Australian Journal of Crop Science   AJCS

Agronomic performance, flowering, physicochemical characteristics and genetic divergence in garlic accessions from Brazil

António Jorge Viegas Taula, Valter Carvalho de Andrade Júnior, Francisco Vilela Resende, Orlando Gonçalves Brito*, Jeferson Carlos de Oliveira Silva, Alysson Gomes Perreira

Mozambican Agricultural Research Institute, Horticulture Sector, Mailbox 3658, Zip code 37200-000, Maputo/MC, Mozambique
Federal University of Lavras, University Campus, Mailbox 3037, Zip code 37200-000, Lavras/MG, Brazil
Brazilian Agricultural Research Corporation, EMBRAPA Vegetables, Zip code 70770-901, Brasília/DF, Brazil

Abstract
The evaluation of garlic accessions is important in the search for superior, adapted and flowering cultivars for botanical seed production. The objective of this work was to assess the agronomic performance, flowering capacity and genetic divergence of 13 experimental garlic accessions bred in Brazil. The experiment was laid out as a completely randomized block design with four replications at Lavras, Minas Gerais, Brazil from May to October 2018. A total of 11 accessions were experimental and two were control varieties, Quitéria and Caçador. The control varieties are commercially produced in Brazil and the 11 experimental accessions are elite. The emergence, emergence speed index, plant height, percentage of overcrowding, average weight of commercial bulb, number of bulbs per bulb, total yield, commercial yield, flowering percentage, length and diameter, soluble solids, titratable acidity, pH and ratio soluble solids and titratable acidity of the exhaust floral were measured. The data obtained were submitted to analysis of variance (p≤0.05), and when significant the effects of genotypes, their means grouped by the Scott-Knott test. We also proceeded to study genetic divergence through multivariate analysis, adopting the canonical variables technique. Variance analysis indicated significant differences between genotypes for emergence speed index, flowering percentage, floral scape diameter, floral scape length and commercial yield. The highest commercial yield and flowering percentage were observed in RAL (8.82 t ha-1) and DDR 6024 (80.92%) access, respectively, which differed only from commercial cultivars (Quitéria and Caçador). The greatest genetic divergence was verified between experimental accessions and commercial cultivars. The experimental accessions presented flowering potential and botanical seed production in the studied region.

Pages 1372-1380 | Full Text PDF| doi: 10.21475/ajcs.21.15.12.p2859
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Effect of dolomitic limestone and organic fertilizers on some physical-chemical properties and the structure of a Vertisol

Pedro Cairo Cairo*, Joaquin Machado de Armas, Bladimir Diaz Martin, Oralia Rodriguez Lopez

Universidad de Atacama, Centro Regional de Investigación y Desarrollo Sustentable (CRIDESAT), Copiapó, 1532000 Chile
Universidad Central de las Villas, Facultad de Ciencias Agropecuarias, Centro de Investigaciones Agropecuarias, Santa Clara, 54830 Cuba

Abstract
The application of natural mineral and organic fertilizers can increase soil productivity. The work was carried out in Vertisols sugarcane areas on the North coast of the province of Villa Clara, municipality of Sagua la Grande, Cuba, with the objective of assessing the effect of dolomitic limestone and organic fertilizers on some physical-chemical properties of a Vertisol. An experiment was conducted with dolomitic limestone levels and combinations of organic fertilizers (4 t ha-1 compost, 15 t ha-1 sugarcane filter cake) and fertilizers (NPK). The design used was stripe blocks. The soil analysis data used at the depth of 0-20 and 20-40 cm were at 8, 19 and 36 months after application of the treatments. The following indicators were evaluated: structure factor, permeability, stable aggregates, plasticity, T value, and exchangeable cations. The Ca/Mg ratio reached a maximum value of 2.58, which shows in the effect of the treatments on the interchangeable cations. Dolomitic limestone and its combinations with organic fertilizers showed significant positive effects on soil structure and consistency, both in the surface layer and in the subsoil, with residual impact over time up to 36 months. The results obtained showed a change in the category of structural indicators from regular to excellent (permeability 1.50-2.40) and from plasticity to moderately plastic (Plastic index 36.64 -13.72).

