REVISTA BRASILEIRA DE MILHO E SORGO

ISOLATION AND IDENTIFICATION OF BROAD-SPECTRUM ANTAGONIST BACTERIA AGAINST PATHOGENIC FUNGI OF MAIZE CROP

2023-10-04T05:28:50-03:00

Fungal diseases may cause significant damage to crops worldwide, generating yield losses, poor grain quality, and health risks to humans and animals. Biological control using antagonistic bacteria offers innovative solutions for sustainable management aiming at plant protection. However, beneficial plant-microorganism interactions are particular, and few antagonists with broad-spectrum activity have been reported. In this work, two bacteria isolated from sorghum seeds were identified by partial sequencing of the 16S rRNA gene and tested in vitro for their capacity to control six important pathogenic fungi of maize: Fusarium verticillioides, Macrophomina phaseolina, Stenocarpella sp., Fusarium graminearum, Colletotrichum graminicola, and Bipolaris sp. The molecular identification revealed that the bacterial isolates belong to the genera Bacillus (strain LIS05) and Paenibacillus (strain LIS04). Both bacterial isolates inhibited the growth of all six phytopathogens by at least 49%. The isolate LIS05 showed the most significant antagonistic potential against the fungal pathogens tested, at an average of 73% inhibition. The highest antagonist activity (86.1% inhibition) was observed in the confrontation test between the isolate LIS05 and C. graminicola. In addition to the mycelial growth inhibition, the isolate LIS04 blocked the production of dark pigments by Bipolaris sp. This study showed that LIS05 and LIS04 are promising alternatives for developing integrated management strategies to control fungal diseases in maize and sorghum.

GROWTH PROMOTION IN MAIZE INOCULATED WITH Trichoderma harzianum

2022-12-07T12:19:52-03:00

The current research evaluated the effectiveness of Trichoderma harzianum in promoting the vegetative growth of maize in a medium containing nutrient solution from seed inoculation with different bio-input doses. The experiment was conducted in an agricultural greenhouse containing 8 liters of polyethylene recipients containing sand, using a completely randomized design with five treatments and six replications. The maize hybrid MSG1001 seeds were inoculated with different doses of the commercial product based on T. harzianum for every 100 kg of seeds. The treatments were: T1: 0 ml (control), T2: 200 ml, T3: 400 ml, T4: 600 ml, and T5: 800 ml. Sowing was performed in recipients containing fine-washed sand and capillarity irrigation with nutrient solution until the end of the experiment. At 28 DAP, the following variables were assessed: shoot length (SL), root length (RL), total plant length (TPL), shoot dry mass (SDM), root dry mass (RDM), total dry mass (TDM), total chlorophyll V3 (TCV3), total chlorophyll V4 (TCV4) and stem diameter (SD). The gradual increase in the doses of bio-input based on T. harzianum, up to 800 ml 100 kg-1 of seeds, promoted an increase of 27%, 81%, 40%, 34%, 64%, and 42% in the variables SDM, RDM, TDM, SD, SL, and TPL, respectively. RL, TCV3, and TCV4 increased to doses of 619, 321.6, and 435.6 ml 100 kg-1 of seeds, respectively. Furthermore, a positive correlation was obtained between bio-input dose and the potassium content and expressive differences in the nutrient content of the control concerning the other treatments, which were obtained in the multivariate analysis. Finally, it is concluded that T. harzianum influences the vegetative growth in maize. However, depending on the dose of the bio-input, it can result in different plant responses.

AUTOMATIC DATA ACQUISITION SYSTEM-ADAS FOR ENERGY OPTIMIZATION IN TRACTORS AND IMPLEMENT

2023-02-13T12:16:26-03:00

The technical dimensioning of the tractor set and implements for each crop and respective areas to be explored establishes the width of the implement, tractor power, and management characteristics to be used. Fuel consumption (l/h), operational work performance (ha/h), and quality of work are the most critical operational performance indicators in the set. The Automatic Data Acquisition System – ADAS (SIAD in Portuguese), developed in 2018, was improved in 2020, to an easy-to-handle system aimed at managing field operations of the tractor+implement set, with a programmable acquisition module, with real-time records, georeferenced and stored in memory at one-second intervals. The ADAS was tested on a bench, and validated with the tractor+implement set plowing in
alluvial soil, in 12 data collection cycles, for an operational evaluation. Comparing the traction efficiency of 43.07% obtained by the tractor+plow set for a slippage of 17.3%, it can be seen that it falls short of the values presented by Janulevičius et al. (2019). In addition, Table 4 indicates that the tractor is working with a very high range of slipping values, ranging from 17.3 to 41.9%, reinforcing the need for adjustments, especially with ballasts, to avoid power loss through the wheels and to keep the tractor moving. The essential information, fuel consumption, and slippage can be read in real-time by the operator, on the box display on the tractor panel, and later, by the technical area, as they are recorded in the microcomputer memory to analyze the operations.

