Anaerobic soil disinfestation with ethanol or sucrose reduces the viability of Meloidogyne javanica and Stromatinia cepivora

Anaerobic soil disinfestation (ASD) is an ecological alternative to chemical soil fumigation. However, little is known about the potential of this technique for the management of Meloidogyne javanica and Stromatinia cepivora. To test the hypothesis that ASD reduces the viability of these two pathogens, we assessed ethanol (5%, v:v) and sucrose (5%, m:v) as carbon sources for ASD, for an incubation period of three weeks. Twenty kilograms of soil naturally infested with M. javanica (82 ± 43 J2 100 cm-3 soil) were placed into a plastic container. Polyester traps, each with 15 S. cepivora sclerotia, were buried at 10 and 20 cm depth per container. ASD with diluted ethanol or sucrose (5% v:v or m:v) was compared to the untreated control (UTC), chemical fumigant metam sodium (MS), and soil saturation with water. In comparison to the UTC, ASD using ethanol reduced the numbers of J2 in soil and the galls in tomato roots by more than 93%, a degree of suppression similar to that achieved when using MS. The viability of sclerotia of S. cepivora was reduced by ASD using ethanol or sucrose from 38.12 to 58.1% compared to the UTC. ASD for three weeks using ethanol or sucrose (5%) reduces the viability of M. javanica and S. cepivora in the microcosm.(AU)

Biometric and morphological adjustments of Eugenia. dysenterica DC. seedlings in response to increased soil water deficit

Water stress can affect all aspects of plant growth and development, compromising its productive potential. The cultivation of fruit species native to the Cerrado and the study of their behavior under conditions of low water availability are necessary activities, in view of their socioeconomic and environmental potential. This study was conducted to evaluate the effect of water deficit on growth and biomass production of the cagaita tree (Eugenia dysenterica DC.), a species endemic to the Cerrado (Brazilian Savannah). The experiment was performed in a greenhouse for 120 days in a randomized block design (RBD), with a double factorial arrangement (2x5), corresponding to two cagaita mother plants and five water conditions. We evaluated the growth and leaf, stem and root functional characteristics. The most severe water deficit conditions reduced shoot growth, number of leaves, production of biomass and dry matter and increased the specific and per plant mass root length of cagaita plants. Deficit extension had negative effects on its growth and development. There was a statistical difference between mother plants, with mother plant 2 being more resistant to drought. The application of a severe or longer water deficit affected shoot growth and reduced the appearance of new leaves. The stress caused by water deficiency allowed an increase in root functional characteristics, supporting the hypothesis that plants under adverse conditions focus on higher biomass production and convert a higher amount of dry matter into the roots. Leaf area did not show to be a functional characteristic, explaining the stress effects in E. dysenterica DC plants.(AU)

Does silicon and salicylic acid contribute in the morphophysiology of Schinus terebinthifolia seedlings under flooding? / O silício e ácido salicílico contribuem na morfofisiologia de mudas de Schinus terebinthifolia sob alagamento?

Flooding can damage the photosynthetic apparatus and initial growth of Schinus terebinthifolia. We aimed this study evaluates the potential of silicon (Si) and salicylic acid (SA) as mitigating agents on the ecophysiological responses and initial growth of S. terebinthifolia subjected to flooding periods. Seedlings were grown under the following conditions: 1) control (non-flooded): daily irrigation, 2) Flooded (F): storage of seedlings in a 500 L plastic pool, keeping the water depth at ± 2.0 cm above the substrate level, 3) F + 1.0 mM Si, 4) F + 2.0 mM Si, 5) F + 1.5 mM SA, and 6) F + 3.0 mM SA, and evaluated to 15 and 30 days. We observed that flooded seedlings formed hypertrophied lenticels on the stem on the 7th day as a stress adjustment strategy. S. terebinthifolia is sensitive to flooding, although it maintains a stable gas exchange for up to 15 days in this condition. The applications of 1.0 mM Si mitigated the pronounced decrease of gas exchange by 30 days. Using 1.0 mM Si and 3.0 mM SA contributed for integrity of the photosynthetic apparatus and to photochemical activities in the reaction centers, in addition favors to higher seedling biomass and quality under flooding. Foliar application of Si and SA is promising practice for photosynthetic metabolic and initial growth of S. terebinthifolia seedlings under flooded stress.

