Initial development of upland rice inoculated and co-inoculated with multifunctional rhizobacteria / Desenvolvimento inicial de arroz de terras altas inoculado e coinoculado com rizobactérias multifuncionais

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.

Updating knowledge in estimating the genetics parameters: Multi-trait and Multi-Environment Bayesian analysis in rice

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.

Grain processing, adaptability, and stability of red rice cultivars / Beneficiamento de grãos, adaptabilidade e estabilidade de cultivares de arroz vermelho

Red rice is consumed in whole grain form due to its beneficial nutritional attributes and has become an option for crop diversification. Several factors during plant development can affect the crop'syield. This study evaluated the adaptability and stability of the post-harvest processing of red rice cultivars and compare them with those of white rice cultivars grown in the municipalities of Campos dos Goytacazes, Seropédica, and Pinheiral, RJ, between 2016 and 2018. Two white rice (BRS Esmeralda and IAC 201) and two red rice cultivars (ENA-AR1601 and Virginia) were distributed in the field under randomized block design with five repetitions. Yield, grain class, ingenuity, and whole grain yield were evaluated. The means of these parameters for cultivars in different locations and years were compared by Tukey's test (P < 0.05). The Eberhart and Russell regression model was used to estimate the adaptability and stability parameters. The grain classification of the cultivars ENA-AR1601 and Virginia was medium and long, respectively. The red rice cultivars ENA-AR 1601 and Virginia showed higher productive performance than the national average. The red rice cultivars and BRS Esmeralda showed highly predictable behavior based on the environmental stimulus. With average values of 62% in the two years evaluated, the red rice cultivars showed excellent processing yield.

O arroz vermelho é um tipo especial de arroz que devido a atributos benéficos a saúde é consumido na forma integral e tornou-se uma opção de diversificação de cultivo. Diversos fatores durante o desenvolvimento da planta podem afetar o rendimento de beneficiamento. Com isso, o objetivo deste trabalho foi avaliar a adaptabilidade, estabilidade e beneficiamento de grãos de cultivares de arroz vermelho e compará-la a de arroz branco produzidas nos municípios de Campos dos Goytacazes, Seropédica e Pinheiral, RJ, durante os anos agrícolas de 2016/2017 e 2017/2018. Os tratamentos foram duas cultivares de arroz branco (BRS Esmeralda e IAC 201) e duas de arroz vermelho (ENA-AR1601 e Virgínia), distribuídos no campo sob o delineamento em blocos ao acaso, com cinco repetições. Foram avaliadas a produtividade, classe do grão, o rendimento de engenho e de grãos inteiros. As médias das cultivares em diferentes locais e anos foram comparadas pelo teste de Tukey (P< 0,05). Foi adotada a metodologia recomendada por Eberhart e Russell para estimativa dos parâmetros de adaptabilidade e estabilidade. A classificação dos grãos das cultivares ENA-AR1601 e Virgínia foi médio e longo, respectivamente. As cultivares de arroz vermelho ENA-AR 1601 e Virgínia apresentaram desempenho produtivo superior a média nacional. As cultivares de arroz vermelho e BRS Esmeralda apresentaram comportamento altamente previsível de acordo ao estímulo ambiental. Com valores médios de 62%, nos dois anos avaliados, as cultivares de arroz vermelho apresentaram excelente rendimento de beneficiamento.

Endophytic bacteria Bacillus safensis and Pseudomonas hibiscicola and their ability to increase rice seedling growth

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

Low fertilizer inputs do not adversely affect yield or performance of Indica hybrid rice

The enhancement of rice production numbers can be achieved by using quality rice cultivars and fertilizers. The double rice cropping model has given rise to an important rice production system in southern China. Exploring the possibility of whether hybrid vigor could make a substantial contribution to early and late season rice production, and how the heterosis expression of hybrid rice functions under different levels of fertilizer application is of great significance. The objective of this study was to evaluate the grain yield and associated plant traits of popular hybrid and inbred rice varieties with large-scale promotion under conditions of customary (high) and combined (low) fertilization in the early and late seasons of 2017-18 in Changsha County, Hunan Province, China. We found that hybrid rice varieties displayed their respective advantages in the early and late rice seasons, but the advantages in their relative yield traits varied. The leading advantages of early season rice were effective panicle number per hill (EPN), 1000-grain weight (KGW), harvest index (HI), yield, and nitrogen use efficiency (NUE), whereas in late season rice, the foremost advantages were grain number per panicle (GNP), HI, yield, and NUE. The EPN was the prime advantage of early season hybrid rice with a short growth period, and the GNP was the main advantage of late season hybrid rice with a long growth period. Notably, the main yield advantage of hybrid rice was stronger under combined (low) fertilization than under customary (high) fertilization. Hence, high yield can be achieved by selecting the best hybrid rice varieties supported by combined fertilization (lower fertilizer use with higher efficiency).

