RESUMEN

Sandy soils contain around 70% sand in their composition, making them highly fragile and susceptible to land degradation. Practices such as no-tillage cultivation, the use of bioinoculants, and the application of organic amendments can restore the organic matter in these soils, ensuring sustainable production. In this context, this work aimed to study the microbiological aspects of two sandy soil areas (Brazilian Northeast and South) under contrasting climatic conditions (tropical and temperate). With this purpose, prokaryotic communities were evaluated, and the plant growth-promoting potential of isolated bacteria was assessed by rice inoculation in sandy soil. Despite the high sand content in both soils, soil from the NE was related to the highest phosphorous, calcium, potassium, copper, sodium, zinc, magnesium, and manganese contents, organic matter percentage, and pH. The Shannon diversity index indicated that prokaryotic communities in NE were more diverse than in SU, and PCA revealed that microbial composition exhibited distinct patterns. The rice inoculation experiments were executed to verify if the bacterial isolates displayed a similar growth promotion potential when inoculated in sandy soil areas subjected to different climatic conditions. When all PGP characteristics evaluated were pooled in a PCA, a similar pattern was observed for SU and NE. Burkholderia sp. SU94 was related to highest PGP characteristics evaluated. Paraburkholderia sp. NE32 showed similar results to those of the non-inoculated control. This similar effect of rice growth in the Northeast and South of Brazil suggests that isolate SU94 adapts to different environmental conditions.

Asunto(s)

RESUMEN

Much work has been dedicated to the quest to determine the structure-activity relationship in synthetic brassinosteroid (BR) analogs. Recently, it has been reported that analogs with phenyl or benzoate groups in the alkyl chain present activities comparable to those shown by natural BRs, depending on the nature of the substituent in the aromatic ring. However, as it is well known that the activity depends on the structure of the whole molecule, in this work, we have synthesized a series of compounds with the same substituted benzoate in the alkyl chain and a hydroxyl group at C3. The main goal was to compare the activities with analogs with -OH at C2 and C3. Additionally, a molecular-docking study and molecular dynamics simulations were performed to establish a correlation between the experimental and theoretical results. The synthesis of eight new BR analogs was described. All the analogs were fully characterized by spectroscopical methods. The bioactivity of these analogs was assessed using the rice lamina inclination test (RLIT) and the inhibition of the root and hypocotyl elongation of Arabidopsis thaliana. The results of the RLIT indicate that at the lowest tested concentration (1 × 10-8 M), in the BR analogs in which the aromatic ring was substituted at the para position with methoxy, the I and CN substituents were more active than brassinolide (50-72%) and 2-3 times more active than those analogs in which the substituent group was F, Cl or Br atoms. However, at the highest concentrations, brassinolide was the most active compound, and the structure-activity relationship changed. On the other hand, the results of the A. thaliana root sensitivity assay show that brassinolide and the analogs with I and CN as substituents on the benzoyl group were the most active compounds. These results are in line with those obtained via the RLIT. A comparison of these results with those obtained for similar analogs that had a hydroxyl group at C2 indicates the importance of considering the whole structure. The molecular-docking results indicate that all the analogs adopted a brassinolide-like orientation, while the stabilizing effect of the benzoate group on the interactions with the receptor complex provided energy binding values ranging between -10.17 and -13.17 kcal mol-1, where the analog with a nitrile group was the compound that achieved better contact with the amino acids present in the active site.

Asunto(s)

RESUMEN

The search for less harmful, ecologically efficient, more specific, and natural alternatives for the control of pathogens is essential. Bauhinia variegata lectin (BvL) is a protein that has numerous biological activities, including antifungal. The present study examines the potential in vitro of B. variegata lectin against the fungus Bipolaris oryzae, responsible for agricultural losses in southern Brazil, due to damage to rice fields during seed germination. Bioassays to assess the inhibition potential of BvL were performed, including fungal growth, spore formation, and germination, in concentrations of 0, 25, 50, and 100 µg mL-1. Only the concentration of 100 µg mL-1 successfully inhibited mycelial growth and spore germination, while in spore formation, all treatments inhibited sporulation. In addition, fluorescence microscopy analysis demonstrated the ability of lectin to bind to the fungus and the lack of detection in the presence of lactose, suggesting its interaction with the fungal cell wall structures. This study highlights the potential of B. variegata seed lectin to control mycelial growth, sporulation, and germination of the phytopathogenic fungus B. oryzae, posing as a new biotechnological possibility for biological control.