Pages 1381-1385 | Full Text PDF| doi: 10.21475/ajcs.21.15.12.p3048
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Topdressing N fertilization on productivity and nutritional status of common bean crop

Junia Maria Clemente, Thais Rodrigues Coser, Harley Sales, Pedro Ruben Viera Fariña, Leonardo Angelo de Aquino

Department of Agronomy, Federal University of Viçosa, Campus Viçosa, Brazil
Yara Fertilizers, Brazil. 3Instituto Paraguaio de Tecnologia Agrícola (IPTA), Brazil
Department of Crop Science, Federal University of Viçosa, Campus Rio Paranaíba, Brazil

Abstract
The present study aimed to compare sources and doses of N on productivity, nutritional status and commercial quality of bean (Phaseolus vulgaris) crop. The treatments consisted of the following N doses: 60, 90 and 110 kg N/ha. The sources were YaraLiva Nitrabor (390, 585 and 715 kg ha-1) and Urea (130, 195 and 240 kg ha-1). Both sources and doses were applied before or after 15 mm irrigation. In case of fertilizers application after 15 mm irrigation, 1 mm of water was applied after application only to lightly soak granules, which was called “drizzle”, simulating a low-intensity rain after fertilizer application. The experiment was designed as randomized block with four replications in a factorial scheme (2x3x2) + 1, during 113 days with sowing on 06/25/2018 and harvest on 10/18/2018. BRS Estilo was the cultivar used in this study. Application of calcium nitrate in moist soil followed by drizzle provide gains around 5.48 kg of bean per kg of topdressing N, while urea provides gains of 2.22 kg of bean per kg of topdressing N.

Pages 1386-1394 | Full Text PDF| doi: 10.21475/ajcs.21.15.12.p3157
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Inulin content of Jerusalem artichoke (Helianthus tuberosus L.) tubers stored at 5 oC in a refrigerator for different durations

R. Sennoi*, R. Puttha

Department of Plant Production Technology, Faculty of Agriculture and Natural Resources, Rajamangala University of Technology Tawan-ok, Chonburi, 20110, Thailand
Faculty of Agricultural Production, Maejo University, San Sai, Chiang Mai 50290, Thailand

Abstract
Jerusalem artichoke is a perennial crop, but it is grown as an annual crop for its inulin containing tubers. Various factors affect inulin content, in which storage duration is one of the significant causes. Therefore, the effect of different storage durations on inulin content of Jerusalem artichoke was investigated in this study. Four Jerusalem artichoke varieties were assigned as factor A, and six durations of storage at 5 oC were assigned as factor B. The 24 treatment combinations of a 4×6 factorial were arranged in a completely randomized design with four replications. After harvest, the tubers were cleaned and stored at 5 oC for five months. Inulin content was analyzed consecutively at 0, 1, 2, 3, 4 and 5 months after storage. Times of storage and varieties were significantly different (P<0.01) for inulin content. Stored tubers had inulin contents ranging from 35.9 to 43.7 % compared to 47.8 % of freshly-harvested tubers. The lowest inulin content was found after 2 months of storage. JA 89 had the highest inulin content (47.80%), whereas CN52867 had the lowest inulin content (35.85%). Regression analysis showed small and insignificant effect of storage time on inulin content, and the results are discussed. The results will be useful for consumers and industries for their concern on storage loss of inulin content after storage.

Pages 1395-1398 | Full Text PDF| doi: 10.21475/ajcs.21.15.12.p3158
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Physiological, biochemical and nutritional changes in soybean in response to application of steel slag

Alessandra Vieira da Silva*, Angélica Cristina Fernandes Deus, Mara Lúcia Cruz de Souza, Fernando Broetto, Leonardo Theodoro Büll

Department of Soil and Environmental Resources, College of Agronomic Sciences, São Paulo State University (Unesp), Botucatu, São Paulo State, Brazil
Rural Engineering Department, College of Agronomic Sciences, São Paulo State University (Unesp), Botucatu, São Paulo State, Brazil

Abstract
Steel slag is a powdery industrial residue that has CaO, MgO and SiO2 in its composition, which enables its use in agriculture for soil acidity correction. Most studies involving this residue have focused on understanding its effects on the soil, not always considering its action on the plant metabolism. Thus, the present study aimed to evaluate physiological, biochemical and nutritional changes in soybean plants due to application of lime and steel slag on the soil surface or by incorporation. The experiment was carried out in the field, with six soil acidity corrective materials: stainless steel slag, steel slag, ladle slag, wollastonite, dolomitic lime and calcined dolomite, plus a negative control, which did not receive correctives. Two application methods were adopted: soil surface application or incorporation. Sixty days after application, the soybean crop was established. Soybean response changed with the application method, since incorporation of corrective materials provided greater production of fresh and dry leaf mass and stem fresh mass, increased chlorophyll b and leaf K levels, and contributed to a greater number of plants per hectare and pods per plant, compared to surface application. Besides such benefits, there was no difference between the effect of application methods on soybean yield, indicating that both incorporation and surface application are efficient in increasing soybean grain yield. The correctives steel slag, wollastonite and calcined dolomite provided significant increases in soybean yield.

