Revista de la Facultad de Ciencias Agrarias
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Effect of protein source on in situ digestibility of sugarcane silage-based diets
Get PDFThe objective of this study was to evaluate the effect of the protein source in sugarcane silage-based diets on the ruminal pH and in situ dry matter digestibility (DMD). The treatments were: 1)- 60% sugarcane silage + 15% soybean meal (SBM); 2)- 60% sugarcane silage + 15% fish meal (FM); 3)- 55% sugarcane silage + 20% canola meal (CM); and T4)- 50% sugarcane silage + 30% coconut meal (CCM). In situ DMD was determined by the nylon bag technique using four cows equipped with ruminal cannula. Five grams of each experimental diet were weighted in nylon bags and incubated for 8, 12, 24, 48, 72 and 96 h. Dry matter digestibility for SBM, CM, and CCM showed higher values compared to FM. A similar pH among treatments was recorded; however, at 4 h decreases in SBM and FM were observed. Sugarcane silage in integral diets with the different protein sources used in this study, did not modify ruminal pH but showed lower DMD when fish meal was the protein source.
Highlights
The use of bacterial inoculum and an additive that promotes the silage process of sugarcane and improves its quality.
Use of sugarcane silage and soybean meal as a protein source increase the ruminal digestibility of dry matter of the diet, and not change ruminal pH.
Sugarcane silage can be used as an ingredient in an integral diet for ruminants.The objective of this study was to evaluate the effect of the protein source in sugarcane silage-based diets on the ruminal pH and in situ dry matter digestibility (DMD). The treatments were: 1)- 60% sugarcane silage + 15% soybean meal (SBM); 2)- 60% sugarcane silage + 15% fish meal (FM); 3)- 55% sugarcane silage + 20% canola meal (CM); and T4)- 50% sugarcane silage + 30% coconut meal (CCM). In situ DMD was determined by the nylon bag technique using four cows equipped with ruminal cannula. Five grams of each experimental diet were weighted in nylon bags and incubated for 8, 12, 24, 48, 72 and 96 h. Dry matter digestibility for SBM, CM, and CCM showed higher values compared to FM. A similar pH among treatments was recorded; however, at 4 h decreases in SBM and FM were observed. Sugarcane silage in integral diets with the different protein sources used in this study, did not modify ruminal pH but showed lower DMD when fish meal was the protein source.
Highlights
The use of bacterial inoculum and an additive that promotes the silage process of sugarcane and improves its quality.
Use of sugarcane silage and soybean meal as a protein source increase the ruminal digestibility of dry matter of the diet, and not change ruminal pH.
Sugarcane silage can be used as an ingredient in an integral diet for ruminants
First record of Feltiella curtistylus Gagné (Diptera: Cecidomyiidae) in Argentina
Get PDFThe first records of Feltiella curtistylus Gagné (Diptera: Cecidomyiidae) in Argentina are reported. Larvae from this species were captured in strawberry (Fragaria x ananassa Duch.) leaflets heavily infested with Tetranychus urticae Koch (Acari: Tetranichidae) in Famaillá, province of Tucumán, Argentina (27º03’S, 65º25’W). In 2015 (June, September and October), 16 larvae were collected; in 2016 (October, November and December), 23 larvae; and in 2017 (September, October and November), 49 larvae. Since F. curtistylus was found associated to a mite of agricultural importance in strawberry crops, this predatory gall midge has a potential for being considered a biological control agent.
Highlights
Feltiella curtistylus Gagné (Diptera: Cecidomyiidae) larvae are mite predators in Brazil and the USA.
During 3 years, in Tucumán, Argentina, Diptera larvae were observed feeding on eggs, protonymphal and adult stages of two-spotted spider mite, in strawberry leaves heavily infested with.
Leaflets with larvae were placed in Petri dishes with the bottom covered with smooth plaster base, and kept humid until adults emerged.
Adult specimens (males and females) were identified by Dr. Raymond Gagné, as Feltiella curtistylus, first record for Argentina.
