Herbicide selectivity and weed control in cowpea

Weeds negatively affect cowpea plants, causing reduced growth, delayed development and yield loss. The aim of this study was to assay selectivity and effectiveness of weed control herbicides in cowpea cropping field conditions. For selectivity evaluation, the herbicide S-metolachlor, was used pre-emergence (PRE), and carfentrazone-ethyl, clethodim, fenoxaprop-p-ethyl, fluazifop-p-butyl and quizalofop-p-ethyl post-emergence (POST). In effectiveness evaluation, S-metolachlor (PRE), and carfentrazone-ethyl (POST), S-metolachlor in PRE and fluazifop-p-butyl (POST), clethodim, carfentrazone-ethyl and clethodim, fenoxapropp-ethyl, carfentrazone-ethyl and fenoxaprop-p-ethyl, fluazifop-p-butyl, carfentrazone-ethyl and fluazifop-pbutyl, quizalofop-p-ethyl and carfentrazone-ethyl and quizalofop-p-ethyl (POST). Two controls were included, one with weeding at 15 and 35 days after sowing (DAS) and the other without weed control. Carfentrazone-ethyl caused mild phytotoxicity in plants seven days after application, but did not reduce yield (2337 kg ha-1). The levels of weed control and productivity obtained with S-metolachlor alone or in association with carfentrazoneethyl or fluazifop-p-butyl, associated or not with carfentrazone-ethyl, were similar to those obtained with weeds. Spraying with carfentrazone-ethyl alone resulted in low control effectiveness and reduced yield (1511 kg ha-1). Weed interference during the crop cycle reduced yield by 77% (531 kg ha-1). The selectivity and effectiveness obtained with the herbicides should be considered as an agronomic and economically-viable

Inbreeding depression in castor bean (Ricinus communis L.) progenies

The purpose of this study was to investigate inbreeding depression (DE) in castor bean. From a population derived from the Guarani cultivar, 60 mother plants were sampled. Three types of progenies were obtained from each one: from self-pollination (AU), from crosses (CR) and from open pollination (PL). Grain yield of the progenies was evaluated in two locations. There was a strong interaction of progenies x locations, which led to obtaining estimates within each location. Broad variation was observed in inbreeding depression, with mean values of 6.7% and 13.4%, comparing AU progenies with PL progenies. It was observed that the population has high potential for selecting promising inbred lines. The frequency of mother plants generating progenies with simultaneous high general combination capacity and low inbreeding depression was low. Recurrent selection will increase the occurrence of parent plants associating these two properties, which is necessary for obtaining superior synthetic varieties

Selection of corn cultivars for yield, stability, and adaptability in the state of Amazonas, Brazil

O objetivo deste trabalho foi avaliar cultivares de milho, cultivadas no Estado do Amazonas, que reúnam simultaneamente alta produtividade de grãos, adaptabilidade e estabilidade. Os ensaios foram conduzidos em sete ambientes do Amazonas, em delineamento de blocos ao acaso, com duas repetições. A produtividade de grãos de 30 cultivares de milho foi avaliada em quatro safras agrícolas, de 2011/2012 a 2014/2015. Os parâmetros genéticos foram estimados pela metodologia REML/Blup. A seleção quanto à adaptabilidade e à estabilidade baseou-se no valor genético predito e na média harmônica do desempenho relativo dos valores genéticos. Apesar da existência de interação genótipo x ambiente, identificaram-se cultivares com elevadas adaptabilidade e estabilidade. Os ambientes Iranduba – várzea, em 2011/2012 e 2014/2015 – e Rio Preto da Eva – terra firme, em 2012/2013 – destacaram-se como favoráveis, enquanto os ambientes Iranduba – terra firme, em 2011/2012 e 2012/2013 – e Manaus – terra firme, em 2012/2013 e 2013/2014 – foram classificados como desfavoráveis. O híbrido simples BRS 1055 apresentou superioridade produtiva e alta estabilidade nessa região. As variedades sintéticas Sint 10771, Sint 10781 e Sint 10699 apresentaram elevada adaptabilidade. BRS Caimbé apresenta adaptabilidade específica para cultivo em ambientes de terra firme do Estado do Amazonas.The objective of this work was to evaluate corn cultivars grown in the state of Amazonas, Brazil, which simultaneously show high grain yield, adaptability, and stability. The trials were carried out in seven environments in the state of Amazonas, in a randomized complete block design, with two replicates. The grain yield of 30 corn cultivars was evaluated in four growing seasons, from 2011/2012 to 2014/2015. The genetic parameters were estimated by the REML/Blup methodology. The selection for adaptability and stability was based on the predicted genetic value and on the harmonic mean of the relative performance of the genetic values. Despite the existence of genotype x environment interaction, cultivars with high adaptability and stability were identified. Iranduba – lowland, in 2011/2012 and 2014/2015 – and Rio Preto da Eva – upland, in 2012/2013 – stood out as favorable environments, while Iranduba – upland, in 2011/2012 and 2012/2013 – and Manaus – upland, in 2012/2013 and 2013/2014 – were classified as unfavorable environments. The single-cross hybrid BRS 1055 showed productive superiority and high stability in this region. The Sint 10771, Sint 10781, and Sint 10699 synthetic varieties showed high adaptability. BRS Caimbé shows specific adaptability to cropping in upland environments of the state of Amazonas, Brazil

