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Soilless potato harvest time for P use selection

Time of potato plant harvest in soilless cultivation for screening phosphorus use efficient genotypes
Darlene Sausen1, Ivan Ricardo Carvalho2, Franciele Antônia Neis1, Suzi Cerezer Uliana1, Ritieli Baptista Mambrin3, Raíssa Schwalbert3, Miriam da Silva Tavares4 and Fernando Teixeira Nisoloso3
1Federal University of Santa Maria, Santa Maria, RS, Brazil.
2Regional University of Northwest of Rio Grande do Sul, Ijuí, RS, Brazil.
3Centro De Ensino Superior Riograndense, Marau, RS, Brazil.
4Goias State University, Posse, GO, Brazil.

The shorter the duration of the selection process of potato genotypes more efficient in the use of P, the lower the casting time of a new plant variety in the market and its growing field, where effectively verify the reduction of use of phosphate fertilizers, which may help to increase the sustainability of the potato production chain.  Therefore, the objective of this study was to determine the time of collection of potato plants grown in a closed system with sand as substrate and subjected to P restriction in nutrient solution aiming at the selection of more efficient genotypes on the P use. For this purpose, seven potato genotypes (SMIC 148-A, Dakota Rose, Sminia 793103-3, SMIB 106-7, 212-3 SMIF, SMIJ 319-1 and P 150), were grown in a closed soilless system with sand as substrate and nutrient solution containing two P levels (low: 2.32mg L-1; and high: 23.2mg L-1). The plants were harvested three sampling times (18, 39 and 62 days after transplanting (DAT)). The data showed that it is not advisable to use the plant growth assessment carried out until 18 DAT for screening of genotypes efficient in the use of phosphorus. However, at 39 DAT most potato genotypes already showed differences in all growth parameters evaluated between P levels, enabling the selection of the most efficient in P use and therefore not necessary cultivation by the end of the crop cycle.

Highlighted Conclusions
1. Selection of potato genotypes for P efficiency based on evaluations performed until 18 days after transplanting is not recommended.
2. At 39 days after transplanting, most potato genotypes already exhibit differences between the levels of P for all growth parameters evaluated, allowing the selection of the most efficient ones with respect to P, thus eliminating the need for cultivation until the end of the crop cycle.


Azospirillum inoculation associated to soil bioactivator in maize

Inoculation methods of Azospirillum brasilense associated to the application of soil bioactivator in the maize crop
Alexandre Wegner Lerner1, Vandeir Francisco Guimarães2, Tauane Santos Brito2*, Victor Matheus Röske2, Roberto Cecatto Junior2, André Silas Lima Silva2 and Julia Carolina Weizenmann2
1Case IH, Sorocaba, São Paulo, Brasil.
2Universidade Estadual do Oeste do Paraná, Cidade, PR, Brasil.

Seeking greater productivity, cost reduction and greater sustainability, plant growth promoting bacteria and soil bioactivators become a viable alternative for maize producers. The objective was to evaluate the effects of inoculation and foliar application of Azospirillum brasilense associated with the application of soil bioactivator on morphometric, physiological and productive characteristics of the maize crop.  Conducted in the field, the experimental design adopted was randomized blocks, with 4 repetitions and the following treatments: control; seed inoculation with Azospirillum brasilense (100 mL per 60,000 seeds); foliar spraying of A. brasilense at the V5 stage of maize; application of soil bioactivator; seed inoculation with A. brasilense + foliar spraying of A. brasilense at the V5 stage of maize; seed inoculation with A. brasilense + application of soil bioactivator; foliar spraying of A. brasilense at the V5 stage of maize + application of soil bioactivator; seed inoculation with A. brasilense + foliar spraying of A. brasilense at the V5 stage of maize + application of soil bioactivator. At the V8, VT and R3 stages morphometric and physiological evaluations were performed. At the VT stage, the inoculation methods of A. brasilense and the application of bioactivator were significant only for the dry mass of reproductive structures. In the R3 stage, plants inoculated by foliar spraying of A. brasilense together with the application of soil bioactivator showed statistically superior heights. The inoculation methods with A. brasilense and the application of soil bioactivator did not influence morphometric attributes throughout the development of maize, not influencing physiological variables. The production components and yield were not affected by the treatments applied.

