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Effects of Thidiazuron and Pollinator visits on Fruit Set and Quality of \u27Maxigala\u27 Apple Trees
Get PDFThe objective of this study was to assess the effects of thidiazuron (TDZ) application and pollinator visits on fruit set and quality in apple trees of the cultivar Maxigala. The experiment was conducted at the Temperate Fruit Farming Experimental Station of the Brazilian Agricultural Research Corporation (EMBRAPA Grape and Wine), in Vacaria, RS, Brazil. The evaluated treatments were: TDZ application; floral visitors combined with TDZ application; floral visitors; and control (no floral visitors with no TDZ application). The highest mean final fruit set was found for the treatment with only TDZ application, followed by that with floral visitors and TDZ application.The objective of this study was to assess the effects of thidiazuron (TDZ) application and pollinator visits on fruit set and quality in apple trees of the cultivar Maxigala. The experiment was conducted at the Temperate Fruit Farming Experimental Station of the Brazilian Agricultural Research Corporation (EMBRAPA Grape and Wine), in Vacaria, RS, Brazil. The evaluated treatments were: TDZ application; floral visitors combined with TDZ application; floral visitors; and control (no floral visitors with no TDZ application). The highest mean final fruit set was found for the treatment with only TDZ application, followed by that with floral visitors and TDZ application
Physiological and growth responses of lettuce plants submitted of 2,4-D simulated drift
Get PDFPesticide drift is due to the transport of the active ingredient to areas not targeted by spraying, causing negative effects on the sensitive crops’ development. The aim of this study was to evaluate lettuce response to simulated 2,4-D drift. Experiments were conducted in the greenhouse, in a randomized complete block design with four replications. The treatments consisted of nine different doses of the 2,4-D herbicide, which are: 0; 1.56; 3.125; 6.20; 12.5; 25; 50; 75; and 100% from the recommended dose (670 g a.a. ha-1). The application occurred when the lettuce plants had four to six true leaves. The analyzed variables were visual injury (phytotoxicity), development parameter (phyllochron), growth (rosette diameter and dry mass of the aerial part), and photosynthetic parameters (gas exchange). The lettuce crop showed high sensitivity to the 2,4-D herbicide, with the lowest dose resulting in significant phytotoxic damage to plants, and from 12.5% of the recommended 2,4-D dose, visual injuries were greater than 90%. The plants´ development and growth were negatively affected by the increased drift doses, culminating in enhanced phyllochron and reduction in rosette diameter and dry mass of the aerial part. The gas exchange of the crop was affected from 6.20% of the recommended dose, causing a reduction in the CO2 assimilation rate, stomatal conductance, transpiration rate and rubisco carboxylation efficiency.Pesticide drift is due to the transport of the active ingredient to areas not targeted by spraying, causing negative effects on the sensitive crops’ development. The aim of this study was to evaluate lettuce response to simulated 2,4-D drift. Experiments were conducted in the greenhouse, in a randomized complete block design with four replications. The treatments consisted of nine different doses of the 2,4-D herbicide, which are: 0; 1.56; 3.125; 6.20; 12.5; 25; 50; 75; and 100% from the recommended dose (670 g a.a. ha-1). The application occurred when the lettuce plants had four to six true leaves. The analyzed variables were visual injury (phytotoxicity), development parameter (phyllochron), growth (rosette diameter and dry mass of the aerial part), and photosynthetic parameters (gas exchange). The lettuce crop showed high sensitivity to the 2,4-D herbicide, with the lowest dose resulting in significant phytotoxic damage to plants, and from 12.5% of the recommended 2,4-D dose, visual injuries were greater than 90%. The plants´ development and growth were negatively affected by the increased drift doses, culminating in enhanced phyllochron and reduction in rosette diameter and dry mass of the aerial part. The gas exchange of the crop was affected from 6.20% of the recommended dose, causing a reduction in the CO2 assimilation rate, stomatal conductance, transpiration rate and rubisco carboxylation efficiency
