Agronomic Variables Research Articles

Investigating the Effect of Farm Management, Soil, and Climate on Hop Diastatic Potential

To investigate potential sources for field-to-field variation in hop diastatic power, three varieties of hops (Mosaic®, Simcoe®, and Strata®) from harvest year 2019 were collected from different fields managed by a single hop grower throughout the hop growing region within Oregon’s Willamette Valley. Fields for this study were selected based on soil type and weather patterns, and eleven fields were identified for sampling (3 Mosaic®, 3 Strata®, and 5 Simcoe®). Farm management data on fertilization rates and pesticide applications were collected by the grower (Coleman Agriculture). Using USGS soil maps, five individual sites within each field were identified for soil sampling, and hop bines near those sites were GPS tagged and hand harvested when they were at similar maturities. After harvest, the hops were analyzed for enzymatic activity using an HPLC method. The relationships between hop enzymatic activity and the farm management, soil, and weather data yielded associations with soil texture, growing degree day accumulation, fertilization practice, and pesticide application. The data also suggest a potential link between hop diastatic power and downy mildew (Pseudoperonospora humuli) or powdery mildew (Podosphaera macularis) infection. The links between hop diastatic power and agronomic variables will allow farmers to minimize hop creep potential in the hop field thereby potentially mitigating the effects that brewers see in the cellar.

Rendimiento de la planta de frijol caupí [Vigna unguiculata (L.) Walp] y calidad nutricional en los sistemas de cultivo intercalado de frijol caupí y sorgo

In traditional row and strip cowpea-sorghum intercropping systems, cowpea forage yield reduces significantly due to intense competition and dominance of sorghum in acquiring growth resources. This field study evaluated novel mixed strip intercropping systems of forage cowpea and sorghum having different number of crops rows arranged under different spatial arrangements. Cowpea was intercropped with sorghum in 8, 12 and 16 rows strips with row-row spacing of 30, 45 and 60 cm. In each strip, equal number of rows of cowpea and sorghum were maintained. Factorial arrangement of randomized complete block design with three replicates was used to execute the field trials during summer seasons of 2013 and 2014. Strips having 12 rows and 60 cm row-row spacing positively affected all agronomic variables of cowpea which led to maximum forage yield (22.2 and 23.7 t ha-1 during 2013 and 2014 respectively) and dry matter biomass (6.63 and 6.94 t ha-1 during 2013 and 2014 respectively). In contrast, 8-rows strips having line spacing of 30 cm outperformed other intercropping systems by yielding the maximum herbage yield and dry matter biomass of sorghum. The intercropping system comprising of 12-rows strips with 60 cm row-row spacing remained superior in recording the maximum crude protein, fats and total ash along with the minimum fiber content of cowpea. In addition, this intercropping system under rest of spatial arrangements also remained unmatched, while 16-rows strips under all planting geometries remained inferior to other intercropping systems. Thus, cowpea intercropping with sorghum in 12-rows strips having 60 cm spacing offers biologically viable solution to improve biomass and forage quality of cowpea in intercropping with sorghum.

Inducción de tolerancia a Globodera spp. con microorganismos promotores de crecimiento en el cultivo de papa (Solanum tuberosum subsp. tuberosum)

The effect of inducing tolerance to the attack of Globodera spp. was tested using three fungi (Trichoderma, Pochonia and Pleurotus) and a bacterium (Bacillus), as growth-promoting microorganisms (PGPR) in potato variety Desiree under greenhouse conditions. Cysts were extracted from the infested soil, from the Municipality of Pocona, 25 cysts were infested in each pot during planting, after 30 days the growth-promoting microorganisms PGPR, strains from FCAyP, were inoculated. The research was carried out under a completely randomized design, with 15 treatments and two controls (absolute control and control with nematode), with 8 repetitions. The evaluations were carried out at 70 days, considering the physiological variables: fresh weight of the foliage, and fresh weight of the root, and at 90 days after harvest, the Nematological variables (final population), Agronomic variables (number of tubers and yield) and analysis of mesofauna (population of collembola and mites). The application of growth promoting microorganisms PGPR helped to induce tolerance to the attack of Globodera spp. and also on the physiology of the plant, which was manifested in the crop yield, being two fungi (Pochonia + Pleurotus) combined, they act synergistically helping the plant to tolerate the attack of the nematode, increased by 20% of yield, still being attacked by the plague. Additional Key Words: Microorganisms, PGPR, Tolerance, Globodera spp, Fungi, Bacteria.

