Australian Journal of Crop Science   AJCS

Nitrogen (N) and sulphate (S) fertilization in wheat crop: effect on the vigor of seeds produced

João Roberto Pimentel, Cristian Troyjack, Ítala Thaísa Padilha Dubal, Marcio Peter, Lanes Beatriz Acosta Jaques, Felipe Koch, Ivan Ricardo Carvalho, Nairiane dos Santos Bilhalva, Simone Morgan Dellagostin, Gustavo Henrique Demari, Francine Lautenchleger, Emanuela Garbin Martinazzo, Tiago Pedó, Tiago Zanatta Aumonde

Universidade Federal de Pelotas, Faculdade de Agronomia Eliseu Maciel, Departamento de Fitotecnia, Pelotas, Rio Grande do Sul, Brasil
Universidade Estadual de Londrina, Departamento de Agronomia, Londrina, Paraná, Brasil
Universidade Federal do Rio Grande, ICB, Instituto de Ciências Biológicas, Rio Grande, Rio Grande do Sul, Brasil
Universidade Regional do Noroeste do Estado do Rio Grande do Sul, Ijuí, RS, Brasil

Abstract
The objective of this work was to evaluate the influence of nitrogen in association with sulfur applied in the field and the influence of this fertilization on the vigor of wheat seeds produced and later evaluated in the laboratory. Field experiments were carried out in the municipalities of Caibaté-RS and Pelotas-RS using the TBIO Sinuelo cultivar adapted to all the regions of Rio Grande do Sul. The experimental design was a randomized block design with a 2x5x2 trifractory scheme (cultivation environments x doses of nitrogen x sulfur management) with 4 replicates. The treatments consisted of the combination of two cultivation environments [Caibaté-RS and Pelotas-RS], five nitrogen doses Urea 45%, [0; 22.5; 45; 67.5 and 90 kg ha-1] applied at the beginning of tillering and sulfur, Sulfuric 90% sulfur, [0 and 60 kg ha-1] applied before sowing, about 7 days. After reaching physiological maturity, the seeds were harvested manually and taken to the seed laboratory. The seeds were dried in a forced ventilation oven at 41ºC until the moisture content stabilized at 12% (wet bulb). We evaluated the first germination count (FGC), accelerated aging (AA), field emergence (FE), shoot length (RL) and seedling root length (SL). The seeds produced in Caibaté-RS have greater vigor in relation to Pelotas-RS. Nitrogen fertilization favors the production of seeds with greater vigor, while sulfur can influence the vigor according to the environment in which the plants are cultivated.

Pages 470-478 | Full Text PDF| doi: 10.21475/ajcs.21.15.04.p1517
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Physiological quality of pitaya seeds subjected to different methods of mucilage extraction

Alessandro Borini Lone, Viviane Yumi Baba, Thiago Alberto Ortiz*, Lucia Sadayo Assari Takahashi

Santa Catarina State Agricultural Research and Rural Extension Agency (EPAGRI), 6800, 88318-112, Itajaí-SC, Brazil
State University of Londrina (UEL), 6001, 86051-990, Londrina-PR, Brazil
Iporã Faculty (FIP), 640, 87560-000, Iporã-PR, Brazil
State University of Londrina (UEL), 6001, 86051-990, Londrina-PR, Brazil

Abstract
The selection of seed extraction methods from flesh fruits depends on the characteristics of the fruit and the seed to ensure their physiological quality, viability, vigor and sanity within the acceptable percentage for each species. The present study aimed to assess the physiological quality of pitaya seeds subjected to different extraction methods of the mucilage surrounding the seeds. The assessed methods were M1 – friction in sieve under running water; M2 – friction in sieve under running water, with addition of CaO; M3 – fermentation for 24 h; M4 – fermentation for 24 h, with addition of sucrose; M5 – fermentation for 48 h; M6 – fermentation for 48 h, with addition of sucrose; M7 – immersion for 2 h in 2.5% HCl solution; M8 – immersion for 2 h in 5.0% HCl solution and M9 – immersion for 2 h in 10.0% HCl solution. The experimental design was entirely randomized. The analyzed variables were germination percentage (%), germination speed index (GSI) and mean germination time (MGT - days), as well as identification and quantification (%) of plant pathogenic fungi based on germination and accelerated aging tests; percentage of viable seeds (%) based on tetrazolium test; and vigor (μS cm-1) based on electrical conductivity test. The method of immersion for 2 h in 10.0% HCl solution (M9) has proven to be advantageous for the extraction of H. undatus seeds to favor seeds with higher physiological quality in a short period.