Organic cultivation of Allium fistulosum under concentrations of Bordeaux mixture
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Allium fistulosum L., belonging to the botanical family Alliaceae, is one of the most produced and commercialized vegetables in the world. In this scenario, this study aimed to evaluate the control of anthracnose in chives subjected to organic cultivation with different concentrations of Bordeaux mixture and its effects on crop yield. The experiment was conducted in elevated soil beds 10-cm high. Seedlings of the chive cultivar ‘Todo Ano’ were produced from plants previously cultivated in the site. Cultivation was carried out under full sunlight, and irrigation was performed by automatic sprinklers with a daily volume of 6 mm. The experiment was in randomized blocks, with 10 treatments in a 2x5 factorial arrangement. Four concentrations of Bordeaux mixture (0.5%; 1.0%; 1.5%; 2.0%) plus one control (water) were used. The second factor evaluated was the weekly and fortnightly application period. Data on the Total Fresh Mass (MFT), Commercial Fresh Mass (MFC), Sick Fresh Mass (MFR), Number of Commercial Leaves (NFC), Number of Sick Leaves (NFR), Commercial Dry Mass (MSC), and Yield (PTV) were collected. No statistically significant interactions were observed for anthracnose control and chive yield. However, in the 4th week of evaluation, differences were observed between the application periods, with the 2.0% concentration and weekly application performing better than the other treatments. The other evaluations did not result in significant statistical interactions between the variables analyzed. The application of Bordeaux mixture has no effects on the control of anthracnose and on the yield of chives.Allium fistulosum L., belonging to the botanical family Alliaceae, is one of the most produced and commercialized vegetables in the world. In this scenario, this study aimed to evaluate the control of anthracnose in chives subjected to organic cultivation with different concentrations of Bordeaux mixture and its effects on crop yield. The experiment was conducted in elevated soil beds 10-cm high. Seedlings of the chive cultivar ‘Todo Ano’ were produced from plants previously cultivated in the site. Cultivation was carried out under full sunlight, and irrigation was performed by automatic sprinklers with a daily volume of 6 mm. The experiment was in randomized blocks, with 10 treatments in a 2x5 factorial arrangement. Four concentrations of Bordeaux mixture (0.5%; 1.0%; 1.5%; 2.0%) plus one control (water) were used. The second factor evaluated was the weekly and fortnightly application period. Data on the Total Fresh Mass (MFT), Commercial Fresh Mass (MFC), Sick Fresh Mass (MFR), Number of Commercial Leaves (NFC), Number of Sick Leaves (NFR), Commercial Dry Mass (MSC), and Yield (PTV) were collected. No statistically significant interactions were observed for anthracnose control and chive yield. However, in the 4th week of evaluation, differences were observed between the application periods, with the 2.0% concentration and weekly application performing better than the other treatments. The other evaluations did not result in significant statistical interactions between the variables analyzed. The application of Bordeaux mixture has no effects on the control of anthracnose and on the yield of chives
Carpochron: a concept for the time interval between the appearance of fruits in consecutive harvests
Get PDFThe aim of this research was to estimate the base temperature for the appearance of fruits at harvest point in the strawberry and to propose a concept to represent the time required for the appearance of fruits in consecutive harvests. The experiment was conducted in 2021 in four seedling transplanting seasons: May (season 1), June (season 2), July (season 3) and August (season 4) of two cultivars: Fronteras and Merced. Twenty-four consecutive fruit harvests were carried out from September 9, 2021, to December 1, 2021, when the number, length (cm), diameter (mm), and fresh weight of the fruits (g) were evaluated. The base temperature for the fruit emission of the strawberry was calculated using the method of the smallest mean square error. Carpochron was estimated at each season and for each cultivar, obtaining a simple linear regression between the number of fruits and the accumulated thermal sum (ºC day) and the number of days after transplanting (DAT), using