Due to prey specificity, this predatory gall midge has a potential for been considered in augmentative biological control strategies in strawberry.The first records of Feltiella curtistylus Gagné (Diptera: Cecidomyiidae) in Argentina are reported. Larvae from this species were captured in strawberry (Fragaria x ananassa Duch.) leaflets heavily infested with Tetranychus urticae Koch (Acari: Tetranichidae) in Famaillá, province of Tucumán, Argentina (27º03’S, 65º25’W). In 2015 (June, September and October), 16 larvae were collected; in 2016 (October, November and December), 23 larvae; and in 2017 (September, October and November), 49 larvae. Since F. curtistylus was found associated to a mite of agricultural importance in strawberry crops, this predatory gall midge has a potential for being considered a biological control agent.
Highlights
Feltiella curtistylus Gagné (Diptera: Cecidomyiidae) larvae are mite predators in Brazil and the USA.
During 3 years, in Tucumán, Argentina, Diptera larvae were observed feeding on eggs, protonymphal and adult stages of two-spotted spider mite, in strawberry leaves heavily infested with.
Leaflets with larvae were placed in Petri dishes with the bottom covered with smooth plaster base, and kept humid until adults emerged.
Adult specimens (males and females) were identified by Dr. Raymond Gagné, as Feltiella curtistylus, first record for Argentina.
Due to prey specificity, this predatory gall midge has a potential for been considered in augmentative biological control strategies in strawberry
Assessing growth and antioxidant properties of greenhouse-grown lettuces (Lactuca sativa L.) under different irrigation and carbon fertilization management
Get PDFPrevious studies demonstrated that moderate water supply restrictions and enhanced CO2 concentration can maintain or improve yield and accumulation of secondary compounds in lettuce under greenhouse conditions. Therefore, the aim of this study was to evaluate the combination of reduced soil moisture content and carbon fertilization in shoot fresh weight (FW) and antioxidant capacity of two Batavia lettuce cultivars (Batabia Rubia Munguia; BRM and Maravilla de Verano; MV). Moderate water restriction treatment was equivalent to 2/3 of the field capacity and elevated CO2 concentration (ECO2) was fixed at ~700 µmol mol-1. While CO2 enrichment exerted a positive effect on shoot FW of MV, especially in combination with water restrictions, the yield of the cultivar BRM was not affected non due to CO2 concentration or irrigation regime. However, antioxidant capacity of BRM plants was increased under ECO2 conditions. These results demonstrate that carbon fertilization and/or moderate water limitations can be strategically used to enhance nutritional value and growth of greenhouse lettuce.
Highlights
Yield improvement and accumulation of antioxidants were evaluated in lettuce under greenhouse conditions.
Enhanced CO2 concentration and water restrictions increased shoot fresh weight of Maravilla de Verano lettuce.
Elevated CO2 conditions increased the antioxidant capacity of the cultivar Batavia Rubia Munguia.
Moderate water limitations did not significantly diminish the growth of lettuce.Previous studies demonstrated that moderate water supply restrictions and enhanced CO2 concentration can maintain or improve yield and accumulation of secondary compounds in lettuce under greenhouse conditions. Therefore, the aim of this study was to evaluate the combination of reduced soil moisture content and carbon fertilization in shoot fresh weight (FW) and antioxidant capacity of two Batavia lettuce cultivars (Batabia Rubia Munguia; BRM and Maravilla de Verano; MV). Moderate water restriction treatment was equivalent to 2/3 of the field capacity and elevated CO2 concentration (ECO2) was fixed at ~700 µmol mol-1. While CO2 enrichment exerted a positive effect on shoot FW of MV, especially in combination with water restrictions, the yield of the cultivar BRM was not affected non due to CO2 concentration or irrigation regime. However, antioxidant capacity of BRM plants was increased under ECO2 conditions. These results demonstrate that carbon fertilization and/or moderate water limitations can be strategically used to enhance nutritional value and growth of greenhouse lettuce.
Highlights
Yield improvement and accumulation of antioxidants were evaluated in lettuce under greenhouse conditions.
