High-throughput phenotyping allows the selection of soybean genotypes for earliness and high grain yield.

BACKGROUND: Precision agriculture techniques are widely used to optimize fertilizer and soil applications. Furthermore, these techniques could also be combined with new statistical tools to assist in phenotyping in breeding programs. In this study, the research hypothesis was that soybean cultivars show phenotypic differences concerning wavelength and vegetation index measurements. RESULTS: In this research, we associate variables obtained via high-throughput phenotyping with the grain yield and cycle of soybean genotypes. The experiment was carried out during the 2018/2019 and 2019/2020 crop seasons, under a randomized block design with four replications. The evaluated soybean genotypes included 7067, 7110, 7739, 8372, Bonus, Desafio, Maracai, Foco, Pop, and Soyouro. The phenotypic traits evaluated were: first pod height (FPH), plant height (PH), number of branches (NB), stem diameter (SD), days to maturity (DM), and grain yield (YIE). The spectral variables evaluated were wavelengths and vegetation indices (NDVI, SAVI, GNDVI, NDRE, SCCCI, EVI, and MSAVI). The genotypes Maracai and Foco showed the highest grain yields throughout the crop seasons, in addition to belonging to the groups with the highest means for all VIs. YIE was positively correlated with the NDVI and certain wavelengths (735 and 790 nm), indicating that genotypes with higher values for these spectral variables are more productive. By path analyses, GNDVI and NDRE had the highest direct effects on the dependent variable DM, while NDVI had a higher direct effect on YIE. CONCLUSIONS: Our findings revealed that early and productive genotypes can be selected based on vegetation indices and wavelengths. Soybean genotypes with a high grain yield have higher means for NDVI and certain wavelengths (735 and 790 nm). Early genotypes have higher means for NDRE and GNDVI. These results reinforce the importance of high-throughput phenotyping as an essential tool in soybean breeding programs.

Irrigation management in soybean crops influences the occurrence of nematodes in the soil / Manejo de irrigação na cultura da soja influencia a ocorrência de nematóides no solo

One of the main limitations of soybean production is related to water availability and organisms found in the soil. Under the hypothesis that soil moisture may influence the nematode population, this study aimed to verify the occurrence of nematodes associated with different irrigation management in soybean crops. The experiment was carried out in a randomized block design. Treatments consisted of a subplot scheme, with four replications. The plots consisted of ten irrigation managements divided into five irrigation frequencies (1,2,3,4, and 5 days) and five additional water depths (25, 50, 75, 100, and 125% of crop evapotranspiration ­ Etc). The subplots were composed of four different soybean cultivars (NA 5909 RR, AS 3680 IPRO, and Desafio RR ePower IPRO). The experiment analyzed the variables plant height, first pod insertion, number of plants, moisture, hundred-grain weight, yield, and occurrence of nematode eggs and adults. Nematodes influence all the production components analyzed, affecting mostly the hundred-grain weight, especially the nematode Helicotylenchus sp., although the Meloidogyne sp. population was larger. The phytonematode population reduces with the increase in soil moisture to levels close to the saturation, indirectly influencing the yield increase.

Uma das principais limitações da produção de soja está relacionada à disponibilidade de água e organismos encontrados no solo. Sob a hipótese de que a umidade do solo possa influenciar a população de nematoides, este estudo teve como objetivo verificar a ocorrência de nematóides associados a diferentes manejos de irrigação em lavouras de soja. O experimento foi conduzido em delineamento de blocos casualizados. Os tratamentos consistiram de um esquema de subparcelas, com quatro repetições. As parcelas consistiram de dez manejos de irrigação divididos em cinco freqüências de irrigação (1,2,3,4 e 5 dias) e cinco lâminas d'água (25, 50, 75, 100 e 125% da evapotranspiração da cultura - Etc). As subparcelas foram compostas por quatro diferentes cultivares de soja (NA 5909 RR, AS 3680 IPRO e Desafio RR ePower IPRO). O experimento analisou as variáveis altura da planta, inserção da primeira vagem, número de plantas, umidade, peso de cem grãos, produtividade e ocorrência de ovos de nematoides e adultos. Os nematóides influenciam todos os componentes de produção analisados, afetando principalmente o peso de cem grãos, especialmente o nematódeo Helicotylenchus sp., Embora o Meloidogyne sp. população era maior. A população de fitonematóides reduz com o aumento da umidade do solo para níveis próximos à saturação, influenciando indiretamente o aumento da produtividade.

