ABSTRACT The biological control, thinking about the integrated management, has been inserted with other management techniques to disease control, such as soybean anthracnose. The aims of this work were to verify the action of Trichoderma and Bacillus isolates in the induction of soybean resistance mechanisms to anthracnose as a function of seed treatment. The statistical design was entirely randomised, in a 5 x 2 (agent species x sampling times) factorial scheme with five replicates. Soybean seeds were treated with Bacillus amyloliquefaciens BV03, B. subtilis BV02, Trichoderma asperellum BV10, Carbendazim + Thiram and distilled water (control). Seven days after seedling emergence, 2 μL of 1 x 10−4 Colletotrichum truncatum spores were inoculated on the cotyledons. Catalase (CAT), peroxidase (POX), phenylalanine ammonia lyase (PAL) and glyceollin (GLY) activities before and after pathogen inoculation, as well as the diameter of the anthracnose lesion on the cotyledons, were evaluated. Data were submitted to analysis of variance and, when significant, the mean values were compared by Fisher’s test (p < 0.05). The treatments did not influence the first sampling time before inoculation. Trichoderma asperellum BV10 increased POX and PAL activities up to 173%, while B. amyloliquefaciens BV03 increased POX activity. Glyceollin was not influenced by the treatments. The T. asperellum BV10 reduces the diameter of the anthracnose lesion by up to 61%. Thus, T. asperellum BV10 has the potential to control soybean anthracnose, improved the response defense against C. truncatum, when performed on seed treatment.

ABSTRACT In recent decades, soybean has been one of the most widely grown crops in Brazil. The soybean looper, Chrysodeixis includens (Walker, [1858]; Lepidoptera: Noctuidae), is one of the main defoliating pests of soybean that cause damage and affect the cost of production. The overall objective of the present study was to characterize the resistance of C. includens to diamide insecticides. To this end, the baseline susceptibility of C. includens to flubendiamide, chlorantraniliprole, and cyantraniliprole was characterized to estimate their concentrations for diagnostic monitoring of resistance in populations collected in commercial soybean crops in southern Brazil during the 2018/19 season. Under field conditions, evaluations were made of the residual activity of three diamide insecticides: chlorantraniliprole + lambda-cyhalothrin, teflubenzuron, methoxyfenozide, and bifenthrin for discrimination between flubendiamide-susceptible and resistant C. includens. Chrysodeixis includens was more tolerant to cyantraniliprole than to flubendiamide and chlorantraniliprole. The field populations had a higher survival rate than the susceptible population. The resistant population showed a resistance ratio to flubendiamide of 70.1-fold. Under field conditions, the residue of the study insecticides, except for bifenthrin, enabled discrimination between flubendiamide-susceptible and resistant C. includens. The data indicate the need to study the cross-resistance relationships between insecticides to improve the rotation recommendation. They also reinforce the importance of using other good management practices, e.g., the use of insecticides based on pest sampling and the choice of other control methods to prevent C. includens from becoming resistant to diamide insecticides.

ABSTRACT Technologies that use rhizobacteria to promote plant growth are increasing in agriculture, results have shown improvements in soil quality, increases in productivity, and decreases in the use of synthetic inputs, The objective of work was to characterize bacterial isolates regarding their biological activity and growth promotion of soybean plants grown in a controlled environment. Fifteen bacteria were isolated from soils with continuous use of biological fertilizer. They were evaluated for enzymes production (amylase and protease), nitrogen fixation, antagonistic activity to phytopathogenic fungi, and indoleacetic acid (IAA) production, Soybean seeds were inoculated with bacterial isolates in a greenhouse and evaluated for plant development and soil chemical attributes. The results showed that 8 of the 15 isolates presented production of amylase, protease, or both and 4 isolates presented nitrogen-fixing capacity. The percentage of isolates with high or moderate inhibitory action against the fungi Sclerotinia sclerotiorum, Macrophomina phaseolina, and Fusarium solani were 73.3%, 66.6%, and 73.3%, respectively. The IAA production varied from 8.56 to 31.33 µg mL-1 (5 isolates had low, 6 had moderate, and 4 had high production). The soybean development was significantly higher in 80% of the treatments with inoculation with bacterial isolates. Five bacterial isolates effectively present all characteristics for use as inoculant (biofertilizer) to promote the development of soybean plants.