Enhanced CO2 concentration and water restrictions increased shoot fresh weight of Maravilla de Verano lettuce.
Elevated CO2 conditions increased the antioxidant capacity of the cultivar Batavia Rubia Munguia.
Moderate water limitations did not significantly diminish the growth of lettuce
A dynamic model for sodium intoxication unravels salt tolerance in grapevine (Vitis vinifera L.) rootstocks
Get PDFA correct selection of salt-tolerant plants should consider the relative effects of the various existing tolerance mechanisms. When toxic ions, like Na+, reach the leaves, they affect the photosynthetic apparatus, reducing plant growth and performance. Leaf concentration of toxic ions depends on exclusion efficiencies at root level, or compartmentation in organs other than leaves. On the other hand, flow within the plant depends on leaf area, transpiration rate, and soil ion concentrations. From this perspective, in a feedback process, leaf area may be, simultaneously, cause and consequence of salt toxicity. To unravel how this feedback process influences salinity damage in grapevines, a dynamic model of Na+ toxicity was developed. The theoretical model proposed a way to estimate plant exclusion and compartmentation efficiencies. Parametrization was based on a 60-days trial with potted cv. Malbec vines (Vitis vinifera L.), own-rooted and grafted onto 101-14Mgt, 1103P and Cereza, under three soil NaCl levels (0, 50 and 100 mM). The model simulated different grapevine rootstock responses to different salinity levels. These simulations evidenced the key role of Na+ exclusion in long-term tolerance. Stomatal adjustment, compartmentation and rootstock conferred vigor showed relatively minor effects.
Highlights:
When toxic ions, like Na+, reach the leaves, they affect plant growth and performance.
Leaf concentration of toxic ions depends on exclusion efficiencies at root level, or compartmentalization in organs other than leaves.
A theoretical and dynamic model of Na+ toxicity proposed a way to estimate plant exclusion and compartmentation efficiencies.
These simulations evidenced the key role of Na+ exclusion in long-term tolerance, while stomatal adjustment, compartmentation and rootstock conferred vigor, showed relatively minor effects.A correct selection of salt-tolerant plants should consider the relative effects of the various existing tolerance mechanisms. When toxic ions, like Na+, reach the leaves, they affect the photosynthetic apparatus, reducing plant growth and performance. Leaf concentration of toxic ions depends on exclusion efficiencies at root level, or compartmentation in organs other than leaves. On the other hand, flow within the plant depends on leaf area, transpiration rate, and soil ion concentrations. From this perspective, in a feedback process, leaf area may be, simultaneously, cause and consequence of salt toxicity. To unravel how this feedback process influences salinity damage in grapevines, a dynamic model of Na+ toxicity was developed. The theoretical model proposed a way to estimate plant exclusion and compartmentation efficiencies. Parametrization was based on a 60-days trial with potted cv. Malbec vines (Vitis vinifera L.), own-rooted and grafted onto 101-14Mgt, 1103P and Cereza, under three soil NaCl levels (0, 50 and 100 mM). The model simulated different grapevine rootstock responses to different salinity levels. These simulations evidenced the key role of Na+ exclusion in long-term tolerance. Stomatal adjustment, compartmentation and rootstock conferred vigor showed relatively minor effects.
Highlights:
When toxic ions, like Na+, reach the leaves, they affect plant growth and performance.
Leaf concentration of toxic ions depends on exclusion efficiencies at root level, or compartmentalization in organs other than leaves.
A theoretical and dynamic model of Na+ toxicity proposed a way to estimate plant exclusion and compartmentation efficiencies.