Phenotypic adaptability of cotton genotypes to the brazilian cerrado for yield and fiber quality / Adaptabilidade fenotípica de genótipos de algodão ao cerrado brasileiro para produtividade e qualidade de fibras

Studies on the adaptability and stability are fundamental for plant breeding as they are an alternative to reduce the effects of genotypes x environments interaction (GxE). Moreover, they help identify cultivars with predictable behavior, which are responsive to environmental improvements, subsidizing cultivar recommendation. This study aimed to evaluate the genotypes x environments interaction in cotton genotypes grown in the Brazilian Cerrado and identify genotypes for favorable and unfavorable environments. During the 2013/2014 and 2014/2015 seasons, 19 competition trials were carried out with cotton in a randomized block design, with 12 treatments, and four replications. The traits cotton seed yield, fiber percentage, fiber length, and fiber strength were evaluated. Results revealed significant GxE interaction for all the fiber traits evaluated. Genotype BRS 369 RF revealed general adaptability and high predictability for the fiber traits evaluated.

Estudos sobre a adaptabilidade e estabilidade são fundamentais para o melhoramento de plantas, pois são considerados uma alternativa para reduzir os efeitos da interação genótipos x ambientes (GxE) e identificar cultivares com comportamento previsível e responsivo a melhorias ambientais, subsidiando a recomendação de cultivares. Este trabalho teve como objetivo investigar a interação genótipos x ambientes em genótipos de algodoeiro cultivados no Cerrado brasileiro e identificar genótipos para ambientes favoráveis e desfavoráveis. Durante as safras 2013/2014 e 2014/2015, foram realizados 19 ensaios de competição com algodão em delineamento de blocos ao acaso, com 12 tratamentos e quatro repetições. As características produtividade de sementes de algodão, porcentagem de fibras, comprimento de fibra e resistência das fibras foram avaliadas. Os resultados revelaram interação significativa da GxE para todas as características da fibra avaliada. O genótipo BRS 369 RF revelou adaptabilidade geral e alta previsibilidade para as características da fibra avaliada.

Selenium toxicity in upland field-grown rice: Seed physiology responses and nutrient distribution using the µ-XRF technique.

Selenium (Se) is an essential element for human and animal, although considered beneficial to higher plants. Selenium application at high concentration to plants can cause toxicity decreasing the physiological quality of seeds. This study aimed to characterize the Se toxicity on upland rice yield, seed physiology and the localization of Se in seeds using X-ray fluorescence microanalysis (µ-XRF). In the flowering stage, foliar application of Se (0, 250, 500, 1000, 1500, 2000 g ha-1) as sodium selenate was performed. A decrease in rice yield and an increase in seed Se concentrations were observed from 250 g Se ha-1. The storage proteins in the seeds showed different responses with Se application (decrease in albumin, increase in prolamin and glutelin). There was a reduction in the concentrations of total sugars and sucrose with the application of 250 and 500 g Se ha-1. The highest intensities Kα counts of Se were detected mainly in the endosperm and aleurone/pericarp. µ-XRF revealed the spatial distribution of sulfur, calcium, and potassium in the seed embryos. The seed germination decreased, and the electrical conductivity increased in response to high Se application rates showing clearly an abrupt decrease of physiological quality of rice seeds. This study provides information for a better understanding of the effects of Se toxicity on rice, revealing that in addition to the negative effects on yield, there are changes in the physiological and biochemical quality of seeds.

Environmental stratification in the brazilian cerrado on the yield and fiber quality of cotton genotypes / Estratificação ambiental no cerrado brasileiro sobre o rendimento e a qualidade da fibra dos genótipos de algodão

Environmental stratification studies are important for the plant breeding, since they allow to adequately plan the experimental network. The objective of this work was to identify similar environments for cotton cultivation in the Brazilian Cerrado regarding yield and fiber quality. Nineteen field studies were carried out in a randomized complete block design with twelve genotypes and four replicates. Agronomic (cotton seed yield and fiber percentage) and technological traits (length, micronaire, fiber strength) were evaluated. These results indicate that there are six environments (PVA3, MON, SHE1, SIN, PPA e TRIN) in which the cotton trials should be installed as a matter of priority owing to the phenotypic response pattern obtained for the evaluated traits. The remaining 13 environments are similar to each other for all traits and can be summarized in strategic locations depending on the ease of installation of the trials

