Introgression of bacterial leaf blight (BLB) resistant gene, Xa7 into MARDI elite variety, MR219 by marker assisted backcrossing (MABC) approach / Introdução do gene resistente à ferragem da folha bacteriana (BLB), xa7 na variedade MARDI elite, MR219 por abordagem de backcrossing assistida por marcador (MABC)

Abstract Bacterial leaf blight (BLB) is one of the major rice diseases in Malaysia. This disease causes substantial yield loss as high as 70%. Development of rice varieties which inherited BLB resistant traits is a crucial approach to promote and sustain rice industry in Malaysia. Hence, this study aims were to enhance BLB disease resistant characters of high yielding commercial variety MR219 through backcross breeding approach with supporting tool of marker-assisted selection (MAS). Broad spectrum BLB resistance gene, Xa7 from donor parent IRBB7 were introgressed into the susceptible MR219 (recurrent parent) using two flanking markers ID7 and ID15. At BC3F4, we managed to generate 19 introgressed lines with homozygous Xa7 gene and showed resistant characteristics as donor parent when it was challenged with Xanthomonas oryzae pv. oryzae through artificial inoculation. Recurrent parent MR219 and control variety, MR263 were found to be severely infected by the disease. The improved lines exhibited similar morphological and yield performance characters as to the elite variety, MR219. Two lines, PB-2-107 and PB-2-34 were chosen to be potential lines because of their outstanding performances compared to parent, MR219. This study demonstrates a success story of MAS application in development of improved disease resistance lines of rice against BLB disease.

Resumo A mancha bacteriana das folhas (BLB) é uma das principais doenças do arroz na Malásia. Essa doença causa perdas substanciais de rendimento de até 70%. O desenvolvimento de variedades de arroz que herdaram características de resistência ao BLB é uma abordagem crucial para promover e sustentar a indústria do arroz na Malásia. Portanto, o objetivo deste estudo foi aumentar os caracteres BLB resistentes a doenças da variedade comercial MR219 de alto rendimento por meio de uma abordagem de cruzamento retrocruzamento com ferramenta de apoio de seleção assistida por marcador (MAS). O gene de resistência a BLB de amplo espectro, Xa7 do pai doador IRBB7, foi introgressado no MR219 suscetível (pai recorrente) usando dois marcadores flanqueadores ID7 e ID15. No BC3F4, conseguimos gerar 19 linhagens introgressadas com o gene Xa7 homozigoto e apresentamos características de resistência como genitor doador quando desafiado com Xanthomonas oryzae pv. oryzae por inoculação artificial. O pai recorrente MR219 e a variedade controle, MR263, estavam gravemente infectados pela doença. As linhas melhoradas exibiram características morfológicas e de desempenho de rendimento semelhantes às da variedade elite, MR219. Duas linhas, PB-2-107 e PB-2-34, foram escolhidas como linhas potenciais por causa de seus desempenhos excelentes em comparação com a mãe, MR219. Este estudo demonstra uma história de sucesso de aplicação de MAS no desenvolvimento de linhas de arroz melhoradas com resistência a doenças contra a doença BLB.

Introgression of bacterial leaf blight (BLB) resistant gene, Xa7 into MARDI elite variety, MR219 by marker assisted backcrossing (MABC) approach

Abstract Bacterial leaf blight (BLB) is one of the major rice diseases in Malaysia. This disease causes substantial yield loss as high as 70%. Development of rice varieties which inherited BLB resistant traits is a crucial approach to promote and sustain rice industry in Malaysia. Hence, this study aims were to enhance BLB disease resistant characters of high yielding commercial variety MR219 through backcross breeding approach with supporting tool of marker-assisted selection (MAS). Broad spectrum BLB resistance gene, Xa7 from donor parent IRBB7 were introgressed into the susceptible MR219 (recurrent parent) using two flanking markers ID7 and ID15. At BC3F4, we managed to generate 19 introgressed lines with homozygous Xa7 gene and showed resistant characteristics as donor parent when it was challenged with Xanthomonas oryzae pv. oryzae through artificial inoculation. Recurrent parent MR219 and control variety, MR263 were found to be severely infected by the disease. The improved lines exhibited similar morphological and yield performance characters as to the elite variety, MR219. Two lines, PB-2-107 and PB-2-34 were chosen to be potential lines because of their outstanding performances compared to parent, MR219. This study demonstrates a success story of MAS application in development of improved disease resistance lines of rice against BLB disease.