Pages 479-483 | Full Text PDF| doi: 10.21475/ajcs.21.15.04.p2335
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Molecular and morphological characterization related to salt stress in natural populations of the Medicago polymorpha species

Abdelnasser Bakhti*, Fatima-Zohra FyadLameche

Rhizobium Biotechnology and Plant Improvement Laboratory, Genetics and Plant Improvement Team, Department of Biology, Faculty of Natural and Life Sciences, University Oran 1, Ahmed Benbella, BP 1524 ELM_Naouer 31000, Oran, Algerie

Abstract
Legumes are important crops due to their nutritional benefits as well as their utility in agriculture rotation. The morphological and molecular markers can elucidate plant response to stresses. In the present study, we investigated indicators of molecular polymorphism related to salt stress tolerance in natural populations of Medicago polymorpha species. The plant samples were collected from different geographical sites in western Algeria. Morphological growth parameters such as root length stem length of plant and T/R ratio were examined under four NaCl concentration levels (0, 68, 102 and 137 mM). The molecular study was carried out using SSR molecular markers on all the studied populations. Significant differences were observed in mean squares of analysis of variance, indicating relation between geographical origins and populations. This analysis showed the existence of two contrasted populations (DZ221 and DZ312). DZ221 is a relatively salt tolerant, and DZ312 is sensitive. The Principal Component Analysis (PCA) was calculated using the PCA function, revealing a high correlation between the morphological traits and the geographical distribution of populations. It divided populations into four distinguished groups respecting their origin geographical sites. The molecular results of the polymorphism degree showed that the natural populations of M. Polymorpha species were strictly homozygous (100%). The PIC index of the three microsatellites was very informative (0.77). Additionally, the results showed that both microsatellites (FMT11 and MTIC297) revealed some alleles detected in the tolerant population (DZ221) suggesting that they can be used as indicators of saline stress tolerance adaptation.

Pages 484-493 | Full Text PDF| doi: 10.21475/ajcs.21.15.04.p2633
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High Robusta coffee plant density is associated with better yield potential at mixed responses for growth robustness, pests and diseases: which way for a farmer?

Godfrey Sseremba*, Godfrey Hubby Kagezi, Judith Kobusinge, Pascal Musoli, David Akodi, Nicholas Olango, Patrick Kucel, Job Chemutai, Joseph Mulindwa, Geofrey Arinaitwe

National Coffee Research Institute, National Agricultural Research Organization, P.O. Box 185, Mukono, Uganda

Abstract
Plant density in Robusta coffee is an unresolved issue in low volume producing countries especially when compared with leading producers. In this study, we aimed to compare the response of Robusta coffee to pest incidence, disease severity, growth and yield potential in two contrasting spacing regimes. Two spacing regimes of 3mx3m and 3mx1m were evaluated for selected parameters in a randomized complete block design with three replications. There was a highly significant difference in pest incidence between the spacing regimes (p<0.01) for all the pests except scales (p=0.126). The black coffee trig borer incidence was higher under close spacing of 3mx1m than for 3mx3m with a mean difference of 13.2%. There was no significant association between spacing regime and leaf rust disease incidence while the association was significant for red blister disease (χ2=33.56, df=1, p<0.001). Significant difference in growth response between spacing regimes (p<0.05) were also obtained for change in canopy height (dCAH), number of primaries, number of stems and leaf size. For instance, dCAH was higher under 3mx1m spacing than for 3mx3m spacing. A significant difference in yield potential existed between the spacing regimes (p<0.05) for average yield per tree and average yield per hectare (aYH). Close spacing produced a higher aYH (5.82 t cc/ha) than wide spacing (4.80 t cc/ha). Whereas yield potential is high at high tree densities, associated prevalence of biotic constraints calls for supportive stress management package for farmers.

Pages 494-503 | Full Text PDF| doi: 10.21475/ajcs.21.15.04.p2676
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Physical characterization of gabiroba fruits (Campomanesia adamantium) from Brazil neotropical savanna

Elias Emanuel Silva Mota, Italo Marcelino Mateus, Luciana Borges e Silva, Kátia Freitas Silva*, Elitânia Gomes Xavier, Joseanny Cardoso da Silva Pereira, Camila Cardoso

Evangelical College of Goianésia – Faceg, CEP 76380-000, Goianésia, GO, Brazil
Goiano Federal Institute, Ceres Campus, CEP 76300-000, Ceres, GO, Brazil

Abstract
Gabiroba is a species with potential for commercial cultivation due to its desirable agronomic characteristics, such as high yield and high levels of soluble solids. The objective of this study was to characterize fruits and seeds phenotypically and to evaluate the genetic structure in three natural subpopulations of Campomanesia adamantium, based on quantitative data. Fruits of gabiroba plants from three subpopulations were collected, sampling 10 mother plants per subpopulation, with collection of at least 10 fruits per matrix, totaling 300 fruits. Physical characterization data of fruits and seeds were submitted to descriptive analysis, analysis of variance and correlation among characters. There was significant variation for the length, width and fruit mass in C. adamantium at all hierarchical levels evaluated: among subpopulations and among mother plants within subpopulations. Most of the variation, for the three variables under study is found among fruits within mother plant, and then, there is greater variation among mother plants within subpopulation. The levels of variation found within the subpopulations were low. The correlation analysis demonstrated the existence of positive and high correlations between the variables such as, fruit length and fruit width, fruit length and fruit mass, fruit width and fruit mass. For a possible breeding program and / or conservation of the species, it is recommended to represent large number of subpopulations to ensure an adequate representativeness of the observed variability.