Os estudos de estratificação ambiental são importantes para a criação de plantas, uma vez que permitem planejar adequadamente a rede experimental. O objetivo deste trabalho foi identificar ambientes similares para cultivo de algodão no Cerrado brasileiro quanto a produtividade e qualidade da fibra. Dezenove experimentos foram realizados em um delineamento de blocos ao acaso com doze genótipos e quatro repetições. Foram avaliados caracteres agronômicos (produtividade de algodão em caroço e porcentagem de fibra) e tecnológicas (comprimento, micronaire, resistência de fibras). Os resultados indicam que existem seis ambientes (PVA3, MON, SHE1, SIN, PPA e TRIN) em que os ensaios de algodão devem ser instalados como prioritários devido ao padrão de resposta fenotípica obtido para os traços avaliados. Os 13 ambientes restantes são semelhantes entre si para todos os caracteres e podem ser resumidos em locais estratégicos, de acordo com a facilidade de instalação dos ensaios.

Studying the link between physiological performance of Crotalaria ochroleuca and the distribution of Ca, P, K and S in seeds with X-ray fluorescence.

This study describes the use of X-ray fluorescence spectroscopy in Crotalaria ochroleuca seed technology. This work evaluated X-ray fluorescence techniques to estimate the physiological performance of different C. ochroleuca seed coat colours based on the concentration and distribution of Ca, P, K, and S in seed structures. The treatments consisted of seeds separated by coat colours (yellow, green, and red) and a control treatment (colour mix according to their natural occurrence in commercial lots), and was carried out in a completely randomized design, with four replications. The physiological performance was evaluated by analyzing the water content, germination, first germination count, germination speed index, electrical conductivity, seedling emergence, and seedling length and dry mass. X-ray fluorescence spectroscopy techniques were carried out with quantitative analyses (Ca, P, K, and S concentration in the seed coat and the whole seed) and qualitative analyses (macronutrient mapping). The EDXRF and µ-XRF techniques are efficient and promising to differentiate the physiological performance of C. ochroleuca seeds, based on the concentration and distribution of Ca, P, K, and S in different structures. Ca is predominant in the seed coat, and K, S, and P are found throughout the embryonic axis. Seeds of yellow and green coats have higher nutrients concentration and distribution in the embryonic axis, revealing high germinative capacity and physiological performance. Seeds of red coat have higher nutrients concentration in the seed coat and lower assimilation, showing less vigour, which interferes directly in the quality of commercial lots.

Accelerated aging in sorghum genotypes / Envelhecimento acelerado em genótipos de sorgo

The accelerated aging test has stood out among vigor tests. It has been used with different objectives, including as an assistance method in the selection of cultivars for plant breeding. This research aimed to analyze the effects of different exposure times to accelerated aging on the germination and vigor of sorghum seeds from different genetic sources. The experiment consisted of a completely randomized design with eight genotypes and four replications. Seeds were subject to an accelerated aging test with four exposure times (0, 24, 72, and 96 h) at a temperature of 47 °C and then evaluated by germination test (G), germination speed index (GSI), mean germination time (MGT), seedling emergence (SE), emergence speed index (ESI), and mean emergence time (MET). All genotypes presented a reduction in germination, GSI, SE, and ESI, and an increase in MGT and MET. The genotype CMX5156A had an increase in seed vigor under conditions of high temperature and relative humidity. Accelerated aging for 72 hours at 47 °C drastically reduces seed vigor. The accelerated aging test can be used to differentiate sorghum genotypes in breeding programs

teste de envelhecimento acelerado tem se destacado entre os testes de vigor, sendo utilizado com diferentes objetivos, inclusive como método assistencial na seleção de cultivares para melhoramento de plantas. Esta pesquisa teve como objetivo analisar os efeitos de diferentes tempos de exposição ao envelhecimento acelerado na germinação e vigor de sementes de sorgo de diferentes fontes genéticas. O experimento consistiu em um delineamento inteiramente casualizado com oito genótipos e quatro repetições. As sementes foram submetidas ao teste de envelhecimento acelerado com quatro tempos de exposição (0, 24, 72 e 96 h) a uma temperatura de 47 °C e avaliadas pelo teste de germinação (G), índice de velocidade de germinação (GSI), tempo médio de germinação. (MGT), emergência de plântulas (SE), índice de velocidade de emergência (ESI) e tempo médio de emergência (MET). Todos os genótipos apresentaram redução na germinação, GSI, SE e ESI, e aumento no MGT e MET. O genótipo CMX5156A apresentou sementes com maior vigor em condições de alta temperatura e umidade relativa. O envelhecimento acelerado por 72 horas a 47 °C reduz drasticamente o vigor das sementes. O teste de envelhecimento acelerado pode ser usado para diferenciar genótipos de sorgo em programas de melhoramento.