Revista de la Facultad de Ciencias Agrarias
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Application stages and doses of tembotrione herbicide in grain sorghum (Sorghum bicolor) crop
Full text linkThe herbicide tembotrione is effective against grassy weeds constituting an important tool in sorghum crops. However, in Brazil, this herbicide is only registered for corn. This study aimed to evaluate the selectiveness of tembotrione combined with atrazine at different doses and developmental stages of grain sorghum. Two experiments were conducted in Rio Verde and Montividiu, state of Goiás, Brazil, in 2018. A randomized block design with four replications, in a 3x2+1+1 factorial arrangement, tested three developmental stages (V3, V5 and V7), two doses of tembotrione (37.8 and 75.6 g ha-1) combined with the herbicide atrazine (1,000 g ha-1), an additional treatment only with atrazine at V3 and a control, free of herbicide. Evident phytotoxicity was observed with the combination of tembotrione and atrazine at V3 and V5 stages. Symptoms included reductions in plant height, sorghum stem diameter, panicle length, and cumulative dry mass of sorghum plant shoots. However, there was no influence on thousand grains mass, regardless of application stages. Tembotrione at 37.8 g ha-1 combined with atrazine at 1,000 g ha-1 was selective for grain sorghum when applied at V7, without affecting grain yield.
Highlights:
Phytotoxicity symptoms of tembotrione and atrazine are more noticeable at V3 stage, beyond reducing the plant height and stem diameter.
Application of tembotrione and atrazine at V3 and V5 stages reduces the accumulation of shoot dry mass.
Spraying of tembotrione (37.8 g ha-1) and atrazine in V7 stage is not reduce the yield of BRS 330 grain sorghum hybrid.The herbicide tembotrione is effective against grassy weeds constituting an important tool in sorghum crops. However, in Brazil, this herbicide is only registered for corn. This study aimed to evaluate the selectiveness of tembotrione combined with atrazine at different doses and developmental stages of grain sorghum. Two experiments were conducted in Rio Verde and Montividiu, state of Goiás, Brazil, in 2018. A randomized block design with four replications, in a 3x2+1+1 factorial arrangement, tested three developmental stages (V3, V5 and V7), two doses of tembotrione (37.8 and 75.6 g ha-1) combined with the herbicide atrazine (1,000 g ha-1), an additional treatment only with atrazine at V3 and a control, free of herbicide. Evident phytotoxicity was observed with the combination of tembotrione and atrazine at V3 and V5 stages. Symptoms included reductions in plant height, sorghum stem diameter, panicle length, and cumulative dry mass of sorghum plant shoots. However, there was no influence on thousand grains mass, regardless of application stages. Tembotrione at 37.8 g ha-1 combined with atrazine at 1,000 g ha-1 was selective for grain sorghum when applied at V7, without affecting grain yield.
Highlights:
Phytotoxicity symptoms of tembotrione and atrazine are more noticeable at V3 stage, beyond reducing the plant height and stem diameter.
Application of tembotrione and atrazine at V3 and V5 stages reduces the accumulation of shoot dry mass.
Spraying of tembotrione (37.8 g ha-1) and atrazine in V7 stage is not reduce the yield of BRS 330 grain sorghum hybrid
A polyphasic study of non-aflatoxigenic Aspergillus flavus Link, isolates from maize in the Chaco semi-arid region of Argentina
Full text linkMaize (Zea mays L.) is one of the most widely planted crops globally with Argentina leading world production and exportation. Santiago del Estero province, east of Tucumán and north of Córdoba encompasses eight agro-climatic zones in the Chaco Semi-arid region, agro-ecologically characterized by a wide temperature range and frequent drought periods that expose the crop to pathogens, particularly Aspergillus flavus. This pathogen is responsible for ear rot and grain contamination with mycotoxins such as aflatoxin B1 and cyclopiazonic acid. This study obtained fungal isolates from ears of maize and characterized them according to toxigenic capability and morphotype of sclerotia (S < 400 μm, associated with high levels of aflatoxins and L > 400 μm, related to variable levels of aflatoxins). In addition, those not producing aflatoxins were studied to determine phylogenetic relationships based on sequences of a segment of the CaM gene. Fifty-eight isolates were obtained in eight localities representing each agro-climatic zone, 30 of which were non-aflatoxigenic, 28 aflatoxigenic, and all producers of ciclopiazonic acid. Six isolates did not produce sclerotia, 51 were L and only one was S, the latter being a non-producer of aflatoxins. The number of sclerotia was positively correlated with the production of aflatoxin B1, while size was negatively correlated. The CaM gene sequences corroborated that the isolates belonged to the A. flavus clade and the high nucleotide similarity among them (99.4% to 100%) revealed almost zero genetic diversity in this geographic region. No significant differences were observed in the proportion of isolates between growing seasons or among agroclimatic districts. This research revealed characteristics of fungus populations in this agricultural region of north Argentina.