Pages 505-509 | Full Text PDF| doi: 10.21475/ajcs.21.15.04.p2749
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Aspects in breeding maize for drought tolerance: Progress and modern breeding approaches

Aleck Kondwakwenda*, Julia Sibiya, Rebecca Zengeni, Cousin Musvosvi

University of KwaZulu-Natal, School of Agriculture, Earth and Environmental Sciences, Private Bag X01, Scottsville 3209, Pietermaritzburg, South Africa

Abstract
Breeding for drought tolerance in plants is challenging because the trait is controlled by multiple genes. Grain yield, the trait of primary interest in maize, is characterized by low heritability, high genotype by environment interaction, and low variation under drought conditions, which further complicates selection. To circumvent these challenges, secondary traits that are highly correlated with grain yield are indirectly selected under drought conditions. Although considerable success in terms of yield gains under drought stress has been reported in both temperate and tropical maize breeding programmes, climate change exacerbated droughts coupled with high population growth necessitates continuous improvement of maize varieties. Understanding the genetics of associated secondary traits is essential in elucidating drought tolerance. The identification of quantitative trait loci (QTL) and candidate genes conferring drought tolerance and the subsequent development of relevant molecular markers ushered in the era of molecular assisted breeding. There is empirical evidence that marker-assisted selection and genomic selection have great potential to increase the yield gains while comprehensive and accurate phenotyping using secondary traits remains the pillar of drought tolerance breeding.

Pages 510-517 | Full Text PDF| doi: 10.21475/ajcs.21.15.04.p2779
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Effect of the season on establishment of some turf grasses under the climatic conditions in eastern Morocco

Khadija CHARIF*, Ibtissam MZABRI, Maria RIMANI, Azzouz BOUKROUTE, Noureddine KOUDDANE, Abdelbasset BERRICHI

Laboratory, Agricultural Production Improvement, Biotechnology and Environment, Department of Biology, Faculty of Sciences, University of Mohammed First, Oujda, Morocco
Laboratory Bioresources, Biotechnology, Ethnopharmacology and Health, Department of Biology, Faculty of Sciences, University of Mohammed First, Oujda, Morocco

Abstract
The turfgrass establishment is an important criterion for the choice of turfgrass species. The faster a lawn is established the more benefits it has to offer for landscapers. The objective of this work is to study the growth speed and development of six species. Four of them are cool-season ones (temperate): Lolium perenne, Festuca arundinacea, Agrostis stolonifera and Poa pratensis while the other two are warm-season ones (tropical): Pennisetum clandestinum and Cynodon dactylon. The species are seeded in two distinct periods: spring and autumn and are studied under the climatic conditions of the eastern region of Morocco which is characterized by a semi-arid Mediterranean climate with continental tendency known for its severe cold in winter. The coverage rate is the parameter considered in order to determine the duration of establishment for each species. The study was conducted in the experimental station of the Faculty of Sciences of Oujda. The results show that the establishment pace differs depending on the season and the nature of the species. Autumn is the suitable season for temperate species, while tropical species have shown a faster growth in spring. Lolium perenne and Cynodon dactylon are the fastest species to establish as they need a maximum of 30 days after the seedlings’ development. Poa pratensis is the last species to cover the total area seeded within 50 and 60 days during the two season’s spring and autumn respectively.

Pages 518-523 | Full Text PDF| doi: 10.21475/ajcs.21.15.04.p2789
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Nitrogen management at sowing and topdressing with the time of supply in the main biotype of oats grown in southern Brazil

Douglas Cézar Reginatto, José Antonio Gonzalez da Silva, Ivan Ricardo Carvalho, Francine Lautenchlegere, Juliana Aozane da Rosa, Cibele Luisa Peter, Luana Henrichsen, Márcia Sostmeyer Jung, Natiane Carolina Ferrari Basso, Claudia Vanessa Argenta, Leonardo Norbert, Cristhian Milbradt Babeski

Exact Sciences and Engineering Department, Regional University of the Northwest of Rio Grande do Sul, Street of Comércio 3000, Universitário, Ijuí/RS – Brazil
Agrarian Studies Department, Regional University of the Northwest of Rio Grande do Sul, Street of Comércio 3000, Universitário, Ijuí/RS – Brazil
State University of Central-West - Street Presidente Zacarias, 875, Guarapuava/PR – Brazil

Abstract
Adjusting the nitrogen dose at sowing and topdressing with the time of application can improve nutrient management and increase oat productivity. The objective of the study is the most efficient and sustainable management of nitrogen use in the adjusted combination of nutrient dose at sowing and for topdressing with the moment of application on the productivity of biomass and oat grains, considering the main systems of cereal succession in southern Brazil.. The experiment was conducted in the years 2015, 2016 and 2017, in Augusto Pestana, RS, Brazil. The design was a randomized block with four replications, in a 4 x 4 factorial model, consisted of four doses of nitrogen at sowing time (0, 10, 30 and 60 kg ha-1), and topdressing dose by the total supplied of 70 and 100 kg ha-1 in succession system soybeans / oats and corn / oats, respectively, in the expectation of grain yield of 4000 kg ha-1, with the supply for topdressing considering four application times (0, 10, 30 and 60 days after emergence). The most efficient and sustainable management of nitrogen use for biomass and oat grains productivity occurs with the total supply of the covered nutrient around 30 days after emergence, regardless of the condition of the agricultural year and succession system.

