Revista de la Facultad de Ciencias Agrarias
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Grain quality of common bean (Phaseolus vulgaris L.) cultivars under low and high nitrogen dose
Get PDFThis study aimed to evaluate the effects of low and high topdressing doses of nitrogen (N) on the qualitative attributes of common beans (Phaseolus vulgaris L.) cultivars and indicate cultivars with better grain technological characteristics. The experimental design was randomized blocks in split plots, with four replicates. Plots comprised 16 common bean cultivars of the commercial grain ‘Carioca’, while subplots comprised two N doses: 20 and 120 kg ha-1 applied as topdressing. The following evaluations were carried out: sieve yield (SY), relative grain production on sieves (RGPS), crude protein content (PROT), final water volume absorbed (FVabs), time for maximum hydration (TMH), hydration ratio (HR), cooking time (CT) and resistance to cooking (RC). The results were subjected to analysis of variance by F test and means were grouped by the Scott-Knott test. Multivariate principal component analysis was used to identify processes. The grain quality of common bean is more dependent on the genotype studied than on agricultural management such as nitrogen fertilization. The increase in the N dose applied as topdressing increases the size of common bean grains and their protein content, but with little influence in grain hydration. FVabs and CT depend on the interaction between cultivar and N doses. CT had an inverse correlation with PROT, but it was little pronounced. The cultivars BRSMG Uai, IAC Alvorada, TAA Dama and TAA Bola Cheia have the best grain quality characteristics.
Highlights:
Cultivar interferes more in the common bean technological quality than nitrogen fertilization.
Grains crude protein content had an inverse correlation with the cooking time.
Nitrogen fertilization increases the grains size and crude protein content of common bean, but with little influence in grain hydration.
The cultivars BRSMG Uai, IAC Alvorada, TAA Dama and TAA Bola Cheia have the best grain quality characteristics.This study aimed to evaluate the effects of low and high topdressing doses of nitrogen (N) on the qualitative attributes of common beans (Phaseolus vulgaris L.) cultivars and indicate cultivars with better grain technological characteristics. The experimental design was randomized blocks in split plots, with four replicates. Plots comprised 16 common bean cultivars of the commercial grain ‘Carioca’, while subplots comprised two N doses: 20 and 120 kg ha-1 applied as topdressing. The following evaluations were carried out: sieve yield (SY), relative grain production on sieves (RGPS), crude protein content (PROT), final water volume absorbed (FVabs), time for maximum hydration (TMH), hydration ratio (HR), cooking time (CT) and resistance to cooking (RC). The results were subjected to analysis of variance by F test and means were grouped by the Scott-Knott test. Multivariate principal component analysis was used to identify processes. Grain quality of common bean resulted to be more dependent on the genotype studied than on the agricultural management, such as nitrogen fertilization. Increasing N dose applied as topdressing increased grain size and protein content, but had little influence on grain hydration. FVabs and CT depended on the interaction between cultivar and N doses. Although low value, CT had an inverse correlation with PROT. The cultivars BRSMG Uai, IAC Alvorada, TAA Dama and TAA Bola Cheia showed the best grain quality characteristics.
Highlights:
Cultivar interferes more in the common bean technological quality than nitrogen fertilization.
Grains crude protein content had an inverse correlation with the cooking time.
Nitrogen fertilization increases the grains size and crude protein content of common bean, but with little influence in grain hydration.
The cultivars BRSMG Uai, IAC Alvorada, TAA Dama and TAA Bola Cheia have the best grain quality characteristics
Crop coefficient estimated by degree-days for ‘Marandu’ palisadegrass and mixed forage
Get PDFConsidering profitability in pasture-based systems, investigating parameters affecting crop coefficients for irrigation management becomes important. In this experiment, we determined the crop coefficient of ‘Marandu’ palisadegrass based on accumulated degree-days and estimated plant water consumption under single (‘Marandu’ alisadegrass) and mixed (‘Marandu’ palisadegrass + black oats + Italian ryegrass) cropping regimes. The research was conducted at the Luiz de Queiroz College of Agriculture in Piracicaba, São Paulo, Brazil, between 2016 and 2017. Evapotranspiration was assessed using weighing lysimeters while crop evapotranspiration was calculated using mean weight variation. Reference evapotranspiration and degree-days were estimated. Data were obtained from an automated weather station. Equations and regression models relating crop coefficient with accumulated degree-days were generated for two seasons (spring/summer and autumn/winter) and evaluated for two year-cycles, from 2015 to 2018. The results showed better prediction accuracy for the single cropping system in spring/summer 2017–18.