Pages 1399-1405 | Full Text PDF| doi: 10.21475/ajcs.21.15.12.p3269
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Morphological and phylogenetic characterization of Fusarium Link.

Leonardo de Jesus Machado Gois de Oliveira, Antonia Alice Costa Rodrigues*, Erlen Keila Candido e Silva, Anna Christina Sanazário de Oliveira, Maria Claudene Barros, Elmary da Costa Fraga, Ivaneide de Oliveira Nascimento, Maria Rosangela Malheiros Silva

Programa de Pós-graduação em Agroecologia, Centro de Ciências Agrárias/CCA, Universidade Estadual do Maranhão, Cidade Universitária Paulo VI. São Luís/MA, CEP. 65055-310, Brasil
Programa de Pós-graduação em Biodiversidade, Ambiente e Saúde, Centro de Estudos Superiores de Caxias – CESC, Caxias/MA, CEP: 65.604-380, Brasil
Universidade Estadual da Região Tocantina do Maranhão, Brasil

Abstract
Identification of Fusarium isolates in a sample at the species level is an important and difficult task because many Fusarium species have similar morphological characteristics. The phylogenetic relations of species have been applied in Fusarium systematic and may solve taxonomic difficulties. The aim of the present study is to characterize pathogeny of Fusarium isolates through morphological analysis (concept of morphological species) associated with symptoms in hosts together with phylogeny analysis (concept of phylogenetic species) using internal transcribed spacer region (ITS) of ribosomal DNA for species identification. For the morphological characterization, Fusarium isolates were grown in PDA culture medium. Then, they were classified based on colony color and the microconidial, macroconidial and chlamydospore structures. The isolates were characterized molecularly by amplifying and sequencing the ITS region of the ribosomal DNA. The sequences generated were compared with those placed in the Genbank and Maximum Likelihood phylogenetic trees were constructed. Out of 14 isolates characterized morphologically and molecularly, five isolates were grouped in the Gibberella fujikuroi species complex in the Liseola section, seven presented characteristics of species from the Elegans section within the F. oxysporum species complex and two isolates presented characteristics of the section Gibbosum species complex in the F. incarnatum-equiseti species complex. Thus, seven isolates (section Elegans) belonged to the species F. oxysporum, two isolates (section Gibbosum) to the species F. equiseti. However, the ITS region of the ribosomal DNA did not provide sufficient evidence to define the species of G. fujikuroi species.

Page 1406-1415 | Full Text PDF| doi: 10.21475/ajcs.21.15.12.p3292
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Quantitative expression analysis of different cold-responsive (COR) and C-repeat binding factors (CBF) genes in wild and cultivated barley under cold acclimation conditions

Nahid Hazrati, Mohammad Hasanzadeh, Saime Ünver İkincikarakaya, Canan Yüksel Özmen, Ali Ergül*

Ankara University, Faculty of Agriculture, Department of Field Crops, 06110, Diskapi, Ankara, Turkey
University of Mohaghegh Ardabili, Faculty of Agriculture and Natural Resources-Moghan, Department of Crop Production, Ardabil, Iran
Ankara University, Biotechnology Institute, 06135, Ankara, Turkey

Abstract
Cold stress affects plant metabolism and transcripts. The effect on plant metabolism was caused both by direct inhibition of metabolic enzymes at cold temperatures and by reprogramming the gene expression. The main objective of this study was to evaluate and identify of expression level of some cold-related genes under control and cold stress conditions in 11 spring/winter barley (Hordeum vulgare L.) varieties and 2 Hordeum spontaneum wild genotypes. For this purpose, expression profile of the main C-repeat binding factor )CBF( genes along with expression profiles of the two cold-responsive )COR( genes in plants exposed to low temperatures (+4 °C) were investigated. In parallel, measurements of leaf water potential of varieties were performed in control and at low temperature conditions. Results revealed that, the expression level changes of COR14b gene under cold conditions are more consistent with those of the upstream CBF9 gene expression levels in different varieties and time points rather than the other upstream gene (CBF1). The dehidrin8 )DHN8( expression level was also related to the CBF9 gene expression level and the decreased expression of the CBF9 gene resulted in decreased expression or non-expression of the DHN8 gene. Based on results, it could be said that CBF9 interacts with CBF1 to regulate DHN8 expression. Wild genotypes showed statistically insignificant expression increment for investigated genes in days 1 and 8 of stress. This result is an indicator of the increase at expression levels in the stress genes of more tolerant varieties.