ESTABLISHING THE REFERENCE RANGE FOR T LYMPHOCYTES SUBPOPULATIONS IN ADULTS AND CHILDREN FROM BRAZIL

SUMMARY In Brazil, the existing reference values for T-lymphocytes subsets are based on data originated in other countries. There is no local information on normal variation for these parameters in Brazilian adults and children. We evaluated the normal variation found in blood donors from five large Brazilian cities, in different regions, and in children living in Salvador, and Rio de Janeiro. All samples were processed by flow cytometry. The results were analyzed according to region, gender, and lifestyle of blood donors. A total of 641 adults (63% males), and 280 children (58% males) were involved in the study. The absolute CD3+, and CD4+ cells count were significantly higher for females (adults and children). Higher CD4+ cell count in adults was associated with smoking, while higher CD8+ count was found among female children. Higher counts, for all T-cells subsets, were detected in blood donors from southeast / south regions while those living in the northern region had the lowest values. Individuals from midwestern and northeastern regions had an intermediate count for all these cells subsets. However, these differences did not reach statistical significance. In Brazil, gender and smoking, were the main determinants of differences in T-lymphocytes reference values.RESUMO Os valores de referências de linfócitos T existentes no Brasil são baseados em dados originados de outros países. Não existem dados locais da variação normal para estes parâmetros em adultos e crianças brasileiras. Avaliamos a variação normal encontrada em doadores de sangue de cinco grandes cidades brasileiras em diferentes regiões e em crianças residentes em Salvador e Rio de Janeiro. Todas as amostras foram processadas por citometria de fluxo. Os resultados foram analisados de acordo com região, gênero e estilo de vida dos doadores. Um total de 641 adultos (63% homens) e 280 crianças (58% meninos) participaram do estudo. Valores absolutos de CD3+ e CD4+ foram significantemente maiores no gênero feminino (adultos e crianças). Maiores valores de CD4+ em adultos foram associados com tabagismo, enquanto que maiores valores de CD8+ foram encontrados entre crianças do sexo feminino. Adultos das regiões sul e sudeste apresentaram maiores valores absolutos para todas as células T enquanto que adultos da região norte, apresentaram menores valores. Indivíduos residentes no nordeste e centro-oeste obtiveram contagens intermediárias para todas as populações de células T. Entretanto, estas diferenças entre as regiões, não demonstraram diferença estatística. No Brasil, gênero e tabagismo foram os principais determinantes para diferenças em valores de referências de linfócitos T