Highlights
The model for determinating crop coefficient (Kc) by accumulated degree-days showed efficient for use in determination local.
The use of the degree days for determination Kc is more vantage because only necessary to measure the air temperature (maximum and minimum).
The equations for determining crop coefficient by accumulated degree days for the spring/summer season in Marandu palisade grass cultive show more precision that in mixture forage system.Considering profitability in pasture-based systems, investigating parameters affecting crop coefficients for irrigation management becomes important. In this experiment, we determined the crop coefficient of ‘Marandu’ palisadegrass based on accumulated degree-days and estimated plant water consumption under single (‘Marandu’ alisadegrass) and mixed (‘Marandu’ palisadegrass + black oats + Italian ryegrass) cropping regimes. The research was conducted at the Luiz de Queiroz College of Agriculture in Piracicaba, São Paulo, Brazil, between 2016 and 2017. Evapotranspiration was assessed using weighing lysimeters while crop evapotranspiration was calculated using mean weight variation. Reference evapotranspiration and degree-days were estimated. Data were obtained from an automated weather station. Equations and regression models relating crop coefficient with accumulated degree-days were generated for two seasons (spring/summer and autumn/winter) and evaluated for two year-cycles, from 2015 to 2018. The results showed better prediction accuracy for the single cropping system in spring/summer 2017–18.
Highlights
The model for determinating crop coefficient (Kc) by accumulated degree-days showed efficient for use in determination local.
The use of the degree days for determination Kc is more vantage because only necessary to measure the air temperature (maximum and minimum).
The equations for determining crop coefficient by accumulated degree days for the spring/summer season in Marandu palisade grass cultive show more precision that in mixture forage system
The effect of residual nitrogen fertilization on the yield components, forage quality, and performance of beef cattle fed on Mombaça grass
Get PDFThe objective of this study was to evaluate the effect of residual nitrogen (N) on pastures of Mombaça grass and its impact on pasture structure and the nutritive value and performance of beef cattle. The experiment analyzed randomized blocks subdivided into plots, with three replications. The research focused on a number of pastures having received three annual doses of N (100, 200 and 300 kg ha-1) from 2015 to 2017, with no N fertilization in 2018. The results indicated that pastures under residual effect of 300 kg ha-1 of N were characterized by higher (P<0.05) rates of forage accumulation than those under the residual effect of 100 kg ha-1 N. Furthermore, this study indicated no effect (P>0.05) on the pasture nutritive value and average daily gain (0.490 kg day-1). The stocking rate was higher (P<0.05) in pastures under the residual effect of 300 kg ha-1 of N, and lower in those at 100 kg ha-1 of N, while weight gain per area followed the trend observed in the stocking rate. The results thus suggest that the suspension of N fertilization for one year after three years of sequential fertilization was responsible for an immediate loss of 50 and 55% of the productivity of plants and animals, respectively.
Highlights:
Fundamental nitrogen fertilization to ensure pasture productivity.
The use of nitrogen fertilization has been limited by cost, due to the extension of the areas involved and the need for frequent applications.
We suspended nitrogen fertilization for one year after using the same doses of nitrogen for three years in order to evaluate a possible residual effect on plant and animal production.
Suspending the N fertilization of Mombaça grass for one year after three years of sequential fertilization with the same doses leaves a residual effect on the pasture structure and performance of beef cattle.
The suspension of nitrogen fertilization reduces the rate of forage accumulation by an average of 50%, causing a 55% reduction in animal productivity.The objective of this study was to evaluate the effect of residual nitrogen (N) on pastures of Mombaça grass and its impact on pasture structure and the nutritive value and performance of beef cattle. The experiment analyzed randomized blocks subdivided into plots, with three replications. The research focused on a number of pastures having received three annual doses of N (100, 200 and 300 kg ha-1) from 2015 to 2017, with no N fertilization in 2018. The results indicated that pastures under residual effect of 300 kg ha-1 of N were characterized by higher (P<0.05) rates of forage accumulation than those under the residual effect of 100 kg ha-1 N. Furthermore, this study indicated no effect (P>0.05) on the pasture nutritive value and average daily gain (0.490 kg day-1). The stocking rate was higher (P<0.05) in pastures under the residual effect of 300 kg ha-1 of N, and lower in those at 100 kg ha-1 of N, while weight gain per area followed the trend observed in the stocking rate. The results thus suggest that the suspension of N fertilization for one year after three years of sequential fertilization was responsible for an immediate loss of 50 and 55% of the productivity of plants and animals, respectively.