O alagamento pode promover danos ao aparato fotossintético e crescimento inicial de Schinus terebinthifolia. Objetivamos nesse estudo avaliar o potencial do silício (Si) e ácido salicílico (AS) como agentes de mitigação sobre as respostas ecofisiológicas e crescimento inicial de S. terebinthifolia submetidas a períodos de alagamento. As mudas foram cultivadas sob as seguintes condições: 1) controle (não alagado): irrigação diariamente, 2) Alagado (A): acondicionamento das mudas em piscina plástica de 500 L, mantendo uma lâmina d'água ± 2,0 cm acima do nível do substrato, 3) A + 1,0 mM Si, 4) A + 2,0 mM Si, 5) A + 1,5 mM AS e 6) A + 3,0 mM AS. Observamos que as mudas alagadas formaram lenticelas hipertrofiadas no caule a partir dos 7 dias como estratégia de ajuste ao estresse. S. terebinthifolia é sensível ao alagamento, embora mantenha estável as trocas gasosas por 15 dias nessa condição. A aplicação de 1.0 mM de Si mitigou o decréscimo pronunciado das trocas gasosas por 30 dias. O uso de 1,0 mM Si e 3,0 mM SA contribuíram para a integridade do aparato fotossintético e atividades fotoquímicas nos centros de reação, além de favorecer maior produção de biomassa e qualidade das mudas sob alagamento. A aplicação foliar de Si e AS é uma prática promissora para o metabolismo fotossintético e crescimento inicial de mudas de S. terebinthifolia sob estresse por alagamento.

Metabolic profile, antimicrobial and toxicity evaluation of Azadirachta indica roots / Perfil metabólico, atividade antimicrobiana e de toxicidade das raízes de Azadirachta indica

ABSTRACT: The constituents of the hydroethanolic extract ofAzadiractaindicaroot were investigated using ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UPLC-QTOOF-MSE). Acute toxicity was evaluated in an experimental animal model. We investigated the antibacterial activities ofA. indicaroots againstSalmonella typhimuriumandStaphylococcus aureusand the antifungal activities against strains ofTrichophyton rubrum, Candida albicansandCandida tropicalis. We identified nine secondary metabolites in the hydroethanolic extract by UPLC-QTOOF-MSE. The extract was highly effective in inhibiting the growth of T. rubrum strains, so it can be effective in combating the dermatophyte tested,but it had no inhibition potential on any bacterial strains orCandidaspecies evaluated. It was possible to infer that the extract had no acute toxicity in relation to the animal model Danio rerio. Therefore, since neem has a high bioactive potential and adapts well to the climate of semiarid regions, growing this species could become a source of income for farmers by its use to produce naturals fungicide and drug, as alternatives to conventional products, which can cause microbiological resistance and/or are toxic to the environment, besides being expensive.

RESUMO: Os constituintes do extrato hidroetanólico da raiz deA. indicaforam investigados por cromatografia líquida de ultra-alta performance acoplada à espectrometria de massas do tipo quadrupolo-tempo de voo (UPLC-QTOOF-MSE). A toxicidade aguda foi avaliada em modelo animal. Investigamos as atividades antibacterianas contra Salmonella typhimuriumeStaphylococcus aureuse as atividades antifúngicas contra cepas deTrichophyton rubrum, Candida albicanseCandida tropicalis. Identificamos nove metabólitos secundários no extrato etanólico por UPLC-QTOOF-MSE. O extrato foi altamente eficaz na inibição do crescimento de cepas de T. rubrum, podendo ser eficaz no combate ao dermatofito avaliado, mas não apresentou potencial de inibição em nenhuma cepa bacteriana ou espécies deCandidaavaliadas. Também foi possível inferir que o extrato não apresentou toxicidade aguda em relação ao modelo animalDanio rerio. Portanto, como o Neem tem alto potencial bioativo e se adapta bem ao clima das regiões semiáridas, o cultivo dessa espécie pode se tornar uma fonte de renda para os agricultores a partir da utilização da planta para produção de fungicida e/ou fármaco naturais como alternativa aos produtos convencionais, que podem causar resistência microbiológica e/ou são tóxicas ao meio ambiente, além de serem caros.

Metabolic profile, antimicrobial and toxicity evaluation of Azadirachta indica roots / Perfil metabólico, atividade antimicrobiana e de toxicidade das raízes de Azadirachta indica

The constituents of the hydroethanolic extract ofAzadiractaindicaroot were investigated using ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UPLC-QTOOF-MSE). Acute toxicity was evaluated in an experimental animal model. We investigated the antibacterial activities ofA. indicaroots againstSalmonella typhimuriumandStaphylococcus aureusand the antifungal activities against strains ofTrichophyton rubrum, Candida albicansandCandida tropicalis. We identified nine secondary metabolites in the hydroethanolic extract by UPLC-QTOOF-MSE. The extract was highly effective in inhibiting the growth of T. rubrum strains, so it can be effective in combating the dermatophyte tested,but it had no inhibition potential on any bacterial strains orCandidaspecies evaluated. It was possible to infer that the extract had no acute toxicity in relation to the animal model Danio rerio. Therefore, since neem has a high bioactive potential and adapts well to the climate of semiarid regions, growing this species could become a source of income for farmers by its use to produce naturals fungicide and drug, as alternatives to conventional products, which can cause microbiological resistance and/or are toxic to the environment, besides being expensive.