Asunto(s)

RESUMEN

In vitro androgenesis is a unique model for producing homozygous doubled haploid plants. The use of haploid biotechnology accelerates to obtain of doubled haploid plants, which is very important in rice breeding. The purpose of this work is to improve the production of doubled haploids in rice anther culture in vitro and selection of doubled haploid plants with valuable traits. The study the influence of nutrient media on the production of calli and plant regeneration processes in anther culture of 35 rice genotypes was revealed a significant influence of nutrient media on callus production. It was shown that the addition to culture medium phytohormones ratio with high level of cytokinin (5.0 mg/L BAP) and a low level of auxin (0.5 mg/L NAA), supplemented with amino acid composition promotes high production of green regenerated plants (68.75%) compared to albino plants (31.25%). As a result, doubled haploid lines of the glutinous variety Violetta were selected, which characterized by a low amylose content variation (from 1.86 to 2.80%). These doubled haploids are superior to the original variety in some yield traits and represent valuable breeding material.

Asunto(s)

RESUMEN

Brassinosteroids (BRs) are an important group of polyhydroxylated naturally occurring steroidal phytohormones found in the plant kingdom in extremely low amounts. Due to the low concentrations in which these compounds are found, much effort has been dedicated to synthesizing these compounds or their structural analogs using natural and abundant sterols. In this work, we report the synthesis of new brassinosteroid analogs obtained from hyodeoxycholic acid, with a 3,6 dioxo function, 24-Nor-22(S)-hydroxy side chain and p-substituted benzoate function at C-23. The plant growth activities of these compounds were evaluated by two different bioassays: rice lamina inclination test (RLIT) and BSI. The results show that BRs' analog with p-Br (compound 41f) in the aromatic ring was the most active at 1 × 10-8 M in the RLIT and BSI assays. These results are discussed in terms of the chemical structure and nature of benzoate substituents at the para position. Electron-withdrawing and size effects seems to be the most important factor in determining activities in the RLIT assay. These results could be useful to propose a new structural requirement for bioactivity in brassinosteroid analogs.

Asunto(s)

RESUMEN

AIM: Bacteria that promote plant growth, such as diazotrophs, are valuable tools for achieving a more sustainable production of important non-legume crops like rice. Different strategies have been used to discover new bacteria capable of promoting plant growth. This work evaluated the contribution of soil diazotrophs to the endophytic communities established in the roots of rice seedlings cultivated on seven representative soils from Uruguay. METHODS AND RESULTS: The soils were classified into two groups according to the C and clay content. qPCR, terminal restriction fragment length polymorphism (T-RFLP), and 454-pyrosequencing of the nifH gene were used for analyzing diazotrophs in soil and plantlets' roots grown from seeds of the same genotype for 25 days under controlled conditions. A similar nifH abundance was found among the seven soils, roots, or leaves. The distribution of diazotrophs was more uneven in roots than in soils, with dominance indices significantly higher than in soils (nifH T-RFLP). Dominant soils' diazotrophs were mainly affiliated to Alphaproteobacteria and Planctomycetota. Conversely, Alpha, Beta, Gammaproteobacteria, and Bacillota were predominant in different roots, though undetectable in soils. Almost no nifH sequences were shared between soils and roots. CONCLUSIONS: Root endophytic diazotrophs comprised a broader taxonomic range of microorganisms than diazotrophs found in soils from which the plantlets were grown and showed strong colonization patterns.

Asunto(s)

RESUMEN

Atmospheric CO2 enrichment has the potential to improve rice (Oryza sativa L.) yield, but it may also reduce grain nutritional quality, by reducing mineral and protein concentrations. Selenium (Se) fertilization may improve rice grain nutritional composition, but it is not known if this response extends to plants grown in elevated carbon dioxide concentration (eCO2). We conducted experiments to identify the impacts of Se fertilization on yield and quality of rice grains in response to eCO2. The effect of the Se treatment was not significant for the grain yield within each CO2 condition. However, the reduction in macronutrients and micronutrients under eCO2 was mitigated in grains of plants fertilized with Se. Fertilization with Se increased the concentration of Se in roots, flag leaves, and grains independently of atmospheric CO2 concentrations. Elevation of the transcripts of ion transport-related genes could, at least partially, explain the positive relationship between mineral concentrations and grain mass resulting from Se fertilization under eCO2. Treatment with Se also increased the accumulation of total protein in grains under eCO2. Overall, our results revealed that Se fertilization represents a potential asset to maintain rice grain nutritional quality in a future with rising atmospheric CO2 concentration.