Highlights:
Aspergillus flavus isolates from ears of maize were characterized according to toxigenic capability, morphotype of sclerotia and phylogenetic relationships.
Fifty-eight isolates were obtained, 30 non-aflatoxigenic, 28 aflatoxigenic, and all producers of ciclopiazonic acid.
Six isolates did not produce sclerotia, 51 were L and only one was S, the latter being a non-producer of aflatoxins.
All isolates belonged to the flavus clade. High nucleotide similarity among the isolates (99.4% to 100%) revealed almost zero genetic diversity in the region.Maize (Zea mays L.) is one of the most widely planted crops globally with Argentina leading world production and exportation. Santiago del Estero province, east of Tucumán and north of Córdoba encompasses eight agro-climatic zones in the Chaco Semi-arid region, agro-ecologically characterized by a wide temperature range and frequent drought periods that expose the crop to pathogens, particularly Aspergillus flavus. This pathogen is responsible for ear rot and grain contamination with mycotoxins such as aflatoxin B1 and cyclopiazonic acid. This study obtained fungal isolates from ears of maize and characterized them according to toxigenic capability and morphotype of sclerotia (S < 400 μm, associated with high levels of aflatoxins and L > 400 μm, related to variable levels of aflatoxins). In addition, those not producing aflatoxins were studied to determine phylogenetic relationships based on sequences of a segment of the CaM gene. Fifty-eight isolates were obtained in eight localities representing each agro-climatic zone, 30 of which were non-aflatoxigenic, 28 aflatoxigenic, and all producers of ciclopiazonic acid. Six isolates did not produce sclerotia, 51 were L and only one was S, the latter being a non-producer of aflatoxins. The number of sclerotia was positively correlated with the production of aflatoxin B1, while size was negatively correlated. The CaM gene sequences corroborated that the isolates belonged to the A. flavus clade and the high nucleotide similarity among them (99.4% to 100%) revealed almost zero genetic diversity in this geographic region. No significant differences were observed in the proportion of isolates between growing seasons or among agroclimatic districts. This research revealed characteristics of fungus populations in this agricultural region of north Argentina.
Highlights:
Aspergillus flavus isolates from ears of maize were characterized according to toxigenic capability, morphotype of sclerotia and phylogenetic relationships.
Fifty-eight isolates were obtained, 30 non-aflatoxigenic, 28 aflatoxigenic, and all producers of ciclopiazonic acid.
Six isolates did not produce sclerotia, 51 were L and only one was S, the latter being a non-producer of aflatoxins.
All isolates belonged to the flavus clade. High nucleotide similarity among the isolates (99.4% to 100%) revealed almost zero genetic diversity in the region
Antibacterial activity and physicochemical characterization of bioplastic films based on cassava (Manihot esculenta Crantz) starch and rosemary (Salvia rosmarinus) essential oil
Full text linkBioplastics composed of renewable sources and antimicrobial components are desirable in food packaging. This study prepared bioplastic films with cassava starch and rosemary essential oil using a casting methodology. Film antibacterial activity, water vapour transmission (Wvt), mechanical resistance, and microstructure were measured after exposure to pathogenic bacteria such as Salmonella enterica, Escherichia coli, Staphylococcus aureus, and Bacillus cereus. Antibacterial activity was evidenced against the pathogens evaluated except for B. cereus. The films showed average values of Wvt 3.6988 (10-14 g/Pa s m), tensile strength 8.90 MPa, young modulus 1679.72 MPa, and elongation at break 4.33%. Film microstructure showed good adhesion to bioplastic components in the matrix. Bioplastics of cassava starch and rosemary oil constitute potential food packaging solutions mainly for fruits, egg-based products or chicken.
Highlights:
Cassava starch, glycerol, tween-80, and rosemary essential oil produced proper antimicrobial films.
Rosemary essential oil promoted antimicrobial action against coli S. entérica and S. aureus in films
The high glycerol/tween-80 increased the flexibility and water vapor transmisión.