Resumo A mancha bacteriana das folhas (BLB) é uma das principais doenças do arroz na Malásia. Essa doença causa perdas substanciais de rendimento de até 70%. O desenvolvimento de variedades de arroz que herdaram características de resistência ao BLB é uma abordagem crucial para promover e sustentar a indústria do arroz na Malásia. Portanto, o objetivo deste estudo foi aumentar os caracteres BLB resistentes a doenças da variedade comercial MR219 de alto rendimento por meio de uma abordagem de cruzamento retrocruzamento com ferramenta de apoio de seleção assistida por marcador (MAS). O gene de resistência a BLB de amplo espectro, Xa7 do pai doador IRBB7, foi introgressado no MR219 suscetível (pai recorrente) usando dois marcadores flanqueadores ID7 e ID15. No BC3F4, conseguimos gerar 19 linhagens introgressadas com o gene Xa7 homozigoto e apresentamos características de resistência como genitor doador quando desafiado com Xanthomonas oryzae pv. oryzae por inoculação artificial. O pai recorrente MR219 e a variedade controle, MR263, estavam gravemente infectados pela doença. As linhas melhoradas exibiram características morfológicas e de desempenho de rendimento semelhantes às da variedade elite, MR219. Duas linhas, PB-2-107 e PB-2-34, foram escolhidas como linhas potenciais por causa de seus desempenhos excelentes em comparação com a mãe, MR219. Este estudo demonstra uma história de sucesso de aplicação de MAS no desenvolvimento de linhas de arroz melhoradas com resistência a doenças contra a doença BLB.

Multiline aiming at phenotypic stability and rice blast resistance

This study aimed to verify the efficiency of multilines in reducing blast progress and their potential benefits to phenotypic stability in rice. The experiments were conducted in the 2016/17 and 2017/18 agricultural years. A randomized block design was performed with three replications, evaluating 12 lines and a multiline, which consisted of five lines from the Cultivation and Use Value (CUV) test. The multiline presented an estimated grain yield above the average of experiments of around seven bags ha-1 and superior performance in early flowering, justifying the high phenotypic stability for these characters. In this case, the line selection for composing the multiline was favorable and efficient, highlighted by a higher agronomic performance than most lines of the CUV test. The multiline is an adequate strategy to provide higher phenotypic stability and reduce blast progress in the field.

Impact of sowing dates on the yield efficiency of upland rice cultivars

The choice of cultivars adapted to different regions and the determination of the best sowing dates are indispensable tools for crop development. This allows the installation of the crop in times favorable to its development, as well as cultivars that manage to reach their maximum yield potential. The objective of this study was to determine the best sowing dates and the cultivars that can adapt to the low-altitude Cerrado region and have the best development and yield efficiency. The experiment was conducted on a typical clayey dystrophic Red Latosol soil. The experimental design was in randomized blocks in a factorial scheme, comprised by four sowing dates during the spring/summer season (October, November, December, and February) and in each sowing date there were eight upland rice cultivars (BRS Esmeralda, ANa 6005, ANa 5015, IPR 117, IAC 203, IAC 500, ANa 7211 and BRSGO Serra Dourada) with four replicates. Sowing in October and November benefited the aerial dry mass and the spikelets fertility however, sowing in November provided higher plant height, which caused lodging in plants. Sowing in December caused the incidence of scald, mainly affecting the cultivar ANa 7211. For all cultivars, sowing in October favored the yield efficiency of upland rice in the low-altitude Cerrado, followed by sowing in November. The cultivars which demonstrated higher yield efficiency in the conditions of the region were BRS Esmeralda and ANa 5015.

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

ABSTRACT: 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.

RESUMO: 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.