Asunto(s)

RESUMEN

Plant-fungus symbioses have functional relevance during plant growth and development. However, it is still unknown whether the endosphere fungi in mature plants originated from soils or seeds. To elucidate the origination of endosphere fungi in mature rice roots, the fungal communities in surface sterilized roots and shoots of mature rice plants germinated in soils, rhizosphere soils and seedlings germinated under sterile conditions were analyzed by Illumina-based sequencing and compared. Total 62 fungal OTUs shared in the seedlings, shoots and roots, 126 OTUs shared in the rhizosphere soils, shoots and roots. Fungal OTUs coexisted in the four types of samples belonged to genera of Rhizophagus, Trichoderma, Fusarium, Atractiella, Myrmecridium, Sporothrix, Microdochium, Massariosphaeria, and Phialemonium. The principle component analysis (PCA) and NMDS plot suggested that the fungal community structure in rhizosphere soils was different from that in seedlings significantly. Rhizosphere soil, shoot and root contained more similar fungal community. The fungal community in seedling was similar to that in shoot and root of mature plants. The results suggested that endophytic fungal communities in mature rice plants originated from both seedlings and rhizosphere soils, and more fungal taxa originated from rhizosphere soils. Mature rice plants contain mycobiome transmitted vertically from seeds, which suggests that inoculation of endophytic fungi isolated from seedlings might be an effective way to introduce beneficial fungal inoculants into rice plants successfully.

Asunto(s)

RESUMEN

Optimum use of fertilizer plays an important role in increasing the performance of traits in rice and other agricultural products. The use of nano-fertilizers can be very important in the optimal use of fertilizer and in increasing the quantity and quality of agricultural products. To investigate the effect of iron and zinc nano-fertilizers on the physiological and morphological characteristics of rice plants (Tarom Hashemi variety) under drought stress conditions, a split plot experiment was carried out in the form of a randomized complete block design in three replications in Mazandaran region. The results of the combined analysis indicated that the effect of iron nano-fertilizer and zinc nano-fertilizer has a significant difference at the level of 0.01 and 0.05 in terms of all the evaluated traits. In the means comparison, it was concluded that normal humidity conditions can have a positive effect on the performance of the traits, but in the S1 stress conditions (drought stress at the rate of 50% of normal irrigation), the traits showed a good performance trend. Furthermore, increasing the amount of iron nano-fertilizer at the F2 level (Iron sulphate 100 kg/ha + 1 foliar spraying of iron chelate 2%) can be very effective in the growth of yield and the desirability of traits. In examining the amount of zinc nano-fertilizer consumption on the traits, showed the most positive performance on the traits at the level of Z2 (Use of 5 mg of zinc nano-fertilizer per kg of experiment soil), but with the increase to the level of Z3 (Use 7.5 mg of zinc nano-fertilizer per kg of experiment soil), this favorability was greatly reduced. The result of the correlation coefficients between the traits and the correlation diagram also showed a positive and significant correlation between the traits. In the graphical analysis, treatments tr33, tr8, tr19, tr24, tr7, tr6, and tr2 were selected as desirable treatments from the polygon graph. Treatments tr19, tr9 and tr6 were recognized as favourable treatments in terms of the treatment ranking diagram in terms of all traits. Based on the treatment selection diagram based on ideal treatment, tr19, tr9 and tr6 treatments were identified as desirable treatments. In general, it is possible to use tr19 (S1×F1×Z2), tr6 (N×F1×Z1) and tr9 (N×F2×Z0) treatments as treatments with high efficiency and power to increase the performance of traits and optimal use of nano-fertilizers in rice cultivation.

Asunto(s)

RESUMEN

Gamma radiation (60Co)-induced mutagenesis offers an alternative to develop rice lines by accelerating the spontaneous mutation process and increasing the pool of allelic variants available for breeding. Ionizing radiation works by direct or indirect damage to DNA and subsequent mutations. The technique can take advantage of in vitro protocols to optimize resources and accelerate the development of traits. This is achieved by exposing mutants to a selection agent of interest in controlled conditions and evaluating large numbers of plants in reduced areas. This chapter describes the protocol for establishing gamma radiation dosimetry and in vitro protocols for optimization at the laboratory level using seeds as the starting material, followed by embryogenic cell cultures, somatic embryogenesis, and regeneration. The final product of the protocol is a genetically homogeneous population of Oryza sativa that can be evaluated for breeding against abiotic and biotic stresses.