Physiological quality of irrigated rice seeds benefited in different UBSin the internal coastal plain of Lagoa dos Patos / Qualidade fisiológica de sementes de arroz irrigado beneficiadas em diferentes UBS’sda planície litorânea interna da Lagoa dos Patos

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.

OsYUCCA2 deficiency in rice growth and development / Influência da deficiência de OsYUCCA2 no crescimento e desenvolvimento do arroz

YUCCA (YUC) proteins have critical roles in plant growth and development through their involvement in auxin production. Rice (Oryza sativa L. cv Nipponbare) has 14 OsYUC proteins, but little is known regarding their functional redundancy. In this study, transgenic rice seedlings expressing GUS-tagged antisense-OsYUC2 under the control of the ubiquitin promoter were used to investigate the effects of OsYUC2 deficiency on seedling growth and development. GUS staining showed that antisense-OsYUC2 was expressed primarily in rapidly dividing cells in callus, vegetative, and reproductive tissues. Phenotypic analysis showed that callus differentiation was compromised in OsYUC2 antisense rice. Adverse vegetative effects were observed in shoot height and embryonic, adventitious, and lateral root numbers. Reproductive tissues were also impacted, with reductions in panicle length, flower number, seed setting number, seed setting rate, and grain weight. Auxin analysis showed that indole-3-acetic acid (IAA) levels were reduced in OsYUC2 antisense rice, and exogenous addition of 3-indolebutyric acid (IBA, an analogue of IAA) partially rescued defective growth phenotypes. Taken together, these results indicated that deficiency of OsYUC2 impairs auxin biosynthesis, thereby affecting rice growth and development.

As proteínas YUCCA (YUC) possuem importantes papéis no crescimento e desenvolvimento das plantas por meio de seu envolvimento na produção de auxinas. O arroz (Oryza sativa L. cv Nipponbare) possui 14 proteínas OsYUC, no entanto, pouco se sabe a respeito da sua redundância funcional. No presente estudo, mudas de arroz transgênico expressando OsYUC2 anti-senso com tag-GUS sob o controle do promotor de ubiquitina foram utilizadas para investigar os efeitos da deficiência de OsYUC2 no crescimento e desenvolvimento de mudas. As manchas de GUS indicaram que OsYUC2 anti-senso foi expressado primordialmente em células que se dividem rapidamente através de calos, tecidos vegetativos e reprodutivos. A análise fenotípica indicou que a diferenciação do calo foi comprometida no arroz OsYUC2 anti-senso. Os efeitos vegetativos adversos foram observados na altura do rebento e no número de raízes embrionárias, adventícias e laterais. Os tecidos reprodutivos também foram impactados, com reduções no comprimento da panícula, número de flores, número de sementes, proporção de sementes e peso de grão. A análise de auxina ilustrou que os níveis de ácido indol-3-acético (IAA) foram reduzidos no arroz anti-senso OsYUC2 e a adição exógena de ácido 3-indolbutírico (IBA, um análogo de IAA) resgatou parcialmente os fenótipos de crescimento defeituosos. Em conjunto, tais resultados indicam que a deficiência de OsYUC2 prejudica a biossíntese de auxina, afetando o crescimento e o desenvolvimento do arroz.

Physiological quality of irrigated rice seeds benefited in different UBSin the internal coastal plain of Lagoa dos Patos / Qualidade fisiológica de sementes de arroz irrigado beneficiadas em diferentes UBSsda planície litorânea interna da Lagoa dos Patos

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)

Silicon as an attenuator of drought stress in plants of Oryza sativa L. treated with dietholate / Silício como atenuador de estresse hídrico em plantas de Oryza sativa L. tratadas com dietholate

Silicon (Si) is an element that can improve the growth and development of rice plants in water-deficient environments because it is an enzymatic stimulant, signaling for production of antioxidant compounds. Therefore, the aim of this study was to examine the relationship between water deficiency and the effect of Si on two rice cultivars whose seeds were treated with dietholate. The experimental design was fully randomized with three replicates, and treatments were organized in a 3x2x2x4 factorial arrangement: three water soil conditions (50% and 100% of soil water retention capacity (WRC) and complete submergence in a water blade of 5.0 cm); two cultivars (IRGA 424 RI and Guri INTA CL); two sources of Si (sodium metasilicate and potassium metasilicate); and four rates of Si (0; 4.0; 8.0 and 16 g L-1). Chlorophyll a and b, leaf area and shoot and root dry weight increased at higher rates of Si under the three soil water regimes. There was an increase in superoxide dismutase and guaiacol peroxidase enzyme activity in the cultivars at higher rates of Si, reducing lipid peroxidation caused by water deficiency. Therefore, Si did indeed attenuate water deficiency stress in rice plants emerging from seeds treated with dietholate.(AU)