Highlights:
Fundamental nitrogen fertilization to ensure pasture productivity.
The use of nitrogen fertilization has been limited by cost, due to the extension of the areas involved and the need for frequent applications.
We suspended nitrogen fertilization for one year after using the same doses of nitrogen for three years in order to evaluate a possible residual effect on plant and animal production.
Suspending the N fertilization of Mombaça grass for one year after three years of sequential fertilization with the same doses leaves a residual effect on the pasture structure and performance of beef cattle.
The suspension of nitrogen fertilization reduces the rate of forage accumulation by an average of 50%, causing a 55% reduction in animal productivity
Effect of urea on gas and effluent losses, microbial populations, aerobic stability and chemical composition of corn (Zea mays L.) silage
Get PDFWe evaluated the effects of urea addition on gas and effluent losses, fermentation profile, microbial populations, aerobic stability and chemical composition of corn silages. A completely randomised design with five levels of urea (0, 0.5, 1.0, 1.5, and 2.0% based on dry matter) and five replicates was used. A decreasing linear effect of urea levels on effluent losses in corn silages was observed. In parallel, an increasing linear effect of urea levels on pH, increasing from 3.49 to 4.12 in silages without urea in relation to silages with the maximum urea level, was also observed. Urea addition improved the aerobic stability of the silages, with 62 h for the silages without urea and from 90 to >96 h for the silages with urea. Based on the results of the principal components, two groups (I and II) could be distinguished. The most discriminating variables in group I were dry matter (-0.9), pH (-1.2) and lactic acid bacteria (-0.9), while in group II, effluent losses (1.0), ethanol (1.0), acetic acid (0.8) and gas losses (0.8) were most important. The use of urea at inclusion levels of around 2% in corn silage reduced gas losses, improved the nutritive value and promote the aerobic stability of silages.
Highlights:
The addition of urea in the corn silages increased the pH values from 3.49 (control) to 4.12 (2% of urea DM).
The use of urea improved chemical composition of corn silages.
The addition of urea reduced the moulds and yeast populations in the corn silages after exposure to air.
Urea addition improved the aerobic stability of the corn silages.We evaluated the effects of urea addition on gas and effluent losses, fermentation profile, microbial populations, aerobic stability and chemical composition of corn silages. A completely randomised design with five levels of urea (0, 0.5, 1.0, 1.5, and 2.0% based on dry matter) and five replicates was used. A decreasing linear effect of urea levels on effluent losses in corn silages was observed. In parallel, an increasing linear effect of urea levels on pH, increasing from 3.49 to 4.12 in silages without urea in relation to silages with the maximum urea level, was also observed. Urea addition improved the aerobic stability of the silages, with 62 h for the silages without urea and from 90 to >96 h for the silages with urea. Based on the results of the principal components, two groups (I and II) could be distinguished. The most discriminating variables in group I were dry matter (-0.9), pH (-1.2) and lactic acid bacteria (-0.9), while in group II, effluent losses (1.0), ethanol (1.0), acetic acid (0.8) and gas losses (0.8) were most important. The use of urea at inclusion levels of around 2% in corn silage reduced gas losses, improved the nutritive value and promote the aerobic stability of silages.
Highlights:
The addition of urea in the corn silages increased the pH values from 3.49 (control) to 4.12 (2% of urea DM).
The use of urea improved chemical composition of corn silages.
The addition of urea reduced the moulds and yeast populations in the corn silages after exposure to air.