Pages 1416-1426 | Full Text PDF| doi: 10.21475/ajcs.21.15.12.p3294
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Genetic variability, heritability and genetic advance of soybean (Glycine max) genotypes based on yield and yield-related traits

Maletsema Alina Mofokeng

Agricultural Research Council-Grain Crops, Private Bag X 1251, Potchefstroom, 2520. South Africa

Abstract
The success of breeding programme relies on the variability present in the breeding material. Selection is also effective when there is significant amount of genetic variability among the individuals in a population. The study aimed at assessing genetic variability, heritability and genetic advance among yield and yield components of soybean genotypes. Eighty-two genotypes maintained at the Agricultural Research Council-Grain Crops were planted in an alpha lattice design, replicated twice in Potchefstroom and Brits in South Africa in 2017/18 growing season. Five plants per genotype were selected and yield and yield related traits were measured. Data were analysed through analysis of variance and genetic parameters were estimated. The results showed highly significant differences among the genotypes based on days to flowering, branch number per plant, hundred seed weight, pod weight per plant, pod length, seed number per plant, seed number per pod and grain yield. Heritability of yield and yield components were ranged from 5.9% to 100%. The most heritable traits were hundred seed weight (100 %), days to flowering (64.13 %) and seed number per pod (67.37%). The genotypic variance ranged from 0.3% to 33% while the phenotypic variation ranged from 1.5% to 44%. The phenotypic and genotypic coefficient of variations was high for grain yield, medium for days to flowering and lowest for hundred seed weight. The phenotypic coefficient of variations (PCV) was higher than genotypic coefficient of variation (GCV) for all characters indicating the influence of environmental factors. The expected genetic advance was high for most of the traits, medium for seed number per pod and hundred seed weight and low for pod number per plant. The expected genetic advance as percent of mean was variable and high for all traits. There was vast variation observed among the soybean genotypes evaluated based on the yield and yield related traits.

Pages 1427-1434 | Full Text PDF| doi: 10.21475/ajcs.21.15.12.p3303
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Antixenosis in cotton genotypes (Gossypium hirsutum var. marie galante) to Spodoptera frugiperda (Lepidoptera: Noctuidae) mediated by trichome and gossypol densities

Patrícia Vaz da Costa da Silva, Célio Borella Junior, Flávio Gonçalves de Jesus, Lúcia Vieira Hoffmann, Ivandilson Pessoa Pinto de Menezes*

Instituto Federal Goiano, Campus Urutaí, Programa de Pós-Graduação Profissional em Proteção de Plantas, Rodovia Geraldo Silva Nascimento, 75790-000, Urutaí, Goiás, Brazil
Embrapa Arroz e Feijão, Laboratório de Biotecnologia Vegetal, Santo Antônio de Goiás, 75375-000, Goiás, Brazil
Instituto Federal do Ceará, Campus Acopiara, Rodovia CE 060, Km 332, 63560-000, Acopiara, Ceará, Brazil

Abstract
Cotton (Gossypium hirsutum L.) is one of the most important crops in Brazil and pest incidence limits its yields. The fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), native to tropical and subtropical America, spread and rapidly became an invasive pest worldwide. It is a polyphagous pest that feeds on up to 353 plant species including cotton. The objective of this study was to evaluate the antixenosis to S. frugiperda in 27 cotton genotypes, comparing varieties with non- commercial genotypes. The attractiveness was estimated in no-choice and free-choice tests, offering leaf discs of the 27 cotton genotypes to S. frugiperda, and counting the number of caterpillars feeding at 3, 5, 10, 15, and 30 minutes and 1, 2, 6, 12, and 24 hours after their release. The numbers of trichomes and gossypol glands per cm2 were measured on abaxial and adaxial surface. The free-choice test was performed in a randomized block design with the 27 genotypes (treatments) and 20 arenas (replicates). The no-choice assay was conducted as a completely randomized design with 18 genotypes and 20 replicates. The non-commercial genotypes PI0440, CE0467, PI0416, BA0512 and MA0425 presented antixenosis against S. frugiperda. In the free-choice test the cultivar BRS Buriti and the genotype PI0429 were the most attractive to S. frugiperda, while in no-choice test, the genotype PI0429 was the most attractive. High trichome density and gossypol glands did not influence the attractiveness of S. frugiperda in cotton genotypes, while the absence of trichomes was repellent to the caterpillars. There is polymorphism among cotton genotypes to attractiveness to the pest, and the genotypes with antixenosis can be used in future study in plant breeding program as donor source of resistance to S. frugiperda.