Highlighted Conclusions
1. The methods of inoculation with Azospirillum brasilense and the application of soil bioactivator did not influence morphometric attributes throughout maize development, and did not influence physiological variables.
2. The yield and production components were not affected by inoculation with A. brasilense and application of soil bioactivator.


PRE herbicides in soybean

Weed management with pre-emergent herbicides in soybean crops
Helis Marina Salomão1, Michelangelo Muzell Trezzi1, Matheus Viecelli2, Fortunato De Bortoli Pagnoncelli Junior2, Felipe Patel2, Leticia Damo3 and Gilvane Frizzon2
1Federal University of Technology, Pato Branco, PR, Brazil.
2Independent Agronomist, Brazil.
3Federal University of Viçosa, Viçosa, MG, Brazil.

The use of pre-emergent herbicides in soybean crops is fundamental, among other reasons, to maintain a clean crop in the initial stages, alter mechanisms, and consequently manage weed resistance. However, there is a considerable demand for information about the efficiency and selectivity of systems with residual herbicides applied in different modalities. This study evaluated the efficiency and selectivity of pre-emergent herbicides doses applied singly or mixed in a tank on soybean crops. The experiment was installed in randomized block design with 21 treatments and four repetitions. The treatments were composed of weeded and unweeded witnesses and pre-emergent application of isolated S-metolachlor or the herbicides diclosulam, flumioxazin, and sulfentrazone isolated or together with S-metolachlor in different doses with the addition of post-emergent S-metolachlor (soybean stage V2). Associations of residuals herbicides applied in pre-emergence or sequential mode increased the control levels of mono and dicotyledonous weeds. The treatments, including single or associated diclosulam and the systems with S-metolachlor sequentially, caused the most significant toxicity (up to 17%) for soybeans. High doses of S-metolachlor (2592.0 g ha-1), diclosulam (33.6 g ha-1), and the associations of S-metolachlor + diclosulam, S-metolachlor + flumioxazin, and S-metolachlor + diclosulam with sequential S-metolachlor should be avoided to obtain higher levels of soybean yield. The use of pre-emergent herbicides demonstrated to be an efficient and viable option to control weeds in soybean crops.

Highlighted Conclusions
1. The association of residual herbicides generally increases the control levels of mixed natural infestations of mono and dicotyledons weeds.
2. It is possible to associate the grain yield of a soybean crop with the control efficiency of weed species and the toxicity of herbicides in the crop.


Mycotoxin of Fusarium reduced by algae

An algal sulphated polysaccharide capable of reducing mycotoxin biosynthesis by Fusarium
Rafael Dal Bosco Ducatti1, Siumar Pedro Tironi2 and Sergio Miguel Mazaro1
1Federal University of Technology – Paraná (UTFPR), Pato Branco, PR, Brazil.
2Federal University of Fronteira Sul (UFFS), Chapecó, SC, Brazil.

The incidence of Fusarium sp. in maize, besides causing drops in yields also causes the bromatological quality of the final product to decrease and mycotoxin accumulation to increase. Nineteen field trials have been performed in 4 different states of Brazil during three consecutive harvest seasons using 17 different maize cultivars aiming at assessing the use of carrageenan as a biological compound to decrease mycotoxin biosynthesis and accumulation and, increase maize silage yields and quality. Overall, carrageenan has proven to raise the bromatological quality of the silage, increase yields and decrease fumonisine and deoxynivalenol contamination by 50.4% and 45.7%, respectively.

Highlighted Conclusion
Carrageenan has the capability to help on the suppression of DON and FUMO biosynthesis/accumulation and to help on the increase of the bromatological quality of maize silage.