Effects of gibberellin priming on seedling emergence and transcripts involved in mesocotyl elongation in rice under deep direct-seeding conditions / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Mesocotyl elongation is a key trait influencing seedling emergence and establishment in direct-seeding rice cultivation. The phytohormone gibberellin (GA) has positive effects on mesocotyl elongation in rice. However, the physiological and molecular basis underlying the regulation of mesocotyl elongation mediated by GA priming under deep-sowing conditions remains largely unclear. In the present study, we performed a physiological and comprehensive transcriptomic analysis of the function of GA priming in mesocotyl elongation and seedling emergence using a direct-seeding

Studies on the cold tolerance of ratoon 'Chaling' common wild rice

BACKGROUND: Rice is the staple food of many people around the world. However, most rice varieties, especially widely grown indica varieties and hybrids, are sensitive to cold stress. In order to provide a basis for the utilization of a common wild rice (CWR, Oryza rufipogon Griff.) named 'Chaling' CWR in cold-tolerant rice breeding and deepen the understanding of rice cold tolerance, the cold tolerance of ratoon 'Chaling' CWR was studied under the stress of the natural low temperature in winter in Changsha, Hunan province, China, especially under the stress of abnormal natural low temperature in Changsha in 2008, taking other ratoon CWR accessions and ratoon cultivated rice phenotypes as control. RESULTS: The results showed that ratoon 'Chaling' CWR can safely overwinter under the natural conditions in Changsha (28° 22' N), Hunan province, China, which is a further and colder northern place than its habitat, even if it suffers a long-term low temperature stress with ice and snow. In 2008, an extremely cold winter appeared in Changsha, i.e., the average daily mean temperature of 22 consecutive days from January 13 to February 3 was - 1.0 °C, and the extreme low temperature was - 4.7 °C. After subjected to this long-term cold stress, the overwinter survival rate of ratoon 'Chaling' CWR was 100%, equals to that of ratoon 'Dongxiang' CWR which is northernmost distribution in the word among wild rice populations, higher than those of ratoon 'Fusui' CWR, ratoon 'Jiangyong' CWR, and ratoon 'Liujiang' CWR (63.55-83.5%) as well as those of ratoon 'Hainan' CWR, ratoon 'Hepu' CWR, and all the ratoon cultivated rice phenotypes including 3 japonica ones, 3 javanica ones, and 5 indica ones (0.0%). CONCLUSIONS: The results indicate that ratoon 'Chaling' CWR possesses strong cold tolerance and certain freezing tolerance.

Mapping of spatiotemporal distribution of Tibraca limbativentris Stal (Hem.: Pentatomidae) in flooded rice crop in Southern Brazil

ABSTRACT The rice stem bug, Tibraca limbativentris Stal (Hem.: Pentatomidae), is one of the main insect pests in Brazilian rice crops. Knowledge of its spatiotemporal distribution can support the development of an effective sampling system and improve IPM strategies. This study aimed to map the spatiotemporal distribution of rice stem bug in flooded rice crop in Southern Brazil. Flooded rice crop was scouted for two seasons to estimate insect densities. Four occurrence categories were observed: no insect, only adults, only nymphs, and both phases. The relationship between phenological stages and insect categories was established. Interpolation (mapping) of occurrence categories of T. limbativentris was performed by multiquadric equations. In two seasons during the rice cycle, the results indicate that rice stem bug "adults" were the most abundant category until the mid-vegetative phase of the rice; "nymphs" were the most abundant from the end of vegetative phase; "adults + nymphs" occurred from the beginning of reproductive phase; there were no rice stem bugs in more than 66% of the area, as they were most concentrated near the edge of the crop. The information presented here provides further knowledge about T. limbativentris spatiotemporal dynamics that can be applied to improve IPM strategies, such as developing sampling plans and localized control measures at the edge of rice fields.

An Exploration of the Oryza sativa L. Cyanidin-3-glucoside on the Cognitive Function in Older Adults with Subjective Memory Impairment

OBJECTIVE: Cyanidin-3-glucoside (C3G), is a component of anthocyanin, have been considered to positively influence cognition and be beneficial for the prevention and treatment of dementia. We aimed to assess the safety and efficacy of cyanidin-3-glucoside-rich Oryza sativa L. (black rice) extract on cognitive function. METHODS: A 12-weeks double-blind randomized, placebo controlled trial assessed safety and cognitive outcomes in participants with subjective memory impairment (n=48) following consumption of 6 black rice extract capsules or a placebo. Cognitive function was assessed using the ADAS-cog and the CERAD-K. Subjective memory impairment also assessed. Safety was assessed by hematologic blood test, urine analysis, and participant reports of adverse events. RESULTS: There was significant improvement on subjective memory in intervention group. There was no statistically significant difference in objective cognitive outcomes following 12 weeks of consuming black rice extract. ADAS-cog scores, however, trended toward improvement in the intervention group compared to the placebo group. There was no adverse event. CONCLUSION: Although significant improvement in objective cognitive function was not proved, we found that C3G-rich Oryza sativa L. extract improves subjective memory in this study. Therefore the results may be informative of the possible effectiveness of the C3G-rich Oryza sativa L. on cognitive function.