Casting method promoted adhesion of the combined components and homogeneous film surface.Bioplastics composed of renewable sources and antimicrobial components are desirable in food packaging. This study prepared bioplastic films with cassava starch and rosemary essential oil using a casting methodology. Film antibacterial activity, water vapour transmission (Wvt), mechanical resistance, and microstructure were measured after exposure to pathogenic bacteria such as Salmonella enterica, Escherichia coli, Staphylococcus aureus, and Bacillus cereus. Antibacterial activity was evidenced against the pathogens evaluated except for B. cereus. The films showed average values of Wvt 3.6988 (10-14 g/Pa s m), tensile strength 8.90 MPa, young modulus 1679.72 MPa, and elongation at break 4.33%. Film microstructure showed good adhesion to bioplastic components in the matrix. Bioplastics of cassava starch and rosemary oil constitute potential food packaging solutions mainly for fruits, egg-based products or chicken.
Highlights:
Cassava starch, glycerol, tween-80, and rosemary essential oil produced proper antimicrobial films.
Rosemary essential oil promoted antimicrobial action against coli S. entérica and S. aureus in films
The high glycerol/tween-80 increased the flexibility and water vapor transmisión.
Casting method promoted adhesion of the combined components and homogeneous film surface
Different scenarios in land suitability assessment for Kernza®-intermediate wheatgrass (Thinopyrum Intermedium), a novel perennial grain crop for Argentina
Full text linkLand degradation, climate change, soil and water contamination have led to increased interest in sustainable agricultural practices. Most agricultural practices are focused on growing annual crops, which require significant amounts of synthetic fertilizers, contribute to CO2 emissions and disrupt natural biological processes. Natural Systems Agriculture has been developed to reverse this paradigm by imitating nature through perennial grain crops. Kernza® intermediate wheatgrass (Thinopyrum Intermedium) is a promising perennial crop producing healthy grain for direct human consumption and forage for livestock while providing multiple ecosystemic services. Given these reasons, consider its cultivation in Argentina is relevant. This research aimed to predict Kernza crop suitability in the Azul district by modeling different climatic and soil densification scenarios. The model showed that Kernza can be grown in Azul, and that southern areas were most suitable. This model allowed generating information for land use planners and farmers to consider planting in Argentina, particularly, in Azul.
Highlights:
Kernza can be grown in Azul district, especially in the deep, loamy soils of the southern areas.
The P50% precipitation scenario was found to be the most suitable for Kernza cultivation.
Considering different soil densification scenarios is crucial, as they affect water availability and water logging.
Kernza offers valuable ecosystem services and holds promise for land use planners and farmers in Azul and Argentina.Land degradation, climate change, soil and water contamination have led to increased interest in sustainable agricultural practices. Most agricultural practices are focused on growing annual crops, which require significant amounts of synthetic fertilizers, contribute to CO2 emissions and disrupt natural biological processes. Natural Systems Agriculture has been developed to reverse this paradigm by imitating nature through perennial grain crops. Kernza® intermediate wheatgrass (Thinopyrum Intermedium) is a promising perennial crop producing healthy grain for direct human consumption and forage for livestock while providing multiple ecosystemic services. Given these reasons, consider its cultivation in Argentina is relevant. This research aimed to predict Kernza crop suitability in the Azul district by modeling different climatic and soil densification scenarios. The model showed that Kernza can be grown in Azul, and that southern areas were most suitable. This model allowed generating information for land use planners and farmers to consider planting in Argentina, particularly, in Azul.
Highlights:
Kernza can be grown in Azul district, especially in the deep, loamy soils of the southern areas.
The P50% precipitation scenario was found to be the most suitable for Kernza cultivation.
Considering different soil densification scenarios is crucial, as they affect water availability and water logging.
Kernza offers valuable ecosystem services and holds promise for land use planners and farmers in Azul and Argentina.