O silício (Si) é um elemento que pode proporcionar melhor crescimento e desenvolvimento às plantas de arroz cultivadas em ambientes com deficiência hídrica, por ser um estimulador enzimático, promovendo sinalização para produção de compostos antioxidantes. Assim, o objetivo deste trabalho foi estudar a relação entre deficiência hídrica e o efeito do Si em duas cultivares de arroz tratadas com dietholate. O delineamento experimental utilizado foi inteiramente casualizado, com três repetições e os tratamentos arranjados em esquema fatorial 3x2x2x4, sendo os fatores: três condições hídricas do solo (50%, 100% da capacidade de retenção de água no solo (CRA) e lâmina dágua de 5,0 cm), duas cultivares (IRGA 424 RI e Guri INTA CL), duas fontes de Si (metassilicato de sódio e metassilicato de potássio) e quatro doses de Si (0; 4,0; 8,0 e 16 g L-1). O índice de clorofila a e b, a área foliar e o teor de massa seca da parte aérea e raiz aumentaram com o aumento das doses de Si nas três condições hídricas do solo. Houve um aumento na atividade das enzimas superóxido dismutase e guaiacol peroxidase nas cultivares estudadas à medida que as doses de Si aumentaram, diminuindo a peroxidação de lipídios, causada pela restrição hídrica. Portanto, o Si atenua o estresse por déficit hídrico em plantas de arroz emergentes de sementes tratadas com dietholate.(AU)

Accelerated aging predicts the emergence of rice seedlings in the field / Envelhecimento acelerado prediz a emergência de plântulas de arroz em campo

Selecting the most appropriate vigor test for rice to predict seedling emergence remains a challenge. This is mainly attributed to the diversity of available tests that evaluate vigor; however, there is a critical need for tests that can show a high correlation with field emergence. Thus, this study aimed to determine which vigor tests are the most efficient in predicting the emergence of rice seedlings, to facilitate correct selection for quality control analyses and pre-sowing for rice seed commercialization. Across two growing seasons, 2016/17 and 2017/18, different seed lots of ‘SCS122 Miura’ rice were subjected to vigor evaluations including germination test, electrical conductivity, cold test, low temperature germination, accelerated aging, root and shoot length, seedling dry weight, emergence speed, and emergence speed index, and greenhouse and field emergence tests. A completely randomized design with four replicates was used for the experiments. All statistical analyses were performed using R software. The germination rate for ‘SCS122 Miura’ seed lots in both growing seasons was greater than 80%. In both growing seasons, unlike the similar results obtained for field emergence, in the laboratory tests, differences were observed between these same seed lots. Electrical conductivity and emergence speed showed a negative correlation with greenhouse and field emergence. The vigor tests for accelerated aging, emergence speed, and dry weight are more efficient in predicting the emergence of rice seedlings. Among the tested methods, accelerated aging (41 °C for 120 h) is one of the most efficient for predicting the emergence of rice seedlings and the best option for laboratory analysis of quality control and pre-sowing owing to its practicality and time required for execution.

A seleção do teste de vigor mais adequado para o arroz para prever a emergência de plântulas permanece um desafio. Isso é atribuído principalmente à diversidade de testes disponíveis que avaliam o vigor; entretanto, há uma necessidade crítica de testes que mostrem uma alta correlação com a emergência a campo. Assim, o presente trabalho teve como objetivo determinar quais testes de vigor são mais eficientes em predizer a emergência de plântulas de arroz, a fim de facilitar a seleção para análises de controle de qualidade e pré-semeadura para comercialização de sementes de arroz. Ao longo de duas safras, 2016/17 e 2017/18, diferentes lotes de sementes de arroz 'SCS122 Miura' foram submetidos a avaliações de vigor, incluindo teste de germinação, condutividade elétrica, teste de frio, germinação a baixa temperatura, envelhecimento acelerado, comprimento de raiz e parte aérea, peso seco de plântula, velocidade de emergência e índice de velocidade de emergência e testes de emergência em casa de vegetação e em campo. O delineamento inteiramente casualizado com quatro repetições foi utilizado para os experimentos. Todas as análises estatísticas foram realizadas com o software R. A taxa de germinação para lotes de sementes 'SCS122 Miura' em ambas as safras foi superior a 80%. Em ambas as safras, diferentes dos resultados semelhantes para a emergência em campo, nos testes de laboratório, foram observadas diferenças entre esses mesmos lotes de sementes. A condutividade elétrica e a velocidade de emergência apresentaram correlação negativa com a emergência em casa de vegetação e no campo. Os testes de vigor pelo envelhecimento acelerado, velocidade de emergência e massa seca são mais eficientes na previsão da emergência de plântulas de arroz. Dentre os métodos testados, o envelhecimento acelerado (41 ° C por 120 h) é um dos mais eficientes para predizer a emergência de plântulas de arroz e a melhor opção para análises [...].