Asunto(s)

RESUMEN

Sulfur (S) is an essential macronutrient for plants and its availability in soils is an important determinant for growth and development. Current regulatory policies aimed at reducing industrial S emissions together with changes in agronomical practices have led to a decline in S contents in soils worldwide. Deficiency of sulfate-the primary form of S accessible to plants in soil-has adverse effects on both crop yield and nutritional quality. Hence, recent research has increasingly focused on unraveling the molecular mechanisms through which plants detect and adapt to a limiting supply of sulfate. A significant part of these studies involves the use of omics technologies and has generated comprehensive catalogs of sulfate deficiency-responsive genes and processes, principally in Arabidopsis together with a few studies centering on crop species such as wheat, rice, or members of the Brassica genus. Although we know that sulfate deficiency elicits an important reprogramming of the transcriptome, the transcriptional regulators orchestrating this response are not yet well understood. In this review, we summarize our current knowledge of gene expression responses to sulfate deficiency and recent efforts towards the identification of the transcription factors that are involved in controlling these responses. We further compare the transcriptional response and putative regulators between Arabidopsis and two important crop species, rice and tomato, to gain insights into common mechanisms of the response to sulfate deficiency.

Asunto(s)

RESUMEN

In order to investigate the stability of qualitative and quantitative traits and choose the most appropriate cultivation method and irrigation regime in rice plants, the experiment was conducted in the form of a split-plot design based on a randomized complete block design in three replications and in two cropping years. The results of compound analysis indicated that the effect of year × irrigation regimes in terms of traits, grain yield, rainfall, productivity 2, number of full grains, number of hollow grains, harvest index, percentage of crushed grains and yield of white rice, the effect of year × Cultivation method characteristics in terms of water consumption, rainfall, productivity 1, number of tillers, plant height, spike length, number of hollow grains, thousand seed weight, small grain percentage and white rice yield and the effect of irrigation regime × cultivation methods in terms of all Traits except traits productivity 2 were significant. The results of the mean comparison of the interaction effect of irrigation regimes and cultivation methods also showed that treatments T1W1, T2W1 and T1W3 are favorable for all evaluated traits. Based on the table of correlation coefficients, correlation diagram and map of the intensity of the correlation in the years of the experiment, it is possible to report the correlation of the grain yield trait with the traits of water consumption, rainfall, plant height, 100- seed weight, full grain number and white rice yield. Also, traits productivity 1, productivity 2 and small grain percentage showed a positive correlation and a negative correlation of these three traits with most of the traits evaluated in the experiment was observed. Based on the analysis of the main components, the first four main components explained the most data variance, and T2W2 and T2W3 treatments were identified as suitable treatments for rice cultivation in terms of the first and second main components.

Para investigar a estabilidade dos caracteres qualitativos e quantitativos e escolher o método de cultivo e regime de irrigação mais adequados em plantas de arroz, o experimento foi conduzido em esquema de parcelas subdivididas em blocos completos em três repetições e em dois anos de colheita. Os resultados da análise composta indicaram os seguintes fatores significativos: o efeito dos regimes de irrigação do ano X em termos de características, rendimento de grãos, pluviosidade, produtividade 2, número de grãos cheios, número de grãos ocos, índice de colheita, porcentagem de grãos esmagados e rendimento de arroz branco, o efeito do ano X, características do método de cultivo relativamente ao consumo de água, precipitação, produtividade 1, número de perfilhos, altura da planta, comprimento da espiga, número de grãos ocos, peso de 1000 sementes, porcentagem de grãos pequenos e rendimento de arroz branco e o efeito da irrigação no regime X, métodos de cultivo em relação a todos os caracteres, exceto os caracteres produtividade 2. Já os resultados da comparação média do efeito de interação entre regimes de irrigação e métodos de cultivo também mostraram que os tratamentos T1W1, T2W1 e T1W3 são favoráveis ​​para todas as características avaliadas. Com base na tabela de coeficientes de correlação, diagrama de correlação e mapa da intensidade da correlação nos anos do experimento, é possível relatar a correlação da característica produtividade de grãos com as características consumo de água, pluviosidade, altura de planta, 100 - peso da semente, número de grãos cheios e rendimento do arroz branco. Além disso, os caracteres produtividade 1, produtividade 2 e porcentagem de grãos pequenos apresentaram correlação positiva e foi observada correlação negativa desses 3 caracteres com a maioria dos caracteres avaliados no experimento. Por fim, com base na análise dos componentes principais, os quatro primeiros componentes principais explicaram a maior variância dos dados, e os tratamentos T2W2 e T2W3 foram identificados como tratamentos adequados para o cultivo de arroz quanto aos primeiro e segundo componentes principais.