ABSTRACT Soybeans are among the world’s main crops because they are excellent sources of proteins, micronutrients, and oil. Considering that abiotic stress affects agribusiness, resulting in losses, the grain yield of the crop must be maintained even at high temperatures. In this context, the objective of this study was to select markers related to soybean yield assessed under high temperatures, using associative mapping. The mapping population included 80 soybean PIs and 15 controls. For phenotyping, genotypes were evaluated at high temperatures in an experiment conducted in Teresina (in the state of Piauí) and four characters of interest for agronomy were evaluated: height of the plant when mature, agronomic value, 100-seed weight, and grain yield. Genotyping was carried out using the Affymetrix Platform (180 K Axiom® Soybean Genotyping Array), and the imbalance in the connection between pairs of markers was calculated through the coefficient of determination using the fast permutation test. The analysis of the association between markers and the phenotype of interest was carried out using a generalized linear model approach, including phenotyping data, SNP markers, and information on population structure. The results revealed that 34.06% of loci showed a significant linkage disequilibrium (p < 0.001), and 16 significant associations were found for the four characters related to heat tolerance. These associations can aid breeders that aim to incorporate high temperature tolerance in programs of soybean genetic improvement via selection assisted by markers.

ABSTRACT The adequacy of spraying technology in the control of Asian rust to factors related to soybean cultivars and fungicide type is fundamental for the efficiency in the control of this disease. In this context, the objective was to evaluate the chemical control of Asian soybean rust and the deposition of the fungicide applied in the crop, according to different volumes and spray nozzles. Four field experiments were set up during the 2014/2015 season, each carried out with one soybean cultivar, using: NA 5909 RR®, NS 7237 IPRO®, BMX Potência RR® and W 712 RR®. The experimental design was randomized blocks in a 2x2x2 factorial arrangement, with four replications. The first factor corresponded to the use of fungicides: [pyraclostrobin + epoxiconazole] and [pyraclostrobin + epoxiconazole] + mancozeb; the second factor, types of spray nozzle: double and triple fan; and the last factor, application volume: 60 and 120 L ha-1. The highest application volume resulted in greater deposition of droplets in the canopy of the plants, regardless of the fungicide, type of spray nozzle and cultivar. The association of fungicides [pyraclostrobin + epoxiconazole] + mancozeb showed greater efficacy in controlling rust, regardless of the type of spray nozzle and the volume applied when compared to [pyraclostrobin + epoxiconazole]. The highest volume of application promoted less disease evolution in the cultivars NA 5909 RR®, NS 7237 IPRO® and BMX Potência RR®. The yields of the cultivar were higher when the combination [pyraclostrobin + epoxiconazole] + mancozeb was used.

ABSTRACT Sourgrass (Digitaria insularis) is one of the main species causing significant losses in Brazilian soybean production systems. Thus, this paper aimed to evaluate sourgrass interference on soybeans grown under Cerrado conditions. Three field experiments were conducted, of which the first two (E1 and E2) simulated sourgrass after pre-sowing burndown, using plants already emerged by the time soybeans were sown; whereas the third (E3) simulated both sourgrass and soybeans emerged simultaneously. Both E1 and E2 were conducted in a randomized complete block design (RCBD) with five treatments based on sourgrass infestation densities (0, 2, 4, 6, and 8 plants m-2) and four replications. In turn, E3 was also carried out in an RCBD but with treatments arranged in a 2 x 5 factorial and four replications. The first factor comprised two soybean cultivars, while the second was sourgrass density levels, just as in E1 and E2. The results showed that increasing sourgrass densities reduced soybean yield regardless of the plant growth stage when the crop was sown. Yield losses were higher when sourgrass plants were already established by the time soybean was sown. Soybean yield losses reached up to 80% under higher sourgrass infestation levels.