Os constituintes do extrato hidroetanólico da raiz deA. indicaforam investigados por cromatografia líquida de ultra-alta performance acoplada à espectrometria de massas do tipo quadrupolo-tempo de voo (UPLC-QTOOF-MSE). A toxicidade aguda foi avaliada em modelo animal. Investigamos as atividades antibacterianas contra Salmonella typhimuriumeStaphylococcus aureuse as atividades antifúngicas contra cepas deTrichophyton rubrum, Candida albicanseCandida tropicalis. Identificamos nove metabólitos secundários no extrato etanólico por UPLC-QTOOF-MSE. O extrato foi altamente eficaz na inibição do crescimento de cepas de T. rubrum, podendo ser eficaz no combate ao dermatofito avaliado, mas não apresentou potencial de inibição em nenhuma cepa bacteriana ou espécies deCandidaavaliadas. Também foi possível inferir que o extrato não apresentou toxicidade aguda em relação ao modelo animalDanio rerio. Portanto, como o Neem tem alto potencial bioativo e se adapta bem ao clima das regiões semiáridas, o cultivo dessa espécie pode se tornar uma fonte de renda para os agricultores a partir da utilização da planta para produção de fungicida e/ou fármaco naturais como alternativa aos produtos convencionais, que podem causar resistência microbiológica e/ou são tóxicas ao meio ambiente, além de serem caros.

Replacement of corn with pre-dried cassava root silage in the diet for dairy goats

The objective of this study was to evaluate the effect of replacement of corn with pre-dried cassava root silage (CRS) on intake, ingestive behavior, production and composition of goat milk. Five lactating Saanen goats were used, with 42.5 ± 4.2 kg body weight and production of 2 kg milk day-1, distributed in a 5 x 5 Latin square with five treatments: 0, 28.6, 58.0, 81.6 and 100% replacement of corn with CRS in the diet dry matter. Goats were monitored for five periods of 15 days each. The intake of dry matter, crude protein and neutral detergent fiber decreased linearly (p <0.05) with the replacement of corn with CRS. Feeding (348.5 ± 62.1 min.) and rumination (468.8 ± 83.8 min.) times were not influenced (p >0.05) by the replacement of corn with CRS, but the ingestion and rumination efficiencies had a linear increase (p > 0.05). Milk production (2.17 ± 0.45 kg day-1), fat (3.49 ± 0.42%), protein (3.11 ± 0.13%) and lactose (4.47 ± 0,11%) of goat milk were not influenced (p >0.05) by the replacement of corn with CRS. Therefore, it is recommended the total replacement of corn with pre-dried cassava root silage in the diet for dairy goats with an average production of 2 kg day-1.(AU)

Root system architecture and seed weight relations in forage pea (Pisum sativum ssp arvense L Poir) / Arquitetura do sistema radicular e relações de peso de sementes em ervilha forrageira (Pisum sativum ssp arvense L Poir)

Forage pea (Pisum sativum ssp. arvense (L.) Poir.) is an important legume crop for fresh and dry herbage production with high input costs as irrigation and fertilization. Selection and breeding of accessions for improved drought tolerance, water, and mineral uptake efficiency become a necessity, rather than a choice. This study evaluated a set of forage pea accessions for the seedling root system architecture diversity and seed reserve utilization, under controlled conditions. Eight cultivars and an elite breeding line were evaluated for the first time in a plexiglass system. The number and lengths of the roots in each depth zone (0, 5, 10, 15+ cm) were evaluated and significant diversity was identified. The cultivar Livioletta had the highest number of roots and total root length. There was a significant correlation between seed weight, seed reserve utilization ratio, and root system vigor. Accessions with the highest seed reserve utilization had the highest total root length and numbers. Seedling root system vigor seems to be effective in predicting the fate of the accessions through maturity. The results suggested a possibility of "seedling root selection" for forage crop breeding.

A ervilha forrageira (Pisum sativum ssp. arvense (L.) Poir.) é uma cultura leguminosa importante para a produção de forragem fresca e seca com alto custo de insumos como irrigação e fertilização. A seleção e reprodução de acessos para melhor tolerância à seca, eficiência de absorção de água e minerais tornam-se uma necessidade, ao invés de uma escolha. Este trabalho teve como objetivo avaliar um conjunto de acessos de ervilha forrageira quanto à diversidade da arquitetura do sistema radicular de mudas e utilização de reservas de sementes, em condições controladas. Oito cultivares e uma linha de melhoramento de elite foram avaliados pela primeira vez em um sistema de plexiglass. O número e o comprimento das raízes em cada zona de profundidade (0, 5, 10, 15+ cm) foram avaliados e uma diversidade significativa foi identificada. A cultivar Livioletta apresentou o maior número de raízes e comprimento total de raízes. Houve uma correlação significativa entre o peso da semente, a taxa de utilização de reserva de semente e o vigor do sistema radicular. Os acessos com a maior utilização de reserva de sementes tiveram o maior comprimento e número total de raízes. O vigor do sistema radicular de mudas parece ser eficaz em predizer o destino dos acessos até a maturidade. Os resultados sugerem a possibilidade de "seleção de raízes de mudas" para o melhoramento da cultura forrageira.