PRODUÇÃO DE MILHO CULTIVADO COM APLICAÇÃO DE COMPOSTO DE ESTÁBULO

2022-11-10T15:57:06-03:00

Os solos do Cerrado naturalmente apresentam alta acidez e baixa disponibilidade de nutrientes, demandando correção e fertilização para obtenção de altas produções. Embora a fertilização mineral promova a melhoria da fertilidade do solo, a fertilização orgânica pode também melhorar as suas propriedades físicas e biológicas. Objetivou-se avaliar os efeitos da substituição da adubação mineral pela adubação orgânica na fertilidade do solo, na nutrição e na produção do milho (Zea mays L.) para silagem. O experimento foi conduzido na fazenda Barreiro Alto (Sete Lagoas- MG) sob delineamento em blocos casualizados, com quatro repetições e nove tratamentos; combinações de adubação mineral (200 a 400 kg ha^-1 de 30-0-10) e orgânica (4 a 8 t ha^-1do composto de estábulo) em cobertura, além da testemunha (sem fertilização). Ao final do ciclo, avaliou-se a produção, os atributos da fertilidade do solo, os teores e os acúmulos de nutrientes nas plantas. As variáveis não foram influenciadas significativamente pelas adubações orgânica e mineral. Em média, o milho acumulou na parte aérea; 254, 33, 213, 53, 36 e 19 kg ha^-1 de N, P, K, Ca, Mg e S, além de 188, 63, 1263, 952 e 487 g ha^-1de B, Cu, Fe, Mn e Zn, respectivamente. A produtividade média de grãos utilizando a adubação mineral foi de 6,7 t ha^-1, ao passo que 7,1 t ha^-1 foram obtidas com a aplicação do adubo orgânico. O composto de estábulo proporciona a mesma nutrição verificada com a adubação mineral ao milho cultivado em solo de boa fertilidade química.

ARRANGEMENTS POPULATION AND ROW SPACING IN THE DEVELOPMENT OF CORN

2023-07-04T09:45:06-03:00

Different arrangements between plants make it possible to optimize
the use of natural resources available in corn production, achieving better yield. Thus,
this work aimed to evaluate some productive traits of the crop in different spatial
arrangements. The leading production indicators of the corn were evaluated at the
Experimental Farm of the São Paulo State University (FCAV – UNESP), campus
in Jaboticabal – SP, Brazil—the statistical design in randomized blocks, with four
replications. The treatments corresponded to 2-row spacings (single-row with 0.90m
and twin-rows, interspersing spacing of 0.45m and 0.90m) and three plant populations
(55,000, 60,000 and 65,000 plants ha -1), composing a 2 x 3 factorial. Confirmatory
and descriptive statistical analyses were carried out, and the statistical process control
constructed control charts. Twin-row spacing showed the best results for yield and
height of the first ear. The 65,000 ha-1 population stood out for its lower data variability
(smaller amplitude), providing more excellent quality in corn grain yield through spatial
optimization of available resources.

Épocas de semeadura e adubação de cobertura no milho 2ª safra na transição Cerrado-Amazônia

2023-10-10T09:48:45-03:00

a semeadura do milho 2ª safra de alto potencial produtivo no ecótono Cerrado-Amazônia, deve ser realizada até o final do mês de fevereiro, para evitar perdas de produtividade pela falta de chuvas no estádio reprodutivo, tendo como data ideal aproximadamente o 20º dia do mês de fevereiro. Por motivos climáticos ou operacionais, muitas vezes o produtor atrasa a semeadura, expondo a lavoura a déficit hídrico. Objetivou-se verificar a produtividade da cultura e o estado nutricional do milho em duas datas de semeio e manejo da adubação de cobertura. O experimento foi conduzido em Santa Carmem–MT, em delineamento experimental de blocos casualizados, com cinco repetições, em esquema fatorial, com 10 épocas de aplicação da 1ª parcela de adubação (200 kg ha^-1) do formulado 20-00-20 em 2 datas de semeadura do milho (19/01 e 27/02), com a 2ª parcela fixa aos 35 DAS. O solo apresentou maior teor de K residual quando o milho foi semeado em janeiro e em relação a adubação de cobertura os maiores valores foram quando estas foram realizadas até nove dias após a semeadura. Para segunda época de semeadura houve maior demanda de K pela cultura, com maior extração pela planta, maior concentração foliar e maior quantidade na palhada, porém com menor teor e exportação nos grãos, decorrente da menor produtividade. Precipitações adequadas e bem distribuídas favorecem a extração, exportação e quantidade de N que retorna ao sistema na 1ª data de semeadura, fato decorrente da maior eficiência de absorção e uso do nutriente.

