Agronomy Science and Biotechnology

Initial growth and chlorophyll indices of maize plants originating from seeds of different shapes and sizes

2023-09-10T19:25:01-03:00

The objective of this work was to evaluate the initial growth and chlorophyll content of maize plants originated from seeds with different sizes and shapes, as well as to establish the relationship between growth traits, chlorophyll index and seed formats. The experimental design was a randomized complete blocks, and the treatments were composed by seeds of four sizes and shapes for each of the two genotype used, and four collection periods (21, 24, 27 and 30 DAE) and four replications. The root and shoot length, stem diameter, leaf area, dry mass of leaf, stem, roots and total, leaf mass ratio, leaf area ratio, specific leaf area and chlorophyll a, b and total chlorophyll were determined. It was verified that seedlings of genotype "A" originated from large round seeds, presented the highest stem diameter, leaf dry mass, stem dry mass, root dry mass and total dry mass. There is a distinct response in the growth of maize plants as a function of the genotype. Regardless of the genotype, the size and shape of seeds do not influence the indexes of chlorophyll a, b and total. There is a positive and strong correlation between seeds of different sizes and shapes with leaf area, leaf dry mass and specific leaf area.

Artificial defoliation and its impact on the agronomic performance of sunflower in a non-preferential season

2023-11-18T15:42:50-03:00

The objective of this work was to evaluate the partitioning of photoassimilates in sunflower plants sown in a non-preferential season coincident with the occurrence of fallow areas in the region, submitted to artificial defoliation with 100% intensity, in different phenological stages of the reproductive period. The experimental design used was randomized blocks with six treatments and three replications, consisting of 18 experimental units and all plants were defoliated. The treatments performed were artificial defoliation, I: No defoliation (control); II: Defoliation at the R1 phenological stage; III: Defoliation at the R3 phenological stage; IV: Defoliation at the R5 phenological stage; V: Defoliation at the R7 phenological stage and VI: Defoliation at the R8 phenological stage. Artificial defoliation performed at 100% intensity at different phenological stages influences the morphological attributes and yield components of sunflower in a distinct way. Defoliations performed at R1 phenological stage have a negative effect on most of the variables analyzed, which provided lower plant height, stem diameter, capitulum diameter, number of rows of achenes, number of achenes per row, achene length, achene width, thousand achene mass and, consequently, in grain yield. This phenological stage was marked by the beginning of the reproductive period, which has a high demand for photoassimilates to maintain plant metabolism and yield. Defoliation performed at R8 phenological stage had better performance for plant height, capitulum diameter, capitulum mass, number of rows of achenes, number of achenes per row, number of plants per hectare and grain yield (>1000 kg ha^-1). The plants of experimental units without defoliation had results similar to those defoliated in the R8 phenological stage, however, they still had better performance for thousand achene mass, achene length, achene width, volume index and even a smaller diameter of missing seeds.

Maize genetic breeding for tolerance to abiotic stress with focus on sustainable use of environmental resources

2023-11-19T11:08:28-03:00

This bibliographic review explored maize genetic breeding to increase tolerance to abiotic stress. The main stresses faced by the crop, such as water stress and nitrogen deficiency, and their negative impacts on grain yield were discussed. Strategies to minimize these effects were examined, focusing on the selection of tolerant genotypes and the strategic positioning of these genotypes in different growing environments. The germplasm bank and genetic diversity were highlighted as crucial resources to identify desirable traits and genes associated with resistance to abiotic stress. The selection of secondary characters, considering their heritability and correlation with characters of interest, allows maximizing the efficiency in the selection of promising genotypes in genetic breeding programs. Test environments simulating stresses, such as water stress and low nitrogen, are essential to evaluate the performance of genotypes and identify the most tolerant ones. The genetic breeding of maize for tolerance to abiotic stress promotes promising solutions to face environmental challenges and ensure the sustainability of agricultural production.

Contamination by aerobic mesophilal and enterobacteriaceae bacteria in a pig refrigerator

2023-11-22T18:54:22-03:00

The study aimed to evaluate the knives, contact surfaces and carcasses for contamination by mesophilic aerobic bacteria and Enterobacteriaceae, in a pig slaughterhouse in the state of Rio Grande do Sul. The present study took place in a pig slaughterhouse, located in the Northwest Region of the State of Rio Grande do Sul, under the Federal Inspection Service (SIF). The experimental design used was randomized blocks organized in a bifactorial scheme, being for the knives: 3 (days of collection) x 3 x 15 (time of collection and knives from the slaughter and deboning process), totaling 135 experimental units for the knives. For water, main contact surfaces and pig carcasses, a unifactorial scheme was used: 3 (days of collection) x 12 surfaces (5 contact surfaces and 7 carcasses), totaling 36 experimental units. Knives used during slaughter operations are a form of contamination. There is deficiency in the pre-operational hygiene procedure of the utensils.