Genetic relations between oil yield and sudden death syndrome (SDS) in soybean

A demanda por óleos vegetais tem sido crescente, principalmente para utilização como fonte de energia renovável na forma de biodiesel. Somando-se a isso, a podridão vermelha das raízes da soja (PVR), ou síndrome da morte súbita, causada pelo fungo Fusarium solani f.sp. glycines, tornou-se uma doença preocupante para os sojicultores, técnicos e pesquisadores, sendo uma estratégia recomendada a adoção de um sistema de controle integrado em que a utilização de cultivares tolerantes é um componente indispensável. Assim, este trabalho teve por objetivo verificar a possibilidade de se reunir em uma mesma planta de soja genes para alta produtividade de óleo e para tolerância a PVR. O sistema genético compreendeu um dialelo parcial 7x7, envolvendo sete genitores com alta produtividade de óleo e sete genitores tolerantes a PVR. A maioria dos genitores compreendeu linhagens experimentais desenvolvidas no Setor de Genética Aplicada às Espécies Autógamas (ESALQ/USP). Os experimentos envolveram as plantas F2, na safra 2008/2009 e progênies F2:3, na safra 2009/2010, para avaliação de caracteres agronômicos, do teor de óleo e produtividade de óleo em campo experimental; já a avaliação da reação a PVR foi realizada em progênies F2:4, em casa de vegetação com inoculação artificial do patógeno, por meio de uma escala de notas para a severidade dos sintomas radiculares. Além disso, por meio de marcadores microssatélites fez-se um estudo de genética de associação entre os marcadores e os caracteres reação a PVR e teor de óleo em três populações. Os resultados evidenciaram a existência de variabilidade nos genitores e nas progênies para todos os caracteres avaliados. O genitor com a maior capacidade geral de combinação e média de teor de óleo foi a cultivar A 7002; por outro lado, os menores valores foram verificados em PI 520733 e IAC 100. Os cruzamentos mais produtivos em óleo foram aqueles que envolveram o genitor A 7002, exceto quando este foi cruzado com IAC 100. Dez cruzamentos (USP 70004 com USP 14-10-38, USP 14-01-20, USP 14-13-16 e M-Soy 8001; USP 14-10-38 com USP 70057 e USP 70080; M-Soy 8001 com USP 70006, USP 70080 e USP 70123; e USP 14-01-20 x USP 70006) destacaram-se por originar a maioria de suas progênies com as melhores características em todos os caracteres, ou seja, apresentaram ciclo precoce ou semi-precoce, altura média, plantas eretas e com valor agronômico bom ou médio, alta produtividade de grãos e de óleo, alto teor de óleo e tolerância a PVR. Nenhum cruzamento originou a maioria de suas progênies com as piores características em todos os caracteres. Teor de óleo apresentou baixa correlação genética com altura da planta na maturidade, acamamento, valor agronômico, produtividade de grãos e reação a PVR. PVR apresentou baixa correlação genética com acamamento, produtividade de grãos, teor de óleo, produtividade de óleo; entretanto, foi possível obter progênies com alta produtividade de grãos e de óleo e tolerantes a PVR. Os marcadores microssatélites mostraram-se polimórficos e, foram associados dois locos SSR ao caráter teor de óleo e outros dois locos ao caráter reação a PVR.The demand for vegetable oils has increased, mainly because of its use as a renewable energy source like biodiesel. Moreover, the sudden death syndrome (SDS) in soybean, caused by the fungus Fusarium solani f.sp. glycines, has become a worrying disease for soybean producers, technicians and researchers, and the adoption of an integrated control system using tolerant cultivars as an essential component has been a recommended strategy. This work aimed to verify the possibility of gathering genes for high oil yield and tolerance to SDS in the same soybean plant. The genetic system comprised a partial diallel 7x7 involving seven parents with high oil yield and seven parents tolerant to SDS. Most of the parents were experimental lines developed at the Sector of Genetics Applied to Self-Pollinated Species (ESALQ/USP). The 2008/2009 trials involved the F2 plants, and the 2009/2010 trials involved the evaluation of F2:3 progenies traits, such as agronomic characters, oil content and oil yield in the experimental field; whereas the analysis of the SDS reaction was tested in F2:4 progenies, in a greenhouse with artificial inoculation of the pathogen through a rating scale for severity of radicular symptoms. Moreover, a study of genetic association among microsatellite markers and the characters reaction to SDS and oil content in three populations was performed. The results showed the existence of variability in parents and progenies for all characters. The parent who had the highest general combining ability and average oil content was the cultivar A 7002; on the other hand, the lowest values were found in PI 520733 and IAC 100. The crosses that originated the best oil content progenies have involved the parent A 7002, except when it was crossed with IAC 100. Ten crosses (USP 70004 with USP 14-10-38, USP 14-01-20, USP 14-13-16 and M-Soy 8001; USP 14-10-38 with USP 70057 and USP 70080; M-Soy 8001 with USP 70006, USP 70080 and USP 70123; USP 14-01-20 x USP 70006) distinguished from the others by originating the majority of their progenies with the best features in all traits, in other words, showed early and semi-early maturity, medium height, upright plants, good or average agronomic value, high grain and oil yield, high oil content and tolerance to SDS. None of the crosses originated the majority of their progeny with the worst characteristics in all traits. Oil content showed low genetic correlation with plant height at maturity, lodging, agronomic value, yield and reaction to SDS. SDS showed a low genetic correlation with lodging, grain yield, oil content, oil yield. However, it was possible to obtain progenies with high grain and oil yield and tolerance to SDS. The microsatellite markers were polymorphic and, moreover, two SSR loci were associated with the character oil content and other two loci to the character SDS reaction

Eficiência da seleção recorrente para redução da altura de plantas em mamoneira (Ricinus communis L

The castor bean (Ricinus communis L.) is high social economic value oil plant and a resource source to Brazil. To attend the increasing necessity of the raw material and the difficulty of production in industrial scale, it is essential the genetic material development in adequate size to facilitate the harvest, with precocious and uniform maturation, purposing the utilization of high technology and becoming possible the oil plant production in higher scale. The objective of this work was to evaluate the recurrent selection efficiency for height s reduction of the castor bean plants Guarani cultivar, adequating its size to facilitate the harvest. Were developed four cycles of recurrent selection through the utilization of self-pollinated progenies in the Guarani cultivar for height s reduction of plants, in edaphclimatic condictions of the São Manuel-SP and Botucatu-SP cities. The evaluations of plant s height and grain s productivity (kg.ha-1) of the four selection cycles and of the original cycle (cycle 0) were realized at São Manuel-SP and Botucatu-SP cities, under a casualised blocks design with five repetitions and useful parcels of 30 m2. The variance s analysis for the characteristics plant s height and grain s productivity was made apart to each place and together for the two places and, afterwards it was realized the comparison of the averages by the Tukey test using 5% of probability. Were estimated for the two places, by the regression s analysis... (Complete abstract click electronic access below)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Agronomic performance of eight corn genotypes in two sowing periods