as base temperature the one estimated in this work. The base temperature for the appearance of consecutive fruits at the harvest point in the strawberry is 11ºC. Carpochron increases with the delay of the transplanting season and the values ranged from 81.97ºC fruit day to 144.93ºC fruit day for cultivars Merced and Fronteras.The aim of this research was to estimate the base temperature for the appearance of fruits at harvest point in the strawberry and to propose a concept to represent the time required for the appearance of fruits in consecutive harvests. The experiment was conducted in 2021 in four seedling transplanting seasons: May (season 1), June (season 2), July (season 3) and August (season 4) of two cultivars: Fronteras and Merced. Twenty-four consecutive fruit harvests were carried out from September 9, 2021, to December 1, 2021, when the number, length (cm), diameter (mm), and fresh weight of the fruits (g) were evaluated. The base temperature for the fruit emission of the strawberry was calculated using the method of the smallest mean square error. Carpochron was estimated at each season and for each cultivar, obtaining a simple linear regression between the number of fruits and the accumulated thermal sum (ºC day) and the number of days after transplanting (DAT), using as base temperature the one estimated in this work. The base temperature for the appearance of consecutive fruits at the harvest point in the strawberry is 11ºC. Carpochron increases with the delay of the transplanting season and the values ranged from 81.97ºC fruit day to 144.93ºC fruit day for cultivars Merced and Fronteras
Do sub-doses of glyphosate and 2,4-D cause hormesis in the pineapple plants? Insights into the response of the pineapple plants to this phenomenon
Get PDFThe slow growth of the pineapple (Ananas comosus (L.) Merr.) during the vegetative phase prolongs the crop cycle, resulting in higher production costs. When used in low doses, some herbicides can stimulate plant growth, a phenomenon known as hormesis. The aim of this study was to determine the effects of sub-doses of glyphosate and 2,4-dichlorophenoxyacetic acid (2,4-D) on growth in the Pérola cultivar of the pineapple. The treatments under study consisted of glyphosate applications of 0, 1.8, 3.6, 7.2, 18, 36, 72, 180, 360 and 720 g a.e. ha-1, and 2,4-D applications of 0, 1.68, 3.35, 6.70, 16.75, 33.5, 67, 167.5, 335 and 670 g a.e. ha-1. The experiments were completely randomised with four replications. The plants were grown in the greenhouse in pots with a capacity of 8 dm3 substrate. Growth variables were evaluated in the plants, together with the total and partitioned accumulated biomass (leaf, stem and root). The data were submitted to analysis of variance and regression. The pineapple showed greater phytotoxicity from the glyphosate herbicide at applications ranging from 18 to 720 g a.e. ha-1 and from 2,4-D in the range of 167.5 to 670 g a.e. ha-1. The hormesis effect was evidenced by the 32.25% increase in root fresh weight at the dose of 1.8 g a.e. ha-1 glyphosate. However, the slow growth of the pineapple was not overcome by the hormesis effect of the herbicides.The slow growth of the pineapple (Ananas comosus (L.) Merr.) during the vegetative phase prolongs the crop cycle, resulting in higher production costs. When used in low doses, some herbicides can stimulate plant growth, a phenomenon known as hormesis. The aim of this study was to determine the effects of sub-doses of glyphosate and 2,4-dichlorophenoxyacetic acid (2,4-D) on growth in the Pérola cultivar of the pineapple. The treatments under study consisted of glyphosate applications of 0, 1.8, 3.6, 7.2, 18, 36, 72, 180, 360 and 720 g a.e. ha-1, and 2,4-D applications of 0, 1.68, 3.35, 6.70, 16.75, 33.5, 67, 167.5, 335 and 670 g a.e. ha-1. The experiments were completely randomised with four replications. The plants were grown in the greenhouse in pots with a capacity of 8 dm3 substrate. Growth variables were evaluated in the plants, together with the total and partitioned accumulated biomass (leaf, stem and root). The data were submitted to analysis of variance and regression. The pineapple showed greater phytotoxicity from the glyphosate herbicide at applications ranging from 18 to 720 g a.e. ha-1 and from 2,4-D in the range of 167.5 to 670 g a.e. ha-1. The hormesis effect was evidenced by the 32.25% increase in root fresh weight at the dose of 1.8 g a.e. ha-1 glyphosate. However, the slow growth of the pineapple was not overcome by the hormesis effect of the herbicides