First record of Plectris aliena Chapin, 1934 (Coleoptera: Melolonthidae) as a potential sugarcane pest in Brazil

Plectris aliena Chapin, 1934, a white grub that promotes serious damage to a variety of crops in North America and Australia, has been reported for the first time in Brazil. Larvae and adults of P. aliena were recorded in sugarcane crops in the state of Mato Grosso do Sul, sampled by trenches in the soil with light traps, respectively, during 2012 and 2013. Root consumption was also determined for the first, second and third instar larvae. The species is univoltine; adults were found mainly in Aug and the peak of third instar larval density was in Apr in all fields sampled. Pupae and adults of P. aliena were observed in the soil profile at depths of up to 60 and 80 cm, respectively. Larvae of P. aliena of the second and third instar consumed the primary and secondary roots of sugarcane, causing serious damage. Third instar larvae consumed 916 mg of root fresh matter, representing 72 % of the sugarcane root system. These results assist in furthering the understanding of its larval dynamics in the soil and provide support for Integrated Pest Management.

First record of Plectris aliena Chapin, 1934 (Coleoptera: Melolonthidae) as a potential sugarcane pest in Brazil

Plectris alienaChapin, 1934, a white grub that promotes serious damage to a variety of crops in North America and Australia, has been reported for the first time in Brazil. Larvae and adults of P. aliena were recorded in sugarcane crops in the state of Mato Grosso do Sul, sampled by trenches in the soil with light traps, respectively, during 2012 and 2013. Root consumption was also determined for the first, second and third instar larvae. The species is univoltine; adults were found mainly in Aug and the peak of third instar larval density was in Apr in all fields sampled. Pupae and adults of P. aliena were observed in the soil profile at depths of up to 60 and 80 cm, respectively. Larvae of P. aliena of the second and third instar consumed the primary and secondary roots of sugarcane, causing serious damage. Third instar larvae consumed 916 mg of root fresh matter, representing 72 % of the sugarcane root system. These results assist in furthering the understanding of its larval dynamics in the soil and provide support for Integrated Pest Management.

Root mass vertical distribution of perennial cool-season grasses grown in pure or mixed swards / Distribuição vertical da massa de raízes de gramíneas perenes de inverno cultivadas puras e em mistura

In this study we tested whether the root biomass of mixtures composed by grass species is greater than their respective monocultures. The treatments were monocultures of Arrhenatherum elatius, Festuca arundinacea, Dactylis glomerata, and a mixture of them, cultivated in a rich-soil environment. Root biomass was evaluated on a single evaluation per season at three soil depths (0-5, 5-10, and 10-20 cm). Mixed swards presented the greatest root biomass, and this was explained by a greater concentration in the topsoil layer (0-5 cm). These findings reinforce the need for permanent soil conservation practices to not jeopardize the benefits of the more abundant root biomass reported in the mixed swards.

O presente estudo testou se a biomassa radicular de misturas compostas por gramíneas é maior do que os seus respectivos monocultivos. Os tratamentos foram monocultivos de Arrhenatherum elatius, Festuca arundinacea, Dactylis glomerata e uma mistura delas, cultivadas em um solo rico em nutrientes. A biomassa da raiz foi avaliada uma vez por estação em três profundidades de solo (0-5, 5-10 e 10-20 cm). Os pastos mistos apresentaram a maior biomassa radicular e isso pode ser explicado pela maior concentração de raízes na camada superficial do solo (0-5 cm). Esses achados reforçam a necessidade de práticas permanentes de conservação do solo para não prejudicar os benefícios da biomassa radicular mais abundante encontrada nos pastos mistos.

Foliar fertilization at the establishment of marandu, mavuno, mulato and ypyporã grasses

Foliar fertilization with macro and micro minerals for the forage grasses establishment can be a less costly alternative for the farmer, however the possible beneÀ ts of this management technique still need to be better studied. The objective with this work was to evaluate the physiological, productive and structural responses of grasses of the Urochloa genus, depending on the application or not of foliar fertilizer during the plant establishment. Four experiments were carried out, in each of which one of the following forage grasses was evaluated: Urochloa brizantha cv. Marandu, Urochloa spp. Mulatto II, Urochloa spp. Mavuno and Urochloa spp. Ipyporã. All the experiments were carried out from November 2018 to March 2019, in a completely randomized design, with four replications. The experimental area of each experiment consisted of four plots with 12.25 m², where half the area of the plots received foliar fertilizer (FH PASTAGEM FOLIAR, with 14% N; 12% P; 12% K; 0.38 % Mg; 10.2% S; 0.24% Cu; 0.18% Mn and 0.63% Zn) and the other half did not. The response variables were evaluated: spad index, leaf area index, canopy light interception, forage production and root density. In all experiments, the foliar fertilizer application during the establishment of Marandu, Mulato II, Mavuno and Ipyporã grasses did not inÁ uence (P>0,05) the spad and leaf area indexes, forage production and root density.(AU)