Comet and cytogenetic tests as tools for evaluating genomic instability in seeds of Oryza sativa L. and Phaseolus vulgaris L. from gene banks

Abstract This study aimed to assess the feasibility of comet and cytogenetic tests as tools for evaluating genomic instability in seeds of Oryza sativa L. (rice) and Phaseolus vulgaris (beans) L. from gene banks. Rice and beans were exposed to methyl methanesulfonate (MMS) as a reference DNA damaging agent. Seeds of two accessions of rice and beans were obtained from Embrapa Rice and Beans - Brazil. Seed groups were imbibed in three concentrations of MMS for three periods of time to carry out cytogenetic tests, and for one period for the comet test. At concentrations of 10 and 15 mg/L, MMS induced cytotoxic and/or mutagenic effects in the meristematic cells of roots from all the accessions of both species. In the comet test, MMS induced genotoxic effects at all the concentrations in the evaluated accessions of rice and beans, except in one accession of beans at the lowest concentration (5 mg/L). Both species showed sensitivity to MMS. The comet test can be proposed for the measurement of genomic instability in accessions of rice and beans in gene banks, as being more sensitive than the cytogenetic tests used.

Contribution of dark septate fungi to the nutrient uptake and growth of rice plants

ABSTRACT The use of dark septate fungi (DSE) to promote plant growth can be beneficial to agriculture, and these organisms are important allies in the search for sustainable agriculture practices. This study investigates the contribution of dark septate fungi to the absorption of nutrients by rice plants and their ensuing growth. Four dark septate fungi isolates that were identified by Internal transcribed spacer phylogeny were inoculated in rice seeds (Cv. Piauí). The resulting root colonization was estimated and the kinetic parameters Vmax and Km were calculated from the nitrate contents of the nutrient solution. The macronutrient levels in the shoots, and the NO3--N, NH4+-N, free amino-N and soluble sugars in the roots, sheathes and leaves were measured. The rice roots were significantly colonized by all of the fungi, but in particular, isolate A103 increased the fresh and dry biomass of the shoots and the number of tillers per plant, amino-N, and soluble sugars as well as the N, P, K, Mg and S contents in comparison with the control treatment. When inoculated with isolates A103 and A101, the plants presented lower Km values, indicating affinity increases for NO3--N absorption. Therefore, the A103 Pleosporales fungus presented the highest potential for the promotion of rice plant growth, increasing the tillering and nutrients uptake, especially N (due to an enhanced affinity for N uptake) and P.

Rice Seed Production Under Conditions of Salinity Stres / Produção de sementes de arroz em condições de estresse por salinidade

ABSTRACT: In the present study, the objective was to evaluate the production and quality of rice seeds of four cultivars under conditions of saline stress caused by irrigation water. The work was carried out at the EliseuMaciel Agronomy College of the Universidade Federal de Pelotas, with four rice cultivars, IRGA 417, Avaxi CL, Inov CL and IAS 12-9 (Formosa). In the experiment, the following saline concentrations were used: 0; 12.5; 25; 37.5; 50; 75 and 100mM. After completing the crop cycle, the following agronomic characteristics were evaluated in each of the plants: number of panicles, total weight of panicles, percentage of full seeds, percentage of seedlings and weight of a thousand seeds. The physiological quality of the seeds harvested from the plants maintained under conditions of salinity stress was evaluated by germination and first count tests. Saline stress reduced the productivity and physiological quality of rice seeds, with different responses from the four cultivars used.

RESUMO: Na presente pesquisa o objetivo foi de avaliar a produção e a qualidade de sementes de arroz de quatro cultivares em condições de estresse salino causado pela água de irrigação. O trabalho foi realizado na Faculdade de Agronomia Eliseu Maciel da Universidade Federal de Pelotas, com quatro cultivares de arroz: IRGA 417, Avaxi CL, Inov CL e IAS 12-9 (Formosa). Para o experimento utilizou-se as seguintes concentrações de salinidade: 0,0 , 12,5, 25 , 37,5 , 50 , 75 e 100mM. Após completar o ciclo da cultura, avaliaram-se as seguintes características agronômicas em cada uma das plantas: número e peso total das panículas, porcentagem de sementes cheias, chochas e peso de mil sementes. A qualidade fisiológica das sementes colhidas das plantas mantidas em condições de estresse por salinidade foi avaliada pelos testes de germinação e de primeira contagem. O estresse salino reduz a produtividade e a qualidade de sementes de arroz, com respostas diferenciadas dos cultivares quando submetidos a condições de estresse salino.