Contribution of physical-chemical variables and passion fruit production in Baixo Acre
Get PDFThis study investigated the production and physical and chemical characteristics of eight sour passion fruit genotypes cultivated in Baixo Acre, AC. Evaluation of fruit number (FN), productivity (PRO), longitudinal diameter, transverse diameter (LD and TD), peel thickness (PT), average fruit mass (AFM), pulp mass (PM), juice yield (JY), soluble solids (SS), titratable acidity (TA), ratio, and pH of genotypes H1, H3, R, V1, V2, V3, V4, and V5 was performed. Univariate, multivariate, and Pearson\u27s correlation analyses were performed. Univariate analyses revealed that the genotype H1 stood out in terms of AFM, JY, and PRO; H3 for TD, LD, JY, and pH; H1, H3, V1, and R for LD; H3 and V5 for pH; and V4 and V5 for NF. A strong positive correlation was observed among the physical variables AFM, PM, LD, and TD. Four genotypes groups were obtained for both genetic divergence and PCA. The H1 genotype presented higher productivity, and the H3 genotype presented better fruit physical attributes
Response of Jabuticaba [Plinia cauliflora (Mart) Kausel] seedlings to herbicides
Get PDFJabuticaba (Plinia sp.) is one of the most important fruit species in the Brazilian flora; it is appreciated for fresh consumption or products produced from its fruits. The establishing of orchards requires the determination of management methods that favor the development and productivity of this species. The objective of this work was to evaluate the response of jabuticaba seedlings to application of herbicides and determine possible phytotoxicity. The experiment was conducted at the Federal Technological University of Paraná, in Dois Vizinhos, PR, Brazil. A randomized block experimental design with four replications was used, with 5 plants per experimental unit. The treatments consisted of applications of pre-emergence herbicides (Dual Gold® and Spider®) and post-emergence herbicides (2,4-D, Ally®, Enlist®, Primatop®, Fusilade®, Imazetapyr, Flex®, Plenum®, and Volcane®). The applied herbicide rates were equivalent to 50% of their commercial recommendation. A spray volume equivalent to 250 L ha-1 was applied, using water as diluent. The following parameters were evaluated 45 days after applications: stem diameter at 1 cm above ground (cm); plant height (cm); numbers of necrotic, chlorotic, shriveled, and healthy leaves; number and length of shoots (cm); survival rate (%); and chlorophyll contents (a, b, and total). The application of the herbicides Ally®, Enlist®, and Flex® resulted in less harmful effects on jabuticaba seedlings. The lowest survival rates were found in plants in the treatments with the herbicides Dual Gold®, Volcane®, and Primatop®.Jabuticaba (Plinia sp.) is one of the most important fruit species in the Brazilian flora; it is appreciated for fresh consumption or products produced from its fruits. The establishing of orchards requires the determination of management methods that favor the development and productivity of this species. The objective of this work was to evaluate the response of jabuticaba seedlings to application of herbicides and determine possible phytotoxicity. The experiment was conducted at the Federal Technological University of Paraná, in Dois Vizinhos, PR, Brazil. A randomized block experimental design with four replications was used, with 5 plants per experimental unit. The treatments consisted of applications of pre-emergence herbicides (Dual Gold® and Spider®) and post-emergence herbicides (2,4-D, Ally®, Enlist®, Primatop®, Fusilade®, Imazetapyr, Flex®, Plenum®, and Volcane®). The applied herbicide rates were equivalent to 50% of their commercial recommendation. A spray volume equivalent to 250 L ha-1 was applied, using water as diluent. The following parameters were evaluated 45 days after applications: stem diameter at 1 cm above ground (cm); plant height (cm); numbers of necrotic, chlorotic, shriveled, and healthy leaves; number and length of shoots (cm); survival rate (%); and chlorophyll contents (a, b, and total). The application of the herbicides Ally®, Enlist®, and Flex® resulted in less harmful effects on jabuticaba seedlings. The lowest survival rates were found in plants in the treatments with the herbicides Dual Gold®, Volcane®, and Primatop®