Accelerated aging predicts the emergence of rice seedlings in the field / Envelhecimento acelerado prediz a emergência de plântulas de arroz em campo

Selecting the most appropriate vigor test for rice to predict seedling emergence remains a challenge. This is mainly attributed to the diversity of available tests that evaluate vigor; however, there is a critical need for tests that can show a high correlation with field emergence. Thus, this study aimed to determine which vigor tests are the most efficient in predicting the emergence of rice seedlings, to facilitate correct selection for quality control analyses and pre-sowing for rice seed commercialization. Across two growing seasons, 2016/17 and 2017/18, different seed lots of ‘SCS122 Miura rice were subjected to vigor evaluations including germination test, electrical conductivity, cold test, low temperature germination, accelerated aging, root and shoot length, seedling dry weight, emergence speed, and emergence speed index, and greenhouse and field emergence tests. A completely randomized design with four replicates was used for the experiments. All statistical analyses were performed using R software. The germination rate for ‘SCS122 Miura seed lots in both growing seasons was greater than 80%. In both growing seasons, unlike the similar results obtained for field emergence, in the laboratory tests, differences were observed between these same seed lots. Electrical conductivity and emergence speed showed a negative correlation with greenhouse and field emergence. The vigor tests for accelerated aging, emergence speed, and dry weight are more efficient in predicting the emergence of rice seedlings. Among the tested methods, accelerated aging (41 °C for 120 h) is one of the most efficient for predicting the emergence of rice seedlings and the best option for laboratory analysis of quality control and pre-sowing owing to its practicality and time required for execution.(AU)

A seleção do teste de vigor mais adequado para o arroz para prever a emergência de plântulas permanece um desafio. Isso é atribuído principalmente à diversidade de testes disponíveis que avaliam o vigor; entretanto, há uma necessidade crítica de testes que mostrem uma alta correlação com a emergência a campo. Assim, o presente trabalho teve como objetivo determinar quais testes de vigor são mais eficientes em predizer a emergência de plântulas de arroz, a fim de facilitar a seleção para análises de controle de qualidade e pré-semeadura para comercialização de sementes de arroz. Ao longo de duas safras, 2016/17 e 2017/18, diferentes lotes de sementes de arroz 'SCS122 Miura' foram submetidos a avaliações de vigor, incluindo teste de germinação, condutividade elétrica, teste de frio, germinação a baixa temperatura, envelhecimento acelerado, comprimento de raiz e parte aérea, peso seco de plântula, velocidade de emergência e índice de velocidade de emergência e testes de emergência em casa de vegetação e em campo. O delineamento inteiramente casualizado com quatro repetições foi utilizado para os experimentos. Todas as análises estatísticas foram realizadas com o software R. A taxa de germinação para lotes de sementes 'SCS122 Miura' em ambas as safras foi superior a 80%. Em ambas as safras, diferentes dos resultados semelhantes para a emergência em campo, nos testes de laboratório, foram observadas diferenças entre esses mesmos lotes de sementes. A condutividade elétrica e a velocidade de emergência apresentaram correlação negativa com a emergência em casa de vegetação e no campo. Os testes de vigor pelo envelhecimento acelerado, velocidade de emergência e massa seca são mais eficientes na previsão da emergência de plântulas de arroz. Dentre os métodos testados, o envelhecimento acelerado (41 ° C por 120 h) é um dos mais eficientes para predizer a emergência de plântulas de arroz e a melhor opção para análises [...].(AU)

Initial development of upland rice plants inoculated with the MAY12 strain of Azospirillum spp / Desenvolvimento inicial de plantas de arroz de terras altas inoculadas com a estirpe MAY12 de Azospirillum spp

The purpose of this study was to evaluate the contribution of the inoculation of the strain Azospirillum MAY12 to the development of rice plants of the cultivar BRS Esmeralda. A completely randomized experiment was performed in a greenhouse, with 8 treatments and 6 repetitions, namely, commercial inoculant (CI) containing strains of Azospirillum brasilense ABV5 and ABV6 (T1), MAY12 (T2), nitrogen control with 50 mg of N or full dose (T3), CI + 30% of N (percentage referring to full dose) (T4), CI + 60% N (T5), MAY12 + 30% N (T6), MAY12 + 60% N (T7) and absolute control (T8). There was a significant increase in the fresh and dry mass of the shoot and roots, height, root volume, and the number of tillers and leaves of plants with the MAY12 inoculation (with and without N added) compared to T8. Treatments containing MAY12 + N increased the total dry mass by ~920% compared to T8, matching the T3 yield. The inoculation of MAY12 in isolation was as efficient as the application of the full dose of N, resulting in an increase of ~115% in height and 373% in root volume of the plants compared to T8. The MAY12 strain demonstrated good performance in the development of the cultivar, which was comparable to the CI in the variables tested. Therefore, inoculation with the MAY12 strain is promising for the partial reduction of nitrogen fertilizers in upland rice cultivation.