These simulations evidenced the key role of Na+ exclusion in long-term tolerance, while stomatal adjustment, compartmentation and rootstock conferred vigor, showed relatively minor effects
Storing soybeans (Glycine max) in silo bags: economic outcomes and grain loss risk
Get PDFSilo bags have the potential to increase grain marketing efficiency and to give farmers additional bargaining power. However, silo bags are prone to tearing that can cause grain losses. This article assesses the economic outcomes of storing soybeans in silo bags, as compared to grain commercial storage facilities, considering the risk of grain losses. A bio-economic model of soybean storage is developed and calibrated for Southeastern Argentina. The soybean loss modelling is based on empirical measurements of silo bag losses. Results indicate that both silo bag and grain storage facility profits break-even, with 2% soybean losses. When soybean losses range between 0% and 5%, optimal storage time varies from 8.5 to 9.6 months, respectively. Results show that silo bag storage may not be optimal with 10% losses, and that a 3% price premium can compensate losses of up to 5%. Silo bags constitute a feasible storage alternative that can provided more flexibility to argentine agro industrial system in situations of limited storage capacity or of logistic problems.
Highlights
Silo bags have the potential to increase grain marketing efficiency, provide farmers with additional bargaining power and improve their economic results.
Silo bags are prone to tearing that can cause grain losses.
A bio-economic model of soybean storage is developed and calibrated for Southeastern Argentina.
Silo bag and storage facility profits break-even with 2% soybean losses, and a price premium of 3% can compensate losses of up to 5%.
Silo bags constitute a feasible storage alternative in situations of limited storage capacity or of logistic problems.Silo bags have the potential to increase grain marketing efficiency and to give farmers additional bargaining power. However, silo bags are prone to tearing that can cause grain losses. This article assesses the economic outcomes of storing soybeans in silo bags, as compared to grain commercial storage facilities, considering the risk of grain losses. A bio-economic model of soybean storage is developed and calibrated for Southeastern Argentina. The soybean loss modelling is based on empirical measurements of silo bag losses. Results indicate that both silo bag and grain storage facility profits break-even, with 2% soybean losses. When soybean losses range between 0% and 5%, optimal storage time varies from 8.5 to 9.6 months, respectively. Results show that silo bag storage may not be optimal with 10% losses, and that a 3% price premium can compensate losses of up to 5%. Silo bags constitute a feasible storage alternative that can provided more flexibility to argentine agro industrial system in situations of limited storage capacity or of logistic problems.
Highlights
Silo bags have the potential to increase grain marketing efficiency, provide farmers with additional bargaining power and improve their economic results.
Silo bags are prone to tearing that can cause grain losses.
A bio-economic model of soybean storage is developed and calibrated for Southeastern Argentina.
Silo bag and storage facility profits break-even with 2% soybean losses, and a price premium of 3% can compensate losses of up to 5%.
Silo bags constitute a feasible storage alternative in situations of limited storage capacity or of logistic problems
Yacon (Smallanthus sonchifolius), propagation from rhizophores with different numbers of buds
Get PDFYacon (Smallanthus sonchifolius) is a plant of Andean origin currently cultivated and consumed in several parts of the world for having numerous nutraceutical properties. An increasing interest in its cultivation demands advanced technical information on this crop, still scarce. Considering this, our study aimed to evaluate the propagation of yacon by rhizophores with different bud number. The experiment was conducted in two phases: the first phase was developed in a seedling nursery, using a completely randomized design with four treatments and 50 repetitions. The treatments consisted of rhizophores with: one to two buds (T1), three to four buds (T2), five to six buds (T3), and seven to eight buds (T4). The second phase was performed in the field with random blocks, four treatments, four repetitions, and the same treatments of the first phase. The following morphological and growth characteristics were assessed: plant height, stem diameter, number of leaves, number of stems per plant, Dickson quality index (DQI), leaf area, leaf dry mass, rhizophores, tuberous root, and productivity. The following physiological features were also analyzed: chlorophyll content (FCI – Falker chlorophyll index), net carbon assimilation rate, leaf transpiration, stomatal conductance, internal carbon concentration, water use efficiency and instantaneous carboxylation efficiency. Seedlings from rhizophores with three to four buds presented the best morphological and growth characteristics, DQI = 0.47 and good performance in the field. In addition, the plants originated from this material (rhizophores with three to four buds) showed greater accumulation of dry matter in the aerial part and tuberous roots, and consequently higher productivity in fresh tuberous roots, constituiting a suitable propagation form for the cultivation of yacon.