Pages 524-530 | Full Text PDF| doi: 10.21475/ajcs.21.15.04.p2803
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Complex soil contamination severely impacts seed-sown crop viability in Australia

Annaclaire G. McDonald, Brad R. Murray, Daniel W. Krix, Megan L. Murray*

School of Life Sciences, University of Technology Sydney, PO Box 123, NSW 2007 Australia

Abstract
Food security is a critical issue for many global communities. Heavy metal contamination in soils present a major and ongoing ecological risk associated with human activities which may impact the viability and safety of seed-sown crops. To better understand the impacts of soil contamination by heavy metals on seed-sown crop viability, we examined germination responses of eight commercially-important fruit and vegetable crop species to copper, zinc, and lead contamination at levels likely to be found in contaminated regions in Australia. We compared the germination attributes of days to first germination, germination period, and total proportion of seeds germinated under concentration limits of heavy metals detected at degraded sites and current Australian National Environment Protection Measure thresholds for domestic soils (i.e., copper 6,000 mg kg-1, zinc 4,700 mg kg-1, lead 300 mg kg-1). The combined heavy metal treatment (i.e. all three metals) significantly inhibited germination for all edible crop species with only carrots able to germinate under complex, multi-metal-contaminated conditions. Seed viability was significantly decreased in mulberry (M. alba var. tatarica, M. nigra, and M. rubra) and lettuce (L. sativa), with lowered seed germination in all metals compared to carrot (D. carota), radish (R. sativus), tomato (S. lycopersicum) and common bean (P. vulgaris). These results indicate heavy metal contamination is a notable risk to seed-sown crop species, with multi-metal contamination events likely to be severely damaging to lettuce, tomato, radish, common bean, and mulberry crops.

Pages 531-537 | Full Text PDF| doi: 10.21475/ajcs.21.15.04.p2806
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Recurrent selection for resistance to Thrips tabaci in a tropical onion population

Gleyce de Oliveira Ferreira, Carlos Antonio Fernandes Santos*, José Adalberto de Alencar, Danillo Olegário Matos da Silva

Universidade Estadual de Feira de Santana, Programa de Pós-graduação em Recursos Genéticos Vegetais. Avenida Transnordestina, s/n, Novo Horizonte, CEP 44036-900 Feira de Santana, BA, Brazil
Empresa Brasileira de Pesquisa Agropecuária (Embrapa Semiárido), Rodovia BR-428, km 152, s/n, Zona Rural, CEP 56302-970 Petrolina, PE, Brazil
Uninassau Petrolina, Avenida Clementino Coelho, 714 - Centro, CEP 56308-100 Petrolina, PE, Brazil

Abstract
Recurrent selection for resistance to onion Thrips tabaci has not been well studied by breeding programmes. Onion thrips is a pest of major concern and is controlled by insecticide spraying, raising production costs and potentially damaging the environment. This study aimed to estimate onion bulb yield genetic gain through six cycles in the ‘BRS Alfa São Francisco’ developed by recurrent selection for T. tabaci resistance. Experiments were carried out in a randomised block design, with three replications, in two locations. The degree of infestation in plants was evaluated five times after transplanting, as well as plant architecture traits and bulb yield. The latest selection cycle presented bulb commercial yield of 32.1 t.ha-1, while the base population ‘Alfa Tropical’ and IPA 10 check cultivar 15.9 and 14.0 t.ha-1, respectively (p<0.01). The broad sense heritability values ranged from 0.65 to 0.74 for bulb yield. The mean genetic gain was 1.0 t.ha-1 or 6% per selection cycle, indicating the efficiency of the method to increase the frequency of favourable alleles for thrips resistance and the possibility of onion cultivation in the total absence of insecticide applications to control this pest, or a reduction in their number.

Pages 538-542 | Full Text PDF| doi: 10.21475/ajcs.21.15.04.p2827
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Cassava wastewater as ecofriendly and low-cost alternative to produce lettuce: impacts on soil organic carbon, microbial biomass, and enzymatic activities

Diogo Paes da Costa, Janisson Bispo Lino, Neyla Thayná Lima, Cícero Luiz Franco Junior, Fabiano da Silva Brito, Lucas Felipe Prohmann Tschoeke, Rafaela Felix da Franca, Renata Oliveira Silva, Erika Valente de Medeiros

Laboratory of environmental Microbiology and Enzymology, Federal Rural University of Pernambuco, Garanhuns 55292-270, Brazil
Laboratory of Toxicology, Federal Rural University of Pernambuco, Garanhuns 55292-270, Brazil