How to store araticum seeds and maintain their physiological quality: en
Get PDFThe purpose of seed storage is its preservation; in this sense, the storage period and types of packaging materials utilized in this process interfere with the conservation of seed vigor. The objective here was to evaluate the physiological potential of araticum seeds in different types of packaging materials and storage periods. The work was developed at the State University of Western Paraná Seed Technology Laboratory (Unioeste) - Campus Marechal C. Rondon - from February to August 2020. The seeds were packed in different packaging materials for three months (February, March, and April / 2020), kept in a cold chamber (16º C and 40% RH). The experimental design used was completely randomized, in a 5 x 7 factorial scheme [five packages (glass, plastic bag, burlap bag, kraft paper, and pet bottle) x seven storage periods (0, 15, 30, 45, 60, 75 and 90 days)]. It is important to note that araticum seeds have dormancy, so they were submerged in 500 mg L-1 of gibberellic acid (GA3) for 24 hours before the setting up of the germination test. Evaluating the physiological aspect of the germination and vigor. The kraft paper packaging is the most suitable for storing araticum seeds. The physiological potential of seeds of this species decreases when its storage period is increased.The purpose of seed storage is its preservation; in this sense, the storage period and types of packaging materials utilized in this process interfere with the conservation of seed vigor. The objective here was to evaluate the physiological potential of araticum seeds in different types of packaging materials and storage periods. The work was developed at the State University of Western Paraná Seed Technology Laboratory (Unioeste) - Campus Marechal C. Rondon - from February to August 2020. The seeds were packed in different packaging materials for three months (February, March, and April / 2020), kept in a cold chamber (16º C and 40% RH). The experimental design used was completely randomized, in a 5 x 7 factorial scheme [five packages (glass, plastic bag, burlap bag, kraft paper, and pet bottle) x seven storage periods (0, 15, 30, 45, 60, 75 and 90 days)]. It is important to note that araticum seeds have dormancy, so they were submerged in 500 mg L-1 of gibberellic acid (GA3) for 24 hours before the setting up of the germination test. Evaluating the physiological aspect of the germination and vigor. The kraft paper packaging is the most suitable for storing araticum seeds. The physiological potential of seeds of this species decreases when its storage period is increased.
Plant extracts and commercial products for controlling black spot and inducing resistance in rose bushes
Get PDFRose is one of the most appreciated flowers in the world; however, fungal diseases can affect its production, decreasing its commercial value. Thus, the objective of this work was to assess the potential of extracts of medicinal plants and commercial products based on plant extracts, plant oils, and potassium phosphite to control black spot (Diplocarpon rosae) in roses by evaluating the activation of plant defense mechanisms. The treatments consisted of using crude aqueous extract (CAE) of Rosmarinus officinalis leaves; CAE of Equisetum arvense stems; CAE of Moringa oleifera seeds; commercial product (CP) based on fermented plant extracts; CP based on potassium phosphite; CP based on plant oils; CP based on citrus mass; and fungicide. Severity of black spot disease, and yield, biometry, chlorophyll contents, and enzyme activity of peroxidase, catalase, and polyphenoloxidase in rose plants were evaluated. The treatments presented no difference from the control (water) for disease incidence and severity and yield. However, the longest stem was found in rose plants in the treatment with potassium phosphite-based commercial product, whereas the thickest stems were found in the three treatments with commercial products. The highest enzyme specific activities of peroxidase, catalase, and polyphenoloxidase were found in plants treated with potassium phosphite, CAE of M. oleifera, and CAE of R. officinalis. The results found showed that the tested natural products did not control black spot in rose bushes, despite their positive effect on plant physiology.Rose is one of the most appreciated flowers in the world; however, fungal diseases can affect its production, decreasing its commercial