Brachiaria brizantha is the most common forage plant used in cattle pastures. The field plant population is the main parameter for cattle nutrition; it is mainly determined by the genotype and physiological quality of the seed, that is, seed vigor. Seed vigor standard tests are considered time-consuming and laborious. Fourier transformed infrared (FTIR) spectroscopy was used to classify the seed cultivar and vigor from two different genotypes of B. brizantha, namely, Marandu and Paiaguás cultivars. Two batches from each group were used for classification by applying FTIR and machine learning algorithms. The algorithms with a higher overall accuracy in the leave-one-out cross-validation were also validated by an external validation using a dedicated set of samples exclusively separated for this purpose. The results indicate that molecular spectroscopy combined with machine learning analysis presents great potential for the classification of B. brizantha seeds.
The use of desiccants may result in seeds with high physiological and sanitary quality due to the shorter period of exposure to field adverse conditions before the maturity stage for harvest. This study evaluated the effect of chemical desiccants and harvest times on the physiological and sanitary quality of soybean seeds. The experiment consisted of a randomized block design, arranged in a factorial scheme (4 × 3) + 1, with four replications. The first factor corresponded to four desiccation (grammoxone-2 L ha -1 , glufosinate -2 L ha -1 , reglone-1.5 L ha -1 , and saflufenacil-40 g ha -1 ) applied at the R 7.1 phenological stage (physiological maturity and 65% moisture with three harvest times (0, 7, and 14 days after the R 8 phenological stage) and additional treatment (control, application of water only, and harvest at the R 8 stage), with four replications. The use of the grammoxone desiccant and seeds harvested at seven days after the R 8 stage resulted in soybean seeds of the highest physiological quality, as observed for the variables germination, moisture damage, mechanical damage, and incidences of Colletotrichum sp., Phomopsis sp., Penicillium sp. Fusarium sp., Cercospora kikuchii, and Alternaria sp. Seeds harvested at the R 8 + 14 stage had the greatest losses in seed quality. The use of ammonium glufosinate and saflufenacil as desiccants is not recommended due to the reduction in the physiological quality of soybean seeds.RESUMO -O uso de dessecantes pode permitir a obtenção de sementes com máxima qualidade fisiológica e sanitária, devido o menor período em que as sementes ficam expostas as condições adversas no campo aguardando o estádio de maturação para colheita. O objetivo neste trabalho foi avaliar o efeito de dessecantes químicos e épocas de colheita sobre a qualidade fisiológica e sanitária em sementes de soja. O ensaio foi realizado em delineamento em blocos casualizados, disposto em esquema fatorial (4 × 3) + 1, sendo quatro herbicidas para a dessecação (gramoxone -2 L ha -1 , glufosinato -2 L ha -1 , reglone -1,5 L ha -1 , saflufenacil 40 g ha -1 ) aplicado no estádio fenológico R 7.1 (maturidade fisiológica e 65% de umidade), com três épocas de colheita (0; sete e 14 dias após o estádio fenológico R 8 -maturação plena), mais o controle (ausência de dessecante e colhida em R 8 ), com quatro repetições. O uso do dessecante gramoxone e as sementes colhidas sete dias após R 8 proporciona maior qualidade fisiológica de sementes de soja, conforme observado nas variáveis germinação, danos por umidade, danos mecânicos e a incidência de Colletotrichum sp., Phomopsis sp., Penicilium sp., Fusarium sp., Cercospora kikuchii e Alternaria sp.. A colheita de sementes no estádio R 8 +14 promove as maiores perdas na qualidade das sementes. O uso de glufosinato de amônio e saflufenacil como dessecantes não são recomendados, devido à redução na qualidade fisiológica das sementes de soja.Palavras-chave: Glycine max. Herbicidas. Maturidade fisiológica. Vigor.