Urea addition improved the aerobic stability of the corn silages
Tropicalization of canola: commercial hybrids show potential for cultivation in the Brazilian Cerrado
No full textCanola is a potential feedstock for the production of biodiesel due to its high levels of energy efficiency. However, Brazil has not yet consolidated its production as typical of temperate regions. Thus, the objective of the study was to evaluate the agronomic performance of canola hybrids in the tropical conditions of the Brazilian Cerrado in order to select promising candidates to contribute to the expansion of canola culture in the country. Eight commercial canola hybrids were evaluated for seven agronomic traits, in three experiments with varying water conditions. The data obtained for each variable were subjected to joint analysis of variance and the averages compared using the Scott-Knott test. The grain yield of the evaluated hybrids was higher than the national average, which includes plantations only in the southern region. The hybrids that stood out in grain yield were Hyola 61 and Hyola 76 followed by Diamond, which besides presenting a high magnitude for this characteristic, was less precocious even in dry conditions. Due to its characteristics, the Diamond hybrid can be considered the best option to be inserted in the crop rotation system. These results are promising and reveal adaptation and cultivation potential of these hybrids in the Brazilian Cerrado.
Highlights
The yield of canola grains in the experiments was promising as the values achieved were above the national average.
Hyola 61, Hyola 76 and Diamond showed prominent grain yield in relation to the other hybrids investigated.
Diamond presented high grain yield and shorter cycle, thus being considered the best option for the crop rotation system.
For the Brazilian Cerrado, the hybrids Hyola 61, Hyola 76 and Diamond are valuable alternatives for planting.Canola is a potential feedstock for the production of biodiesel due to its high levels of energy efficiency. However, Brazil has not yet consolidated its production as typical of temperate regions. Thus, the objective of the study was to evaluate the agronomic performance of canola hybrids in the tropical conditions of the Brazilian Cerrado in order to select promising candidates to contribute to the expansion of canola culture in the country. Eight commercial canola hybrids were evaluated for seven agronomic traits, in three experiments with varying water conditions. The data obtained for each variable were subjected to joint analysis of variance and the averages compared using the Scott-Knott test. The grain yield of the evaluated hybrids was higher than the national average, which includes plantations only in the southern region. The hybrids that stood out in grain yield were Hyola 61 and Hyola 76 followed by Diamond, which besides presenting a high magnitude for this characteristic, was less precocious even in dry conditions. Due to its characteristics, the Diamond hybrid can be considered the best option to be inserted in the crop rotation system. These results are promising and reveal adaptation and cultivation potential of these hybrids in the Brazilian Cerrado.
Highlights
The yield of canola grains in the experiments was promising as the values achieved were above the national average.
Hyola 61, Hyola 76 and Diamond showed prominent grain yield in relation to the other hybrids investigated.
Diamond presented high grain yield and shorter cycle, thus being considered the best option for the crop rotation system.
For the Brazilian Cerrado, the hybrids Hyola 61, Hyola 76 and Diamond are valuable alternatives for planting
Methodological proposal for the characterization of accessions in Germplasm Banks using Generalized Procrustes Analysis applied to incomplete but connected trials
Get PDFCharacterization of plant material conserved in germplasm banks allows the study and analysis of the genetic variability within a collection. When germplasm banks have a large number of accessions, field evaluation should be performed using assays with manageable accession subsets. Common checks connecting the different assays are required to compare these accession subsets. In this study, the Generalized Procrustes Analysis was proposed as a basis for obtaining a factorial plane where all individuals are projected. This technique is applied to genotypes common to all assays, iteratively generating scale factors and rotation matrices. Accessions only belonging to a given assay are considered supplementary elements. This proposal was illustrated using datasets of 54 maize accessions from the Pergamino Active Germplasm Bank of the Experimental Station at the Instituto Nacional de Tecnología Agropecuaria (INTA) in Argentina. The proposal achieved highly satisfactory results.
Highlights:
In field evaluation of large germplasm collections, the material must be divided into manageable experimental trials, in which different accession subsets are evaluated in different environments.
A new algorithm based on Generalized Procrustes Analysis (GPA) allowed to find the consensus of several configurations of individuals connected by common checks.
The characterization data analysis strategy was illustrated using a set of accessions from the Argentine Maize Germplasm Bank.
The new proposal stands as a useful tool for evaluate germplasm collections, providing good results with easy implementation and considering the multivariate structure of the data set.Characterization of plant material conserved in germplasm banks allows the study and analysis of the genetic variability within a collection. When germplasm banks have a large number of accessions, field evaluation should be performed using assays with manageable accession subsets. Common checks connecting the different assays are required to compare these accession subsets. In this study, the Generalized Procrustes Analysis was proposed as a basis for obtaining a factorial plane where all individuals are projected. This technique is applied to genotypes common to all assays, iteratively generating scale factors and rotation matrices. Accessions only belonging to a given assay are considered supplementary elements. This proposal was illustrated using datasets of 54 maize accessions from the Pergamino Active Germplasm Bank of the Experimental Station at the Instituto Nacional de Tecnología Agropecuaria (INTA) in Argentina. The proposal achieved highly satisfactory results.