Climatic factors of a region determine the critical periods of corn crop development and affect the sowing planning in order to reduce the negative effects on yield. This study aimed to evaluate the agronomic performance of eight corn genotypes and two sowing dates in the edaphoclimatic conditions of Manaus, Amazonas. Four experiments were carried out in the agricultural years 2016/2017 and 2017/2018, conducted in two sowing periods under harvest season and off-season conditions each year. The sown of the harvest season and off-season were made in October and March, respectively. The experiments were conducted in a randomized block design, with eight genotypes (four varieties - BR 106, BR 5011 Sertanejo, BRS 4103, and BRS Caimbé; and four hybrids - AG 1051, BRS 1055, BRS 3040, and BRS 3046), and four replicates evaluated in two sowing periods for each year. The data were submitted to individual variance analysis for each sowing period, joint for each year, and to the means comparison test. Corn cultivation at the Manaus region could be carried out both during the harvest season, sowing at the beginning of the rainy period (October), and in the off-season, with sowing near the end of the rainy period (March). Hybrids have higher yield potential than open-pollinated varieties for both grain and green ear cultivation, regardless of sowing, harvest, or off-season

Selectivity and efficiency of herbicides in cassava on the floodplain of the Solimões river

Cassava is grown on the floodplains of the Solimões river and guarantees food security and income for farmers. However, negative interference of weeds can result in a significant yield loss in the crop. Therefore, the aim of this study was to evaluate the selectivity of herbicides and efficiency of chemical weed control in the cassava ‘Aipim-manteiga’ cultivar, in the floodplain of the Solimões river, in Iranduba, Amazonas. The experimental design was in randomized blocks with four replications. The herbicides evaluated were clomazone (1080 g ha-1), diuron (1750 and 2500 g ha-1) and oxadiazon (400 and 800 g ha-1), applied alone or with hoeing 90 days after planting (DAP). Two control treatments were included: weeding (hoeing) at 30, 60, 90 and 120 DAP and with no weed control. Clomazone caused mild toxicity in the plants, while with diuron and oxadiazon toxicity was moderate; all three were considered safe for the crop. The plant population of the crop was not affected by the herbicides. Clomazone afforded effective weed control up to 45 DAP only, and weeding was necessary at 90 DAP to eliminate negative interference by the weeds on crop yield. Diuron and oxadiazon were effective in controlling weeds throughout the crop cycle of the cassava. Weed interference during the crop life cicle reduced yield by 83.8%

Herbicide selectivity and weed control in cowpea

Weeds negatively affect cowpea plants, causing reduced growth, delayed development and yield loss. The aim of this study was to assay selectivity and effectiveness of weed control herbicides in cowpea cropping field conditions. For selectivity evaluation, the herbicide S-metolachlor, was used pre-emergence (PRE), and carfentrazone-ethyl, clethodim, fenoxaprop-p-ethyl, fluazifop-p-butyl and quizalofop-p-ethyl post-emergence (POST). In effectiveness evaluation, S-metolachlor (PRE), and carfentrazone-ethyl (POST), S-metolachlor in PRE and fluazifop-p-butyl (POST), clethodim, carfentrazone-ethyl and clethodim, fenoxapropp-ethyl, carfentrazone-ethyl and fenoxaprop-p-ethyl, fluazifop-p-butyl, carfentrazone-ethyl and fluazifop-pbutyl, quizalofop-p-ethyl and carfentrazone-ethyl and quizalofop-p-ethyl (POST). Two controls were included, one with weeding at 15 and 35 days after sowing (DAS) and the other without weed control. Carfentrazone-ethyl caused mild phytotoxicity in plants seven days after application, but did not reduce yield (2337 kg ha-1). The levels of weed control and productivity obtained with S-metolachlor alone or in association with carfentrazoneethyl or fluazifop-p-butyl, associated or not with carfentrazone-ethyl, were similar to those obtained with weeds. Spraying with carfentrazone-ethyl alone resulted in low control effectiveness and reduced yield (1511 kg ha-1). Weed interference during the crop cycle reduced yield by 77% (531 kg ha-1). The selectivity and effectiveness obtained with the herbicides should be considered as an agronomic and economically-viable