Environmental stimulus in lettuce genotype in agroecological cultivation system

2023-11-24T18:01:06-03:00

Vegetable production system has presented and developed strategies to increase the level of sustainability of production, adding information that expands agroecological production, resulting in better use of different components necessary for production. This study aims to evaluate the effect of different coverages in relation to the expression of the genotype in three crops of different agricultural years, enabling the best use of natural resources, bringing effective subsidies for a more sustainable production. The study was conducted in three growing seasons, in 2017, 2018 and 2019 crop years, in a randomized block design with four replications, using three soil covers (corn silage residue, elephant grass straw and soil without vegetation cover) and a lettuce cultivar (Lettuce “Iceberg”). It was possible to observe through the analysis of variance that only the year variable promoted alterations on the analyzed characters, with no effect of the different coverages. The highest production occurred in 2019 for all variables analyzed. Regarding the estimate of Pearson's linear correlation, it was possible to obtain significance at 0.01% of probability for the variables average total weight and productivity, with a significance of 1% of probability for the variables average diameter, average longitudinal diameter and productivity. There was no effect of soil cover for the variables of lettuce production and productivity, possibly related to excess water from precipitation in 2017, 2018 and 2019. In addition, the complementary effect of irrigation in the years of the experiment was, possibly, superior to the demand of the crop by reducing the effect of ground cover on soil water dynamics.

Enhancing the efficiency and sustainability of foliar fertilization in agriculture

2023-12-20T00:39:54-03:00

When considering foliar fertilization, many questions arise about the differences between chelation, complexation, and their efficiency in supplying nutrients to plants. How efficiently are chelated and complexed nutrients absorbed by plants? Are chelates and complexes absorbed by plants? How do they perform in foliar and soil applications? Do they exhibit greater efficiency when compared to pure inorganic fertilizers? and, which ones are the best: soluble, sparingly soluble, or insoluble inorganic fertilizers? Although many people believe chelation and complexation are similar, some differences must be considered when choosing products to better supply plants with nutrients, avoid problems with tank mixtures, and enhance plant nutrition efficiency. The same is true for the vast variety of inorganic sources of fertilizers available for agriculture. They do not behave the same. For instance, inorganic water-soluble fertilizers such as nitrates, sulfates, and chlorides present different performances and should be chosen not only based on their nutrient concentration, availability, and price. All this information will assist farmers and technicians in better defining and selecting products to improve sustainability, efficiency, and achieve better results.

Contrast between Brazil and other countries in nutraceutical components of Camelina sativa grains

2024-05-11T13:20:01-03:00

Camelina sativa, also known as false flax, is a species can be cultivated in a variety of climates, seasons and soil types, due to its short development cycle and tolerance to drought and low temperatures. In the composition of its grains, it presents a high amount of oil and rich in unsaturated fatty acids. In view of this, the objective of this work was to compare the composition of the nutraceutical components of Camelina sativa L. grains cultivated in Brazil and countries in Europe, Asia and North America. About 20 kg of grains were collected and then a homogeneous sample of 1kg of grains was cleaned to perform the centesimal composition of the grains. Afterwards, a search for information was carried out on the cultivation of Camelina sativa L. in other countries and the collection of information on the centesimal composition of the grains of this oleaginous plant. The collection of information was based on obtaining published scientific articles on the nutraceutical composition of Camelina sativa in regions of Europe, Asia and North America. Brazil presents a promising environment for the cultivation of Camelina sativa, with superior performance for the content of stearic acid, linoleic acid, linolenic acid and palmitic acid. The fatty acids profile decreased with the reduction of the minimum air temperature. The mineral material, palmitic acid and linolenic acid are positively correlated.