Effects of postharvest treatments based on calcium and silicon in hydro-cooling on the basic quality attributes of ʹBingʹ sweet cherries (Prunus avium L.) during storage
Full text linkCa2+ and Si2+ treatments confer resistance to biotic and abiotic stresses in many fruits. In sweet cherries, Ca2+ improves shelf life extension during storage, but only CaCl2 is used. On the other hand, there is scarce information on CaCO3 as a source of Ca2+, which has shown increased firmness in berries. This study evaluated different treatments based on Ca2+ (CaCl2 and CaCO3) + Si2+ (SiO2) alone and combined with immersion in hydro-cooling (0°C) on physicochemical characteristics of ʹBingʹ sweet cherries (Prunus avium L.) during storage at low temperature (4°C). Results demonstrate that alone or combined treatments (Ca2+ and Si2+) with hydro-cooling significantly affected skin and flesh color of sweet cherries. Chromaticity (C*) was increased in treated fruits, indicating an intense red color, especially in those cherries treated with CaCl2. Furthermore, firmness was increased during storage in treatments with Ca2+, while SiO2 treatment increased total soluble solids (TSS). Therefore, combined treatments of Ca2+ and Si2+ with hydro-cooling might be a promising postharvest strategy to maintain desirable physicochemical characteristics in sweet cherries during low-temperature storage.
Highlights:
Treatments based on Ca2+ (CaCl2 and CaCO3) and Si2+ (SiO2) alone and combined in hydro-cooled solutions extend storage capacity at low temperatures.
Ca2+ and Si2+ treatments intensify the skin color of sweet cherries.
CaCO3 as a source of Ca2+, has shown increased firmness in berries.
Ca2+ and Si2+ treatments combined with hydro-cooling maintain physicochemical characteristics in sweet cherries during storage.
Ca2+ and Si2+ treatments confer resistance to biotic and abiotic stresses in many fruits. In sweet cherries, Ca2+ improves shelf life extension during storage, but only CaCl2 is used. On the other hand, there is scarce information on CaCO3 as a source of Ca2+, which has shown increased firmness in berries. This study evaluated different treatments based on Ca2+ (CaCl2 and CaCO3) + Si2+ (SiO2) alone and combined with immersion in hydro-cooling (0°C) on physicochemical characteristics of ʹBingʹ sweet cherries (Prunus avium L.) during storage at low temperature (4°C). Results demonstrate that alone or combined treatments (Ca2+ and Si2+) with hydro-cooling significantly affected skin and flesh color of sweet cherries. Chromaticity (C*) was increased in treated fruits, indicating an intense red color, especially in those cherries treated with CaCl2. Furthermore, firmness was increased during storage in treatments with Ca2+, while SiO2 treatment increased total soluble solids (TSS). Therefore, combined treatments of Ca2+ and Si2+ with hydro-cooling might be a promising postharvest strategy to maintain desirable physicochemical characteristics in sweet cherries during low-temperature storage.
Highlights:
Treatments based on Ca2+ (CaCl2 and CaCO3) and Si2+ (SiO2) alone and combined in hydro-cooled solutions extend storage capacity at low temperatures.
Ca2+ and Si2+ treatments intensify the skin color of sweet cherries.
CaCO3 as a source of Ca2+, has shown increased firmness in berries.
Ca2+ and Si2+ treatments combined with hydro-cooling maintain physicochemical characteristics in sweet cherries during storage.
Weed control in different germination fluxes with preemergent herbicides on sugarcane straw under dry periods
Full text linkPreemergent herbicides are a frequent weed control strategy. Considering different crop germinative fluxes, these products must present long-lasting weed control. This study evaluated preemergent herbicides in different germination fluxes of Merremia aegyptia, Mucuna aterrima and Ricinus communis when applied to different quantities of straw and different simulated dry periods. The experiment was conducted in a 4 × 2 × 2 factorial design with four replications. The treatments included four dry periods (0, 30, 60, and 90 days), two straw quantities (0 and 10 t ha 1), and two germination fluxes. The herbicides amicarbazone (1225 g ha-1), imazapic (147 g ha- 1), sulfentrazone (800 g ha-1), and tebuthiuron (900 g ha-1) were applied for preemergence weed control, and germination flush fluxes were evaluated at 7, 14, 21, 28, and 35 days after emergence (DAE) while verifying plant dry mass. Amicarbazone controlled less than 80% of the studied species at the 90-day dry period in the presence of straw. Imazapic did not present control residue for any of the species analyzed. Sulfentrazone showed the same control pattern at all germination fluxes, regardless of the amount of straw. Tebuthiuron successfully controlled all species in the first germination flush, exceeding 80% regardless of the amount of straw. Herbicides associated with straw quantities and dry periods have a significant impact on M. aegyptiaca, M. aterrima and R. communis.
Highlights:
The herbicide amicarbazone demonstrated efficacy in controlling during the first germination period of the three weed species.