Highlights:
Seedlings from rhizophores with three to four buds presented the best morphological and growth characteristics.
The results indicate differences in photosynthetic capacity among seedlings.
Possibility of estimating the CO2 assimilation in yacon plants through chlorophyll contents, determined by "ClorofiLOG" (model FL1030, Falker), a device that has lower cost and simple handling than other photosynthesis analyzers, like IRGA Licor 6400XT, representing a significant methodological contribution.
Study shows that the number of buds in the yacon propagule (rhizophores) has a direct influence, from seedling phase to final production and that their weight should not be a factor for selection.Yacon (Smallanthus sonchifolius) is a plant of Andean origin currently cultivated and consumed in several parts of the world for having numerous nutraceutical properties. An increasing interest in its cultivation demands advanced technical information on this crop, still scarce. Considering this, our study aimed to evaluate the propagation of yacon by rhizophores with different bud number. The experiment was conducted in two phases: the first phase was developed in a seedling nursery, using a completely randomized design with four treatments and 50 repetitions. The treatments consisted of rhizophores with: one to two buds (T1), three to four buds (T2), five to six buds (T3), and seven to eight buds (T4). The second phase was performed in the field with random blocks, four treatments, four repetitions, and the same treatments of the first phase. The following morphological and growth characteristics were assessed: plant height, stem diameter, number of leaves, number of stems per plant, Dickson quality index (DQI), leaf area, leaf dry mass, rhizophores, tuberous root, and productivity. The following physiological features were also analyzed: chlorophyll content (FCI – Falker chlorophyll index), net carbon assimilation rate, leaf transpiration, stomatal conductance, internal carbon concentration, water use efficiency and instantaneous carboxylation efficiency. Seedlings from rhizophores with three to four buds presented the best morphological and growth characteristics, DQI = 0.47 and good performance in the field. In addition, the plants originated from this material (rhizophores with three to four buds) showed greater accumulation of dry matter in the aerial part and tuberous roots, and consequently higher productivity in fresh tuberous roots, constituiting a suitable propagation form for the cultivation of yacon.
Highlights:
Seedlings from rhizophores with three to four buds presented the best morphological and growth characteristics.
The results indicate differences in photosynthetic capacity among seedlings.
Possibility of estimating the CO2 assimilation in yacon plants through chlorophyll contents, determined by "ClorofiLOG" (model FL1030, Falker), a device that has lower cost and simple handling than other photosynthesis analyzers, like IRGA Licor 6400XT, representing a significant methodological contribution.
Study shows that the number of buds in the yacon propagule (rhizophores) has a direct influence, from seedling phase to final production and that their weight should not be a factor for selection
Selection of soybean F3 populations for agronomic and physiological traits and vegetation indices using multivariate approaches
Get PDFThe objective of this work was to select F3 segregating populations for agronomic and physiological traits and vegetation indices. The experiment was carried out in the 2018/2019 crop seasons in a randomized block design with three replicates and 10 F3 populations (P1, P2, P3, P4, P5, P6, P7, P8, P9, and P10). The evaluated traits were: number of days to maturity; number of pods per plant; number of nodes per plant; number of lateral stems per plant; grain yield, photosynthesis; stomatal conductance; internal CO2 concentration; transpiration; NIR, Red-edge, Red and Green wavelength; and NDVI and NDRE vegetation indices. In the physiological traits evaluated in soybean F3 populations, the P8 and P6 populations presented the highest averages for photosynthesis, while the P3, P10 and P9 populations presented the highest concentration values, CO2 (Ci), transpiration (E,) and stomatal conductance (gs). Therefore, the vegetation indices evaluated in soybean F3 populations, the populations P7, P2 and P1 presented higher averages for near and red infrared wavelengths. P5 and P4 showed a higher NDRE vegetation index and P8 showed a higher red wavelength. For agronomic traits, population P2 showed better results for the traits number of nodes per plant (NNP) and the number of lateral stems per plant (NHL). Populations P1 and P3 had a higher number of days for physiological maturation (NDM). The P7 population presented the highest number of pods per plant (NVP), and the P6 population the highest grain yield (PROD).