ABSTRACT Alternative management measures have been used to reduce nematode population levels in affected areas. In this perspective, the objective was to evaluate the efficiency of nematicides based on fungus and bacterium, associated with poultry litter applied via ground in the management of Pratylenchus brachyurus and Heterodera glycines in soybean and corn crops in succession. The experiment was conducted in the 2018/19 growing season in the municipality of Ipameri– GO (-17°34’55.58”S−48°12’02.35”O) in naturally infested field, arranged in a randomized block design, with 10 treatments and 4 replicates, being: T1- Witness/ control, T2- Poultry litter, T3- P. lilacinum + T. harzianum, T4- B. subtilis + B. licheniformis, T5- P. chlamydosporia, T6- Abamectina, T7- P. lilacinum + T. harzianum + Poultry litter, T8- B. subtilis + B. licheniformis + Poultry litter, T9- P. chlamydosporia + Poultry litter, T10- Abamectina + Poultry litter. The poultry litter was added in the soil 10 days before planting. The plots were composed of 6 lines of 6 m, with a spacing of 0.5 m. In the soybean crop at 45 and 90 days after sowing (DAS), the fresh weight of the roots (MFR), nematological variables and productivity were evaluated. In corn, only nematological variables were evaluated at 60 DAS. The treatments using P. lilacinum + T. harzianum and B. subtillis + B. licheniformes increased the MFR and reduced the number of P. brachyurus and H. glycines at the root. P. chlamydosporia associated with poultry litter increased in productivity in soybean plants.

ABSTRACT No isolated factor influences soybean development and production more than the sowing date, but the responses of cultivars sown on different sowing dates depends on their sensitivity to environmental conditions. Thus, this study evaluated the adaptability and stability of 17 soybean genotypes in relation to yield, as well as to the grain oil and protein contents as a function of different sowing times. The experiment was designed in randomized blocks with three replications and a 17 × 5 factorial scheme. The genotypes were: Conquista, CD 223 AP, Elite, Garantia, Bioagro lineage, M-Soy 8400, M-soy 8001, Nambu, Sambaíba, Esplendor, UFVS 2006, UFVS 2005, UFVTN 102, UVF 18, UFV 16, Valiosa, Vencedora, and the five sowing dates were: SD1 = 11/3, SD2 = 11/20, SD3 = 12/07, SD4 = 12/23, and SD5 = 01/09. The M-Soy 8001, UFV 18 and Garantia genotypes showed high oil contents, with adaptation to all sowing dates and stability when sown on the most favorable dates. The Bioagro lineage, CD 223 AP, and Garantia genotypes were adapted and stable when sown on all sowing dates and had higher protein contents than the other genotypes, regardless of the sowing date. The Elite, Nambu, and Garantia genotypes were adapted and stable when sown on the most favorable sowing dates and presented high grain yields when sown in early December. The findings indicate that the Garantia genotype is the most suitable for the growing conditions of the central-north region of the state of São Paulo.

