Em busca do aumento da produtividade do feijoeiro e de várias outras culturas de interesse econômico, foram realizadas inúmeras pesquisas utilizando reguladores de crescimento, hormônios e nutrientes, principalmente em aplicações foliares com a finalidade de acelerar o desenvolvimento da planta, melhorar suas características agronômicas, garantir maior sanidade e desempenho em campo. A aplicação de reguladores vegetais bioestimulantes com a finalidade de aumentar a produtividade das culturas é prática ainda pouco usual na agricultura. Assim, objetivou-se com este estudo avaliar o efeito da aplicação de bioestimulante vegetal associado a um indutor de resistência nos componentes de produção do feijoeiro. Foram utilizadas cinco doses de um bioestimulante (ácido indolbutírico, cinetina e ácido giberélico), sendo 0; 0,5; 1,0; 1,5 e 2,0 L ha-1, combinado com quatro doses de um indutor de resistência (0,5; 1,0; 2,0 e 3,0 L ha-1) no feijão comum, cv. IAC Formoso, em sistema de plantio direto. O experimento foi conduzido em Selvíria-MS, no ano agrícola 2013/14. O delineamento experimental foi em blocos casualizados, em esquema fatorial (5x4), com quatro repetições. Foram avaliados os componentes da produção e a produtividade de sementes da cultura. O indutor de resistência proporcionou maiores valores de matéria verde (52,08 g planta-1) e seca (17,29 g planta-1) de feijoeiro, respectivamente, nas doses de 2,04 L ha-1 e 2,15 L ha-1. A maior produtividade (3756 kg ha-1) foi obtida na dose de 0,78 L ha-1 do bioestimulante. O uso do bioestimulante vegetal pode ser uma alternativa viável para o aumento de produtividade do feijoeiro.

The use of computational tools has become notable in seed quality control to assist in confirming seed lots of higher potential. Thus, the aim of this study was to use a computational approach to investigate analysis of morphological parameters that characterize primary root emergence in evaluation of tomato seed vigor. For that purpose, five seed lots were analyzed for germination and vigor (seedling emergence and analysis of seedling images). A parallel analysis of primary root emergence was made using computer-assisted imaging; the images recorded as germination proceeded were processed with the ImageJ® software to obtain aspect ratio and seed area parameters. Vigor differences among tomato seed lots can be identified based on primary root emergence, and computer image processing based on aspect ratio proves to be an efficient procedure to characterize emergence of the primary root in evaluation of tomato seed vigor.

Seeds of high physiological quality are defined by their superior germination capacity and uniform seedling establishment. Here, it was investigated whether multispectral images combined with machine learning models can efficiently categorize the quality of peanut seedlots. The seed quality from seven lots was assessed traditionally (seed weight, water content, germination, and vigor) and by multispectral images (area, length, width, brightness, chlorophyll fluorescence, anthocyanin, and reflectance: 365 to 970 nm). Seedlings from the seeds of each lot were evaluated for their photosynthetic capacity (fluorescence and chlorophyll index, F0, Fm, and Fv/Fm) and stress indices (anthocyanin and NDVI). Artificial intelligence features (QDA method) applied to the data extracted from the seed images categorized lots with high and low quality. Higher levels of anthocyanin were found in the leaves of seedlings from low quality seeds. Therefore, this information is promising since the initial behavior of the seedlings reflected the quality of the seeds. The existence of new markers that effectively screen peanut seed quality was confirmed. The combination of physical properties (area, length, width, and coat brightness), pigments (chlorophyll fluorescence and anthocyanin), and light reflectance (660, 690, and 780 nm), is highly efficient to identify peanut seedlots with superior quality (98% accuracy).

In recent years, technological innovations have allowed significant advances in the diagnosis of seed quality. Seeds with superior physiological quality are those with the highest level of physiological maturity and the integration of rapid and precise methods to separate them contributes to better performance in the field. Autofluorescence-spectral imaging is an innovative technique based on fluorescence signals from fluorophores present in seed tissues, which have biological implications for seed quality. Thus, through this technique, it would be possible to classify seeds in different maturation stages. To test this, we produced plants of a commercial cultivar (MG/BR 46 “Conquista”) and collected the seeds at five reproductive (R) stages: R7.1 (beginning of maturity), R7.2 (mass maturity), R7.3 (seed disconnected from the mother plant), R8 (harvest point), and R9 (final maturity). Autofluorescence signals were extracted from images captured at different excitation/emission combinations. In parallel, we investigated physical parameters, germination, vigor and the dynamics of pigments in seeds from different maturation stages. To verify the accuracy in predicting the seed maturation stages based on autofluorescence-spectral imaging, we created machine learning models based on three algorithms: (i) random forest, (ii) neural network, and (iii) support vector machine. Here, we reported the unprecedented use of the autofluorescence-spectral technique to classify the maturation stages of soybean seeds, especially using the excitation/emission combination of chlorophyll a (660/700 nm) and b (405/600 nm). Taken together, the machine learning algorithms showed high performance segmenting the different stages of seed maturation. In summary, our results demonstrated that the maturation stages of soybean seeds have their autofluorescence-spectral identity in the wavelengths of chlorophylls, which allows the use of this technique as a marker of seed maturity and superior physiological quality.