O objetivo deste trabalho foi avaliar a contribuição da inoculação da estirpe de Azospirillum MAY12 no desenvolvimento de plantas de arroz da cultivar BRS Esmeralda. Foi realizado um experimento inteiramente casualizado em casa de vegetação, tendo oito tratamentos e seis repetições: inoculante comercial (IC) contendo as estirpes de Azospirillum brasilense AbV5 e AbV6 (T1), MAY12 (T2), testemunha nitrogenada com 50 mg de N ou dose cheia (T3), IC + 30% de N (percentual referente à dose cheia) (T4), IC + 60% de N (T5), MAY12 + 30% de N (T6), MAY12 + 60% de N (T7) e testemunha absoluta (T8). Houve aumento significativo da massa fresca e seca da parte aérea e de raízes, altura, volume de raízes e do número de perfilhos e de folhas das plantas com a inoculação de MAY12 (com e sem adição de N) em relação a T8. Os tratamentos contendo MAY12 + N aumentaram em torno de 920% a massa seca total em relação a T8, equiparando-se ao rendimento T3. A inoculação de MAY12, isoladamente, foi tão eficiente quanto a aplicação da dose cheia de N para o aumento em torno de 115% da altura e de 373% do volume de raízes das plantas em relação a T8. A estirpe MAY12 apresentou bom desempenho no desenvolvimento da cultivar equiparando-se com o IC nas variáveis testadas. Portanto, a inoculação com a estirpe MAY12 mostra-se promissora para a redução parcial de fertilizantes nitrogenados no cultivo de arroz de terras altas.

Initial development of upland rice plants inoculated with the MAY12 strain of Azospirillum spp / Desenvolvimento inicial de plantas de arroz de terras altas inoculadas com a estirpe MAY12 de Azospirillum spp

The purpose of this study was to evaluate the contribution of the inoculation of the strain Azospirillum MAY12 to the development of rice plants of the cultivar BRS Esmeralda. A completely randomized experiment was performed in a greenhouse, with 8 treatments and 6 repetitions, namely, commercial inoculant (CI) containing strains of Azospirillum brasilense ABV5 and ABV6 (T1), MAY12 (T2), nitrogen control with 50 mg of N or full dose (T3), CI + 30% of N (percentage referring to full dose) (T4), CI + 60% N (T5), MAY12 + 30% N (T6), MAY12 + 60% N (T7) and absolute control (T8). There was a significant increase in the fresh and dry mass of the shoot and roots, height, root volume, and the number of tillers and leaves of plants with the MAY12 inoculation (with and without N added) compared to T8. Treatments containing MAY12 + N increased the total dry mass by ~920% compared to T8, matching the T3 yield. The inoculation of MAY12 in isolation was as efficient as the application of the full dose of N, resulting in an increase of ~115% in height and 373% in root volume of the plants compared to T8. The MAY12 strain demonstrated good performance in the development of the cultivar, which was comparable to the CI in the variables tested. Therefore, inoculation with the MAY12 strain is promising for the partial reduction of nitrogen fertilizers in upland rice cultivation.(AU)

O objetivo deste trabalho foi avaliar a contribuição da inoculação da estirpe de Azospirillum MAY12 no desenvolvimento de plantas de arroz da cultivar BRS Esmeralda. Foi realizado um experimento inteiramente casualizado em casa de vegetação, tendo oito tratamentos e seis repetições: inoculante comercial (IC) contendo as estirpes de Azospirillum brasilense AbV5 e AbV6 (T1), MAY12 (T2), testemunha nitrogenada com 50 mg de N ou dose cheia (T3), IC + 30% de N (percentual referente à dose cheia) (T4), IC + 60% de N (T5), MAY12 + 30% de N (T6), MAY12 + 60% de N (T7) e testemunha absoluta (T8). Houve aumento significativo da massa fresca e seca da parte aérea e de raízes, altura, volume de raízes e do número de perfilhos e de folhas das plantas com a inoculação de MAY12 (com e sem adição de N) em relação a T8. Os tratamentos contendo MAY12 + N aumentaram em torno de 920% a massa seca total em relação a T8, equiparando-se ao rendimento T3. A inoculação de MAY12, isoladamente, foi tão eficiente quanto a aplicação da dose cheia de N para o aumento em torno de 115% da altura e de 373% do volume de raízes das plantas em relação a T8. A estirpe MAY12 apresentou bom desempenho no desenvolvimento da cultivar equiparando-se com o IC nas variáveis testadas. Portanto, a inoculação com a estirpe MAY12 mostra-se promissora para a redução parcial de fertilizantes nitrogenados no cultivo de arroz de terras altas.(AU)

Upland rice: phenotypic diversity for drought tolerance

Upland rice is cultivated mostly in Latin America and Africa by small farmers and in areas with risk of dry spells. This study evaluated morphophysiological mechanisms of upland rice associated to drought adaptation. A set of 25 upland rice genotypes were grown in a plant phenotyping platform during 2015 and 2017 under regular irrigation and water restriction. We evaluated morphophysiological traits in shoots (vegetative structures growth, gas exchange, water use efficiency, carboxylation efficiency, water status) and roots (length, surface area, volume and diameter), as well as agronomic traits (grain yield and its components). There was a reduction in grain yield by up to 54 % and 58 % in 2015 and 2017, respectively, under water deficit. Five upland rice genotypes with the best yield performances in both water treatments applied were recommended to the upland rice-breeding program: Bico Ganga, BRS Esmeralda, BRSMG Curinga, Guarani, and Rabo de Burro. In this study, morphophysiological traits associated to drought tolerance concerned the plant high capacity to save water in the leaves, low leaf water potential, high ability to reduce vegetative structures, high water use efficiency, high photosynthetic capacity, and improved capacity to absorb water from drying soil, either by osmotic adjustment or additional investment into the root system. Therefore, we concluded that different secondary traits contributed to drought tolerance and should be evaluated along with grain yield to improve efficiency of breeding selection.(AU)