Chia (Salvia hispanica L.) is a plant native to central and western Mexico and northern Guatemala belonging to the Lamiaceae family, well known for its seeds containing antioxidants, dietary fibers, and ?-linolenic acid, which helps to prevent different diseases, such as diabetes, obesity, cancer and Alzheimer. In Brazil, there is not much information about the crop, mainly about the physiological quality of its seeds. Therefore, the objective was to establish vigor testing methods to evaluate the physiological quality of chia seeds. Five seed lots were used, in which germination tests, seedling emergence, emergence velocity index and variations in the electrical conductivity test were carried out. The volume of distilled water was 25 and 50 mL, the number of seeds was 50 and 100, the temperature was 20, 25 and 30 °C, the soaking period was 1, 2, 4, 6, 12, 18 and 24 hours and variations in there was accelerated aging test by the traditional method and saturated NaCl solution, being periods of aging as 24, 48, 72 and 96 hours and temperatures of 38, 41 and 44 °C. It is concluded that both the electrical conductivity test and the accelerated aging test are efficient in evaluating the physiological quality of chia seeds. The electrical conductivity test must be performed with 100 seeds in 50 mL of distilled water, for four hours soaking at 25 or 30 °C; and the accelerated aging test should be performed at 44 °C for 24 hours by the traditional method or 41 °C for 24 hours using saturated NaCl solution.
Predicting maize yield using spectral information, temperature, and different irrigation management through machine learning algorithms provide information in a fast, accurate, and non-destructive way. The use of multispectral sensor data coupled with irrigation management in maize allows further exploration of water behavior and its relationship with changes in spectral bands presented by the crop. Thus, the objective of this study was to evaluate, by means of multivariate statistics and machine learning techniques, the relationship between irrigation management and spectral bands in predicting maize yields. Field experiments were carried out over two seasons (first and second seasons) in a randomized block design with four treatments (control and three additional irrigation levels) and eighteen sample repetitions. The response variables analyzed were vegetation indices (IVs) and crop yield (GY). Measurement of spectral wavelengths was performed with the Sensefly eBee RTK, with autonomous flight control. The eBee was equipped with the Parrot Sequoia multispectral sensor acquiring reflectance at the wavelengths of green (550 nm ± 40 nm), red (660 nm ± 40 nm), red-edge (735 nm ± 10 nm), and NIR (790 nm ± 40 nm). The blue length (496 nm) was obtained by additional RGB imaging. Data were subjected to Pearson correlations (r) between the evaluated variables represented by a correlation and scatter plot. Subsequently, the canonical analysis was performed to verify the interrelationship between the variables evaluated. Data were also subjected to machine learning (ML) analysis, in which three different input dataset configurations were tested: using only irrigation management (IR), using irrigation management and spectral bands (SB+IR), and using irrigation management, spectral bands, and temperature (IR+SB+Temp). ML models used were: Artificial Neural Network (ANN), M5P Decision Tree (J48), REPTree Decision Tree (REPT), Random Forest (RF), and Support Vector Machine (SVM). A multiple linear regression (LR) was tested as a control model. Our results revealed that Random Forest has higher accuracy in predicting grain yield in maize, especially when associated with the inputs SB+IR and SB+IR+Temp.
