimed to assess the tocopherol content and evaluate the fatty acid profile in soybean oil supplemented with salvia extract during heating, so as to verify the isolated and synergistic effect of natural and synthetic antioxidants. In order to obtain the extract, the lyophilized and crushed salvia was subjected to extraction by ethyl alcohol for 30 min, with a 1:20 salvia:ethyl alcohol ratio, under continuous agitation. Afterwards, the mixture was filtered and the supernatant was subjected to the rotary evaporator at 40 °C. Later the control treatments, ES (3000 mg kg-1 salvia extract), TBHQ (50 mg kg-1), and mixture (ES+50 mg kg-1 TBHQ) were prepared and subjected to 180 °C for 20 h. Samples were taken in time intervals 0, 10, and 20 h and analysed in terms of tocopherol content and fatty acid profile. Regarding the tocopherol and fatty acid profile analysis, it was found that the extract proved efficient in oil protection, when added isolated to soybean oil subjected to thermo oxidation. According to the results, salvia extract is a viable alternative that might be applied in industrialized processing of oils as natural antioxidant.

Distribuição de inseticidas em frutos do cafeeiro (coffea arabica l.) e eficiência no controle da broca-do-cafeeiro (Hypothenemus Hampei F.)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Thermal behavior of malonylglucoside isoflavones in soybean flour analyzed by RPHPLC/DAD and eletrospray ionization mass spectrometry

Soybean (Glycine max (Merrill) L) contains high content of aglycone isoflavones, as well as glucoside and malonylconjugates. In this work, the content of isoflavones in defatted soy flour was determined by reversed-phase high-performance liquid chromatography (RPHPLC) after alcoholic extraction in methanol/water mixture in the ratio 80:20 (v/v). It was observed that the heating treatment transformed the malonylglucosides into glucoside isoflavones. After heat treatment at 121 degrees C for 30 min, nearly all malonylisoflavones were converted into glucoside, but acetylisoflavones were not detected via RPHPLC analysis. Electrospray ionization mass spectrometry confirmed the presence of malonylisoflavones in heat-treated defatted soy flour by direct infusion analysis. (c) 2012 Elsevier Ltd. All rights reserved.

Establishing a soybean germplasm core collection

Core collections are of strategic importance as they allow the use of a small part of a germplasm collection that is representative of the total collection. The objective of this study was to develop a soybean core collection of the USDA Soybean Germplasm Collection by comparing the results of random, proportional, logarithmic, multivariate proportional and multivariate logarithmic sampling strategies. All but the random sampling strategy used stratification of the entire collection based on passport data and maturity group classification. The multivariate proportional and multivariate logarithmic strategies made further use of qualitative and quantitative trait data to select diverse accessions within each stratum. The 18 quantitative trait data distribution parameters were calculated for each core and for the entire collection for pairwise comparison to validate the sampling strategies. All strategies were adequate for assembling a core collection. The random core collection best represented the entire collection in statistical terms. Proportional and logarithmic strategies did not maximize statistical representation but were better in selecting maximum variability. Multivariate proportional and multivariate logarithmic strategies produced the best core collections as measured by maximum variability conservation. The soybean core collection was established using the multivariate proportional selection strategy. (C) 2010 Elsevier B.V. All rights reserved.

Action of growth regulators on flowering and pod production of soybean cultivar Davis

This research deals with the effects of growth regulators on flowering and pod formation in soybean plant (Glycine max cv. Davis). Under greenhouse conditions, soybean plants were sprayed with 2,3,5-triiodobenzoic acid (TIBA) 20 ppm, Agrostemmin (1g/10 ml/3 l) gibberellic acid (GA) 100 ppm, and (2-chloroethyl) trimethylammonium chloride (CCC) 2,000 ppm. Application of TIBA increased number of flowers. 'Davis' soybean treated with CCC and TIBA presented a tendency to produce a lower number of pods.

Genetic diversity and host plant preferences revealed by simple sequence repeat and mitochondrial markers in a population of the arbuscular mycorrhizal fungus Glomus intraradices.

Arbuscular mycorrhizal fungi (AMF) are important symbionts of plants that improve plant nutrient acquisition and promote plant diversity. Although within-species genetic differences among AMF have been shown to differentially affect plant growth, very little is actually known about the degree of genetic diversity in AMF populations. This is largely because of difficulties in isolation and cultivation of the fungi in a clean system allowing reliable genotyping to be performed. A population of the arbuscular mycorrhizal fungus Glomus intraradices growing in an in vitro cultivation system was studied using newly developed simple sequence repeat (SSR), nuclear gene intron and mitochondrial ribosomal gene intron markers. The markers revealed a strong differentiation at the nuclear and mitochondrial level among isolates. Genotypes were nonrandomly distributed among four plots showing genetic subdivisions in the field. Meanwhile, identical genotypes were found in geographically distant locations. AMF genotypes showed significant preferences to different host plant species (Glycine max, Helianthus annuus and Allium porrum) used before the fungal in vitro culture establishment. Host plants in a field could provide a heterogeneous environment favouring certain genotypes. Such preferences may partly explain within-population patterns of genetic diversity.

Alterações de características químicas do solo e resposta da soja ao calcário e gesso aplicados na superfície em sistema de cultivo sem preparo do solo

O experimento foi desenvolvido em um Latossolo Vermelho-Escuro distrófico, em Ponta Grossa (PR), com o objetivo de avaliar os efeitos da aplicação de calcário e gesso na superfície sobre as características químicas do solo e resposta da soja cultivada em sistema de cultivo sem preparo do solo. O delineamento experimental empregado foi o de blocos ao acaso em parcela subdividida, com três repetições. Foram utilizadas quatro doses de calcário dolomítico, com 84% de PRNT: 0, 2, 4 e 6 t ha-1, e quatro doses de gesso agrícola: 0, 4, 8 e 12 t ha-1. A calagem foi realizada em julho, e a aplicação de gesso em novembro de 1993. A cultura da soja foi avaliada nos anos agrícolas de 1993/94 e 1995/96. A soja não respondeu à aplicação de calcário e gesso na superfície, em solo com pH (CaCl2 0,01 mol L-1) 4,5 e 32% de saturação por bases na camada de 0-20 cm. A calagem proporcionou correção da acidez do solo, revelada pela elevação do pH e redução do alumínio trocável, até a profundidade de 10 cm e em camadas subsuperficiais, mostrando que a ação do calcário aplicado na superfície, em áreas com cultivos já estabelecidos, não preparadas convencionalmente, pode atingir camadas mais profundas de solo. Esse efeito foi observado doze meses após a aplicação do corretivo, tendo sido mais pronunciado após vinte e oito meses. A aplicação de gesso causou redução do alumínio trocável, elevou os teores de cálcio em todo o perfil do solo e provocou lixiviação de bases, principalmente de magnésio, tendo sido esta mais acentuada na presença de maiores teores de magnésio trocável no solo. Após vinte e quatro meses, foram recuperados cerca de 40% do S-SO4 e 60% do cálcio aplicados pelo gesso na dose de 12 t ha-1, até a profundidade de 80 cm. Desse total recuperado, apenas 10% do S-SO4 e 25% do cálcio foram encontrados na camada de 0-20 cm de solo.