Phosphorus nutrition in beans

Phosphorus partition, phytic acid concentration and grains productivity of beans cultivars as a response to phosphate nutrition
Ritieli Baptista Mambrin1, Darlene Sausen2, Diogo Moura1, Ivan Ricardo Carvalho3, Vinícius Jardel Szareski4 and Giordano Gelain Conte4
1Centro De Ensino Superior Riograndense, Marau, RS, Brasil.
2Universidade Federal do Rio Grande do Norte, Parnamirim, RN, Brasil.
3Universidade Regional do Noroeste do Estado do Rio Grande do Sul, Ijuí, RS, Brasil.
4Universidade Federal de Pelotas, Capão do Leão, RS, Brasil.

The objectives of this work were to evaluate the phosphorus partition in tissues, in different growth stages, the phytic acid concentration in grains and the beans yield, as a response to the phosphorus supply in the culture environment, and the analysis of the association between these characters. The experiments were conducted in non-acclimatized greenhouse. The data was submitted to variance analysis, considering all the effects as fixed, with exception of the error, which was considered random. Since it was significant the effect of the triple interaction phosphorus concentration x genotype x growing season (C x G x E), it was realized the deployment of it in three double interactions with the use of complex variance. The phosphorus values in common bean leaves at initial growing stages are close to the ones found in grains. For the genotypes Pérola and IPR88 Uirapurú, the highest phosphorus values in plants tissues and of phytic acid occurred in phosphorus concentrations in the nutritive solution between 1.38 and 2.00 mmol L-1. Phosphorus concentrations in the nutritive solution between 1.37 and 1.96 mmol L-1 result in higher phosphorus concentration in leaves at third trifoliate leaf, in stem at flowering, in leaves, stem and legumes at legumes filling and grains at maturation. Also, higher phytic acid concentration in grains, at the fall-winter and spring-summer seasons. The evaluation of phosphorus concentration in the vegetal tissues from the legume filling stage is promising and allows indirect selection to grains productivity.

Highlighted Conclusion
The concentration of P in plant tissues during the legume filling stage is promising and allows indirect genetic selection to grains productivity.

Corynespora cassiicola affecting soybean

Yield and economic losses caused by Corynespora cassiicola on soybean under chemical control
Deivid Sacon1, Alexandre Jacques Bottan2, Laura Caroline Zanella2, Aline Netto2 and Leandro Luiz Borges3
1Instituto de Biotecnologia Aplicada à Agropecuária, Viçosa, MG, Brasil.
2ABC Agrícola, Sapezal, MT, Brasil.
3Universidade do Estado de Minas Gerais, Passos, MG, Brasil.

Target Spot is an important disease in soybean caused by the necrotrophic fungus Corynespora cassiicola. Recently, this fungus has gained importance in large crops such as soybeans and for its insensitivity fungicides reports. In this study, three assays were carried out with different application treatments in order to evaluate fungicide applications to control Target Spot and their interference on soybean productivity. Different application treatments were tested including fungicide products, doses, mixtures and number of applications, as well as estimate the application’s economic viability. Cultivar TMG 2378 IPRO was used and the applications were performed with a CO2 sprayer pressurized in a randomized block design with four replications. The harvest of 2.7 m2 useful area in the plot center was carried out with a stationary plot harvester and the yield was estimated for kg ha-1. For an economic analysis of the application treatments, the soybeans sale was considered at a fixed price of US$ 264 t-1, while the operating cost at a value of US$ 8. The fungicides spraying cost was estimated in kg of grains ha-1 based on the average of two budgets made. The fungicide mixtures bixafen+prothioconazole+trifloxystrobin+mancozeb and trifloxystrobin+ prothioconazole+mancozeb presented both yield increase and economic viability compared to control.

Highlighted Conclusion
Mixtures of bixafen+prothioconazole+trifloxystrobin+mancozeb and trifloxystrobin+ prothioconazole+mancozeb have yield and economic viability to control Corynespora cassiicola.

Herbicides and water conditions on Ipomoea grandifolia control and enzyme activity

Control of Ipomoea grandifolia and antioxidant enzyme activity with bentazon and glyphosate at times and soil water conditions
Helis Marina Salomão, Michelangelo Müzell Trezzi, Fortunato de Bortoli Pagnoncelli Junior, Adriano Suchoronczek, Matheus Viecelli and Katia Cristina Dalpiva Hartmann
Federal University of Technology (UTFPR), Pato Branco, PR Brazil.