Este estudo teve como objetivo obter informações qualitativas e quantitativas de um cerrado sentido restrito na microbacia do pasto ruim, no município de Chapadão do Sul, com base em um inventário florestal. Para a coleta de dados foram amostradas cinco parcelas de 1.000m² (10x100m) e mesurados todos os indivíduos com diâmetro a altura do solo (DAS) ≤ 5 cm. Foram coletados dados de DAS e DAP (diâmetro a altura do peito), altura total, espécie, parcela e subparcela. Foram calculados parâmetros fitossociológicos horizontais e verticais como frequência, densidade, e dominância, absolutas e relativas, índice de valor de importância (IVI), e posição sociológica. O total de 1327 indivíduos mensurados está distribuído em 35 famílias botânicas, 56 gêneros e 69 espécies. A área basal e densidade por hectare foi 29,1m² e 2354 indivíduos. A diversidade da floresta foram 3,33 e 0,94, calculados pelo método de Shannon-Weaver e Simpson, respectivamente, equabilidade de Pielou foi 0,78, indicando heterogeneidade alta e dominância de espécies. As espécies com maior importância na floresta foram:
O presente trabalho baseia-se na hipótese de que o cultivo de diferentes coberturas vegetais poderia suprimir o banco de sementes de plantas daninhas, além de melhorar as condições do solo e incrementar a produtividade. O objetivo deste trabalho foi avaliar o banco de sementes de plantas daninhas com diferentes coberturas vegetais. O delineamento experimental utilizado foi em blocos casualizados com nove tratamentos e quatro repetições. Os tratamentos foram constituídos pelas coberturas vegetais: crotalária (Crotalaria juncea), milheto (Pennisetum americanum), nabo forrageiro (Raphanus sativus), sorgo (Sorghum bicolor), Urochloa brizantha, U. piatã, U. ruziziensis, mistura de sementes (nabo forrageiro + milheto) e o pousio. Foi avaliado o fluxo germinativo das plantas daninhas a partir de amostras de solo, retiradas das áreas onde semeou-se os tratamentos e levando-as para a casa de vegetação, onde foi realizada a quantificação e identificação das sementes de plantas daninhas germinadas. As famílias Asteraceae, Convolvulaceae e Fabaceae se destacaram com ocorrência em maior número de coberturas vegetais. O uso de coberturas vegetais propicia a redução do fluxo de emergência de plantas daninhas a partir do banco de sementes. As coberturas nabo, nabo+milheto e U. piatã foram as que mais reduziram o fluxo de germinação de plantas daninhas, enquanto o pousio, crotalária e Urochloa ruziziensis tiveram menor capacidade de reduzir esse fluxo.
The application of silicon is becoming popular in agriculture as an alternative for integrated crop management, owing to the diverse benefits resulting from the accumulation of silicon in grasses and the resultant resistance conferred in plants against biotic and abiotic stresses. The objective of this study was to evaluate whether the application of silicon, via seed coating and leaf application, influences the production and yield components of maize in the second crop. The experimental design was divided into split plots, in which the plots were composed of phyllosilicate doses (0, 5, 10, 15, and 20 g kg-1 of seeds) in the seed coatings and the subplots were composed of foliar applications of potassium silicate (1.0 L ha-1 in pre-dip and 15 days after). We evaluated the plant height, spike insertion height, spike and corncob diameter, number of rows per spike, number of grains per row, the mass of 100 grains, and productivity. The foliar application of potassium silicate had no effect on the yield and yield components of the corn crop. The use of phyllosilicate via seed coating increased the production components and yield of the second corn crop.
The use and incorporation of basalt powder in the soil have grown every year, and there are still no studies showing its effects on the physiological quality of soybean seeds. Thus, considering the importance of this response in the production system, the objective of the present work was to evaluate the physiological condition of soybean seeds after applying different doses of basalt powder in the soil. The experimental design used was completely randomized in a 3 × 4 factorial scheme, with three replications. The treatments consisted of three soybean cultivars, and four doses of basalt powder (0, 1, 3, and 5 t ha-1) produced in the 2018/2019 harvest in the region of Chapadão do Sul, MS. The tests carried out were: first germination count, germination, electrical conductivity, dry mass of the upper plant and roots, and tetrazolium test (vigor, viability, mechanical damage, moisture, and bed bug damage). The results were submitted to the normality test and analysis of variance, followed by comparisons of means by the Tukey test at the level of 5% probability. The results showed for the first time the combined effects of both factors tested only on the variables: electrical conductivity, root length, vigor, viability, and mechanical damage. The response obtained was dependent on the cultivars evaluated, which differed for all measured characteristics.
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