Abstract
The processing of cassava roots for starch extraction in factories generates a large amount of cassava wastewater (CW), which is rich in nutrients that are beneficial to plants. The reuse of this agro-industrial by-product is important for farmers and the environment as an alternative means to support soil fertility and plant production. Lettuce is the most important salad vegetable grown in the world. The objective of this study was to evaluate the impact of CW doses on soil organic carbon, basal respiration, microbial biomass, enzymatic activities, and lettuce growth in an Entisol. The experiment was conducted in pots in a greenhouse at room temperature in a completely randomized design with ten replications. The treatments consisted of the application of CW in increasing volumes that corresponded to fractions of the field capacity (FC) of the soil (100% FC = 206.6 ml dm-3): 0% (negative control), 10%, 20%, 30%, 40%, and 50% of field capacity (FC) per pot. An additional treatment without CW was also included, applying only 1.0 g of mineral fertilizer per pot (20% N, 10% P, and 20% K). After 28 days of emergence, the 10% FC treatment responded similarly to mineral fertilizer, increasing the length of the branches (+42%), number of leaves (+45%), aerial fresh matter (+202%) and the concentrations of Chlorophyll A (+ 33%), and Chlorophyll B (+40%), in addition to soil organic carbon (+15%), all compared to the control. The enzymatic activities in the soil were shown to be sensitive to CW dosage, especially for urease, which grew linearly as a function of the increased pH and K+ ions in the soil with the application of CW. The dose 20.7 ml CW dm-3 (10% FC) was that most increased plant variables, but the nutritional status of the soil and microbial activities benefited more from higher doses, starting from 30% FC, a scenario that could benefit plants more in future phenological stages, when there will be greater nutritional demand.

Pages 543-552 | Full Text PDF| doi: 10.21475/ajcs.21.15.04.p2831
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Production of pout pepper (Capsicum chinense) under irrigation depths and nitrogen doses in the Brazilian Cerrado

Juliane de Souza Beltrão, Marcio Koetz, Edna Maria Bonfim-Silva*, Tonny José Araújo da Silva, Jefferson Vieira José

Federal University of Rondonópolis, UFR, Institute of Agricultural and Technological Sciences, 5055, Students Avenue, Rondonópolis, 78.735-901, Brazil
Multidisciplinary Center, Federal University of Acre, Cruzeiro do Sul, AC 69895-000, Brazil

Abstract
Correct management of water and fertilizers can enable the profitable and ecologically correct cultivation of pout pepper (Capsicum chinense). In this context, the objective of this study was to assess the effect of drip irrigation depths and nitrogen doses on the cultivation of pout pepper in a Latossolo Vermelho (Oxisol) of the Cerrado region. The experiment was conducted in the field in a randomized block design, at the Federal University of Mato Grosso –Campus of Rondonópolis. The treatments were five irrigation depths (40, 60, 80, 100 and 120% of ETc) and five nitrogen doses (0, 60, 120, 180 and 240 kg ha-1), with 4 replicates. Fresh and dry weights of fruits, number of fruits, plant yield and water productivity were analyzed. Nitrogen fertilization caused significant differences in fresh and dry weights of fruits (873.95 and 133.03 g plant-1), respectively, as well as in the number of fruits (319.05 fruits plant-1) and plant yield (14.9 t ha-1). Water productivity showed a response surface with a stationary point of minimum (7.13 kg L-1). Adequate doses of nitrogen and irrigation depths promote good development of pout pepper cultivated in Latossolo Vermelho (Oxisol) of the Cerrado region.

Pages 553-558 | Full Text PDF| doi: 10.21475/ajcs.21.15.04.p2858
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Estimated losses in soybean (Glycine max (L.) Merril) harvest according to the speed and rotation of the trail system

Jarlyson Brunno Costa Souza, Mádilo Lages Vieira Passos, Eduardo Arouche da Silva, Armando Lopes de Brito Filho, Samira Luns Hatum de Almeida, Ana Karla da Silva Oliveira, Lusiane de Sousa Ferreira, Washington da Silva Sousa, Edmilson Igor Bernardo Almeida, Rouverson Pereira da Silva

State University of São Paulo “Julio de Mesquita Filho”, Jaboticabal, SP, Brasil
Federal University of Ceará, Fortaleza, CE, Brasil
University of São Paulo, Piracicaba, SP, Brasil
Federal University of Maranhão, Chapadinha, MA, Brasil
Federal University of Espirito Santo, Alegre, ES, Brasil

Abstract
The soybean crop (Glycine max. (L.) Merril) shows strong participation in the Brazilian economy. Therefore, the aim of the present study was to quantify the losses in the cutting and feeding platform and in the trail system in mechanized soybean harvest by analyzing different speed and rotation adjustments of the trailing cylinder. The experiment was carried out in a commercial soybean plot on a farm located in the municipality of Brejo (MA), during the 2017/2018 harvest. The harvester evaluated was a Case IH 8120, with a maximum power of 34.2 kW, axial flow system, and 12.2-m platform equipped with a conveyor system (draper). The experiment was conducted in two different areas. Area 1 was planted with the Brasmax® Opus (BMX Opus) cultivar, while area 2 was cultivated with the BRS 9383 cultivar. The treatments consisted of three machine speeds (4 km h-¹, 6 km h-¹, and 7 km h-¹), associated with the rotation levels of 500 rpm and 800 rpm in the trail system. The experimental design used were randomized blocks in a 3 x 2 factorial arrangement, with four replications. For the BMX Opus cultivar, harvest losses did not influence the travel speeds and rotations evaluated in the experiment due to the marked instability within the treatments. The BRS 9383 cultivar showed satisfactory results at a speed of 4 km h-1 combined with a rotation of 800 rpm, which obtained acceptable numbers for the soybean harvest (54.09 kg ha-1).