Characterization of milk and water-based kefir microbiota

2024-09-19T16:36:20-03:00

The production of functional foods is expanding and requiring research results in the areas of food, health, chemistry, pharmaceuticals, etc. Within this context, the inclusion of kefir in the diet has been gaining ground, as it meets the requirements of a functional food. Kefir can be defined as a fermented, acidic milk with a low alcohol content and produced from grains that contain microorganisms that carry out the fermentation process. Kefir can be produced using various means, such as milk or water-based substrates. In both process, the production is very similar. Kefir is composed of microorganisms such as bacteria and yeasts that are often welcomed by the population as a probiotic source and are regularly used in the production of food and/or medicine by the industry. To produce water kefir, sucrose is used, and the process is carried out at temperatures ranging from 20℃ to 25℃, with an incubation time between 12 and 72 hours in this context. The objective of this work was to present a literature review on the characterization of milk and water-based kefir.

Multivariate approach applied to phenotypic traits as a function of the selection of soybean cultivars

2024-10-07T22:28:08-03:00

The objective of this work was to identify superior soybean cultivars through a multivariate approach applied to phenotypic traits. This study was developed in the 2023/2024 agricultural harvest, in the experimental area of the Regional Institute for Rural Development, at UNIJUÍ. It is located in the municipality of Augusto Pestana, in the state of Rio Grande do Sul, Brazil. The experimental design used was randomized blocks with internal blocks, with the treatment being ten cultivars and five replications. The trial of ten cultivars in the northwest of the state of Rio Grande do Sul demonstrated that the soybean cultivar with the highest yield was NS5922IPRO, with 5235.3 kg ha^-1. The multivariate approaches formed two groups to explain the factors that influenced yield, where the first was discrepant for the variables Euschistus heros, phytotoxicity, Fusarium solanie, Macrophomina phaseolina, Conyza bonariensis, production zone area, number of total nodes in the branch, branch number, root length, number of vegetables with 4 grains, number of vegetables with 0 grains and vegetable grain weight of 2 grains. The second similar group for the variables Diabrotica speciosa, Caliothrips brasiliensis, Euschisthus heros, Phakopsora pachyrhizi and Cercospora sojina, area of production zone, number of vegetables with zero grains. The trial of ten cultivars in the northwest of the state of Rio Grande do Sul demonstrated that the soybean cultivar with the highest yield was NS5922IPRO, with 5235.3 kg ha^-1. The multivariate approaches formed two groups to explain the factors that influenced grain yield.

Determining factors for the selection of soybean cultivars and the cause and effect relationships with grain yield

2024-10-07T23:20:27-03:00

The objective of the present study was to apply the trail analysis model to extract the cause and effect action on soybean grain yield as a function of agronomic attributes. The present study was developed in the agricultural years of 2023 and 2024. The experimental design used was strips with randomized blocks, consisting of 10 cultivars and five replications. Through the means comparison test, the highest grain yields were observed in the cultivars C 2531 E, BMX Vênus CE, B 5595 CE and NEO581 CE. It was observed that in addition to the higher grain yield, the cultivar C 2531 CE also presented a higher grain weight per plant, despite having the lowest final plant height and productive zone height among the cultivars. As for BMX Vênus CE, it was observed that despite its medium height, it presented a shorter internode length on the main stem, which optimized the number of total nodes on the main stem, in addition to presenting a high grain weight per plant. Cultivar B 5595 CE can be highlighted for its greater final plant height, as well as greater height of the productive zone, promoting a greater number of total nodes on the main stem. Another highlight of this cultivar is the high number of plants per final linear meter, indicating its adaptability in the field. The cultivar NEO581 E, despite having one of the smallest heights among the cultivars, presented one of the highest grain yields, which can be attributed to the stability of the cultivar in the field, as it showed intermediate performance for all agronomic traits.

Agronomic performance of soybean and its relation with the production environment

2024-10-07T23:51:23-03:00

The objective of the work is to identify the agronomic performance of soybeans and correlate meteorological attributes with yield components. The study was carried out at the Escola Fazenda of the Regional University of the Northwest of the State of Rio Grande do Sul - UNIJUÍ, located in Augusto Pestana – RS. The experimental design used was randomized blocks, consisting of 10 genotypes and five replications. Descriptive analysis was performed using mean plus standard deviation for variables that presented a coefficient of variation greater than 35%; normality and homogeneity tests were also performed, as well as analysis of variance, Tukey mean comparison tests and linear correlations supported by the t-test. Soybean grain yield is closely linked to meteorological elements, which play a crucial role in the fluctuations and frustrations of soybean agricultural harvests in the municipalities of Rio Grande do Sul. The significant correlations between yield indicate that the water factor is what more affects production. The TMG7362IPRO cultivar had a higher yield with 73 bags per ha^-1. -Iin this context, the soybean GMR also influenced yield in relation to climatic relations and had a better positioning.