First record of Plectris aliena Chapin, 1934 (Coleoptera: Melolonthidae) as a potential sugarcane pest in Brazil

ABSTRACT: Plectris alienaChapin, 1934, a white grub that promotes serious damage to a variety of crops in North America and Australia, has been reported for the first time in Brazil. Larvae and adults of P. aliena were recorded in sugarcane crops in the state of Mato Grosso do Sul, sampled by trenches in the soil with light traps, respectively, during 2012 and 2013. Root consumption was also determined for the first, second and third instar larvae. The species is univoltine; adults were found mainly in Aug and the peak of third instar larval density was in Apr in all fields sampled. Pupae and adults of P. aliena were observed in the soil profile at depths of up to 60 and 80 cm, respectively. Larvae of P. aliena of the second and third instar consumed the primary and secondary roots of sugarcane, causing serious damage. Third instar larvae consumed 916 mg of root fresh matter, representing 72 % of the sugarcane root system. These results assist in furthering the understanding of its larval dynamics in the soil and provide support for Integrated Pest Management.

Hydrogen peroxide is involved in drought stress long-distance signaling controlling early stomatal closure in tomato plants / O peróxido de hidrogênio está envolvido na sinalização de longa distância do déficit hídrico controlando o fechamento estomático precoce em plantas de tomate

It has long been hypothesized that hydrogen peroxide (H2O2) may play an essential role in root-to-shoot long-distance signaling during drought conditions. Thus, to better understand the involvement of H2O2 in drought signaling, two experiments were carried out using tomato plants. In the first experiment, a split-root scheme was used, while in the second experiment, the tomato plants were grown in a single pot and subjected to drought stress. In both experiments, H2O2 and catalase were applied together with irrigation. Control plants continued to be irrigated according to the water loss. In the split-root experiment, it was verified that the application of H2O2 to roots induced a clear reduction in plant transpiration compared to untreated or catalase-treated plants. In the second experiment, we observed that H2O2-treated plants exhibited similar transpiration when compared to untreated and catalase-treated plants under drought stress. Similarly, no difference in water use efficiency was observed. Thus, we conclude that the increase in H2O2 in the root system can act as a long-distance signal leading to reduced transpiration even when there is no water limitation in the shoot. But it has little effect when there is a reduction in the shoot water potential.

Tem sido hipotetizado que o peróxido de hidrogênio (H2O2) pode desempenhar um papel essencial na sinalização de longa distância entre a raiz e a parte aérea sob condições de seca. Assim, para melhor entender o envolvimento do H2O2 na sinalização da seca, dois experimentos foram realizados com plantas de tomate. No primeiro, foi utilizado o esquema de raízes divididas, enquanto no segundo, os tomateiros foram cultivados em um único vaso e submetidos ao déficit hídrico. Em ambos os experimentos, o H2O2 e a catalase foram aplicados juntamente com a irrigação. As plantas do grupo controle continuaram a ser irrigadas de acordo com a perda de água. No experimento de raiz dividida, verificou-se que a aplicação de H2O2 nas raízes induziu uma clara redução na transpiração da planta em comparação com plantas não tratadas ou tratadas com catalase. No segundo experimento, observamos que plantas tratadas com H2O2 apresentaram transpiração semelhante quando comparadas com plantas não tratadas e tratadas com catalase sob seca. Da mesma forma, não foi observada diferença na eficiência do uso da água. Assim, concluímos que o aumento do H2O2 no sistema radicular pode atuar como um sinal de longa distância levando à redução da transpiração mesmo quando não há limitação hídrica na parte aérea. Mas tem pouco efeito quando há redução do potencial hídrico da parte aérea.

Machine learning applied to the prediction of root architecture of soybean cultivars under two water availability conditions / Machine learning aplicado à predição da arquitetura radicular de cultivares de soja sob duas condições de disponibilidade hídrica

The objective of this study was to evaluate the performance of four machine learning models, as well as multitask learning, to predict soybean root variables from simpler variables, under two water availability conditions. In order to do so, 100 soybean cultivars were conducted in a greenhouse under a control condition and a stress condition. Aerial part and root variables were evaluated. The machine learning models used to predict complex root variables were artificial neural network (ANN), random forest (RF), extreme gradient boosting (EGBoost) and support vector machine (SVM). A linear model was used for comparison purposes. Multitask learning was employed for ANN and RF. In addition, feature importance was defined using RF and XGBoost algorithms. All the machine learning models performed better than the linear model. In general, SVM had the greatest potential for the prediction of most of the root variables, with better values of RMSE, MAE and R2. Dry weight of the aerial part and root volume exhibited the greatest importance in the predictions. The models developed using multitask learning performed similarly to the ones conventionally developed. Finally, it is concluded that the machine learning models evaluated can be used to predict root variables of soybean from easily measurable variables, such as dry weight of the aerial part and root volume.(AU)