Leaf appearance rate and phyllochron on millet sowing dates

2023-07-04T15:16:28-03:00

The objective of this study was to determine the leaf appearance rate and phyllochron as affected by millet sowing dates. The experiment was conducted with six sowing dates (11/28/2019, 12/03/2019, 12/10/2019, 12/17/2019, 12/30/2019 and 01/14/2020). The sowing was performed in plots with six rows of 2 m length and spacing of 0.25 m between rows. After emergence, for each sowing date, five plants were marked and the number of leaves was counted twice a week until flowering. For each plant relative to each sowing date (30 plants), the number of leaves (NL), leaf appearance period (LAP, in days), accumulated thermal sum (TSa, in ºC day), leaf appearance rate (LAR, on days leaf^-1) and phyllochron in °C day leaf^-1 were determined. Among the sowing dates, there is no variation in the number of leaves, with an average of 18.07 leaves. LAP varies between 49 and 88 days, TSa between 697.57 and 1299.47 °C day, LAR between 3.26 and 5.40 days leaf^-1, and phyllochron between 45.05 and 80.81 °C day leaf^-1. Millet shows better vegetative development (lower LAP, TSa, LAR and phyllochron) in early sowing (11/28/2019, 12/03/2019 and 12/10/2019) compared to later sowing (12/17/2019, 12/30/2019 and 01/14/2020).

INCIDENCE OF CHARCOAL ROT (Macrophomina phaseolina) IN MAIZE HYBRIDS IN DIFFERENT ENVIRONMENTS DURING OFF-SEASON

2022-11-29T12:07:05-03:00

Maize cultivation in Brazil can occur during the summer or off-season. Diseases are significant contributors to production losses. Charcoal rot (Macrophomina phaseolina) is the primary disease affecting off-season maize crops. This study aimed to assess the incidence of charcoal rot in commercially available maize hybrids under different soil water availability conditions during the off-season. The experiments were conducted at the Embrapa Research Facility, located at Invernadinha Farm. The experimental design was a randomized block design with three replicates. The first experimental crop was sown on February 21, 2022, in a red-yellow Latosol soil environment (Environment 1). The second was sown on March 3, 2022, in a Concretionary Petric Plinthosol soil environment (Environment 2). Ten hybrids were used in each experiment. Plant height was measured after the plants reached physiological maturity, and ten stalk samples were collected from each plot. Afterward, the microsclerotia of M. phaseolina were identified visually in the laboratory. Data are expressed as percentages and subjected to a joint analysis of variance. These results indicate that soil conditions of higher water stress, in conjunction with elevated temperatures, significantly enhanced the development of charcoal rot and directly affected plant productivity. A joint analysis of the environments revealed that the AS1820, AS1822, and P3707 hybrids had the lowest average incidence of charcoal rot and the highest yields.

MORPHOPHYSIOLOGICAL AND PHOTOSYNTHETIC RESPONSES OF CORN GENETIC MATERIALS TO APPLICATION FORMS AND DOSES OF Azospirillum brasilense