The presence of sugarcane straw significantly influenced the herbicides' control efficacy, especially during prolonged dry periods.
The combination of straw and extended dry periods resulted in a reduction in control rates with tebuthiuron.Preemergent herbicides are a frequent weed control strategy. Considering different crop germinative fluxes, these products must present long-lasting weed control. This study evaluated preemergent herbicides in different germination fluxes of Merremia aegyptia, Mucuna aterrima and Ricinus communis when applied to different quantities of straw and different simulated dry periods. The experiment was conducted in a 4 × 2 × 2 factorial design with four replications. The treatments included four dry periods (0, 30, 60, and 90 days), two straw quantities (0 and 10 t ha 1), and two germination fluxes. The herbicides amicarbazone (1225 g ha-1), imazapic (147 g ha- 1), sulfentrazone (800 g ha-1), and tebuthiuron (900 g ha-1) were applied for preemergence weed control, and germination flush fluxes were evaluated at 7, 14, 21, 28, and 35 days after emergence (DAE) while verifying plant dry mass. Amicarbazone controlled less than 80% of the studied species at the 90-day dry period in the presence of straw. Imazapic did not present control residue for any of the species analyzed. Sulfentrazone showed the same control pattern at all germination fluxes, regardless of the amount of straw. Tebuthiuron successfully controlled all species in the first germination flush, exceeding 80% regardless of the amount of straw. Herbicides associated with straw quantities and dry periods have a significant impact on M. aegyptiaca, M. aterrima and R. communis.
Highlights:
The herbicide amicarbazone demonstrated efficacy in controlling during the first germination period of the three weed species.
The presence of sugarcane straw significantly influenced the herbicides' control efficacy, especially during prolonged dry periods.
The combination of straw and extended dry periods resulted in a reduction in control rates with tebuthiuron
Landform heterogeneity drives multi-stemmed Neltuma flexuosa growth dynamics. Implication for the Central Monte Desert forest management
Full text linkDrylands represent the main earth biome, providing ecosytemic services to a large number of people. Along these environments, woodlands are often dominated by multi-stemmed trees, which are exploited by local inhabitants to obtain forest products for their livelihood. In central-west Argentina, Neltuma flexuosa (algarrobo) woodlands are distributed across different landform units, varying in topographical and soil characteristics. This research aimed to reconstruct stem-growth time until harvestable diameter was achieved, and biological rotation age according to topo-edaphic variability in three algarrobo forests using dendrochronological methods. Results indicated that landform heterogeneity modulated species radial growth, influencing stem increments and cutting cycle period. In this sense, a decreasing trend in tree productivity emerged along a loamy-to-sandy textured soil gradient. These findings provide useful novel information for N. flexuosa forest management, suggesting the need to account for spatial landform/soil heterogeneity when examining desert forest dynamics.
Highlights:
Neltuma flexuosa provides forest product (poles) to Central Monte Desert (Argentina) local inhabitants.
N. flexuosa wood productivity was assessed for different topo-edaphic landforms.
Cutting cycle was reached at younger ages at river and paleo-river landforms.
Wood extraction must consider landscape heterogeneity.Drylands represent the main earth biome, providing ecosytemic services to a large number of people. Along these environments, woodlands are often dominated by multi-stemmed trees, which are exploited by local inhabitants to obtain forest products for their livelihood. In central-west Argentina, Neltuma flexuosa (algarrobo) woodlands are distributed across different landform units, varying in topographical and soil characteristics. This research aimed to reconstruct stem-growth time until harvestable diameter was achieved, and biological rotation age according to topo-edaphic variability in three algarrobo forests using dendrochronological methods. Results indicated that landform heterogeneity modulated species radial growth, influencing stem increments and cutting cycle period. In this sense, a decreasing trend in tree productivity emerged along a loamy-to-sandy textured soil gradient. These findings provide useful novel information for N. flexuosa forest management, suggesting the need to account for spatial landform/soil heterogeneity when examining desert forest dynamics.
Highlights:
Neltuma flexuosa provides forest product (poles) to Central Monte Desert (Argentina) local inhabitants.
N. flexuosa wood productivity was assessed for different topo-edaphic landforms.
Cutting cycle was reached at younger ages at river and paleo-river landforms.