Highlights
Soybean F3 populations were selected for agronomic and physiological traits and vegetation indices.
Principal components were used to select these populations.
Factor analysis allowed us to understand the relationship between the traits evaluated.The objective of this work was to select F3 segregating populations for agronomic and physiological traits and vegetation indices. The experiment was carried out in the 2018/2019 crop seasons in a randomized block design with three replicates and 10 F3 populations (P1, P2, P3, P4, P5, P6, P7, P8, P9, and P10). The evaluated traits were: number of days to maturity; number of pods per plant; number of nodes per plant; number of lateral stems per plant; grain yield, photosynthesis; stomatal conductance; internal CO2 concentration; transpiration; NIR, Red-edge, Red and Green wavelength; and NDVI and NDRE vegetation indices. In the physiological traits evaluated in soybean F3 populations, the P8 and P6 populations presented the highest averages for photosynthesis, while the P3, P10 and P9 populations presented the highest concentration values, CO2 (Ci), transpiration (E,) and stomatal conductance (gs). Therefore, the vegetation indices evaluated in soybean F3 populations, the populations P7, P2 and P1 presented higher averages for near and red infrared wavelengths. P5 and P4 showed a higher NDRE vegetation index and P8 showed a higher red wavelength. For agronomic traits, population P2 showed better results for the traits number of nodes per plant (NNP) and the number of lateral stems per plant (NHL). Populations P1 and P3 had a higher number of days for physiological maturation (NDM). The P7 population presented the highest number of pods per plant (NVP), and the P6 population the highest grain yield (PROD).
Highlights
Soybean F3 populations were selected for agronomic and physiological traits and vegetation indices;
Principal components were used to select these populations;
Factor analysis allowed us to understand the relationship between the traits evaluated
Diversity and conservational status of vascular plants of "Sierra de las Quijadas" National Park (San Luis, Argentina)
Get PDFThe "Sierra de las Quijadas" National Park, located in the NW of San Luis province, covers 150,252 hectares and preserves a sample of the Chaco-Monte ecotone, with communities of the "Dry Chaco", and "Monte" ecoregions (partly "Monte of plains and plateaus" and partly "Monte of Sierras and bolsons"). It includes mixed forests, shrubby steppes, groves and galleries, rings of halophytes, "pajonales" and rushes. Our goals were to inventory and analyze the vascular flora as well as to identify the endemisms that require greater protection. We recorded 356 species distributed in 208 genera of 58 plant families. Eight taxa are new records for the native vascular flora of the province of San Luis. While 120 taxa are endemic to Argentina, four species turned out to be exclusive of the Park and surroundings: Atriplex quixadensis (Chenopodiaceae), Senecio hualtaranensis (Asteraceae), Sclerophylax difulvioi (Solanaceae) and Gomphrena colosacana var. andersonii (Amaranthaceae). These taxa suffer varying degrees of threat from population restriction, intense erosion and anthropic action: 3 are critically endangered (CR), other 3 are endangered (EN), 10 are vulnerable (VU), 25 near threatened (NT) and 79 cause minor concern (LC), requiring in many cases immediate and continued protection. Dicotyledons (74%) and Monocotyledons (25%) predominate, plus 2 Monilophyta species and 3 Gymnospermae. The six best represented families are Poaceae, Asteraceae, Fabaceae, Solanaceae, Verbenaceae and Bromeliaceae, which account for 56% of the species. Phanerophytes and Hemicryptophytes life-forms reach 24% each, followed by Chamaephytes (22%) and Therophytes (16%). This reveals a remarkable adaptation of the flora to the long dry season.
Highlights
A first check-list of the vascular flora of the Sierra de las Quijadas National Park is presented, in the ecotone Dry Chaco and Monte, one of the most arid places in Argentina.
The Park preserves 356 species and 99 infraspecific taxa (3.6% of the Argentinean flora). Eight of them are new records for the province of San Luis.