Upland rice: phenotypic diversity for drought tolerance

Upland rice is cultivated mostly in Latin America and Africa by small farmers and in areas with risk of dry spells. This study evaluated morphophysiological mechanisms of upland rice associated to drought adaptation. A set of 25 upland rice genotypes were grown in a plant phenotyping platform during 2015 and 2017 under regular irrigation and water restriction. We evaluated morphophysiological traits in shoots (vegetative structures growth, gas exchange, water use efficiency, carboxylation efficiency, water status) and roots (length, surface area, volume and diameter), as well as agronomic traits (grain yield and its components). There was a reduction in grain yield by up to 54 % and 58 % in 2015 and 2017, respectively, under water deficit. Five upland rice genotypes with the best yield performances in both water treatments applied were recommended to the upland rice-breeding program: Bico Ganga, BRS Esmeralda, BRSMG Curinga, Guarani, and Rabo de Burro. In this study, morphophysiological traits associated to drought tolerance concerned the plant high capacity to save water in the leaves, low leaf water potential, high ability to reduce vegetative structures, high water use efficiency, high photosynthetic capacity, and improved capacity to absorb water from drying soil, either by osmotic adjustment or additional investment into the root system. Therefore, we concluded that different secondary traits contributed to drought tolerance and should be evaluated along with grain yield to improve efficiency of breeding selection.

Épocas e densidades de semeadura sobre o desempenho agronômico do arroz irrigado no sistema pré-germinado / Sowing time and density on the agronomic performance of irrigated rice in the pre germinated system

Nos últimos anos, os produtores de arroz irrigado do Litoral Sul de Santa Catarina têm antecipado a semeadura da cultura para o início do mês de setembro, visando viabilizar o cultivo do rebrote. Paralelamente a isto, eles têm aumentado a densidade de semeadura para compensar o menor crescimento da cultura. Este trabalho foi conduzido com o objetivo de analisar os efeitos da época e densidade de semeadura sobre o desempenho agronômico do arroz no sistema pré-germinado. O experimento foi implantado no município de Praia Grande, SC, na safra 2018/2019. O trabalho foi conduzido no delineamento experimental de blocos ao acaso, arranjados em parcelas subdivididas. Na parcela principal testaram-se três épocas de semeadura: 10/09 (semeadura antecipada), 15/10 (semeadura preferencial) e 20/11 (semeadura tardia). Nas subparcelas avaliaram-se quatro densidades de semeadura: 80, 120, 160 e 200 kg de sementes ha-1. Foram avaliados caracteres morfológicos, o rendimento de grãos e seus componentes. O rendimento de grãos variou de 6.277 a 9.605 kg ha-1 e foi afetado pela interação entre época e densidade de semeadura. A máxima produtividade foi obtida com a semeadura feita na época preferencial, com densidade de 120 kg ha-1. Na semeadura antecipada, o rendimento aumentou linearmente 12,54 kg ha-1 para cada kg de sementes adicionado à menor densidade. A máxima produtividade obtida nesta época de semeadura foi de 7.858 kg ha-1 com 200 kg ha-1 de sementes. A densidade de semeadura teve pouco impacto sobre a produtividade na semeadura tardia. Nesta época de semeadura, o maior rendimento (8.546 kg ha-1) foi registrado na densidade de 120 kg ha-1. A densidade ótima para maximizar a produtividade do arroz pré-germinado no Litoral Sul de Santa Catarina depende da época de semeadura, sendo mais alta quando a cultura é semeada antecipadamente.

In recent years, paddy rice growers from the south of Santa Catarina, Brazil, have anticipated the sowing date to the beginning of September, aiming to harvest the crop ratoon. In addition to that, they have increased the sowing density to mitigate the smaller plant growth. The objective of this work was to analyze the effects of sowing time and density on the agronomic performance of pregerminated rice. Theexperiment was set in the city of Praia Grande, SC, Brazil, during the 2018/2019 growing season. A randomized block design was used, with treatments arranged in split plots. Three sowing dates were tested in the main plots: September 10 (early sowing), October 15 (preferential sowing), and November 20 (late sowing). Four sowing densities were evaluated in the split plots: 80 kg, 120 kg, 160 kg, and 200 kg of seeds per hectare. Morphological characteristics and the yield and components of grains were assessed.Grain yield ranged from 6,277 kg ha-1 to 9,605 kg ha-1 and was affected by the interaction between sowingdate and density. The highest yield was achieved when rice was sowed on October 15 at the density of 120 kg ha-1. On the earliest sowing date, grain yield increased linearly by 12.54 kg ha-1 for each kg of added seed above the lowest density evaluated in the trial. The highest grain productivity achieved on this sowing date was 7,858 kg ha-1. Plant density had a small impact on rice yield at the latest sowing date. The highest yield at this planting time (8,546 kg ha-1) was gathered at the density of 120 kg ha-1. The optimum seed density to maximize pregerminated rice yield in the south of Santa Catarina depends on thesowing date and is higher when the crop is sowed early.