Pages 1435-1441 | Full Text PDF| doi: 10.21475/ajcs.21.15.12.p3310
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Plant growth promoting rhizobacteria enhance the ratoon productivity of sugarcane

Chanyarat Paungfoo-Lonhienne*, Nantida Watanarojanaporn, Ian Petersen, Ratchaniwan Jaemsaeng, Peeraya Klomsa-ard, Klanarong Sriroth

School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
Mitr Phol Sugarcane Research Center Co., Ltd., Phu Khiao, Chaiyaphum, 36110, Thailand

Abstract
Less than half of the applied chemical fertiliser in intensive cropping systems is utilised by the target crops, with the remaining nutrients contributing to environmental pollution. Reducing the pollution derived from inefficient use of chemical fertilisers has enormous importance for agriculture. Recently, studies have shown that plant growth promoting rhizobacteria (PGPR) Paraburkholderia sp. SOS3 along with a combination of organic and chemical fertilisers can offer a viable avenue to enhance sugarcane growth while reducing the concentration of chemical fertilisers. Here, we further investigated the effects of adding PGPR with combined organic and chemical fertilisers on sugarcane ratoon productivity (i.e. the second-year ratoon crop). The ratoon crop regenerated from sugarcane fertilised with the chemical-organic fertilisation in the first year, with or without PGPR (4 replicates), was grown in industry-standard practice in the second year. The results show that PGPR inoculation during the initial planting strongly promotes the growth of the ratoon sugarcane in the second year without reapplication of the PGPR. These findings show the high potential of using PGPR along with a combination of organic and chemical fertilisers for improving ratoon crop productivity in sugarcane.

Pages 1442-1445 | Full Text PDF| doi: 10.21475/ajcs.21.15.12.p3311
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Production of round wood from planted forests and price of pulp and paper and other forestry purposes in southern Brazil

Gustavo Silva Oliveira*, Romano Timofeiczyk Junior, Ailson Augusto Loper, Pedro José Steiner Neto, Ricardo Ribeiro Alves

Department of Rural Economy and Extension, Federal University of Paraná – UFPR, Curitiba, Paraná, Brazil
Department of Forest Engineering, Federal University of Pampa - UNIPAMPA, São Gabriel – Rio Grande do Sul, Brazil

Abstract
The aim of the study is to analyze the production of round wood from planted forests and the price of pulp and paper and other forestry purposes in southern Brazil, from 2000 to 2019. In this study, we worked with historical series from secondary data collected from the Brazilian Institute of Geography and Statistics IBGE, referring to the produced and traded quantity in forestry (m³), forestry production value (one thousand dollars) and price ($/m³), obtained through the ratio between the production value and the respective produced quantities in each year. The silviculture production value (PV) is a derived variable calculated by the weighted average of quantity and average current price paid to the producer (m³), according to the harvest and commercialization periods of each product. The price evolution (P) was separated according to purpose and obtained through the quotient between the production value and respective quantities produced in each year. The trend models were estimated, in which annual growth rates of the real price and produced quantity were calculated for the two roundwood purposes in the evaluated period. Then, we sought to fit the results according to the possibilities of shift of the supply and demand curves. The results indicate that pulp and paper presented positive rates of produced quantity and price, of 5.8775 and 1.3704, respectively. The nomenclature for other purposes had a positive rate for the produced quantity (4.1929) and a negative rate for price (-0.3203). Thus, logwood for pulp and paper showed a dominant shift in the demand curve to the right, showing a rising market, while for other purposes, there was a dominant shift in supply to the right, corroborating the concept of positive variation in quantity and a negative variation in price. Given these results, it is important to highlight that the study refers to one federative unit in Brazil, which signals the recommendation that other similar studies be carried out in other states to better understand the impact of production and price of these purposes on the Brazilian market.