O objetivo deste estudo foi avaliar o desempenho de quatro modelos de machine learning, bem como multitask learning, para predizer variáveis radiculares de soja a partir de variáveis simples, em duas condições de disponibilidade hídrica. Para isso,100 cultivares de soja foram conduzidas em casa de vegetação sob uma condição controle e uma condição estresse. Foram avaliadas as variáveis da parte aérea e da raiz. Os modelos machine learning usados para predizer variáveis complexas do sistema radicular foram rede neural artificial (RNA), random forest (RF), extreme gradient boosting (EGBoost) e support vector machine (SVM). O modelo linear foi usado para fins de comparação. O multitask learning foi empregado para RNA e RF. Além disso, a importância das variáveis foi definida usando algoritmos RF e XGBoost. Todos os modelos de machine learning apresentaram melhor desempenho do que o modelo linear. Em geral, SVM apresentou o maior potencial de predição da maioria das variáveis raiz, com melhores valores de RMSE, MAE e R2. O peso seco da parte aérea e o volume da raiz exibiram as maiores importâncias nas predições. Os modelos desenvolvidos por meio do multitask learning apresentaram desempenhos semelhantes aos desenvolvidos convencionalmente. Por fim, conclui-se que os modelos de machine learning avaliados podem ser usados para predizer variáveis radiculares de soja a partir de variáveis facilmente mensuráveis, como massa seca da parte aérea e volume radicular.(AU)

Soybean development under different Aphelenchoides besseyi and Meloidogyne incognita populations / Desenvolvimento da soja sob diferentes populações de Aphelenchoides besseyi e Meloidogyne incognita

The green stem Aphelenchoides besseyi and gall Meloidogyne incognita phytonematodes cause soybean yield losses. Thus, the objective of this study was to evaluate the effects of different populations of A. besseyi and M. incognita on soybeans. The experiment had 10 treatment groups [T1: control, T2: A. besseyi (500), T3: M. incognita (2,000), T4: A. besseyi (250) + M. incognita (2,000), T5: A. besseyi (500) + M. incognita (2,000), T6: A. besseyi (250) + M. incognita (4000), T7: A. besseyi (500) + M. incognita (4,000) individuals, T8: A. besseyi (250) + M. incognita (8,000), T9: A. besseyi (500) + M. incognita (5,000), and T10: A. besseyi (1,000) + M. incognita (8,000) individuals] with six replicates. Inoculations were done on day 10 after soybean germination, and evaluations were conducted after 60 d. Plant height, shoot fresh weight, root fresh weight, number of pods (NP), pod fresh weight, number of grains (NG), grain yield (GY), amount of A. besseyi in the shoot, and M. incognita in the roots were analyzed. The 500 A. besseyi + 8,000 M. incognita treatment reduced all variables and led to considerable damage to soybean development. In addition, GY, NG, and NP were reduced in the different nematode population density groups, influencing soybean agronomic characteristics.(AU)

Entre as espécies de fitonematoides que provocam perdas de produção à cultura da soja estão os nematoides da haste verde (Aphelenchoides besseyi) e o das galhas (Meloidogyne incognita). Diante disso, o objetivo deste trabalho foi estudar os efeitos de diferentes níveis populacionais de A. besseyi e M. incognita na soja. O experimento foi realizado com nove combinações de diferentes níveis populacionais dos nematoides (T1 ­ Controle não inoculado, T2 - A. besseyi 500 indivíduos, T3 - M. incognita 2000 indivíduos, T4 - A. besseyi + M. incognita 250 + 2000 indivíduos, T5 - A. besseyi + M. incognita 500 + 2000 indivíduos, T6 - A. besseyi + M. incognita 250 + 4000 indivíduos, T7 - A. besseyi + M. incognita 500 + 4000 indivíduos, T8 - A. besseyi + M. incognita 250 + 8000 indivíduos, T9 - A. besseyi + M. incognita 500 + 8000 indivíduos e T10 - A. besseyi + M. incognita 1000 + 8000 indivíduos) e seis repetições. As variáveis analisadas foram: altura de planta, massa fresca da parte aérea (MPA), massa fresca de raízes (MR), número de vagens (V), massa fresca de vagens (MV), número de grãos (G), massa fresca de grãos (MG), quantidade de A. besseyi na parte aérea e de M. incognita nas raízes. O mapa de calor indicou que populações iniciais inoculadas de 500 A. besseyi + 8000 M. incognita apresentou maiores danos ao desenvolvimento da soja, reduzindo todas as variáveis analisadas. As variáveis MG, G e V reduziram na presença de diferentes densidades populacionais das espécies de fitonematoides nematoides, influenciando negativamente o desenvolvimento da soja.(AU)

Solar collector for soil disinfestation to produce Meloidogyne enterolobii free tomato seedlings in semiarid conditions / Coletor solar para desinfestação de solo para a produção de mudas de tomateiro livres de Meloidogyne enterolobii em condições semiáridas