Pages 559-563 | Full Text PDF| doi: 10.21475/ajcs.21.15.04.p2868
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Planting recommendations for yacon (Smallanthus sonchifolius) in lowland conditions

Mateus Augusto Lima Quaresma, Fábio Luiz de Oliveira, Leonardo F Rocha, Ariany das Graças Teixeira*, Diego Mathias Natal da Silva, Leandro Pin Dalvi, Marcelo Antonio Tomaz

Department of Agronomy, Center of Agricultural Sciences and Engineering, Universidade Federal do Espírito Santo, Alegre-ES, Brazil
Departament of Plant, Soil and Agricultural Systems, Southern Illinois University, Carbondale-IL, United States of America

Abstract
The purpose of this work was to test yacon planting practices in low elevation conditions. The experimental design was a randomized block design (RBD) with subdivided plots and four replications. Treatments comprised of three planting methods: furrow; ridges and pits; each treatment was divided into subplots, which were four planting depths: 5, 10, 15, and 20 cm. The following variables were tested: sprouting speed, vigorous sprouting rate, average time for sprouting, rhizophore mortality rate, soil temperature and moisture, shoot dry weight, and yield of rhizophores, tuberous roots, total yield, and marketable tuberous roots. The planting methods using pits and furrows had lower seedling mortality rates (30,2 and 41,4% compared to ridges), while furrow led to a higher total tuber yield (17,5 and 18,9% higher than ridges and pits), using depths of 5 and 10 cm. The system with pits also achieved significant yields at 10 cm depth. Using ridges as the planting method would be possible, at depths of 10 and 15 cm, but yields would be lowered. For the conditions of this study, the highest yield of marketable roots was obtained using furrow at 5 and 10 cm of panting depth.

Pages 564-569 | Full Text PDF| doi: 10.21475/ajcs.21.15.04.p2873
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Chemical composition and antifungal potential of essential oils from different aerial parts of Protium ovatum Engl.

Wendel C. de Sousa, Josemar G. Oliveira Filho, Cassia C. F. Alves, Moacir R. Forim, Cristiane de M. Cazal*

Instituto Federal de Educação, Ciência e Tecnologia Goiano, Rio Verde, GO, Brazil
Departamento de Química, Universidade Federal de São Carlos, São Carlos, SP, Brazil
Instituto Federal de Educação, Instituto Federal de Ciência e Tecnologia Sudeste Minas Gerais, Barbacena, MG, Brazil

Abstract
Protium ovatum is a Brazilian endemic species widely distributed between the Cerrado and Amazon biomes. Here, we evaluate the chemical composition of the essential oils (EO) of different shoot organs from P. ovatum including stems, petioles, leaves, flowers, ripe and unripe fruits, and investigate their antifungal potential against Sclerotinea sclerotiorum. The EO were obtained by hydrodistillation in a Clevenger-type apparatus and analysed by GC-MS, followed by PCA analysis. The antifungal activity was performed by agar diffusion. Fruits had the highest essential oil contents among the shoot parts. The constituents were found varyingin the different organs: α-Pinene (0.80-18.3%), β-Pinene (0.58-5.17%), Myrcene (0.52-27.3%), Limonene (3.15-59.7%), Caryophyllene E (3.67-16.4%), Germacrene D (6.34-27.4%), and δ-Cadinene (2.29-7.63%). The essential oil from ripe fruit showed the strongest antifungal activity, with the highest Inhibition of Mycelial Growth (IMG) (50.11%) at the lowest concentration assayed (18.75μg.mL-1). This is the first report on the chemical composition of the essential oils from stems, petioles, flowers, and ripe fruits of P. ovatum and their antifungal activity against S. sclerotiorum, making it a potential source of antimicrobial agents.

Pages 570-576 | Full Text PDF| doi: 10.21475/ajcs.21.15.04.p2915
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Methods for overcoming dormancy in Brachiaria brizantha seeds

Tiago O. Souza, Marcela C. Nery*, Marcela A. Magalhães, Mahany G. Martins, Fernanda C. Nery, Cíntia M. T. Fialho

Department of Agronomy, Federal University of the Jequitinhonha and Mucuri Valleys, Diamantina, Minas Gerais, Brazil
Department of zootechnics, Federal University of the Jequitinhonha and Mucuri Valleys, Diamantina, Minas Gerais, Brazil
Department of Biosystems Engineering, Federal University of São João del-Rei, São João Del-Rei, Minas Gerais, Brazil
Department of Agronomy, Federal Technological University of Parana, Santa Helena, Parana, Brazil