value. Thus, the objective of this work was to assess the potential of extracts of medicinal plants and commercial products based on plant extracts, plant oils, and potassium phosphite to control black spot (Diplocarpon rosae) in roses by evaluating the activation of plant defense mechanisms. The treatments consisted of using crude aqueous extract (CAE) of Rosmarinus officinalis leaves; CAE of Equisetum arvense stems; CAE of Moringa oleifera seeds; commercial product (CP) based on fermented plant extracts; CP based on potassium phosphite; CP based on plant oils; CP based on citrus mass; and fungicide. Severity of black spot disease, and yield, biometry, chlorophyll contents, and enzyme activity of peroxidase, catalase, and polyphenoloxidase in rose plants were evaluated. The treatments presented no difference from the control (water) for disease incidence and severity and yield. However, the longest stem was found in rose plants in the treatment with potassium phosphite-based commercial product, whereas the thickest stems were found in the three treatments with commercial products. The highest enzyme specific activities of peroxidase, catalase, and polyphenoloxidase were found in plants treated with potassium phosphite, CAE of M. oleifera, and CAE of R. officinalis. The results found showed that the tested natural products did not control black spot in rose bushes, despite their positive effect on plant physiology
Lettuce yield response to application of rhizobacteria and nitrogen to the growth substrate
Get PDFRhizobacteria of agronomic interest can promote plant growth, increase productivity, and reduce the demand for nitrogen (N) fertilizers by improving the N use efficiency in crops. The objective of this study was to assess the effects of rhizobacteria and nitrogen on the yield of lettuce plants (cultivar Vera). The experiment was carried out in a greenhouse, using a completely randomized design in a 2×2×2×2 factorial arrangement, with five repetitions. The factors consisted of single and combined applications of liquid inoculants (1 mL) based on Azospirillum brasilense, Bacillus subtilis, and Bradyrhizobium japonicum, as well as nitrogen (75 kg ha-1) in the growth substrate. The variables assessed were total and commercial shoot fresh and dry weights, root dry weight, total dry weight, and numbers of total and commercial leaves, and shoot nitrogen content. Lettuce yield components improved with nitrogen fertilizer application. The single application of rhizobacteria did not increase lettuce yield, as the plants had decreases in root weight in response to Bradyrhizobium japonicum and decreases in total and commercial shoot dry weights, root dry weight, and total dry weight when Bacillus subtilis was used. However, the combined application of Azospirillum brasilense, Bacillus subtilis, and nitrogen increased the lettuce number of commercial leaves and shoot nitrogen content when one or another microbial specie was associated with nitrogen fertilizer.Rhizobacteria of agronomic interest can promote plant growth, increase productivity, and reduce the demand for nitrogen (N) fertilizers by improving the N use efficiency in crops. The objective of this study was to assess the effects of rhizobacteria and nitrogen on the yield of lettuce plants (cultivar Vera). The experiment was carried out in a greenhouse, using a completely randomized design in a 2×2×2×2 factorial arrangement, with five repetitions. The factors consisted of single and combined applications of liquid inoculants (1 mL) based on Azospirillum brasilense, Bacillus subtilis, and Bradyrhizobium japonicum, as well as nitrogen (75 kg ha-1) in the growth substrate. The variables assessed were total and commercial shoot fresh and dry weights, root dry weight, total dry weight, and numbers of total and commercial leaves, and shoot nitrogen content. Lettuce yield components improved with nitrogen fertilizer application. The single application of rhizobacteria did not increase lettuce yield, as the plants had decreases in root weight in response to Bradyrhizobium japonicum and decreases in total and commercial shoot dry weights, root dry weight, and total dry weight when Bacillus subtilis was used. However, the combined application of Azospirillum brasilense, Bacillus subtilis, and nitrogen increased the lettuce number of commercial leaves and shoot nitrogen content when one or another microbial specie was associated with nitrogen fertilizer