In this study, we validated a solar collector for disinfest soil infested by Meloidogyne enterolobii for tomato seedlings production in semiarid conditions. An experiment using a randomized block design was conducted with six exposure times of the sieved substrate in the solar collector of zinc tubes. The treatments consisted of 0 (control), 6, 12, 24, 30 and 36 hours of exposure, with five replicates. After 12 hours of soil exposure in the solar collector, no galls were observed in the tomato roots, neither were eggs and second stage juveniles of M. enterolobii were observed in the soil. Based in the results obtained in this study, the solar collector was efficient in the disinfest of soil infested by M. enterolobii aiming production of tomato seedlings in semiarid conditions.

Neste estudo validamos um coletor solar para desinfestar solo com Meloidogyne enterolobii para a produção de mudas de tomateiro em condições semiáridas. Um experimento no delineamento em blocos casualizados foi conduzido com seis tempos de exposição de solo peneirado em um coletor solar de tubos de zinco. Estes consistiram de 0 (controle), 6, 12, 24, 30 e 36h de exposição, com cinco repetições cada. Após 12h de exposição do solo ao calor no coletor solar, nenhuma galha foi observada em raízes de tomateiro, assim como ovos ou juvenis de segundo estágio de M. enterolobii não foram observados no solo. Dessa maneira, o uso do coletor solar foi eficiente na desinfecção de solo infestado por M. enterolobii visando a produção de mudas de tomateiro em condições semiáridas.

Análises fisiológicas e de crescimento e produtividade da mandioca sob níveis de irrigação / Physiological and growth analysis and productivity of cassava under irrigation levels

O objetivo dessa pesquisa foi avaliaro crescimento,produtividade easrespostas fisiológicas da mandioca sob níveis de irrigação na Zona da Mata de Alagoas. O delineamento estatístico utilizado foi blocos casualizados, em esquema de parcelas subdivididas, com quatro repetições. Os tratamentos foram seis níveis de irrigação, em função da evapotranspiração da cultura ­ETC(L0= 0% (sequeiro), L1= 40%, L2= 80%, L3= 120%, L4= 160% e L5= 200% da ETC). As variáveis foram divididas em grupos: crescimento e produção (avaliadas em seis períodosbimestrais ­1 ano) e as fisiológicas (taxa fotossintética líquida e transpiratória, temperatura foliar, condutância estomática, eficiência instantânea do uso de água, rendimento quântico potencial, eficiência quântica efetiva do fotossistema II (ΦPSII) eíndice SPADforam avaliadas em cinco períodos bimestrais ­10 meses).Obalanço hídrico dos níveis de irrigação, foi realizado em escala decendial. A evapotranspiração anual da cultura da mandiocaestimada foi1.030 mm, e nas áreas de sequeiro, a chuva efetiva somouapenas 522 mm, o que geroudéficit hídrico de 508 mm, e isso torna evidente a importância de utilização da irrigação em cultivos na região. De maneira geral, crescimento, produtividade e as respostas fisiológicas da mandioca são superiores em áreas irrigadas quando comparadas com cultivos de sequeiro e a irrigação proporciona as produtividades de raízes e biomassa total de 97 e 155 t ha-1, sob os níveis de irrigação de 129 e 136% da ETC, respectivamente, na região estudada.(AU)

The objective of this research was to evaluate the growth, productivity and the physiological responses of cassava under irrigation levels in the Alagoas Forest Zone. The statistical design used was randomized blocks, in a split-plot scheme, with four replications. The treatments were six levels of irrigation, depending on the evapotranspiration of the crop ­ETC(L0=0% (Rainfed), L1= 40%, L2= 80%, L3= 120%, L4= 160% and L5= 200% of the ETC). The variables were divided into groups: growth and production (evaluated in six bimonthly periods -1 year) and the physiological (net photosynthetic rate and transpiratory,leaf temperature, stomatal conductance, instantaneous water use efficiency, potential quantum yield, effective quantum efficiency of photosystem II and SPAD indexwere evaluated in five bimonthly periods ­10 months). The water balance of the irrigation levels was carried out, on a decendial scale. The annual evapotranspiration of cassava addedaround 1,030 mm, and in dryland areas, the effective rainfall is only 522 mm, which generates a water deficit of 508 mm, and this makes the importance evident of use of irrigation in crops in the region. In general, cassava growth, yield andthephysiological responses are superior in irrigated areas when compared with therainfed crops, and irrigation providestheroot and total biomass yields of 97 and 155 Mg ha-1,under the irrigation levels of 129 and 136% of the ETC, respectively, in the studied region.(AU)