Abstract
Brachiaria brizantha is a forage species widely used in Brazilian pastures and its seeds have contamination in several areas of countries. Its high germination is fundamental in pasture formation. However, it is common for seeds of this species to have natural dormancy, negatively influencing pasture formation, resulting in losses to the producer. Thus, the objective of this study was to determine a methodology to overcome dormancy of ‘Marandu’ and ‘Piatã’ B. brizantha seeds. Four batches from the 2016/2017 and 2017/2018 harvests were used. Initially, batch profile was evaluated by the following characteristics: determination of moisture content, weight of a thousand seeds, first germination count, germination, germination speed index, initial stand, emergency, emergency speed index and fungi incidence in seeds. The seeds were subjected to the following treatments to overcome dormancy: mechanical (removal of glume, palea and lemma), sulfuric acid (98%, 36 N), potassium nitrate (0.2%), heat treatment (70 °C and 85 °C, during 5h, 10h, 15h and 20h) and a control. The obtained results allow inferring that the causes of dormancy of ‘Piatã’ seeds are of a physical nature, with the tissues surrounding the seed being the main factor that prevent germination. The mechanical method and scarification with sulfuric acid the most efficient in overcoming dormancy. The mechanical treatment with removal of the glumella is efficient to overcome the dormancy ofB. brizantha seeds, providing an increase in the germination percentage.

Pages 577-585 | Full Text PDF| doi: 10.21475/ajcs.21.15.04.p2938
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Retranslocation of nutrients in coffee leaves of cultivars Red Catuaí IAC 144 and IAC 125 RN.

Carlos Diego da Silva*, Alian Cássio Pereira Cavalcante, Marcos Fabian Sanabria Franco, Pedro Ruben Viera Fariña, Guilherme Antônio Vieira de Andrade, and Leonardo Angelo de Aquino

Universidade Federal de Viçosa (UFV), Rio Paranaíba, MG, Brasil
Universidade Federal de Viçosa (UFV), Viçosa, MG, Brasil
Universidade Federal de Lavras (UFLA), Lavras, MG, Brasil
Instituto Paraguaio de Tecnologia Agrária - IPTA, Chore, San Pedro, Paraguai

Abstract
Knowledge of the retranslocation of nutrients in plants can help in the management of coffee fertilization, especially with regard to the ideal time and method of application and the need for installments. The aim of this study was to evaluate the retranslocation of nutrients in coffee leaves of two varieties. The treatments consisted of two varieties of coffee (Red Catuaí IAC 144 and IAC 125 RN) and coffee leaves in four phenological stages (young leaves, diagnostic, senescent and deciduous). The index leaf of Catuaí Vermelho IAC 144 showed the highest photosynthetic rate and stomatal conductance, while the internal conductance of CO2 was higher in young and senescent leaves, and the index and senescent leaves showed the highest efficiencies in the use of water. The chlorophyll a, b and total chlorophyll has higher concentrations in the index leaf, while the highest carotenoids occurred in young and senescent leaves. The highest levels of N, P, K and Zn in Catuaí Vermelho IAC 144 was occurred in young leaves and the highest Ca and Fe in senescent leaves. The highest levels of N, P and K in the IAC 125 RN variety was occurred in young leaves, Ca and Mg in deciduous leaves and S in senescent and deciduous leaves. Nutrients with low mobility in the plant must be parceled, the application of Zn leaves is an alternative method of supplying this nutrient, as it has retranslocation via phloem.

Pages 586-593 | Full Text PDF| doi: 10.21475/ajcs.21.15.04.p3019
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Oil extraction and cake bromatological properties of crambe (Crambe abyssinica) are affected by extraction at different temperatures and rotation speeds

Cristiano Fernando Lewandoski*, Reginaldo Ferreira Santos, Doglas Bassegio, Samuel Nelson Melegari de Souza, Jair Antonio Cruz Siqueira, Diane Maschio de Souza, Leonardo Silva Reis, Paulo Lima Bueno

Universidade Estadual do Oeste do Paraná, UNIOESTE, CEP 85819130, Cascavel, PR, Brazil

Abstract
Temperature and rotation speed are operational parameters that influence oil screw press efficiency. The objective of this study was to evaluate the oil physicochemical properties, cake bromatological properties, and oil extraction yield from crambe (Crambe abyssinica Hochst) seeds by mechanical pressing at different temperatures and rotation speeds in a mechanical extruder. A 4 × 5 factorial experimental design was employed to determine the effects of these parameters. The experimental design incorporated four temperature ranges (110–120, 120–130, 130–140, and 140–150°C) and five screw rotation speeds (1000, 1200, 1400, 1600, and 1800 rotations per minute, RPM), with four repetitions. The physicochemical properties of the oil and crambe cake, and the cake bromatological properties were affected by extraction at different temperatures and extruder rotation speeds. The oil density and viscosity (quality parameters), and the crambe cake bromatological factors, crude fiber, ash, lipid, and moisture content were found to be higher at extraction temperatures in the 140–150°C range. The maximum oil yield was achieved by extraction at a temperature of 140–150°C and a rotation speed of 1800 RPM. The protein and carbohydrate content of the crambe cake decreased with increasing temperature and rotation speed. The oil yield increased by 56% as temperatures increased from the 110–120°C range to the 140–150°C range, and by 41% when the rotation speed increased from 1000 to 1800 RPM. The screw configuration influenced the crambe and cake properties. These results can be used to determine the appropriate configuration of the screw.