Asunto(s)

RESUMEN

A split-plot experiment was conducted in a randomized complete block design with three replications in two cropping years at Mazandaran Rice Research Institute to study cultivation and irrigation regimes. The main factor is three-level irrigation regimes, permanent irrigation throughout the day (T1), irrigation two days after water disappears from the soil (T2) and permanent soil saturation (T3) the second factor is three-level cultivation methods., Plowless cultivation (W1), stack 60 cm (W2), and stack 80 cm (W3). Based on the results obtained from the combined analysis, the effect of the year was significant in terms of rainfall, productivity 2, number of tillers, number of empty grains, 1000-grain weight, percentage of the crushed grain, and white rice yield. The effect of the main factor was significant for all traits except productivity 1 and plant height. Based on the results of comparing the mean effect of year × treatment, four treatments, without plowing with permanent irrigation throughout the day in the first and second year of the experiment, cultivation without plowing with irrigation two days after water disappears from the soil in the second year of experiment and cultivation without Plowing with permanent saturated irrigation in the first and second years of the experiment was identified in terms of grain yield as suitable planting methods with appropriate irrigation regimes. Based on the results obtained from the polygon view in different years of the experiment, T3W1, T3W2, and T1W1 treatments can be suggested as desirable treatments in terms of irrigation regimes and cultivation methods in this rice cultivar. According to the ranking diagram of treatments based on traits in the years of experimentation, T1W1, T2W2 and T1W3 were introduced as the most desirable treatments for cultivating this rice cultivar.

Um experimento de parcelas subdivididas foi conduzido em um delineamento de blocos completos casualizados com três repetições em dois anos de cultivo no Mazandaran Rice Research Institute para estudar os regimes de cultivo e irrigação. O principal fator são os regimes de irrigação em três níveis, irrigação permanente ao longo do dia (T1), irrigação dois dias após o desaparecimento da água do solo (T2) e saturação permanente do solo (T3); o segundo fator são os métodos de cultivo em três níveis: cultivo sem arado (W1), empilhar 60 cm (W2) e empilhar 80 cm (W3). Com base nos resultados obtidos na análise combinada, o efeito do ano foi significativo em termos de precipitação pluviométrica, produtividade 2, número de perfilhos, número de grãos vazios, peso de 1.000 grãos, porcentagem de grãos triturados e rendimento de arroz branco. O efeito do fator principal foi significativo para todas as características, exceto produtividade 1 e altura de planta. Com base nos resultados da comparação do efeito médio ano x tratamento, quatro tratamentos, sem aração com irrigação permanente ao longo do dia no primeiro e segundo ano do experimento, cultivo sem aração com irrigação dois dias após o desaparecimento da água do solo no segundo ano de experimento e cultivo sem aração com irrigação saturada permanente no primeiro e segundo ano do experimento, foi identificado em termos de produtividade de grãos como métodos de plantio adequados com regimes de irrigação adequados. Com base nos resultados obtidos na visão poligonal em diferentes anos do experimento, os tratamentos T3W1, T3W2 e T1W1 podem ser sugeridos como tratamentos desejáveis ​​em termos de regimes de irrigação e métodos de cultivo nessa cultivar de arroz. De acordo com o diagrama de classificação dos tratamentos baseados em características nos anos de experimentação, T1W1, T2W2 e T1W3 foram introduzidos como os tratamentos mais desejáveis ​​para o cultivo dessa cultivar de arroz.

Asunto(s)