Weed management with herbicides requires favorable environmental conditions, that maximize efficiency, such as soil humidity and timing of application. The aim of this study was to assess the effect of the application timing of bentazon and glyphosate herbicides on the control and activity of antioxidant enzymes in Ipomoea grandifolia, under different conditions of soil water availability. Two experiments, one for each herbicide (bentazon and glyphosate), were conducted in a factorial design with four replicates. The first factor was the two rates of each herbicide (504 and 720 g i.a. ha-1 of bentazon and 651 and 911.4 g i.a. ha-1 of glyphosate). The second factor was the six application times (1 am; 5 am; 9 am; 1 pm; 5 pm and 9 pm). The third factor, soil water content (100% and 50% of field capacity). Plus, two controls without herbicide application. At 21 days after application (DAA) of bentazon and 28 DAA of glyphosate, the fresh mass of the aboveground plants was measured. In addition, the activities of the enzymes superoxide dismutase (SOD), catalase (CAT) and peroxidase (POX) were determined. For plants under water restriction, an increase of approximately 20% in fresh mass was observed compared in plants without water restriction, indicating lower control efficiency under water stress condition. For bentazon, at 1 pm has been observed the lowest herbicide efficiency, the other times were the most efficient, and did not differ. For glyphosate, the application at 9 am was the most efficient, while at 1 am provided the worst control efficiency. Higher CAT and SOD activities after bentazon application were observed at 1 pm. Among the three enzymes evaluated, SOD presented the highest activity after glyphosate application. Generally, the times of the day with the highest peak of enzymatic activity were distinct between with and without water restriction.

Highlighted Conclusions
1. Water restriction reduces the efficiency of bentazon and glyphosate.
2. Better efficiency for bentazon was observed at 1 am, 5 am, 9 am, 5 pm and 9 pm.
3. Better efficiency for glyphosate was observed at 9 am.

Akaike criteria and physiological indexes on black oak seeds

Akaike criteria and selection of physiological multi-character indexes for the production of black oat seeds
Natã Balssan Moura1, Ivan Ricardo Carvalho1*, José Antonio Gonzalez da Silva1, Murilo Vieira Loro1, Maurício Horbach Barbosa2, Francine Lautenchleger3, Volmir Sergio Marchioro4 and Velci Queiróz de Souza5
1Northwestern Regional University of the State of Rio Grande do Sul, Ijuí, RS, Brazil.
2Tropical Genetic Improvement, Rondonópolis, MT, Brazil.
3University of the Midwest (Unicentro), Guarapuava, PR, Brazil.
4Federal University of Santa Maria, Frederico Westphalen, RS, Brazil.
5Federal University of Pampa, São Gabriel, RS, Brazil.

The selection of characters provides the identification of complex characteristics, the objective of the work was to use the Akaike criteria and multiple regressions to prove the multi character selection and the interrelationships based on the Phenotypic, Standardized, Willians, Multiplicative, Mulamba and Mock indexes for the selection of black oat genotypes with high physiological potential of seeds. The study was conducted in Fortaleza dos Valos – RS in an experimental design used in randomized blocks with three replications. The trends for the selection of various Step Wise variables and the Akaike criteria are similar for most selection indices. For selection indexes, the phenotypic index and the standardized index correlate with the morphological characteristics, being mainly for the number of tillers. The genetic and multiplicative indices correlate with the characteristics of the seed. The phenotypic selection index was the one that stood out the most, regardless of the criterion used. This index correlates positively with the number of tillers. To select plants that present superior quality seeds, individuals with characteristics such as smaller panicles and with less spikelet ramifications and less panicle mass are sought.

Highlighted Conclusions
1. The phenotypic selection index was the one that stood out the most.
2. To obtain quality seeds, plants with smaller panicles, less spiky branching and less panicle mass are sought.