Épocas e densidades de semeadura sobre o desempenho agronômico do arroz irrigado no sistema pré-germinado / Sowing time and density on the agronomic performance of irrigated rice in the pre germinated system

Nos últimos anos, os produtores de arroz irrigado do Litoral Sul de Santa Catarina têm antecipado a semeadura da cultura para o início do mês de setembro, visando viabilizar o cultivo do rebrote. Paralelamente a isto, eles têm aumentado a densidade de semeadura para compensar o menor crescimento da cultura. Este trabalho foi conduzido com o objetivo de analisar os efeitos da época e densidade de semeadura sobre o desempenho agronômico do arroz no sistema pré-germinado. O experimento foi implantado no município de Praia Grande, SC, na safra 2018/2019. O trabalho foi conduzido no delineamento experimental de blocos ao acaso, arranjados em parcelas subdivididas. Na parcela principal testaram-se três épocas de semeadura: 10/09 (semeadura antecipada), 15/10 (semeadura preferencial) e 20/11 (semeadura tardia). Nas subparcelas avaliaram-se quatro densidades de semeadura: 80, 120, 160 e 200 kg de sementes ha-1. Foram avaliados caracteres morfológicos, o rendimento de grãos e seus componentes. O rendimento de grãos variou de 6.277 a 9.605 kg ha-1 e foi afetado pela interação entre época e densidade de semeadura. A máxima produtividade foi obtida com a semeadura feita na época preferencial, com densidade de 120 kg ha-1. Na semeadura antecipada, o rendimento aumentou linearmente 12,54 kg ha-1 para cada kg de sementes adicionado à menor densidade. A máxima produtividade obtida nesta época de semeadura foi de 7.858 kg ha-1 com 200 kg ha-1 de sementes. A densidade de semeadura teve pouco impacto sobre a produtividade na semeadura tardia. Nesta época de semeadura, o maior rendimento (8.546 kg ha-1) foi registrado na densidade de 120 kg ha-1. A densidade ótima para maximizar a produtividade do arroz pré-germinado no Litoral Sul de Santa Catarina depende da época de semeadura, sendo mais alta quando a cultura é semeada antecipadamente.(AU)

In recent years, paddy rice growers from the south of Santa Catarina, Brazil, have anticipated the sowing date to the beginning of September, aiming to harvest the crop ratoon. In addition to that, they have increased the sowing density to mitigate the smaller plant growth. The objective of this work was to analyze the effects of sowing time and density on the agronomic performance of pregerminated rice. Theexperiment was set in the city of Praia Grande, SC, Brazil, during the 2018/2019 growing season. A randomized block design was used, with treatments arranged in split plots. Three sowing dates were tested in the main plots: September 10 (early sowing), October 15 (preferential sowing), and November 20 (late sowing). Four sowing densities were evaluated in the split plots: 80 kg, 120 kg, 160 kg, and 200 kg of seeds per hectare. Morphological characteristics and the yield and components of grains were assessed.Grain yield ranged from 6,277 kg ha-1 to 9,605 kg ha-1 and was affected by the interaction between sowingdate and density. The highest yield was achieved when rice was sowed on October 15 at the density of 120 kg ha-1. On the earliest sowing date, grain yield increased linearly by 12.54 kg ha-1 for each kg of added seed above the lowest density evaluated in the trial. The highest grain productivity achieved on this sowing date was 7,858 kg ha-1. Plant density had a small impact on rice yield at the latest sowing date. The highest yield at this planting time (8,546 kg ha-1) was gathered at the density of 120 kg ha-1. The optimum seed density to maximize pregerminated rice yield in the south of Santa Catarina depends on thesowing date and is higher when the crop is sowed early.(AU)

Microdochium albescens may affect the physiological quality of irrigated rice cultivar seeds / Microdochium albescens pode afetar a qualidade fisiológica de sementes de cultivares de arroz irrigado