2023-02-13T20:33:39-03:00

Brazil is the third largest maize-producing country in the world, despite having soils that are often acidic and have low nutrient reserves. However, the high cost of fertilizers generated the need for developing alternative technologies to reduce production costs. This work aimed to evaluate the effect of application methods and rates of Azospirillum brasilense on morphophysiological and photosynthetic parameters of maize genotypes. A randomized block experimental design was used, in a 4×4×2 factorial arrangement, with three replications. The parameters evaluated were chlorophyll contents; the fresh and dry weight of plant shoot components; root dry weight; culm diameter; root volume; leaf area; plant height; the number of developed leaves; initial, maximum, variable, and final fluorescence; and photochemical efficiency. Applying A. brasilense at rates of up to 200 mL ha-1 increased the total chlorophyll contents of leaves by 15.4% compared to the plants without inoculation. The maize variety SCS 156 presented higher shoot biomass production, regardless of inoculation, application method, or rate used; the varieties SCS 154 and SCS 155 presented significant increases in this parameter with the application of A. brasilense rates of up to 200 mL ha-1. Regarding the inoculant application methods, the variety SCS 155 presented better development when inoculated in the shoots. In contrast, the varieties SCS 155 and SCS 156 and the hybrid VIP 3 showed better growth when inoculated in the soil at planting.

Early fertilization during winter cultivation and its residual effect on silage maize grown sequentially

2022-11-01T15:47:12-03:00

The objective of this study was to evaluate the effect of an early application of potassium (K) fertilizer on pearl millet (Pennisetum glaucum L.) grown during fall/winter on the performance of maize (Zea mays L.) silage grown in succession. Using a randomized block design, in the fall/winter harvest, the plots were composed of millet and six doses of K (0, 30, 60, 90, 120 and 150 kg K₂O ha^-1) as muriate of potash (57% K₂O) in addition to fallow. In the summer harvest, during the cultivation of maize, six doses of K₂O were applied complementary to the doses applied in the autumn/winter harvest to total 120 kg K₂O ha^-1 (120, 90, 60, 30, 0) and 0 kg K₂O ha^-1 for the no cover treatment. An additional treatment that was planted to received the recommended fertilization amount (60 and 90 kg ha^-1 of K₂O for planting and broadcasting, respectively). For the millet, was evaluated plant height, green and dry biomass yields, and soil cover at 30, 60, 90 and 120 days after harvest . For maize, agronomic traits, leaf nutrient content and green and dry biomass yields were evaluated. The early application of K fertilizer did not alter the yield components of millet and silage maize. However, the straw produced by the millet was efficient at promoting soil cover in the off-season.

Azospirillum brasilense inoculation improves the morphophysiological aspects of maize in soils with high and low nitrogen contents

2024-04-21T14:35:07-03:00

The objective of this research was to evaluate the morphophysiology, root system and biomass in maize plants inoculated by A. brasilense at two nitrogen doses in the soil. The experiment was carried out in a greenhouse using a completely randomized design. A dose that guaranteed N120 grain yield (120 kg ha^-1) and another that reduced N20 availability by 100% (20 kg ha^-1) was stipulated. The inoculant used was a mixture of two homologous A. brasilense strains, Az1 (CMS 7+1626) and Az2 (CMS 11+1626). The treatments consisted of a combination of nitrogen doses and inoculation by A. brasilense, with four replications. Root morphology, nitrate and arginase reductase, pigment content, height and leaf area were evaluated. Inoculation by A. brasilense Az1 and Az2 increases root volume and specific length. Nitrate reductase and arginase activities in the soil were higher with A. brasilense, as well as chlorophylls, height and leaf area at 20 kg ha^-1 nitrogen in the soil. At 120 kg ha^-1nitrogen, A. brasilense also increases specific root length and nitrate reductase activity, resulting in greater maize height and leaf area. A. brasilense favors the exploration of the soil profile for the absorption of water and nutrients. Inoculation improves the morphophysiology of maize in low soil nitrogen, but does not reduce the use of nitrogen fertilizers in this crop. Inoculation by A. brasilense is an efficient, ecological and low-cost technology that contributes to the sustainability of maize production.

AGRONOMIC CHARACTERISTICS OF CORN GRAIN CORRELATED TO TREATMENTS WITH Azospirillum brasilense, SILICION AND NITROGEN FERTILIZATION