Syneresis and chemical characteristics of fermented rice extract with probiotic bacteria and waxy maize starch

Abstract The objective of this work was to elaborate fermented extracts using rice bran and broken rice grains (proportion 8:92) with probiotic bacteria and different concentrations of waxy maize starch (WMS) in order to obtain products with low level of syneresis and desirable physical-chemical characteristics, and to evaluate the content of phenolic compounds, antioxidant capacity and chemical composition of the extract selected and flavored with strawberry aroma and strawberry syrup. A randomized design was used with five treatments (0, 4, 8, 12 and 16 g 100 g-1 of WMS) and four replications. The fermented rice extract had increased soluble solids (from 12.97 to 14.23 °Brix) and total acidity (from 0.29 to 0.30 g 100 g-1), whereas total soluble sugars (from 9.24 to 8.73 g 100 g-1) and syneresis (from 10.16 to 0.99 g 100 g-1) decreased with gradual increments of waxy maize starch. The fermented rice extract containing 12 g 100 g-1 WMS reduced the syneresis by 89% compared to the control without waxy maize starch. The fermented rice extract with 12 g 100 g-1 of waxy maize starch flavored with strawberry aroma and strawberry syrup shows high nutritional value, antioxidant capacity, content of total phenolic compounds, and marketing potential, particularly for consumers with special needs, such as those allergic to lactose or soybean proteins, as an alternative food ready for consumption.

Genotype selection and addition of fertilizer increases grain yield in upland rice in Suriname / Seleção de genótipos e adição de fertilizantes aumenta a produtividade de grãos do arroz de terras altas no Suriname

ABSTRACT The upland rice farmers in Suriname use local varieties and low level technologies in the field. As a result, the upland rice grain yield is low, at about 1 000 kg ha-1. Our objective was to evaluate the use of upland rice cultivars from Suriname and Brazil, and the effect of nitrogen, N, phosphorus, P, and potassium, K, fertilizers on cultivation variables. We undertook four field trials in the Victoria Area, in the Brokopondo District, using a randomized block design each with four replications. The most productive rice varieties were BRS Esmeralda (grain yield 2 903 kg ha-1) and BRS Sertaneja (2 802 kg ha-1). The highest grain yield of 2 620 kg ha-1 was achieved with a top dressing application of 76.41 kg N ha-1 20 days after sowing. For P, the highest grain yield of 3 085 kg ha-1 was achieved with application of 98.06 kg ha-1 P2O5 applied at sowing. An application rate of 31.45 kg ha-1 of K2O at sowing achieved the highest grain yield of 2 952 kg ha-1. Together, these application rates of N, P and K resulted in rice grain yield of about 3 000 kg ha-1, which is three times greater than the national average for upland rice. We demonstrate that the use of improved rice varieties matched to the local conditions, and application of appropriate fertilizers, are management practices that can result in significant increases in rice grain yield in Suriname.

RESUMO Produtores de arroz de terras altas no Suriname usam cultivares locais e baixo nível tecnológico. Assim, a produtividade é baixa (1 000 kg ha-1). Nosso objetivo foi avaliar o uso de cultivares de arroz de terras altas do Suriname e do Brasil, e o efeito de taxas de nitrogênio, N, fósforo, P e potássio, K sobre variáveis de cultivo. Foram instalados quatro ensaios de campo usando em cada experimento o delineamento de blocos casualizados com quatro repetições. As mais produtivas cultivares de arroz foram BRS Esmeralda (produtividade de 2 903 kg ha-1) e a BRS Sertaneja (2 802 kg ha-1). A mais alta produtividade de grãos de 2 620 kg ha-1 foi alcançada pela aplicação em cobertura de 76.41 kg N ha-1, aos 20 dias após a semeadura. Para P, a mais alta produtividade de grãos de 2 620 kg ha-1 foi alcançada com a aplicação de 98.06 kg ha-1 de P2O5 na semeadura. Uma aplicação da dose de 31.45 kg ha-1 K2O na semeadura permitiu o maior rendimento de grãos, 2 952 kg ha-1. Juntas, essas taxas de aplicação proporcionaram rendimento de grãos de arroz em torno de 3 000 kg ha-1, o que é três vezes maior que a média nacional do país para arroz de terras altas. O uso de variedades melhoradas de arroz adaptadas às condições locais, e a aplicação de doses adequadas de nutrientes são práticas de manejo que podem resultar em significativo aumento no rendimento de cultivos de arroz de terras altas no Suriname.