RESUMO Objetivou-se com este trabalho avaliar os parâmetros fitomorfológicos da cultura da soja em um sistema de integração lavoura-pecuária e inoculados com Azospirillum brasilense. O experimento foi conduzido em Santa Maria, em dois agrícolas (2012/2013 e 2013/2014), num delineamento experimental de blocos casualizados, com três repetições. No período de inverno a pastagem de aveia preta e azevém foi manejada com ovinos em diferentes sistemas de pastejo: (I) - pastejo convencional (PC), onde os animais permaneciam na pastagem por todo o período experimental sem um controle da altura da pastagem, (II,III e IV) - altura da pastagem na saída dos animais de 10, 20 e 30 cm e uma testemunha sem pastejo (SP), três doses de nitrogênio (0, 50 e 100 kg ha-1) e com ou sem inoculação (Azospirillum brasilense). A semeadura da soja foi realizada em semeadura direta em 16 de novembro de 2012 e 01 de dezembro de 2013, utilizando-se a cultivar BMX Potência RR. Em cada parcela, se utilizou sete fileiras de plantas com espaçamento de 0,45 m, sendo que em quatro fileiras as sementes foram inoculadas com a bactéria Azospirillum brasilense. Foram avaliadas variáveis fitomorfológicas e a produtividade de grãos. Em sistema de integração lavoura-pecuária a cultura da soja possui melhores produtividades quando estabelecida sobre pastagem de aveia preta e azevém manejadas com alturas de pastejo entre 20 e 30 cm. As áreas sob pastejo convencional no inverno proporcionam plantas de soja menores, com menores inserções de primeira e última vagem. A inoculação com Azospirillum brasilense não deve ser usada isoladamente na cultura da soja. | ABSTRACT The objective of this study was to evaluate the phytomorphological parameters of soybean in a crop-livestock system inoculated with Azospirillum brasilense. The experiment was conducted in Santa Maria, Brazil, for two agricultural years (2 Paper extracted from the doctoral thesis of the first author. 012/2013 and 2013/2014) in a randomized complete block design with three replications. In the winter, the black oat and ryegrass pasture was managed with sheep under different grazing systems: (I) - a conventional grazing (CG) system, where the animals remained in the pasture throughout the experimental period without any pasture height control; (II, III, and IV) - systems with post-grazing pasture heights of 10, 20, and 30 cm, respectively; and (NG) - one control without grazing. All treatments received two nitrogen doses (50 and 100 kg ha-1) and inoculation or no inoculation (A. brasilense). The soybean cultivar BMX Potência RR was sown using no-tillage on 16 November 2012 and 1 December 2013. In each plot, seven rows of plants with spacing of 0.45 m were used, and in four rows, the seeds were inoculated with the bacterium A. brasilense. The phytomorphological variables and grain productivity were evaluated. In a croplivestock system, soybean has better productivity when established on black oat and ryegrass pasture managed with post-grazing pasture heights of between 20 and 30 cm. Areas under conventional grazing in the winter led to smaller soybean plants with lower first and last pod heights. Inoculation with A. brasilense should not be used alone in soybean cultivation.

RESUMO O trabalho teve como objetivo estudar variações nos parâmetros envolvidos no teste do pH do exsudato e alagamento para caracterização da qualidade fisiológica de sementes de soja. Inicialmente, foi determinado o teor de água e realizados os testes de germinação, primeira contagem, emergência e índice de velocidade de emergência. No teste do pH do exsudato foram estudadas variações no período de embebição e temperatura; e no teste de alagamento foram estudadas variações na quantidade de água e temperatura. O experimento foi realizado em delineamento inteiramente casualizado com quatro repetições, e as médias comparadas pelo teste de Scott-Knott a 5% de probabilidade. Foi estimado o coeficiente de correlação de Pearson entre os testes do pH do exsudato e alagamento com a emergência de plântulas. O teste do pH do exsudato pode ser utilizado na avaliação do potencial fisiológico de sementes de soja, sendo que este deve ser realizado na temperatura de 20 ºC por 30 minutos de embebição. O teste de alagamento é eficiente na avaliação do vigor de sementes de soja, podendo ser realizado nas combinações 25 ºC/50 mL ou 30 ºC/75 mL, durante 4 h. | ABSTRACT The present study aimed to assess the variations in the parameters of the exudate pH and flooding tests to evaluate the physiological quality of soybean seeds. We subjected the lots of soybean seeds to germination, emergence, exudate pH, and flooding tests. Further, water content of the seeds, first count of germination, and emergence speed index were also determined. The exudate pH test studied the variations in the soaking period and temperature, while the flooding test assessed the variations in the amount of water and temperature at different periods of immersion. The experiment design was completely randomized. The results were presented as means and were compared using the Scott-Knott test at 5% probability. The Pearson’s correlation coefficient between the exudate pH and emergence of seedlings, and also between the flooding test result and emergence of seedlings were calculated. The results of the study indicated that the exudate pH test can be used to evaluate the physiological quality of soybean seeds after 30 min of imbibition at 20 °C. Further, the flooding test was efficient in evaluating the vigor of soybean seeds after 4 h of immersion either in 50 mL of distilled water at 25 °C or in 75 mL of distilled water at 30 °C.