Plant arrangement on soybean performance

Agronomic performance of soybean with indeterminate growth habit in different plant arrangements
Daniel Augusto Silveira1, Beatriz Braga Silveira2, Cássio Egídio Cavenaghi Prete2, Carlos André Bahry3 and Maicon Nardino4
1Syngenta Proteção de Cultivos Ltda, Londrina, PR, Brasil.
2Universidade Estadual de Londrina, Londrina, PR, Brasil.
3Universidade Tecnológica Federal do Paraná, Dois Vizinhos, PR, Brasil.
4Universidade Federal de Viçosa, Viçosa, MG, Brasil.

Plant arrangements are a practice that has remained constant for decades, with little research about soybeans, with contrasting rainfall conditions. The purpose of this work was to evaluate the agronomic performance of indeterminate soybean with variation for the plant arrangements, populations and in cultivation of crops. The research was conducted in Arapongas-PR with an experimental design of randomized blocks, organized in a 6x3x2 factorial scheme, with four replications. The variation factors were six populations (100, 200, 300, 400, 500 and 600 thousand plants ha-1), three plant arrangements (0.25 cm, 0.50 cm and 0.25×0.50 cm in paired-rows) and two cultivation of crops. The statistical analysis sought to evaluate the interactions and break down the simple effects and the main effects. Row spacing influenced the variables grain yield, height of the first pod insertion, plant height and leaf area index. Populations with up to 300 thousand plants reached the highest levels of grain yield. The plant arrangement for the paired-rows is superior to traditional spacing, with 4,732 kg ha-1 for the spacing 0.25×0.50 m, 3,817 kg ha-1 for the spacing 0.50 m and 3,628 kg ha-1 for the spacing 0.25 m.

Highlighted Conclusions
1. The agronomic performance of the CA7442 RR1 soybean cultivar, with undetermined habit, is influenced by the spatial arrangement, by the plant population.
2. There is a tendency to reduce grain yield in higher populations under water stress conditions.
3. The arrangement of paired-rows in relation to single-rows revealed grain yield 20% higher for harvests with normal precipitation

Weed interference in canola

Periods of weed plant interference in canola
Daiani Brandler1*, Leandro Galon1, Altemir José Mossi1, Thalita Pedrozo Pilla1, Rodrigo José Tonin1, Cesar Tiago Forte2, Felipe Bianchessi1, Emanuel Rodrigo de Oliveira Rossetto1 and Siumar Pedro Tironi3
1Federal University of Fronteira Sul, Erechim, RS, Brazil.
2Federal University of Santa Maria, Santa Maria, RS, Brazil.
3Federal University of Fronteira Sul, Chapecó, SC, Brazil.

The objective of this work was to determine the periods of interference of turnip, ryegrass and black oats infesting the canola crop. Two models of interference were studied: first, the canola cohabited with weeds for increasing periods up until 0, 7, 14, 21, 28, 35 and 42 days after the emergency (DAE) and throughout the cycle; second, the culture was kept free of the infestation for the same periods described previously. At 51 DAE, the variables related to canola and weed morphophysiology were determined. In the harvest of the crop, was measured the number of siliques, a thousand grain mass and grain yield. The physiological variables, photosynthetic rate, internal CO2 concentration, perspiration rate, stomach conductance of water vapors, carboxylation efficiency and efficient water use did not show significant variation. The dry mass was reduced by 79.21% when canola culture was always in competition with ryegrass, turnip and black oat weeds. The number of siliques and the mass of one thousand grains also decreased as the period of competition with the turnip, ryegrass and black oat weeds increased. The period before the interference (PAI) of the weeds ryegrass, turnip and black oats goes up to 25 DAE of canola. The critical interference prevention period (PCPI) for canola culture goes from 25 to 60 DAE. And the total interference prevention period (PTPI) is 60 DAE. Interference from weeds has reduced by 94.05% the productivity of canola grains when it has not received control of ryegrass, turnip and black oats.

Highlighted Conclusion
Weeds have to be controlled from 25 to 60 days after emergence to prevent canola yield reduction by up to 94%.