Stand out 4 species that are unique to the Park, of which 3 are critically endangered (CR) and the remaining one is vulnerable (VU).
Another 116 species are endemic to Argentina, including 3 endangered (EN), 9 vulnerable (VU), and 25 almost threatened (NT) with extinction.
The prevalence of chamaephytes, hemicryptophytes, cryptophytes and therophytes (70%) reveal the high degree of adaptation to the prolonged dry season.The "Sierra de las Quijadas" National Park, located in the NW of San Luis province, covers 150,252 hectares and preserves a sample of the Chaco-Monte ecotone, with communities of the "Dry Chaco", and "Monte" ecoregions (partly "Monte of plains and plateaus" and partly "Monte of Sierras and bolsons"). It includes mixed forests, shrubby steppes, groves and galleries, rings of halophytes, "pajonales" and rushes. Our goals were to inventory and analyze the vascular flora as well as to identify the endemisms that require greater protection. We recorded 356 species distributed in 208 genera of 58 plant families. Eight taxa are new records for the native vascular flora of the province of San Luis. While 120 taxa are endemic to Argentina, four species turned out to be exclusive of the Park and surroundings: Atriplex quixadensis (Chenopodiaceae), Senecio hualtaranensis (Asteraceae), Sclerophylax difulvioi (Solanaceae) and Gomphrena colosacana var. andersonii (Amaranthaceae). These taxa suffer varying degrees of threat from population restriction, intense erosion and anthropic action: 3 are critically endangered (CR), other 3 are endangered (EN), 10 are vulnerable (VU), 25 near threatened (NT) and 79 cause minor concern (LC), requiring in many cases immediate and continued protection. Dicotyledons (74%) and Monocotyledons (25%) predominate, plus 2 Monilophyta species and 3 Gymnospermae. The six best represented families are Poaceae, Asteraceae, Fabaceae, Solanaceae, Verbenaceae and Bromeliaceae, which account for 56% of the species. Phanerophytes and Hemicryptophytes life-forms reach 24% each, followed by Chamaephytes (22%) and Therophytes (16%). This reveals a remarkable adaptation of the flora to the long dry season.
Highlights
A first check-list of the vascular flora of the Sierra de las Quijadas National Park is presented, in the ecotone Dry Chaco and Monte, one of the most arid places in Argentina.
The Park preserves 356 species and 99 infraspecific taxa (3.6% of the Argentinean flora). Eight of them are new records for the province of San Luis.
Stand out 4 species that are unique to the Park, of which 3 are critically endangered (CR) and the remaining one is vulnerable (VU).
Another 116 species are endemic to Argentina, including 3 endangered (EN), 9 vulnerable (VU), and 25 almost threatened (NT) with extinction.
The prevalence of chamaephytes, hemicryptophytes, cryptophytes and therophytes (70%) reveal the high degree of adaptation to the prolonged dry season
SSR markers linked to stem canker resistance in soybean Glycine max
Get PDFIn this work, we studied 40 samples of Diaporthe phaseolorum var. meridionalis (Dpm), causal agent of stem canker in soybeans (SCS). In the susceptible genotype Golondrina65 the isolate RSF12 showed the highest percentage of the dead plant index (DP = 85.7 %) and was used to characterize all known sources of resistance to Dpm. The soybean MJ19RR experimental line showed the best behaviour against this isolate with a DP = 2.4 % and was used to develop a segregating population with the susceptible cultivar FT-2001. In the F2 generation, the chi-square test determined a 3:1 ratio of resistant plants against susceptible plants, as expected for a dominant gene. In order to advance in our study we propose, as objective, to locate in the soybean genetic map the resistance to Diaporthe phaseolorum var. meridionalis. The Bulked Segregant Analyses and the genetic linkage study identified a region of chromosome 6 of the genetic map of soybean, located at 13.3 cM from the Satt433 locus associated with resistance to SCS. The soybean experimental line MJ19RR was selected as the best source of resistance, and it is available in the active bank of soybean germplasm of INTA, for the genetic control of this disease. The results obtained in this work represent a first approximation for the understanding of the genetic basis of resistance to SCS.