Pages 594-601 | Full Text PDF| doi: 10.21475/ajcs.21.15.04.p3054
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Soil quality bioindicators in initial eucalyptus growth under organomineral fertilization based on sugarcane filter cake

Julio Cesar Delvaux*, Reginaldo de Carmargo, Regina Maria Quintão Lana, Miguel Henrique Rosa Franco, Mayara Cristiana Stanger, Rafael Arcanjo Gonçalves, Ernane Miranda Lemes, Paulo Sérgio Balbino Miguel

Instituto Federal de Educação, Ciência e Tecnologia do Triângulo Mineiro, Campus Ituiutaba, Ituiutaba, Minas Gerais, Brazil
Instituto de Ciências Agrárias, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil
Instituto Federal de Educação, Ciência e Tecnologia de Roraima, Campus Amajari, Amajari, Roraima, Brazil

Abstract
Pelletized organomineral fertilizers (OMFs) are a promising, sustainable alternative for eucalyptus fertilization, the most widely cultivated hardwood tree globally. However, little is known about the effects of OMFs on initial plant development and soil quality. We evaluated the effects of different doses of a pelletized OMF derived from sugarcane filter cake (0%, 50%, 100%, 150%, and 200% relative to the recommended phosphorus dose for cultivation) and a mineral treatment (mineral fertilizer at the recommended dose for eucalyptus), as well as the effects of time (30, 60, 90, and 120 days after transplanting), on the morphophysiological responses of eucalyptus plants (diameter at neck height, plant height, and chlorophyll a and b content) and soil pH, microbial biomass (MBC), and microbial activity (soil basal respiration [SBR]). Increases in fertilizer dose led to increased chlorophyll a values, but values decreased under the highest doses (150% and 200%). OMF addition led to an initial increase in soil pH, followed by a reduction. The highest values of plant height, stem diameter, and fresh and dry masses of leaves, stems, and roots were observed when the OMF dose of 50% was administered. MBC values were inversely proportional to the OMF dose, and the SBR and metabolic quotient (qCO2) values observed under the 50% and 100% treatments were equal to or better than those observed under the mineral fertilizer treatment. Pelletized OMFs derived from filter cake could potentially replace mineral fertilization in the early development of Eucalyptus urophylla × Eucalyptus grandis without damaging soil quality.

Pages 602-609 | Full Text PDF| Supplementary PDF | doi: 10.21475/ajcs.21.15.04.p3071
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Performance of pre-emergence herbicides in weed competition and soybean agronomic components

Marcelo de Sousa da Silva*, Tiago Vieira da Costa, José Augusto Lima Furtado, Jarlyson Bruno Costa Souza, Eduardo Arouche da Silva, Lusiane de Sousa Ferreira, Carlos Augusto Alves Cardozo Silva, Edmilson Igor Bernardo Almeida, Washington da Silva Sousa, Leonardo Bernardes Taverny de Oliveira, José Roberto Brito freitas, Job Teixeira de Oliveira

Universidade Federal do Maranhão, 65500-000, Chapadinha-MA, Brazil
Universidade Estadual Paulista Júlio Mesquita Filho, 14884-900, Jaboticabal-SP, Brazil
Universidade de São Paulo, 13418-900, Piracicaba-SP, Brazil
Universidade Federal do Espírito Santo, 29500-000, Alegres-ES, Brazil

Abstract
Soybean is the most important oilseed over the world. Different factors interfere in its development, among them, the interference of weeds. Thus, the objective was to analyze the performance of pre-emergence herbicides on the weed competition and agronomic components of soybean. For this, an experiment was carried out in commercial farming. The experimental design was in randomized blocks with three treatments and nine repetitions. The following treatments were tested: S-metolachlor (1,152 g a.i. ha-1); diclosulam (35 g a.i. ha-1; 42 g a.i. ha-1) + imazethapyr (164.8 g a.i. ha-1). Two phytosociological surveys were carried out at 21 and 32 days after sowing (DAS) for controlling the weed competition. At 14, 21, 32, and 37 DAS, stem height and diameter were analyzed, while at 115 DAS, the production components were estimated. The application of S-metolachlor (1,152 g a.i. ha-1) was efficient for pre-emergence weed control of weed competition in commercial soybean crops. Through this treatment, the conventional cultivar Ansc 89109 produced between 130,5 and 255,8 kg per hectare, this result is superior those obtained in plots treated with diclosulam (35 g a.i ha-1) + imazethapyr (164.8 g a.i. ha-1) and diclosulam (42 g a.i. ha-1) + imazethapyr (164.8 g a.i. ha-1). Thus, the application of higher-doses of diclosulam (42 g a.i. ha-1) in a mixture with imazethapyr (164.8 g a.i. ha-1) is not recommended since it presents eminent agronomic, environmental, and economic risks.

Pages 610-617 | Full Text PDF| doi: 10.21475/ajcs.21.15.04.p3100