Mechanical damage is a serious problem for the physiological potential of soybean seeds, especially when combined with chemical treatment. The aim of this study was to investigate the effects of chemical treatment on the physiological potential of soybean seeds with increasing levels of mechanical damage. Soybean seeds (cv. M6410 IPRO) of two lots with differences in vigor were subjected to five levels of mechanical damage (zero, one, two, three, and four impacts) brought about in a controlled manner. After characterization of the effect of the impacts on seed physical integrity (X-ray, X-ray microtomography, tetrazolium, and sodium hypochlorite), the seeds were subjected to four combinations of chemical treatment with fungicides (carbendazim and thiram), insecticides (imidacloprid and thiodicarb), micronutrients (cobalt and molybdenum), polymer (Peridiam®), and drying powder (Talkum Gloss®). Seed germination and vigor were evaluated sixty days after chemical treatment. A progressive increase in mechanical damage, especially that which causes cracks in the seed coat, reduces the physiological potential of soybean seeds and increases their sensitivity to the phytotoxic effect of the chemical treatment. The physical integrity of the seed coat is crucial for the success of technologies used for chemical seed treatment.

Glyphosate-resistant (GR) soybean is widely used in agriculture, however, plants exposed to herbicide show physiological changes. This study investigated the effect of treatments with glyphosate on the metabolism of N compounds, crop yield and physiological quality of seeds in GR soybean. The plants were grown in field experiment, located in the city of Selvíria, MS, Brazil. Glyphosate was applied postemergence at V 4 crop stage in a dose-response, including four rates (0; 360; 720 and 1440 g e. a. ha -1 ) with four replicates. Crop yield, physiological and biochemical features were determined. The results revealed previously unreported stimulant effects of glyphosate on GR soybean plants. Glyphosate changed the ureide shape in leaves, but did not change the concentration of total ureides, indicating maintenance of biological nitrogen fixation in plants exposed to herbicide. Amino acids concentration increased in plants submitted to higher doses. GR soybean showed higher crop yield and seed vigor with increased glyphosate doses. The results of this study indicate that glyphosate does not cause stress to the plant; however, it modulates a distinct response in plant development due to the protective gene inserted. This study can serve as a matrix for additional studies in order to seek clarification of responses of resistant/tolerant plants to glyphosate.

A adubação verde com Crotalaria juncea é uma estratégia vastamente utilizada no Cerrado para melhorar as características químicas, físicas e biológicas do solo, em uma matriz que apresenta limitações naturais para o desempenho adequado dos cultivos. O objetivo do trabalho foi de verificar o acúmulo de nutrientes e produção de matéria seca por C. juncea cultivada em solo de Cerrado. Dois experimentos foram realizados nos anos de 2015 e 2016, em um Latossolo Vermelho distrófico, no município de Selvíria, MS, Brasil. As semeaduras foram realizadas a lanço em área previamente preparada com aração e gradagem, sem utilização de adubação. Aos 80 dias após a semeadura e antes do pleno florescimento, as plantas foram manejadas com roçadora. Foram feitas as seguintes avaliações: (a) Massa seca: amostras obtidas de cada parcela foram levadas à estufa, realizou-se a mensuração da massa seca e o valor médio foi extrapolado para unidade de kg ha -1 . (b) Acúmulo de nutrientes: após coleta de amostras das plantas, determinou-se os teores de macro e micronutrientes e, posteriormente, multiplicou-se o teor de cada nutriente pela massa seca de C. juncea produzida, obtendo-se o acúmulo de macronutrientes (g kg -1 ) e micronutrientes (mg kg -1 ). O adubo verde apresentou elevada produção de matéria seca e excelente acúmulo de nitrogênio, potássio e ferro. Palavras chave: reciclagem de nutrientes, adubação verde, prática conservacionista ACCUMULATION OF NUTRIENTS AND DRY MATTER PRODUCED BY Crotalaria juncea CULTIVED IN CERRADO ABSTRACTThe green manuring with Crotalaria juncea is a strategy widely used in the Cerrado to improve the chemical, physical and biological characteristics of the soil, in a matrix that presents natural limitations to the proper performance of the crops. The objective of this work was to verify the accumulation of nutrients and dry matter production by C. juncea cultivated in Cerrado soil. Two experiments were carried out in the years 2015 and 2016, in a dystrophic Red Latosol, in the city of Selvíria, MS, Brazil. Seeds were insered in an area with conventional preparation, without the use of fertilization. At 80 days after sowing and before blooming, the plants were managed mechanically. The following evaluations were performed: (a) Dry matter production: the samples obtained from the plants were desiccated and the average dry matter yield was extrapolated to a unit of kg ha -1 . (b) Accumulation of nutrients: after collecting plant samples, the macronutrients and micronutrients contents were determined and, posteriorly, the content of each nutrient was multiplied by the dry mass of C.* mssmarcio@yahoo.com

The scarcity of information on the maturation physiology of the peanut seed (Arachis hypogaea L.; Virgínia group) makes harvesting high quality seeds a challenge for the seed industry. During two consecutive crop seasons, we studied the acquisition of physiological quality of peanut seeds during maturation in tropical conditions. We bring new insights about the period of late maturation of seeds and the influence of the maternal environment on physiological quality. We monitored water content, dry weight, ability of germination, desiccation tolerance, vigor and longevity. In addition, we monitored temperature and precipitation throughout plant growth. We demonstrate that the physiological quality of peanut seeds is acquired during development, with a maximum between 57 and 76 days after flowering in the late stage of maturation. This final period represents about 25% of the development, considered the best time to harvest peanut seeds with the highest quality. Our findings also support the idea that the adequate proportion of rainfall and thermal sum in the maternal environment are factors that favor the acquisition of peanut seed longevity.