RESUMEN

Leptochloa chinensis (L.) Nees (Chinese sprangletop) is a weed that is becoming a serious threat in upland and lowland rice. A field study was conducted at the Agronomic Research Farm, University of Sargodha, Punjab, Pakistan, during the summer seasons of 2018 and 2019 to evaluate the effect of L. chinensis density on the yield of direct-seeded fine rice. Treatments comprised of L. chinensis densities of 0, 5, 10, 15, 20 and 25 plants m-2, and the experiment was laid out in a randomized complete block design with four replications of each treatment. The results suggest that the presence of L. chinensis significantly hampered the grain yield of direct-seeded rice. Weed infestation caused 63% and 69% yield losses where 25 L. chinensis plants m-2 were sustained in 2018 and 2019, respectively. Yield reduction was due to the reduction in 1000-grain weight (22.9 and 29.1%), number of tillers m-2 (65.8 and 60.0%), and number of grains panicle-1 (53.3 and 60%) in 2018 and 2019, respectively. The highest weed infestation (25 plants m-2) produced the highest weed dry biomass (687 and 669 g m-2), N uptake (19.3 and 19.3 kg ha-1), P uptake (1.92 and 2.32 kg ha-1), and K uptake (20.53 and 20.27 kg ha-1) in 2018 and 2019, respectively. The lowest weed infestation (5 plants m-2) produced minimum weed dry biomass (47 and 85 g m-2), N uptake (1.6 and 2.9), P uptake (0.3 and 0.5), and K uptake (1.7 and 30 kg ha-1) in 2018 and 2019, respectively. The economic threshold of L. chinensis as estimated to cause 6.73% and 6.08% yield loss by the prediction model was 1.70 and 1.73 plants m-2 during 2018 and 2019, respectively. It can be concluded that L. chinensis is a serious weed in direct-seeded rice and it should be controlled when its density reaches 1.70-1.73 plants m-2 to avoid significant yield losses.(AU)

Leptochloa chinensis (L.) Nees (chinese sprangletop) é uma planta daninha que está se tornando uma séria ameaça no arroz de terras altas e baixas. Um estudo de campo foi realizado na Fazenda de Pesquisa Agronômica, Universidade de Sargodha, Punjab, Paquistão, durante as estações de verão de 2018 e 2019 para avaliar o efeito da densidade de L. chinensis na produção de arroz fino de semeadura direta. Os tratamentos foram compostos por densidades de L. chinensis de 0, 5, 10, 15, 20 e 25 plantas m-2, e o experimento foi delineado em blocos casualizados com quatro repetições de cada tratamento. Os resultados sugerem que a presença de L. chinensis prejudicou significativamente a produtividade de grãos do arroz de semeadura direta. A infestação de ervas daninhas causou perdas de rendimento de 63% e 69%, onde 25 plantas de L. chinensis m-2 foram mantidas em 2018 e 2019, respectivamente. A redução da produtividade deveu-se à redução no peso de mil grãos (22,9 e 29,1%), número de perfilhos m-2 (65,8 e 60,0%) e número de panículas-1 (53,3 e 60%) em 2018 e 2019, respectivamente. A maior infestação de plantas daninhas (25 plantas m-2) produziu a maior biomassa seca de plantas daninhas (687 e 669 g m-2), absorção de N (19,3 e 19,3 kg ha-1), absorção de P (1,92 e 2,32 kg ha-1) , e absorção de K (20,53 e 20,27 kg ha-1) em 2018 e 2019, respectivamente. A menor infestação de plantas daninhas (5 plantas m-2) produziu biomassa seca mínima de plantas daninhas (47 e 85 g m-2), absorção de N (1,6 e 2,9), absorção de P (0,3 e 0,5) e absorção de K (1,7 e 30 kg ha-1) em 2018 e 2019, respectivamente. O limiar econômico de L. chinensis estimado para causar perda de rendimento de 6,73% e 6,08% pelo modelo de previsão foi de 1,70 e 1,73 plantas m-2 durante 2018 e 2019, respectivamente. Pode-se concluir que L. chinensis é uma planta daninha importante em arroz de semeadura direta e deve ser controlada quando sua densidade atingir 1,70-1,73 plantas m-2 para evitar perdas significativas de produtividade.(AU)

Asunto(s)

RESUMEN

Inoculation and co-inoculation of upland rice with multifunctional rhizobacteria can promote plant growth, especially the root system. Thus, this study aimed to evaluate the effect of inoculation and co-inoculation with Azospirillum sp. and Bacillus sp. in the early development of upland rice. The experiment was conducted using a completely randomized design with 4 treatments and 10 replications, totaling 40 plots. The treatments were: 1) Ab-V5 (Azospirillum brasilense), 2) BRM 63573 (Bacillus sp.), 3) co-inoculation of Ab-V5 + BRM 63573, and 4) control (without rhizobacteria). Inoculation and co-inoculation with the multifunctional rhizobacteria Ab-V5 and BRM 63573 provided positive effects on the initial development of upland rice. Inoculation with isolate BRM 63573 had significant effects on root length, shoot, and total biomass, while inoculation with isolate Ab-V5 had significant effects on root length and production of root and total biomass. Co-inoculation treatment had significant effects on variables such as diameter, volume, total surface, root biomass, and total biomass. The control treatment (without multifunctional rhizobacteria) had the worst results for most of the analyzed variables.