Pages 1446-1451 | Full Text PDF| doi: 10.21475/ajcs.21.15.12.p3313
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Evaluation of regrowth ability of soybeans for forage utilization under two-cutting systems

Yogi Sidik Prasojo, Genki Ishigaki*, Masatsugu Hashiguchi, Melody Muguerza, Ryo Akashi

Department of Animal Nutrition and Feed Science, Faculty of Animal Science, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia
Interdisciplinary Graduate School of Agriculture and Engineering, University of Miyazaki, Gakuen kibanadai Nishi 1-1, Miyazaki, 889-2192, Japan
Sumiyoshi Livestock Science Station, Field Science Education Research Center, Faculty of Agriculture, University of Miyazaki, Shimanouchi 10100-1, Miyazaki, 880-0121, Japan
Faculty of Agriculture, University of Miyazaki, Gakuen kibanadai Nishi 1-1, Miyazaki, 889-2192, Japan

Abstract
Soybean (Glycine max) has the potential as forage feed because of its high protein content and low fiber. Intercropping soybean with tropical forage grasses can improve forage quality and increase yield. However, their optimum cutting interval under mixed cropping system is still unknown. This study aimed to investigate regrowth ability and performance of soybean plant under two different cutting heights in Miyazaki, Southwestern of Japan, which has a humid subtropical climate with relatively high temperature and evenly distributed precipitation throughout the year. The experimental design was randomized block design arrange in 3  2 factorial scheme (soybean cultivars  cutting treatments). Three soybean accessions (Glycine max ‘Fukuyutaka’, G. max ‘Kohamdaizu’ and G. gracilis ‘Moshidou Gong 503’) with 5 replications were cultivated under single seeding condition. Soybeans were defoliated after 50 d of cultivation under low level cutting height (LC, 7.5 cm) and high level cutting height (HC, 12 cm). ‘Fukuyutaka’ achieved 100% regrowth rate in both LC and HC. Although the regrowth rate for ‘Kohamadaizu’ was 100% in the HC, it was only 20% in LC. ‘Fukuyutaka’ was more robust and high tolerant for defoliation stress than that of ‘Kohamadaizu`. In other hand, no plants exhibited regrowth in both cutting heights for ‘Moshidou Gong 503’. For ‘Fukuyutaka’ and ‘Kohamadaizu’, the number of branching nodes with re-emergent leaves was significantly higher in the HC. In both cutting height of ‘Fukuyutaka’, plant continued elongating and exhibited vigorous growth until 2nd cutting. The cutting height levels, height of cotyledonary node and growth stage of soybean plant when harvested at the 1st cutting significantly affected the regrowth ability of soybeans. In conclusion, ‘Fukuyutaka’ showed the ability for regrowth under LC and HC. HC provided significantly higher fresh matter and dry matter weight than that LC. Further study is needed to evaluate the performance of ‘Fukuyutaka’ under intercropping cultivation with tropical forage grasses. This is the first report to establish an approach for two-cutting soybean as forage.

Pages 1452-1458 | Full Text PDF| doi: 10.21475/ajcs.21.15.12.p3315
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Modification of soybean plant architecture through growth regulators and population variation

Willian Pelisser da Rosa, Andréia Caverzan, Geraldo Chavarria*

Faculty of Agronomy and Veterinary Medicine, Agronomy Post-Graduate Program, University of Passo Fundo, Passo Fundo, Rio Grande do Sul, Brazil

Abstract
An important limitation to increased soybean [Glycine max (L.) Merr.] grain yield is excessive plant growth. The use of growth regulators and population adjustment is imperative for the management of soybean. This study aimed to evaluate whether lactofen, used as a growth regulator, and a reduction in plant population affected the architecture of soybean and increased its production efficiency. The study was carried out under field conditions during the 2017–2018 and 2018–2019 seasons. The experimental design was in completely randomised blocks with five treatments and five replications: T1 (control), T2 (application of 140 g a.i. ha−1 of lactofen at phenological stage V3), T3 (application of 140 g a.i. ha−1 of lactofen at phenological stage V6), T4 (plant population 20% lower than recommended) and T5 (plant population 40% lower than recommended). The plant height, the number of nodes, the number of branches, stem diameter, and the internode distance were affected by lactofen application at stage V3. Lactofen use at stage V3 also increased the coverage percentage and the number of droplets per square centimetre of phytosanitary products. The interception of solar radiation was higher with lactofen application at stage V3 and that treatment provided the highest yield. Therefore, the use of lactofen as a growth regulator improves soybean grain yield. A reduction in plant population had the greatest effect on grain number and weight. Plant density should be maintained as recommended to avoid a decrease in grain yield.