Germination of chief fire seeds cockscomb cultivar under saline stress conditions induced by sodium chloride

2024-10-14T16:11:49-03:00

Cockscomb plant, Chief fire cultivar, is used as an ornamental, medicinal and non-conventional food plant (NCFP) and is cultivated from the north to the center-west of Brazil; however, these areas suffer from adverse environmental factors such as salinity stress. The objective of this study was to evaluate the seed germination performance and vigor of Celosia cristata L. var. Chief Fire seedlings exposed to salinity during the germination phase. To carry out the work, C. cristata seeds were sown in gerboxes conditioned to increasing doses of sodium chloride (NaCl), obtained by dissolving the salt in distilled water, obtaining electrical conductivities of 2.0; 4.0; 6.0 and 8.0 dS.m^-1, constituting the treatments. An additional group was treated only with distilled water and was used as a control for the experiment. The experiment was conducted in a completely randomized design, with a total of five treatments and four replicates of 25 seeds. The parameters assessed were: first germination count, germination, germination speed index (GVI), mean germination time (MGT), length of aerial part and primary root. The data was submitted to analysis of variance and the means were compared using the Scott-Knott test at 5% significance. Based on the results obtained, it can be concluded that the conditions of salt stress induced by NaCl were not harmful to the germination of C. cristata, presenting itself as a species tolerant to water salinity during seed germination, since the variables analyzed showed no signs of deleterious effects as the salt concentration was increased.

Grain yield predictor model using agronomic aspects and vegetative indices of soybean

2024-10-23T23:29:06-03:00

The objective of this work was to evaluate, through a predictive model, which factors influence soybean yield, using agronomic aspects and vegetative indices, in addition to identifying the best soybean cultivar for the northwest of Rio Grande do Sul. The experimental design used was strips with randomized blocks, consisting of 10 cultivars and five blocks. Analyzing the quantitative characters, the positive contributions to yield came from the grain weight of vegetables with two grains, and the grain weight of the plant, having a strong influence on the average grain yield. The vegetable grain weight with three grains contributed negatively to the yield, as the average grain weight was lower than expected, lowering the average grain yield. For the vegetation indices that contributed positively, the GRAY, IGB and RGRI index stand out, while the BGI, GLI2, GRAY2, IGR, IRB, NRBDI and NG indices had negative contributions to the average grain yield. The NEO 581 E cultivar showed better yield performance, reaching 5780 kg ha⁻¹, followed by the SOYTECH 541 I2X cultivar, which reached a yield of 5356 kg ha⁻¹. The predictive model identified the main variables that influenced final yield, with Cercospora sojina and Corynespora casiicola, grain weight in three-grain legumes, plant grain weight, GRAY index, IGB, NGBDI and RGRI, the variables that contributed positively to grain yield.

Influence of nitric oxide donor on the physiological quality of seeds of Myrcia retorta Cambess

2024-11-17T16:15:37-03:00

Brazil, with its vast biodiversity, is home to several species of the Myrtaceae family with significant ornamental potential that is still underutilized. Myrcia retorta Cambess is a endemic Brazilian plant wich stands out as a promising species for ornamental cultivation. The objective of this study was to evaluate the effect of the nitric oxide donor S-nitrosoglutathione (GSNO) on the germination of M. retorta seeds, with the aim of optimizing germination conditions for the domestication of this species. The seeds were divided into two batches based on their morphology: Batch 1 (spherical seeds) and Batch 2 (flattened seeds). The seeds were treated with five concentrations of GSNO (0, 2.5, 5, 10, and 15 mM) and the parameters evaluated included germination percentage, shoot and root length, and time to stabilization of germination. In batch 1, doses of 2.5 mM and 5 mM GSNO resulted in faster germination stabilization (6 and 7 days, respectively) compared to the control (9 days). In addition, these doses increased germination percentage by 15% and 12%, respectively. However, higher concentrations (10 mM and 15 mM) were found to be phytotoxic, reducing shoot length by 30% and 45% and root length by 28% and 42%, respectively. In batch 2, although no statistically significant differences were observed, a trend towards reduced germination and growth with increasing GSNO doses was observed. It is concluded that GSNO positively affects the germination and initial development of M. retorta at low concentrations, especially in spherical seeds, suggesting its potential in the domestication process of the species for ornamental purposes. However, doses higher than 5 mM should be avoided due to toxicity risks, highlighting the need to optimize concentrations for practical application.