A inoculação e coinoculação do arroz de terras altas com rizobactérias multifuncionais pode promover o crescimento das plantas, especialmente do sistema radicular. Assim, este estudo teve como objetivo avaliar o efeito da inoculação e coinoculação com Azospirillum sp. e Bacillus sp. no desenvolvimento inicial do arroz de terras altas. O experimento foi conduzido em delineamento inteiramente casualizado com 4 tratamentos e 10 repetições, totalizando 40 parcelas. Os tratamentos foram: 1) Ab-V5 (Azospirillum brasilense), 2) BRM 63573 (Bacillus sp.), 3) coinoculação de Ab-V5 + BRM 63573 e 4) controle (sem rizobactérias). A inoculação e coinoculação com as rizobactérias multifuncionais Ab-V5 e BRM 63573 proporcionaram efeitos positivos no desenvolvimento inicial do arroz de terras altas. A inoculação com o isolado BRM 63573 teve efeitos significativos no comprimento da raiz, parte aérea e biomassa total, enquanto a inoculação com o isolado Ab-V5 teve efeitos significativos no comprimento da raiz e produção de raiz e biomassa total. O tratamento com coinoculação teve efeitos significativos em variáveis como diâmetro, volume e superfície total de raiz e biomassa de raiz e total. O tratamento controle (sem rizobactérias multifuncionais) apresentou os piores resultados para a maioria das variáveis analisadas.

Asunto(s)

RESUMEN

Among the multi-trait models selected to study several traits and environments jointly, the Bayesian framework has been a preferred tool when constructing a more complex and biologically realistic model. In most cases, non-informative prior distributions are adopted in studies using the Bayesian approach. However, the Bayesian approach presents more accurate estimates when informative prior distributions are used. The present study was developed to evaluate the efficiency and applicability of multi-trait multi-environment (MTME) models within a Bayesian framework utilizing a strategy for eliciting informative prior distribution using previous data on rice. The study involved data pertaining to rice (Oryza sativa L.) genotypes in three environments and five crop seasons (2010/2011 until 2014/2015) for the following traits: grain yield (GY), flowering in days (FLOR) and plant height (PH). Variance components, genetic and non-genetic parameters were estimated using the Bayesian method. In general, the informative prior distribution in Bayesian MTME models provided higher estimates of individual narrow-sense heritability and variance components, as well as minor lengths for the highest probability density interval (HPD), compared to their respective non-informative prior distribution analyses. More informative prior distributions make it possible to detect genetic correlations between traits, which cannot be achieved with non-informative prior distributions. Therefore, this mechanism presented to update knowledge for an elicitation of an informative prior distribution can be efficiently applied in rice breeding programs.

Asunto(s)

RESUMEN

Seed coating is an alternative delivery system for beneficial plant microorganisms into the soil. Although seed coats are widely used for the application of agrochemicals, the incorporation of beneficial microorganisms has not been explored deeply and their survival on seeds while in storage is unknown. The study aimed to evaluate the effect of the coating process on microbial survival and on plant growth promotion. Two coating formulations were designed, and assessed by two coating processes: rotating drum and fluidized bed. The rotating drum process resulted in more uniform coatings than in the fluidized bed process. In addition, with this coating technique, lower viability losses over time were observed. The rotatory drum prototype containing a biopolymer and a clay mineral derivate (P90) showed the best behavior at the three temperatures evaluated, with superior viabilities compared to the other prototypes and the lowest loss of viability after 12 months. The formulation of this coating prototype may preserve the viability of Trichoderma koningiopsis Th003 up to 15 months at 8 °C, 9 months at 18 °C, and 3 months at 28 °C, which are very promising shelf-life results. Regarding the effect of seed coating on plant growth, prototypes showed higher yields > 16% than the control, comparable to the conventional use of Tricotec® WG, which may reduce the number of applications and water consumption for dissolution of the inoculant. The results demonstrated that the formulation composition, as well as the coating process may impact the microbial survival on seeds.

Asunto(s)

RESUMEN

The objective of the study is to evaluate the evolution of the physical and physiological quality of rice seeds throughout the processing process, analyzing the efficiencyof the equipment used in three Seed Processing Units (UBS) to produce certified seeds, located in the region of the inner coastal plain of Lagoa dos Patos. We know that the seed has to be made in the field, starting with the choice of the area, providing a good management and controlling invaders, pests and diseases, but we believe that UBS has a very important role in seed quality, and this is the purpose of this study. Each unit with its equipment on its production line was analyzed. The cultivar IRGA 424 RI was used in the three units, samples were taken at the exit of each equipment, tests for seedling emergence, germination, physical purity and determination of other contaminatingspecies were carried out. A gradual increase in purity and germination was observed along the processing line in the three UBS’s, except for the determination of weedy rice, where equipment was not efficient.