Dark septate endophyte decreases stress on rice plants

Abstract Abiotic stress is one of the major limiting factors for plant development and productivity, which makes it important to identify microorganisms capable of increasing plant tolerance to stress. Dark septate endophytes can be symbionts of plants. In the present study, we evaluated the ability of dark septate endophytes isolates to reduce the effects of water stress in the rice varieties Nipponbare and Piauí. The experiments were performed under gnotobiotic conditions, and the water stress was induced with PEG. Four dark septate endophytes were isolated from the roots of wild rice (Oryza glumaepatula) collected from the Brazilian Amazon. Plant height as well as shoot and root fresh and dry matter were measured. Leaf protein concentrations and antioxidant enzyme activity were also estimated. The dark septate endophytes were grown in vitro in Petri dishes containing culture medium; they exhibited different levels of tolerance to salinity and water stress. The two rice varieties tested responded differently to inoculation with dark septate endophytes. Endophytes promoted rice plant growth both in the presence and in the absence of a water deficit. Decreased oxidative stress in plants in response to inoculation was observed in nearly all inoculated treatments, as indicated by the decrease in antioxidant enzyme activity. Dark septate endophytes fungi were shown to increase the tolerance of rice plants to stress caused by water deficiency.

Richness and density of aquatic benthic macroinvertebrates after exposure to fungicides and insecticides in rice paddy fields

ABSTRACT The objective of this study was to verify the richness and density of aquatic benthic macroinvertebrates after exposure to fungicides and insecticides of the rice paddy fields. In the crop seasons of 2012/13 and 2013/14, field experiments were performed, which consisted of single-dose applications of the fungicides trifloxystrobin + tebuconazole and tricyclazole, and the insecticides lambda-cyhalothrin + thiamethoxam and diflubenzuron, in 10 m2 experimental plots, over rice plants in the R3 stage. Control plots with and without rice plants were maintained in order to simulate a natural environment. Soil samples were collected during rice cultivation for assessment of the macroinvertebrate fauna. Chemical-physical parameters assessed in the experiments included temperature, pH and oxygen dissolved in the water and pesticide persistence in the water and in the soil. The application of a single dose of the pesticides and fungicides in the recommended period does not cause significant negative effects over the richness and density of the macroinvertebrates. Tebuconazole, tricyclazole and thiamethoxam showed high persistence in the irrigation water of rice paddy fields. Thus, the doses and number of applications of these products in crops should be carefully handled in order to avoid contamination of the environment.

Antimutagenic and Antioxidant Activities of Thai Rice Brans

BACKGROUND: Rice bran is the outer layer of the rice grain, and contains high amounts of bioactive phytochemicals. Here, we investigated and compared chemopreventive properties of purple and white rice bran extracts. METHODS: Rice bran was extracted with dichloromethane and methanol. Chemical constituents in the extracts were analyzed by colorimetric assay and high performance liquid chromatography. The mutagenicity and antimutagenicity of the extracts were determined via the Salmonella mutation assay. The anticarcinogenic enzyme induction and antioxidant activities of the extracts were examined using Hepa1c1c7 cells and 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay, respectively. RESULTS: The methanol extracts of rice bran contained high amounts of phenolic acids, flavonoids, anthocyanins, and phytic acid, whereas large amounts of γ-oryzanol and vitamin E were presented in the dichloromethane extract. None of the extracts were mutagenic to Salmonella typhimurium. All rice bran extracts had strong antimutagenic effects against aflatoxin B1- and 2-amino-3,4-dimethylimidazo [4,5-f]quinoline-induced mutagenesis. The inhibitory effect against 2-aminofluorene-induced mutagenesis was found in the dichloromethane extract, while only the methanol extract of purple rice bran exhibited antimutagenic effects against benzo(a)pyrene. None of the extracts induced quinone reductase activity in Hepa1c1c7 cells. Additionally, the greatest antioxidant capacity was found in the methanol extract of purple rice bran. CONCLUSIONS: The methanol extract of purple rice bran containing high amount of phenolic acids, flavonoids, anthocyanins, and phytic acid showed the most effective antioxidant and antimutagenic activities by inhibiting mutagenic metabolizing enzymes and/or scavenging free radicals. These results demonstrate the nutritional and medical value of Thai rice for cancer prevention.