Highlights:
In field evaluation of large germplasm collections, the material must be divided into manageable experimental trials, in which different accession subsets are evaluated in different environments.
A new algorithm based on Generalized Procrustes Analysis (GPA) allowed to find the consensus of several configurations of individuals connected by common checks.
The characterization data analysis strategy was illustrated using a set of accessions from the Argentine Maize Germplasm Bank.
The new proposal stands as a useful tool for evaluate germplasm collections, providing good results with easy implementation and considering the multivariate structure of the data set
Effect of plot size and plant spatial arrangement on the efficiency of family selection in sugarcane
Get PDFThe purpose of this study was to identify the ideal sample size representing a family in its potential, to identify superior families and, in parallel, determine in which spatial arrangement they may have a better accuracy in the selection of new varieties of sugarcane. For such purpose, five families of full-sibs were evaluated, each with 360 individuals, in the randomized blocks design, with three replications in three different spacing among plants in the row (50 cm, 75 cm, and 100 cm) and 150 cm between the rows. To determine the ideal sample size, as well as the better spacing for evaluation, the bootstrap method was adopted. It was observed that 100 cm spacings provided the best average for the stalk numbers, stalk diameter and for estimated weight of stalks in the stool. The spacing of 75 cm between the plants allowed a better power of discrimination among the families for all characters evaluated. At this 75 cm spacing was also possible to identify superior families with a sample of 30 plants each plot and 3 reps in the trial.
Highlights
The bootstrap method was efficient to determine the ideal sample size, as well as the best spacing for evaluation.
The 75-cm spacing had the highest power of discrimination among families, indicating that this spacing is the most efficient in evaluating sugarcane families for selection purposes.
From all the results and considering selective accuracy as the guiding parameter for decision making, the highest values obtained considering the number of stalks and weight of stalks in the stools were found at the 75-cm spacing.The purpose of this study was to identify the ideal sample size representing a family in its potential, to identify superior families and, in parallel, determine in which spatial arrangement they may have a better accuracy in the selection of new varieties of sugarcane. For such purpose, five families of full-sibs were evaluated, each with 360 individuals, in the randomized blocks design, with three replications in three different spacing among plants in the row (50 cm, 75 cm, and 100 cm) and 150 cm between the rows. To determine the ideal sample size, as well as the better spacing for evaluation, the bootstrap method was adopted. It was observed that 100 cm spacings provided the best average for the stalk numbers, stalk diameter and for estimated weight of stalks in the stool. The spacing of 75 cm between the plants allowed a better power of discrimination among the families for all characters evaluated. At this 75 cm spacing was also possible to identify superior families with a sample of 30 plants each plot and 3 reps in the trial.
Highlights
The bootstrap method was efficient to determine the ideal sample size, as well as the best spacing for evaluation.
The 75-cm spacing had the highest power of discrimination among families, indicating that this spacing is the most efficient in evaluating sugarcane families for selection purposes.
From all the results and considering selective accuracy as the guiding parameter for decision making, the highest values obtained considering the number of stalks and weight of stalks in the stools were found at the 75-cm spacing
Peanut yield under irrigation levels in off-season cultivation
Get PDFWater deficit is considered the most critical environmental factor for peanut production in Brazil, as it constitutes one of the major constraints to the expansion of its cultivation in the suitable crop zones of the country. Determining crop water demand is fundamental to increasing yield with lower water consumption. The present study aimed to evaluate the effects of full and deficit irrigation levels (L1 = 8%, L2 = 27%, L3 = 63%, L4 = 94% and L5 = 100% replenishment of crop evapotranspiration) on the development, growth and yield of peanut crop sown in two times, February and March. Treatments were distributed in a split-plot randomized complete block design, with four replicates, using a line-source sprinkler system. Irrigation depths from 65 to 314 mm were applied with the levels L1 to L5 during the first and second cropping cycles. Full irrigation with sowing in March was more advantageous due to yield increase of up to 30% compared to sowing in February, but crop cycle was 25 days longer. Water stress caused by deficit irrigation reduced plant height, seed mass and pod yield, while full irrigation (L5) led to yields from 4,141 to 5,102 kg ha-1 for February and March, approximately three times higher than those obtained with the lowest irrigation level (L1).