O objetivo do estudo, é avaliar a evolução da qualidade física e fisiológica das sementes de arroz ao longo do processo de beneficiamento, analisando a eficiência dos equipamentos utilizados em trêsUnidades de Beneficiamentos de Sementes (UBS), de produção de sementes certificadas, localizadas na região da planície costeira interna da Lagoa dos Patos. Sabemos que asemente tem que ser feita no campo, começando pela escolha da área, proporcionando um bom manejo e controlando as invasoras, pragas e doenças, mas acreditamos que a UBS tem um papel muito importante na qualidade da semente e este é o propósito deste estudo. Foram analisadas cada unidade com seus equipamentos em sua linha de produção. Utilizou-se a cultivar IRGA 424 RI nas três unidades, as amostras foram feitas na saída de cada equipamento, realizou-se os testes de emergência de plântulas, germinação, pureza física e determinação de outras espécies contaminantes. Observou-se um aumento gradativo na pureza e germinação ao longo da linha de beneficiamento nas trêsUBS’s, exceto na determinação de arroz daninho, onde equipamentos não se mostraram eficientes.

Asunto(s)

RESUMEN

The objective of the study is to evaluate the evolution of the physical and physiological quality of rice seeds throughout the processing process, analyzing the efficiencyof the equipment used in three Seed Processing Units (UBS) to produce certified seeds, located in the region of the inner coastal plain of Lagoa dos Patos. We know that the seed has to be made in the field, starting with the choice of the area, providing a good management and controlling invaders, pests and diseases, but we believe that UBS has a very important role in seed quality, and this is the purpose of this study. Each unit with its equipment on its production line was analyzed. The cultivar IRGA 424 RI was used in the three units, samples were taken at the exit of each equipment, tests for seedling emergence, germination, physical purity and determination of other contaminatingspecies were carried out. A gradual increase in purity and germination was observed along the processing line in the three UBSs, except for the determination of weedy rice, where equipment was not efficient.(AU)

O objetivo do estudo, é avaliar a evolução da qualidade física e fisiológica das sementes de arroz ao longo do processo de beneficiamento, analisando a eficiência dos equipamentos utilizados em trêsUnidades de Beneficiamentos de Sementes (UBS), de produção de sementes certificadas, localizadas na região da planície costeira interna da Lagoa dos Patos. Sabemos que asemente tem que ser feita no campo, começando pela escolha da área, proporcionando um bom manejo e controlando as invasoras, pragas e doenças, mas acreditamos que a UBS tem um papel muito importante na qualidade da semente e este é o propósito deste estudo. Foram analisadas cada unidade com seus equipamentos em sua linha de produção. Utilizou-se a cultivar IRGA 424 RI nas três unidades, as amostras foram feitas na saída de cada equipamento, realizou-se os testes de emergência de plântulas, germinação, pureza física e determinação de outras espécies contaminantes. Observou-se um aumento gradativo na pureza e germinação ao longo da linha de beneficiamento nas trêsUBSs, exceto na determinação de arroz daninho, onde equipamentos não se mostraram eficientes.(AU)

Asunto(s)

RESUMEN

Endophytic bacteria Bacillus safensis RS95 and Pseudomonas hibiscicola RS121 were evaluated for their ability to promote the growth of rice seedlings and produce indole-acetic acid (IAA) and siderophores and to solubilize phosphates. 'Guri' rice seeds were immersed in bacterial endophyte cell suspensions (separated and two-strain mixed), as well as in Escherichia coli DH5α, phosphate-buffered saline (PBS) and water treatments (negative controls). Seeds were sown on agar-water in Petri plates placed vertically at an angle of 65°. The ability of plant growth-promoting endophytic bacteria (PGPEB) to produce IAA and siderophores was determined by Salkowski colorimetric and chrome azurol S (CAS) assays, respectively. Mineral phosphate solubilization activity was calculated by inoculating the endophytes onto medium containing insoluble phosphate. PGPEB showed a positive effect on the growth of rice seedlings, causing a mean growth of shoots and primary-roots of 60 and 67%, respectively. Bacterial strains also showed positive traits for IAA and siderophore production, as well as phosphate-solubilization activity

Asunto(s)