Pages 1459-1465 | Full Text PDF| doi: 10.21475/ajcs.21.15.12.p3322
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Susceptibility of Urochloa species subjected to pre-emergence application of [imazapyr + imazapic] herbicide

Fenelon Lourenço de Sousa Santos*, Adriano Stephan Nascente, Mabio Chrisley Lacerda, Francine Neves Calil, Fernando Couto de Araújo

Department of Agronomy – Universidade Federal of Goiás – UFG, Brazil
National Research Center for Rice and Beans - Embrapa Arroz e Feijão, Brazil

Abstract
Intercropping imidazolinone resistance crops, resistant to herbicides imazapyr + imazapic, with forage species may be a viable alternative to recover degraded pasture areas. This practice requires herbicides to slow down development of the forage and avoid reduced rice yield. However, as it is a relatively new technology, the proper management of this herbicide to control forage is not known. The objective of this study was to determine the susceptibility of forages Urochloa ruziziensis, U. brizantha cv. Paiaguás, and U. brizantha cv. Marandu, submitted to the pre-emergence application of the herbicides [imazapyr + imazapic]. The experimental design was completely randomized in a 3×5+3 factorial scheme with five replications. Treatments consisted of the combination of the three species (Urochloa ruziziensis, U. brizantha cv. Paiaguás, and U. brizantha cv. Marandu) and five intervals between herbicide application in the soil and forage sowing (0; 5; 10; 15; and 20 days after its application), in addition to three control treatments, without herbicide application. This study found that application of herbicide on the day of forage sowing for intercropping with imidazolinone resistance crops is not feasible. Increasing the time interval between herbicide application and forage sowing provides increased development of U. brizantha cvs. Marandu and Paiaguás. The species U. ruziziensis is more susceptible to pre-emergence application imazapyr + imazapic. According to our results, U. brizantha cvs. Marandu and Paiaguás are more suitable to be managed by imidazolinone herbicides to recover degraded pasture areas.

Pages 1466-1470 | Full Text PDF| doi: 10.21475/ajcs.21.15.12.p3339
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Do chemical and nutritional compounds change during the storage of Jabuticaba (Plinia cauliflora)?

Aline Priscilla Gomes da Silva, Poliana Cristina Spricigo, Fernanda Bueno Campos, Aline Gomes de Oliveira, Thais Pádua de Freitas, Angelo Pedro Jacomino*

University of São Paulo, “Luiz de Queiroz” College of Agriculture, Crop Science Department, Piracicaba, SP, Av. Pádua Dias 11, CEP 13418-900, Brazil
Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, MI, 44824, USA

Abstract
Jabuticaba (Plinia cauliflora) is a native Brazilian Atlantic Rainforest fruit tree. Its fruits are purplish berries with a short shelf life, due to fermentative processes that begin shortly after harvest. Recently, commercial jabuticaba exploitation has intensified, justifying the application of postharvest technologies. In this context, this study aimed to evaluate the chemical characteristics and nutraceutical compounds of “ponhema” jabuticabas stored at room and cold temperatures. Chemical analyzes (soluble solids (SS), titratable acidity (TA), pH, soluble sugars, soluble pectins and pectinamethylesterase (PME) activity), and nutraceutical compounds (total anthocyanins (TA), yellow flavonoids (YF), total phenolic compounds (TFC)) were performed. A completely randomized experimental design was applied. Analyzes were performed every 2 days, at days 0, 2, 4 for the room temperature (25° C) assay and at days 0, 2, 4 and 6 for the cold temperature (13° C) experiment. Fruits stored under cold temperature presented lower acetaldehyde and ethanol contents, as well as high soluble sugar, total anthocyanin, and total phenolic compound levels. Fruits stored at room temperature displayed marked wilting and fermentation on the fifth day of storage, preventing their consumption after this period. Fruits presented a shelf-life gain of up to two days when stored at cold temperature, displaying better characteristic maintenance, such as soluble solids, titratable acidity, pH and soluble sugars, which were verified by the acetaldehyde and ethanol tests. Total anthocyanin and phenolic compound levels were higher in fruits stored at cold temperature.