Wood extraction must consider landscape heterogeneity
Effect of three different fixed-time AI protocols on follicular dynamics and pregnancy rates in suckled, dual-purpose cows in the Ecuadorian Amazon
Full text linkReproductive performance is crucial for profitability of dual-purpose cow-calf production in the Ecuadorian Amazon. To evaluate three different fixed-time artificial insemination (FTAI) protocols in suckled, dual-purpose cows in the Ecuadorian Amazon. Lactating, Brown Swiss cows (n=301) received 2 mg estradiol benzoate (EB) and an intravaginal device containing 0.5 g of progesterone (P4) on Day 0. They were allocated randomly into the following three treatment groups: Cows in the EB group received 500 μg cloprostenol (PGF2α), and P4 devices were removed on Day 7, and 1 mg EB was administered on Day 8. Cows in the ECP group were treated as those in the EB group, except that they received 0.5 mg estradiol cypionate (ECP) at the time of P4 device removal on Day 7 instead of EB on Day 8. Cows in the J-Synch group had the P4 device removed and PGF2α administered on Day 6. All cows were FTAI on Day 9; cows in the J-Synch group also received 100 μg gonadorelin at that time. Although the diameter of the dominant follicle and the resulting CL were greater (P<0.05) in cows in the J-Synch group, pregnancies per AI did not differ (P>0.2) among groups (EB: 51.0%, ECP: 53.0% and J-Synch: 59.4%). The three protocols tested were applied successfully in suckled, dual-purpose cows with no differences in pregnancies per AI.
Highlights:
Estradiol and progesterone based FTAI protocols can be successfully applied in dual purpose cows in the tropics, with P/AI ≥50%.
Proestrus prolongation increased dominant follicle diameter at the time of FTAI and also CL diameter 7 days pos treatment
Although differences were not significant, the protocol with the prolonged proestrus (J-Synch) resulted in higher P/AI than the two protocols with short proestrus.
Regardless of the protocol used, there was a positive association between estrus manifestation, follicle diameter at the time of FTAI and CL diameter 7 days post treatment.Reproductive performance is crucial for profitability of dual-purpose cow-calf production in the Ecuadorian Amazon. To evaluate three different fixed-time artificial insemination (FTAI) protocols in suckled, dual-purpose cows in the Ecuadorian Amazon. Lactating, Brown Swiss cows (n=301) received 2 mg estradiol benzoate (EB) and an intravaginal device containing 0.5 g of progesterone (P4) on Day 0. They were allocated randomly into the following three treatment groups: Cows in the EB group received 500 μg cloprostenol (PGF2α), and P4 devices were removed on Day 7, and 1 mg EB was administered on Day 8. Cows in the ECP group were treated as those in the EB group, except that they received 0.5 mg estradiol cypionate (ECP) at the time of P4 device removal on Day 7 instead of EB on Day 8. Cows in the J-Synch group had the P4 device removed and PGF2α administered on Day 6. All cows were FTAI on Day 9; cows in the J-Synch group also received 100 μg gonadorelin at that time. Although the diameter of the dominant follicle and the resulting CL were greater (P<0.05) in cows in the J-Synch group, pregnancies per AI did not differ (P>0.2) among groups (EB: 51.0%, ECP: 53.0% and J-Synch: 59.4%). The three protocols tested were applied successfully in suckled, dual-purpose cows with no differences in pregnancies per AI.
Highlights:
Estradiol and progesterone based FTAI protocols can be successfully applied in dual purpose cows in the tropics, with P/AI ≥50%.
Proestrus prolongation increased dominant follicle diameter at the time of FTAI and also CL diameter 7 days pos treatment
Although differences were not significant, the protocol with the prolonged proestrus (J-Synch) resulted in higher P/AI than the two protocols with short proestrus.
Regardless of the protocol used, there was a positive association between estrus manifestation, follicle diameter at the time of FTAI and CL diameter 7 days post treatment
Yield and development of winter and spring rapeseed (Brassica napus L.) at different sowing dates in temperate environments
Full text linkOptimal sowing dates should match the crop-critical perio with favorable conditions. In rapeseed, growth stages change among spring and winter cultivars. This study characterized changes in rapeseed phenology with varying sowing dates to determine critical periods in both winter and spring cultivars. The trial took place in Balcarce, Argentina, where a winter-type variety and a spring-type were sown on eight different dates in a randomized complete block design with three replicates. Phenology was monitored weekly, and yield was evaluated at the end of the season. Changes in sowing dates and cultivars led to variations in the timing of critical periods. Considering the experimental conditions, the optimal sowing window was between April and July for sowing either rapeseed cultivar. However, the winter variety did not bloom for sowing dates after July, while the spring variety showed yield reductions due to frosts for sowing dates before the end of April. Changes in sowing date resulted in differences in timing and duration of vegetative and reproductive stages, generally leading to shorter crop cycles. However, in late sowing, winter cultivars lengthened their life cycle to the point of not reaching flowering during the growing season.