2022-07-18T16:09:34-03:00

This work aimed to analyze the effects of using the Azospirillum brasilense bacteria with different doses of calcium and magnesium silicate applied on the soil, at different levels of nitrogen fertilization for the topdressing, on the agronomic characteristics of corn grain. The experiment was carried out in the Midwest region of Goiás under a randomized block design, in a 2x3x2 factorial scheme, formed by 2 doses of N in topdressing; 3 doses of Azospirillum brasiliense; and 2 doses of CaSiO₃ and MgSiO₃. The various agronomic characteristics of maize evaluated were plant height and stem diameter with 35 and 55 Days After Seedling Emergence, weight of 100 grains and yield, highlighting results of 30.7 and 29.2 g for weight of one hundred grains and 6712, 9 and 6390.5 kg ha^-1for yield, and both results were obtained on the dosages of 50 kg ha^-1of N in topdressing and 200 kg ha^-1of fertilization with CaSiO₃ and MgSiO₃. The dosages of 50 kg ha^-1of N in topdressing and 200 ha^-1 of CaSiO₃ and MgSiO₃ in planting increased the height of plants with 35 DASE, weight of one hundred grains and yield, although the interaction of these two treatments did not provide a significant difference, confirming in this way the importance of N fertilization in topdressing, and showing that the recommended CaSiO₃ and MgSiO₃ dosage for corn crop is less than 400 kg ha^-1.

SEEDLING SELECTION OF SORGHUM FOR DROUGHT TOLERANCE BASED ON ROOT MORPHOLOGY

2022-11-24T14:34:01-03:00

Selection for drought tolerance is one of the main challenges of sorghum breeding programs, and early phenotyping, in the seedling phase, can increase selection gains for this trait. This work evaluated characteristics related to root morphology as indicators for early selection of tolerant genotypes to water restriction. Twenty-six hybrids were evaluated, of which twenty-three were experimental and three commercial (BRS310, DKB540 and 1G282). The hybrids were grown in tube-shaped containers in a greenhouse with non-stress stressed water. The evaluated characteristics were Root length (RL), root surface area (SA), root diameter (RD), root volume (RV), surface area of very thin roots (from 0-1 mm in diameter) (SA1), as well as the root/shoot dry mass ratio (R/S). Under water restriction, the hybrids with the best performances for most of the evaluated characteristics were BRS310, 1516057, 1719034, 1719026, 1716041, 1G282, 1516059, 1720052, 1716049, 1718036 and 1716045. The characteristics RV, SA, SA1 and R/S showed the greatest contribution in the selection of these hybrids.

HETEROSIS AND INBREEDING DEPRESSION IN GRAIN SORGHUM HYBRIDS

2023-02-16T11:37:22-03:00

This study aimed to estimate the heterosis, heterobeltiosis, and inbreeding depression in grain sorghum hybrids. Twenty-five hybrids were evaluated in two seasons. The evaluated traits were days to flowering (FL), plant height (PH), grain yield (GY), and thousand grains mass (M1000). The contrast tested were F1 hybrids vs. check cultivars, F1 hybrids vs. parental lines, and F1 hybrids vs. F2 hybrids. The hybrids 1167048, 1099044, 1170017, and 1169054 had a five-day less flowering time than their parental lines. The hybrid 1170017 had a high grain yield (6.23 t ha-1) with 43.55% of heterobeltiosis. The diversity between lines was narrow. However, hybrids with higher grain yield, heterosis, and heterobeltiosis showed higher genetic distances from their parental lines. The inbreeding depression between F1 vs. F2 was 30%, indicating that using F1 hybrids seeds is worthwhile.

COMPARISON OF PROTOCOLS FOR CHROMOSOME DUPLICATION IN HAPLOID MAIZE

2023-02-13T09:47:15-03:00

Different methods of chromosome duplication are used to obtain doubled haploids in maize; however, comparisons of efficiency among protocols have only begun to appear in the literature. Therefore, this study aimed to compare the efficiency of three protocols of chromosome duplication. A randomized block experimental design was used, with three replications composed of three treatments of chromosome duplication (duplication by colchicine injection in plants, duplication by immersion of roots in colchicine solution, and duplication by immersion of newly germinated seedlings in colchicine solution). Two hundred seventy haploid seeds were obtained from crossing the genotype source 91500212 with the haploid inducer hybrid Tail P1 × Tail P2, with 90 seeds for each treatment. In the chromosome duplication through injection, a colchicine solution at 0.125% was applied to the stem of the seedlings 15 days after germination. In the chromosome duplication through root immersion, 15 days after germination, the roots of the seedlings were immersed in a 1% colchicine solution for six hours, followed by removing colchicine residues and transplanting them in trays with the substrate. Finally, in the chromosome duplication of newly germinated seedlings, three days old seedlings were immersed in a 0.06% colchicine solution for 12 hours, then removed from the solution and transplanted in trays with the substrate. Twenty days after treatment, the plants were transplanted in 20-liter pots with fertilized soil in a greenhouse, beginning data collection. Results indicate that the injection protocol showed better survival, better practicality of application, and lower costs and risks.