Highlights
Peanut has great importance in the food and industry of several countries.
The results of this research apply to regions that require irrigation, which is of about 70% of the areas of the globe with this legume.
This paper contributes with information that emphasizes the possibility of cultivation in the drought season, aiming at the expansion of the crop and the production of quality seeds using irrigation.Water deficit is considered the most critical environmental factor for peanut production in Brazil, as it constitutes one of the major constraints to the expansion of its cultivation in the suitable crop zones of the country. Determining crop water demand is fundamental to increasing yield with lower water consumption. The present study aimed to evaluate the effects of full and deficit irrigation levels (L1 = 8%, L2 = 27%, L3 = 63%, L4 = 94% and L5 = 100% replenishment of crop evapotranspiration) on the development, growth and yield of peanut crop sown in two times, February and March. Treatments were distributed in a split-plot randomized complete block design, with four replicates, using a line-source sprinkler system. Irrigation depths from 65 to 314 mm were applied with the levels L1 to L5 during the first and second cropping cycles. Full irrigation with sowing in March was more advantageous due to yield increase of up to 30% compared to sowing in February, but crop cycle was 25 days longer. Water stress caused by deficit irrigation reduced plant height, seed mass and pod yield, while full irrigation (L5) led to yields from 4,141 to 5,102 kg ha-1 for February and March, approximately three times higher than those obtained with the lowest irrigation level (L1).
Highlights
Peanut has great importance in the food and industry of several countries.
The results of this research apply to regions that require irrigation, which is of about 70% of the areas of the globe with this legume.
This paper contributes with information that emphasizes the possibility of cultivation in the drought season, aiming at the expansion of the crop and the production of quality seeds using irrigation
Forage production and leaf proportion of lucerne in subtropical environments: cultivar, cutting frequency and canopy effects: Forage production and nutritive value of lucerne in subtropical environments
No full textIn subtropical and humid environments the ‘winter-active’ cultivars of lucerne usually produce more forage with lower leaf proportion (i.e. leaf to stem ratio) than the ‘winter-dormant’ ones. Present research analyze (i) if differences in forage production changes with cutting frequency, and (ii) if differences in leaf proportion are intrinsic (i.e. ‘cultivar differences’) or are due to variations in plant morphology (i.e. ‘aerial biomass and canopy height’). In two subtropical locations a factorial experiment including three alfalfa cultivars (FD4= ‘winter-dormant’, FD6=‘semi-dormant’, FD9=‘winter-active’) and three cutting frequencies (‘high’, ‘intermediate’ and ‘low’) was established. As the cutting frequency decrease (i.e. from ‘high’ to ‘low’) the more winter-active cultivars were more productive than the more winter-dormant ones (FD9>FD6>FD4) due mainly to a higher stem production. However, differences between cultivars disappear (FD9=FD6=FD4) as the cutting frequency increases (i.e. from ‘low’ to ‘high’ cutting frequency). Compared at similar canopy height, differences between cultivars in leaf proportion were practically irrelevant. We confirm that (i) in subtropical and humid environments, the differences in forage production between cultivars contrasting in their winter activity depend of the cutting frequency, and that (ii) the leaf proportion depends mainly of plant morphology, especially canopy height’, being irrelevant the cultivar and the environment.
Highlights
This paper shows that (i) differences in forage production between cultivars of lucerne depend on the cutting frequency, and that (ii) leaf proportion is governed by plant morphology, especially canopy height.
Forage production was similar between cultivars at high cutting frequency but at low cutting frequency winter-active and semi-dormant cultivars (FD6 and FD9) produce more forage than winter dormant (FD4) ones.