Highlights:
Adjustments in sowing dates and cultivar types changed the timing and duration of vegetative and reproductive stages.
Late sowing extended winter cultivar cycles, occasionally preventing flowering within the season.
Winter cultivars failed to flower after July sowing, while spring cultivars faced yield reductions from frosts in early sowing.Optimal sowing dates should match the crop-critical perio with favorable conditions. In rapeseed, growth stages change among spring and winter cultivars. This study characterized changes in rapeseed phenology with varying sowing dates to determine critical periods in both winter and spring cultivars. The trial took place in Balcarce, Argentina, where a winter-type variety and a spring-type were sown on eight different dates in a randomized complete block design with three replicates. Phenology was monitored weekly, and yield was evaluated at the end of the season. Changes in sowing dates and cultivars led to variations in the timing of critical periods. Considering the experimental conditions, the optimal sowing window was between April and July for sowing either rapeseed cultivar. However, the winter variety did not bloom for sowing dates after July, while the spring variety showed yield reductions due to frosts for sowing dates before the end of April. Changes in sowing date resulted in differences in timing and duration of vegetative and reproductive stages, generally leading to shorter crop cycles. However, in late sowing, winter cultivars lengthened their life cycle to the point of not reaching flowering during the growing season.
Highlights:
Adjustments in sowing dates and cultivar types changed the timing and duration of vegetative and reproductive stages.
Late sowing extended winter cultivar cycles, occasionally preventing flowering within the season.
Winter cultivars failed to flower after July sowing, while spring cultivars faced yield reductions from frosts in early sowing
Gas exchange in yellow melon (Cucumis melo) crop under controlled water deficit (RDI) and application of a biostimulant
Full text linkThe São Francisco River Valley region in Brazil is a major producer of irrigated melons, facing stresses due to climate change. New strategies for crop management are essential to maintain sustainable cultivation. This study aims to evaluate the characteristics of melons under controlled irrigation deficit (RDI) and the use of a biostimulant. The experiment followed a completely randomized design with sub subdivided plots. The main plots represented water levels: full irrigation (100% soil water availability - SWA) and deficit levels (80%, 60%, and 40% SWA). The subplots represented biostimulant application (with and without), and the sub-subplots represented collection periods: time I (17 to 26 days after planting - DAP), time II (27 to 36 DAP), and time III (37 to 46 DAP). The variable analyzed was gas exchange. Water restriction affects melons; however, some physiological characteristics show greater tolerance, demonstrating an adaptive response to moderate water deficit (80% SWA), regardless of the evaluation period. This allows for better water use efficiency. The biostimulant applied was not effective in promoting adjustments in the evaluated gas exchanges.
Highlights:
Gas exchange is influenced by irrigation management and involved in plant production.
Biostimulant application promote plant growth and development.
The use Regulated deficit irrigation (RDI) strategy in irrigation management, optimize water use efficiency without compromising yield.The São Francisco River Valley region in Brazil is a major producer of irrigated melons, facing stresses due to climate change. New strategies for crop management are essential to maintain sustainable cultivation. This study aims to evaluate the characteristics of melons under controlled irrigation deficit (RDI) and the use of a biostimulant. The experiment followed a completely randomized design with sub subdivided plots. The main plots represented water levels: full irrigation (100% soil water availability - SWA) and deficit levels (80%, 60%, and 40% SWA). The subplots represented biostimulant application (with and without), and the sub-subplots represented collection periods: time I (17 to 26 days after planting - DAP), time II (27 to 36 DAP), and time III (37 to 46 DAP). The variable analyzed was gas exchange. Water restriction affects melons; however, some physiological characteristics show greater tolerance, demonstrating an adaptive response to moderate water deficit (80% SWA), regardless of the evaluation period. This allows for better water use efficiency. The biostimulant applied was not effective in promoting adjustments in the evaluated gas exchanges.
Highlights:
Gas exchange is influenced by irrigation management and involved in plant production.
Biostimulant application promote plant growth and development.
The use Regulated deficit irrigation (RDI) strategy in irrigation management, optimize water use efficiency without compromising yield