Physiological potential of irrigated rice seeds treated with amino acids and under salt stress / Potencial fisiológico de sementes de arroz irrigado tratadas com aminoácidos e submetidas a estresse salino

Salt stress in rice plants affects growth, development and crop yield. However, seed treatment can reduce the deleterious effects caused by salt stress. The use of amino acids in agriculture has increased, both in Brazil and in other countries, due to higher productivity and provide better quality of plants treated with amino acids. The objective of this study was to evaluate the effect of amino acid coating on the physiological potential of rice seeds under salt stress. The experimental design was a completely randomized three-way factorial design with two batches of seeds, two levels of amino acid treatment (with or without amino acid) and five salt concentrations (0.0, 25.0, 50.0, 75.0 and 100.0 mM) with four replicates. The physiological quality of seeds was assessed by a germination test, first germination count, cold test, accelerated aging, seedling shoot and root lengths, and dry weight of shoots and roots. It is concluded that the seed treatment with amino acids results in better physiological performance of rice seeds when subjected to salt stress, which affects negatively the physiological quality of seeds.

O estresse salino em plantas de arroz afeta o crescimento, o desenvolvimento e a produtividade da cultura. Sendo assim, o tratamento de sementes pode constituir uma tecnologia, para diminuir os efeitos deletérios causados pelo estresse salino. A utilização de aminoácidos se difundiu muito, tanto na agricultura brasileira quanto em outros países, devido aos benefícios proporcionados às plantas por meio do fornecimento de substâncias orgânicas que resultam em maiores produtividades e conferem melhor qualidade nas diversas culturas. Nesse contexto, o objetivo desta pesquisa foi avaliar o efeito da aplicação de aminoácidos, via tratamento de sementes, no potencial fisiológico de lotes de sementes de arroz submetidos ao estresse salino. O delineamento experimental utilizado foi inteiramente casualizado em esquema fatorial AxBxC (Fator A- Lote 1 e Lote 2; Fator B- Com aminoácido e sem aminoácido; Fator C- concentrações salinas: 0, 25, 50, 75 e 100 mM), com quatro repetições. A qualidade fisiológica das sementes foi avaliada pelos testes de germinação, primeira contagem da germinação, teste de frio, envelhecimento acelerado, comprimento da parte aérea e raiz e massa seca da parte aérea e raiz. Conclui-se que o tratamento de sementes com aminoácidos proporciona melhor desempenho fisiológico de sementes de arroz quando submetidas a estresse salino, que afeta negativamente a qualidade fisiológica.

Yield loss and economic thresholds of yellow nutsedge in irrigated rice in function of cultivars / Perdas de produtividade e níveis de dano econômico de tiririca-amarela em arroz irrigado em função de cultivares

Weeds cause reduction in the rice yield. Little is known about the competitive ability of yellow nutsedge (Cyperus esculentus) with rice and the extent of the economic threshold (ET). The aim of this study was to determine the fit of the regression model to estimate hyperbolic yield losses and ET of yellow nutsedge in rice due to the cycle of cultivars (BRS Querência - Early cycle and IRGA 424 - mid cycle). For this, a field study of competition in the agricultural year 2010/11 was conducted. Yield losses and ET of yellow nutsedge in rice crop is function on the competitive ability of rice cultivar used. The use of rice cultivar with early cycle, BRS Querência, increases the ETs of weed in rice crops compared to the use of IRGA 424, mid-cycle. The hyperbola satisfactorily estimated yield losses that yellow nutsedge causes in rice crops. The explanatory variable, population of yellow nutsedge, was the best fitted to the model. Increases in yield, price paid for rice and control efficiency promoted by the herbicide and decreased cost of weed control, promote ET reduction in yellow nutsedge in rice crops, justifying the adoption of control measures of smaller populations of the weed.