Lucerne cultivars showing the same leaf proportion when they were compared at similar canopy height suggesting that leaf proportion is not an intrinsic trait
Changes in leaf proportion were better explained by changes in canopy height than by changes in thermal time.In subtropical and humid environments the ‘winter-active’ cultivars of lucerne usually produce more forage with lower leaf proportion (i.e. leaf to stem ratio) than the ‘winter-dormant’ ones. Present research analyze (i) if differences in forage production changes with cutting frequency, and (ii) if differences in leaf proportion are intrinsic (i.e. ‘cultivar differences’) or are due to variations in plant morphology (i.e. ‘aerial biomass and canopy height’). In two subtropical locations a factorial experiment including three alfalfa cultivars (FD4= ‘winter-dormant’, FD6=‘semi-dormant’, FD9=‘winter-active’) and three cutting frequencies (‘high’, ‘intermediate’ and ‘low’) was established. As the cutting frequency decrease (i.e. from ‘high’ to ‘low’) the more winter-active cultivars were more productive than the more winter-dormant ones (FD9>FD6>FD4) due mainly to a higher stem production. However, differences between cultivars disappear (FD9=FD6=FD4) as the cutting frequency increases (i.e. from ‘low’ to ‘high’ cutting frequency). Compared at similar canopy height, differences between cultivars in leaf proportion were practically irrelevant. We confirm that (i) in subtropical and humid environments, the differences in forage production between cultivars contrasting in their winter activity depend of the cutting frequency, and that (ii) the leaf proportion depends mainly of plant morphology, especially canopy height’, being irrelevant the cultivar and the environment.
Highlights
This paper shows that (i) differences in forage production between cultivars of lucerne depend on the cutting frequency, and that (ii) leaf proportion is governed by plant morphology, especially canopy height.
Forage production was similar between cultivars at high cutting frequency but at low cutting frequency winter-active and semi-dormant cultivars (FD6 and FD9) produce more forage than winter dormant (FD4) ones.
Lucerne cultivars showing the same leaf proportion when they were compared at similar canopy height suggesting that leaf proportion is not an intrinsic trait
Changes in leaf proportion were better explained by changes in canopy height than by changes in thermal time
Root-shoot growth and time to transplant of different lettuce genotypes during nursery
No full textAlthough vegetable nursery growers decide on plug sizes based on the types, production time and schedule of the crops to grow, they usually choose individual small cell sizes because these allow short plant-raising periods and reduced costs. However, larger plugs produce a finished plant after transplant in a shorter period of time than smaller plugs. Nursery growers end the propagation period when roots take up the plug cell and plantlets can be removed from the plug tray without damage. Thus, this study aimed to investigate the effect of three plug-cell sizes and a single BAP application (100 mg L-1) on the shoot and root growth and time to transplant of different lettuce genotypes. Nursery decreased as plug cell volume increased and with the single BAP spray. A novelty result was that the transplant dates were assigned when the marginal root dry weight accumulation decreased, i.e., based on objective rather than on subjective observations. The significant leaf area and dry weight accumulation found could be explained by growth parameters such as the rate of leaf appearance, the relative rate of leaf area expansion, the relative growth rate, the net assimilation rate and the partition coefficient from root: shoot allometries.
Highlights
Root restriction due to small plugs in transplant trays delay lettuce transplant.
Exogenous cytokinin (BAP) overcame root restriction and decreased time to transplant.
Time to transplant can be addressed on an objective basis: it were assigned when the marginal root dry weight accumulation decreased.Although vegetable nursery growers decide on plug sizes based on the types, production time and schedule of the crops to grow, they usually choose individual small cell sizes because these allow short plant-raising periods and reduced costs. However, larger plugs produce a finished plant after transplant in a shorter period of time than smaller plugs. Nursery growers end the propagation period when roots take up the plug cell and plantlets can be removed from the plug tray without damage. Thus, this study aimed to investigate the effect of three plug-cell sizes and a single BAP application (100 mg L-1) on the shoot and root growth and time to transplant of different lettuce genotypes. Nursery decreased as plug cell volume increased and with the single BAP spray. A novelty result was that the transplant dates were assigned when the marginal root dry weight accumulation decreased, i.e., based on objective rather than on subjective observations. The significant leaf area and dry weight accumulation found could be explained by growth parameters such as the rate of leaf appearance, the relative rate of leaf area expansion, the relative growth rate, the net assimilation rate and the partition coefficient from root: shoot allometries.
Highlights
Root restriction due to small plugs in transplant trays delay lettuce transplant.
Exogenous cytokinin (BAP) overcame root restriction and decreased time to transplant.
Time to transplant can be addressed on an objective basis: it were assigned when the marginal root dry weight accumulation decreased