Highlights
The PCR sensitivity is a good strategy for detecting markers linkage using bulk segregant analysis.
The MJ19RR soybean genotype is a new promising source of resistance to soybean stem canker.
A single gene determined the genetic resistance to soybean stem canker.In this work, we studied 40 samples of Diaporthe phaseolorum var. meridionalis (Dpm), causal agent of stem canker in soybeans (SCS). In the susceptible genotype Golondrina65 the isolate RSF12 showed the highest percentage of the dead plant index (DP = 85.7 %) and was used to characterize all known sources of resistance to Dpm. The soybean MJ19RR experimental line showed the best behaviour against this isolate with a DP = 2.4 % and was used to develop a segregating population with the susceptible cultivar FT-2001. In the F2 generation, the chi-square test determined a 3:1 ratio of resistant plants against susceptible plants, as expected for a dominant gene. In order to advance in our study we propose, as objective, to locate in the soybean genetic map the resistance to Diaporthe phaseolorum var. meridionalis. The Bulked Segregant Analyses and the genetic linkage study identified a region of chromosome 6 of the genetic map of soybean, located at 13.3 cM from the Satt433 locus associated with resistance to SCS. The soybean experimental line MJ19RR was selected as the best source of resistance, and it is available in the active bank of soybean germplasm of INTA, for the genetic control of this disease. The results obtained in this work represent a first approximation for the understanding of the genetic basis of resistance to SCS.
Highlights
The PCR sensitivity is a good strategy for detecting markers linkage using bulk segregant analysis.
The MJ19RR soybean genotype is a new promising source of resistance to soybean stem canker.
A single gene determined the genetic resistance to soybean stem canker
Soil compaction caused by the impact of machinery traffic during corn (Zea mays) harvest
Get PDFThe aim of this work was to study soil compaction caused by the traffic of two types of combine harvesters and a tractor plus a grain cart with two loading conditions (fully loaded hoppers-empty hoppers) during corn harvest on vertic argiudoll soil by means of direct seeding system. Soil penetration resistance (PR) and soil bulk density (BD) were measured to a depth of 40 cm in five sampling sites. Response variables deter-minations were also analyzed. The tractor and the fully loaded grain cart traffic caused greater soil compaction in all the sampling depths, exceeding 60 cm on both sides of the footprint center. What is more, the values obtained from PR and BD measurements were higher than those values considered suitable for normal root growth. This was only evident in the tread width of the tires during the passing of the two fully loaded combine harvesters. The analysis of inflation pressures and tire loads used, indicated in some cases, poor concordance between these variables. The analysis also indicated that the tires were inflated to the limit of resistance.
Highlights
According to the results obtained, it is convenient to develop a controlled traffic farming strategy for harvesting.
Some machines have tires that do not withstand the demands.
The repeated passes of machinery caused more compaction than the mass involved.The aim of this work was to study soil compaction caused by the traffic of two types of combine harvesters and a tractor plus a grain cart with two loading conditions (fully loaded hoppers-empty hoppers) during corn harvest on vertic argiudoll soil by means of direct seeding system. Soil penetration resistance (PR) and soil bulk density (BD) were measured to a depth of 40 cm in five sampling sites. Response variables deter-minations were also analyzed. The tractor and the fully loaded grain cart traffic caused greater soil compaction in all the sampling depths, exceeding 60 cm on both sides of the footprint center. What is more, the values obtained from PR and BD measurements were higher than those values considered suitable for normal root growth. This was only evident in the tread width of the tires during the passing of the two fully loaded combine harvesters. The analysis of inflation pressures and tire loads used, indicated in some cases, poor concordance between these variables. The analysis also indicated that the tires were inflated to the limit of resistance.
Highlights
According to the results obtained, it is convenient to develop a controlled traffic farming strategy for harvesting.
Some machines have tires that do not withstand the demands.
The repeated passes of machinery caused more compaction than the mass involved