Knowledge of the effect of the seedborne inoculum is important for knowing the level of tolerance of the pathogen by the seed. This research evaluated the effect of the incidence of the fungus Microdochium albescens on the physiological quality of the seeds of different cultivars of irrigated rice. The study was carried out in the seed testing laboratory (STL), phytopathology laboratory and in greenhouse, located at the Center of Agroveterinary Sciences of the Santa Catarina State University, Lages, SC, Brazil. Seeds from six irrigated rice cultivars produced in the Alto Vale do Itajaí Region in the 2016/17 harvest, were used. The lots were submitted to the seed health test, identifying four lots per cultivar with a natural incidence of M. albescens, with two lots of each cultivar with an incidence greater than 40% and two lots equal or less than 40%, totaling 24 seed lots. The following evaluations were carried out on the lots: germination, accelerated aging test, emergence in a greenhouse at 14 days, emergence speed index (ESI), emergence speed (ES), shoot length, root length and fresh and dry mass. There was a significant interaction between cultivar and level of incidence only in the variables germination, vigor and root length. Fresh mass, shoot length and ESI were not affected, regardless of cultivar and incidence of fungus in the seed. The irrigated rice cultivars SCS118 Marquês and SCSBRS Tio Taka are susceptible to a high incidence (> 40%) of the fungus M. allbescens.(AU)

O conhecimento do efeito do inóculo na semente é importante para conhecimento do nível de tolerância do patógeno pela semente. Objetivo deste trabalho foi avaliar o efeito da incidência do fungo Microdochium allbescens sobre a qualidade fisiológica das sementes de diferentes cultivares de arroz irrigado. O estudo foi realizado nos laboratórios de análises de sementes (LAS), fitopatologia e na casa de vegetação, localizados no Centro de Ciências Agroveterinárias da Universidade do Estado de Santa Catarina, Lages, SC. Utilizaram-se sementes de seis cultivares de arroz irrigado produzidas na Região do Alto Vale do Itajaí na safra 2016/17. Os lotes foram submetidos ao teste de sanidade de sementes, identificando-se quatro lotes por cultivar com incidência natural de M. albescens, sendo designados dois lotes de cada cultivar com incidência superior a 40% e dois lotes igual ou inferior a 40%, totalizando 24 lotes de sementes. Foram realizadas as seguintes avaliações nos lotes: germinação, teste de envelhecimento acelerado, emergência em casa de vegetação aos 14 dias, índice de velocidade de emergência (IVE), velocidade de emergência (VE), comprimento de parte aérea, comprimento de raiz e massa seca. Houve interação significativa entre cultivar e nível de incidência apenas nas variáveis germinação, vigor e comprimento de raiz. A massa fresca, comprimento da parte aérea e IVE não foram afetados, independente do cultivar e incidência do fungo na semente. Os cultivares de arroz irrigado SCS118 Marquês e SCSBRS Tio Taka são suscetíveis à alta incidência (> 40%) do fungo M. albescens.(AU)

PhenoRoots: an inexpensive non-invasive phenotyping system to assess the variability of the root system architecture

The root system architecture (RSA) of plants and its functioning play a fundamental role in a number of plant growth mechanisms including water and nutrient uptake. Optimization of the RSA is important for stable and increased plant productivity under adverse conditions. Despite its great importance, studying the RSA is notoriously laborious because of the difficulty of accessing the rooting system of plants. We developed a root phenotyping platform, PhenoRoots, which allows for the non-invasive study of plant RSA. The system was built using inexpensive material and was designed to provide medium throughput. Substrate or soil-filled rhizotrons are used to grow plantlets, whose roots are directly visible through a glass plate. An experiment conducted on a panel of twenty Upland cotton (Gossypium hirsutum L.) varieties demonstrated the usefulness of the platform in assessing RSA traits. A number of traits, destructive and non-destructive, related to the RSA were measured and statistically analyzed. The non-destructive traits based on image analysis of roots were more accurate and showed high correlation with the time-consuming destructive measurements. The platform allowed for capturing the phenotypic and genetic variability found in the panel of cotton varieties, and to define three contrasting RSA patterns. PhenoRoots provides an inexpensive alternative to the medium throughput analysis of RSA traits in plants.

PhenoRoots: an inexpensive non-invasive phenotyping system to assess the variability of the root system architecture

The root system architecture (RSA) of plants and its functioning play a fundamental role in a number of plant growth mechanisms including water and nutrient uptake. Optimization of the RSA is important for stable and increased plant productivity under adverse conditions. Despite its great importance, studying the RSA is notoriously laborious because of the difficulty of accessing the rooting system of plants. We developed a root phenotyping platform, PhenoRoots, which allows for the non-invasive study of plant RSA. The system was built using inexpensive material and was designed to provide medium throughput. Substrate or soil-filled rhizotrons are used to grow plantlets, whose roots are directly visible through a glass plate. An experiment conducted on a panel of twenty Upland cotton (Gossypium hirsutum L.) varieties demonstrated the usefulness of the platform in assessing RSA traits. A number of traits, destructive and non-destructive, related to the RSA were measured and statistically analyzed. The non-destructive traits based on image analysis of roots were more accurate and showed high correlation with the time-consuming destructive measurements. The platform allowed for capturing the phenotypic and genetic variability found in the panel of cotton varieties, and to define three contrasting RSA patterns. PhenoRoots provides an inexpensive alternative to the medium throughput analysis of RSA traits in plants.(AU)