Pages 1471-1477 | Full Text PDF| doi: 10.21475/ajcs.21.15.12.p3384
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Effects of mulching on the weed community and grain yield of upland rice cultivars

Givago Lopes Alves, Raimundo Nonato Viana Santos, Antônia Alice Costa Rodrigues, Maria José Pinheiro Correa, Mário Luiz Ribeiro Mesquita*, Maria Rosângela Malheiros Silva

Universidade Estadual do Maranhão, Programa de Pós-Graduação em Agroecologia, São Luís, Maranhão, Brasil
Universidade Estadual do Maranhão, Departamento de Química e Biologia, São Luís, Maranhão, Brasil
Universidade Estadual do Maranhão, Programa de Pós-Graduação em Agricultura e Ambiente UEMA, Brasil

Abstract
This study evaluated the effects of mulching on upland rice cultivars Comecru and Cambará and the weed community under four amounts of babassou (Attalea speciosa Mart. ex Spreng.) straw mulching namely: 0, 15, 20, 25 t ha-1 with a view to control weeds. The experiment was laid out in a randomized complete block design in a 2 x 4 factorial scheme with four replications. The rice plant height, percentage of fertile panicles, number of spikelets per panicle, weight of 100 grains and grain yield were assessed. We also assessed the weed community by computing the following phytosociological parameters: density, frequency and the importance value index (IVI) of each species. Babassou straw mulching reduced weed density and dry mass between rows of upland rice cultivars and increased the rice yield. The weed species with the highest Importance Value Index (IVI) in the treatments with no mulching were Cyperus iria, Fimbristylis dichotoma and Digitaria ciliaris. Rice grain yield was increased with the increase in the amount of straw. Comecru cv. had the highest suppressive effect on weeds with significantly higher grain yield (1,214.85 kg-1) than Cambará cv. (878.72 kg ha-1). We conclude that the higher amounts (20 and 25 t ha-1) of babassou straw mulching suppressed weeds, providing less competition with the rice cultivars, which resulted in an increase in the number of rice panicles, weight of 100 grains, spikelet fertility and grain yield in both rice cultivars.

Pages 1478-1484 | Full Text PDF| doi: 10.21475/ajcs.21.15.12.p3425

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Assessment of yield and quality of quinoa accessions grown in Ferralsols following seasonal difference

Nguyen Van Minh and Tinh Van Nguyen*

Faculty of Agriculture and Forestry, Tay Nguyen University, 567 Le Duan Street, Dak Lak province 63000, Vietnam
Department of Basic Science, Buon Ma Thuot University, Dak Lak province 63000, Vietnam

Abstract
The quinoa accession varieties have been cultivated in Vietnam in recent decades. The initial results indicate that these varieties have well adapted to Vietnam’s climate, even better than some of their mother areas. However, further evaluation of the impact of the seasonal region on quinoa growth and development is necessary for a tropical country like Vietnam. Therefore, this study aimed to analyze the yield and quality of quinoa accession varieties planted on Ferralsolsl in the Dak Lak province of Vietnam in three distinct seasons. Ten quinoa accession varieties include Leucan Boldo, Riobamba, 27 - 6R, EDK – 4, 59 – ALC, ISLUGA, Atlas, Cahuil, Moradas and Haiwan were examined. Field experiments were conducted based on the Randomized Complete Block Design (RCBD) in triplicated repeat. Various plant agronomical traits including plant height, branch number, the total number of the main bunch, length of the bunch, number of grains per bunch, grains weight, as well as the contents of protein, and starch were investigated. Finally, the biological and practical productivity of ten quinoa accessions was determined. In general, the obtained results showed that the quinoa varieties are grown from January to April 2020 (Season 1) had higher quality and yield than those grown in other seasons. Collectively, the variety Atlas showed the highest-quality indexes including agronomical traits such as approximately 37 branches per plant or its bunch length was around 27 cm, and its practical productivity was 22.2 quintals per hectare follow by the Moradas, Cahui, and Haiwan varieties. Taken together, our data indicated that the correlation of the seasonal factor in Dak Lak province of Vietnam is different for each quinoa variety.

Pages 1485-1491 | Full Text PDF| doi: 10.21475/ajcs.21.15.12.p3429