As Plantas daninhas causam redução da produtividade do arroz. Pouco se conhece sobre a habilidade competitiva da tiririca-amarela (Cyperus esculentus) com o arroz e qual seu nível de dano na cultura (NDE). O objetivo desse estudo foi determinar o ajuste do modelo hiperbólico estimando perdas de produtividade e NDEs de tiriricaamarela no arroz em função do ciclo das cultivares (BRS Querência ­ ciclo precoce e IRGA 424 ­ ciclo médio). Para tal, foi conduzido estudo de competição a campo no ano agrícola 2010/11. Perdas de produtividade e NDE de tiririca-amarela no arroz variam em função da habilidade competitiva da cultivar utilizada. O uso da cultivar de ciclo precoce, BRS Querência, aumenta os NDE da infestante no arroz quando comparada ao uso da IRGA 424, de ciclo médio. A hipérbole estima satisfatoriamente as perdas de produtividade que a tiririca-amarela causa à cultura do arroz. A variável explicativa população de tiririca-amarela é a que mais se ajustou ao modelo. Aumentos da produtividade, do preço pago pelo arroz e da eficiência de controle promovido pelo herbicida e a diminuição do custo de controle da planta daninha, promovem redução nos NDE de tiririca-amarela no arroz, justificando adoção de medidas de controle sob menor população da planta daninha.

Control of globe fringerush ( Fimbristylis miliacea ) and selectivity to rice crop irrigated with bispyribac-sodium + metsulfuron-methyl associated with adjuvants / Controle de cominho (Fimbristylis miliacea) e seletividade à cultura do arroz irrigado com bispyribac-sodium + metsulfuron-methyl associados a adjuvantes

This study aimed to evaluate the control of globe fringerush (Fimbristylis miliacea ) and selectivity to rice crop irrigated with an in-tank mixture of bispyribac-sodium + metsulfuron-methyl associated with adjuvants. The experiment was conducted in the municipality of Douradina, Paraná state, Brazil (23º12'32.0" South, 53º17'39.9" West), in the agricultural year of 2012/2013. An experimental randomized complete block design with ten treatments and four replications was used. The treatments consisted of applying an in-tank mixture of the herbicides bispyribac-sodium + metsulfuron-methyl at two doses (32+1.3 and 40+3.3 g ai ha-1) associated with the adjuvants Iharaguen(tm) (375 mL.ha-1), Orobor N1(tm) (75 mL.ha-1), LI 700(tm) (150 mL.ha-1) and TA 35(tm) (50 mL.ha-1), as well as weeded and unweeded control. Although the effectiveness of globe fringerush (F. miliacea ) control with the in-tank mixture of the herbicides bispyribac-sodium + metsulfuron-methyl associated with Iharaguen(tm) and Orobor N1(tm) has been significantly higher than the effectiveness of these herbicides associated with LI 700(tm) and TA 35(tm), there were no significant differences among the treatments in terms of selectivity and grains yield of the rice cultivar Epagri 108.(AU)

O objetivo deste trabalho foi avaliar o controle de cominho (Fimbristylis miliacea ) e a seletividade à cultura do arroz irrigado com a mistura em tanque de bispyribac-sodium + metsulfuron-methyl associada a adjuvantes. Conduziu-se o experimento no município de Douradina (23º12'32,0" Sul, 53º17'39,9" Oeste), PR, no ano agrícola 2012/2013. O delineamento experimental utilizado foi o de blocos completos casualizados com dez tratamentos e quatro repetições. Os tratamentos foram constituídos pela aplicação da mistura em tanque dos herbicidas bispyribac-sodium + metsulfuron-methyl, em duas doses (32+1,3 e 40+3,3 g i.a. ha-1), e com adjuvantes Iharaguen(r) (375 mL.ha-1), Orobor N1(r) (75 mL.ha-1), LI 700(r) (150 mL.ha-1) e TA 35(r) (50 mL.ha-1), assim como de testemunha capinada e sem capina. Apesar de a eficácia de controle de cominho (F. miliacea ) com a mistura em tanque de bispyribac-sodium + metsulfuron-methyl associada aos adjuvantes Iharaguen(r) e Orobor N1(r) ter sido significativamente superior ao LI 700(r) e TA 35(r), não foram constatadas diferenças significativas entre os tratamentos em termos de seletividade e produtividade de grãos para o cultivar de arroz Epagri 108.(AU)