Control of Meloidogyne paranaensis mediated by silicon

The potential of silicon (Si) to control nematodes is often reported in association with the resistance induction mechanism. The objective of this work was to evaluate the hypothesis of resistance induction in plants against nematodes through the application of Si. In vitro experiments were carried out to evaluate the effect of Si and potassium chloride (KCl) on the hatching and mortality of Meloidogyne paranaensis juveniles. For the purpose of a greenhouse experiment, tomato plants were used as a model for bifurcated roots, using the respective control treatments, KCl and distilled water. Ten days after treatment, 2,000 eggs of M. paranaensis were inoculated. At 55 days post-inoculation, the reproduction factor and number of nematodes per gram of root were evaluated. Additionally, the tissue nutrient concentration and gas exchange variables were analyzed. Silicon reduces nematode viability, when in direct contact with the nematode in in vitro experiments and in bifurcated plants. When plants were treated with Si on one side of the root, no nematode control was observed on the opposite corresponding side. Results suggested that Si has a positive effect on the reduction of M. paranaensis population, but probably induced resistance to nematode only through direct action.

Control of Meloidogyne paranaensis mediated by silicon

The potential of silicon (Si) to control nematodes is often reported in association with the resistance induction mechanism. The objective of this work was to evaluate the hypothesis of resistance induction in plants against nematodes through the application of Si. In vitro experiments were carried out to evaluate the effect of Si and potassium chloride (KCl) on the hatching and mortality of Meloidogyne paranaensis juveniles. For the purpose of a greenhouse experiment, tomato plants were used as a model for bifurcated roots, using the respective control treatments, KCl and distilled water. Ten days after treatment, 2,000 eggs of M. paranaensis were inoculated. At 55 days post-inoculation, the reproduction factor and number of nematodes per gram of root were evaluated. Additionally, the tissue nutrient concentration and gas exchange variables were analyzed. Silicon reduces nematode viability, when in direct contact with the nematode in in vitro experiments and in bifurcated plants. When plants were treated with Si on one side of the root, no nematode control was observed on the opposite corresponding side. Results suggested that Si has a positive effect on the reduction of M. paranaensis population, but probably induced resistance to nematode only through direct action.(AU)

Upland rice seedling performance promoted by multifunctional microorganisms / Desempenho de plântulas de arroz de terras altas promovido por microrganismos multifuncionais

Multifunctional microorganisms can contribute to the development of plant root systems and positively affect the grain yield of crops. However, studies of the use of these microorganisms to benefit root development in rice plants are scarce. The objective of this study was to determine the effect of rhizobacterial inoculation of the seeds on the root development of upland rice seedlings. The experiment was carried out in the agricultural microbiology laboratory of Embrapa Rice and Beans, and we adopted a completely randomized design with eight replications. The treatments consisted of the inoculation of rice seeds with the rhizobacteria 1. Pseudomonas fluorescens (BRM 32111), 2. Burkholderia pyrrocinia (BRM 32113), 3. Serratia sp. (BRM 32114), 4. Bacillus sp. (1301), 5. Azospirillum brasilense (Ab-V5), 6. Azospirillum sp. (1381), and a 7. control treatment (without microorganisms). Treatment using the microorganism Azospirillum sp. (1381) provided the longest roots, greatest root volume and highest total dry mass of roots, at 86.34, 111.53 and 29.41%, respectively, significantly superior to the control treatment. In addition, treatments Ab-V5 and Bacillus sp. (1301) resulted in a root diameter of 13.81 and 13.06%, respectively, larger than that of the control treatment. The use of these multifunctional microorganisms was efficient for promoting the root development of rice seedlings.(AU)

Microrganismos multifuncionais podem contribuir para o desenvolvimento do sistema radicular de plantas afetando positivamente a produtividade de grãos das culturas. Objetivou-se determinar o efeito da inoculação de rizobactérias em sementes no desenvolvimento radicular de plântulas do arroz de terras altas. O experimento foi conduzido no laboratório de microbiologia agrícola da Embrapa Arroz e Feijão, e adotando delineamento experimental inteiramente casualizado, com oito repetições. Os tratamentos consistiram da inoculação em sementes de arroz com as rizobactérias 1. Pseudomonas fluorescens (BRM 32111), 2. Burkholderia pyrrocinia (BRM 32113), 3. Serratia sp. (BRM 32114), 4. Bacillus sp. (1301), 5. Azospirillum brasilense (Ab-V5), 6. Azospirillum sp. (1381), e 7. tratamento controle (sem microrganismo). O tratamento com a utilização do microrganismo Azospirillum sp. (1381) proporcionou maior comprimento radicular, volume de raízes e massa seca total de raízes, sendo respectivamente, 86,34, 111,53 e 29,41%, superior ao tratamento controle e diferiu significativamente. Além disso, os tratamentos Ab-V5 e Bacillus sp. (1301) proporcionaram maior diâmetro radicular nas plantas de arroz, sendo 13,81 e 13,06 % respectivamente superior ao tratamento controle. O uso destes microrganismos multifuncionais foi eficiente em sua capacidade de proporcionar incrementos no desenvolvimento radicular de plântulas de arroz.(AU)