Influence of integrated crop-livestock-forest on morphological composition and nutritional value of Marandu palisadegrass under continuous grazing

This study characterizes the changes in leaf mass, morphological composition and nutritional value of leaf blades of palisadegrass (Urochloa brizantha cv. Marandu) under continuous grazing in the first year of implementation of pasture and after second year of the eucalyptus planting in an Integrated Crop-Livestock System and Integrated Crop-Livestock-Forest, which were tested in the four seasons. The experimental design was in random blocks, with three treatments: Crop-Livestock System (ICL) and Integrated Crop-Livestock-Forest with two eucalyptus tree densities (ICLF-1L, 196 eucalyptus trees ha-1 and ICLF-3L, 448 eucalyptus trees ha-1) and four replicates. Sixty castrated Nellore cattle with initial weight of 235.43 ± 25.46 kg and mean age of 16 ± 2.81 months were used during the growing phase under continuous grazing. The agronomic variables were: total dry mass of forage, leaves, stem and dead material; leaf: stem and live: senescent material ratios; and accumulation rate. The leaf: stem and live: senescent material relation did not obtain any difference between the evaluated systems. Dry matter, crude protein, fiber fractions and digestibility of leaf blades were evaluated. Dry mass of the forage (6775 kg ha-1), stem (2175 kg ha-1), senescent material (3175 kg ha-1) and dry matter content (28.6%) were greater in the ICL, whereas crude protein (11.3%) was greater in the ICLFs. On the other hand, accumulation rate and dry mass of leaf blades did not change between systems. Thus, until the first year of grazing, tree systems have advantages, because the forage production (accumulation rate) and leaf mass are similar to those of plants in full sun, besides showing higher nutritional value.

Estimation of biometric, physiological, and nutritional variables in lettuce seedlings using multispectral images

ABSTRACT The formation of seedlings is one of the most important phases of lettuce cultivation. Therefore, any strategy that aims to obtain high-quality seedlings can increase productivity. One of these strategies is the prediction of morphophysiological attributes based on optical properties. The objective of this study was to quantitatively estimate the biometric variables of lettuce from parametric and non-parametric models based on the response of multispectral camera images. The experiment was conducted in a greenhouse in the municipality of Uberaba, Minas Gerais State, Brazil. Twenty days after sowing, multispectral images of the plants were captured using a MAPIR Survey 3 camera. To compose the estimation models, along with the original bands of the camera, the multispectral vegetation indices were calculated using the calibrated original camera bands. Bands B550, B660, and B850 and the near-infrared indices contributed significantly to estimating the physiological variable models, with B850 contributing the most to the biometric and nutritional variables. From the near-infrared band (B850) and derived indices, it was possible to estimate all the agronomic variables from the models generated by the M5 algorithm, with an accuracy of up to 1.6% for the maximum quantum yield. Thus, it is possible to quantify the biometric, physiological, and nutritional variables of lettuce using a multispectral camera. Among the Mapir camera bands, B660 exhibited the greatest variability, showing that the red range was the most sensitive.

Productivity and profitability of peanut at various land suitability in North Lombok Regency of Nusa Tenggara Barat Province

Peanuts (Arachis hypogaea L.) are the second main commodity in the annual cropping pattern in lowland and dryland in North Lombok District of NTB Province. However, peanut productivity is still low, and it varies across regions, which might be due to the traditional crop management of farmers and the difference in land suitability classes. Effects of crop varieties and land suitability on the peanut productivity have not been evaluated in the Region. Thus, this study aimed to evaluate the productivity and profitability of peanut varieties at various land classification in KLU NTB. The experiment was arranged in a Split Plot Design consisting of three classes of land suitability as main plot and six peanut varieties as sub-plot with three replications. The results showed that the land suitability classes have a significant effect on the agronomic variables of peanut varieties, including plant height, number of branches, number of pods and productivity. The highest peanut yield was obtained at suitable land class (S1), followed by moderately suitable land class (S2) and marginally suitable land class (S3) at 2.37 ton.ha-1, 2.08 ton.ha-1 and 1.71 ton.ha-1, respectively. Likewise, the R/C ratio follows a similar pattern to productivity in various land suitability classes. The highest yield (above 2 ton.ha-1) in each land suitability class was produced by Kelinci variety, followed by Tuban, Bima and Talam varieties. Those varieties have potential prospective to be developed in North Lombok Regency.

Agronomic Evaluation and Physiological Quality in Triticale, under Two Production Systems in the Laguna Region

Objective: To evaluate ten triticale genotypes to assess the quality of the seeds under two production systems, with cut and without cut, in the municipalities of Matamoros (L1) and Francisco I. Madero (L2), Coahuila,Mexico.Design/Methodology/Approach: The agronomic variables evaluated were: Grain yield (GY), number of seeds per spike (NSS), spike length (SL), number of spikelets per spike (SS) and plant height (PH). Variables in the laboratory were: normal seedlings (NS), abnormal seedlings (AS), seeds without germinating (SWG), dry seedling weight (DW), plumule length (PL) and radicle length (RL). Statistical analysis was performed with the PROC ANOVA procedure, of the SAS software.Results: A higher grain yield was found for Matamoros (L1) compared to Francisco I. Madero (L2); however,for the variable number of seeds per spike it was higher in the latter (L2). For the physiological quality of seeds in L2, the highest values were in the variables normal seedlings and radicle length. In the comparison of production systems, the best response was for the system without cut in both locations; therefore, good quality triticale seed can be produced with acceptable grain yield.Study Limitations/Implications: It is necessary to describe the performance of triticale in the springsummer agricultural cycle in the central region of the country.Findings/Conclusions: The productive performance of triticale genotypes was variable depending on the production system, and there was also a different effect on the physiological quality of the harvested seed

Technical feasibility of geotextile fabric in bell pepper production under different irrigation levels

The Soiltain® DW geotextile fabric, used in water treatment plants, has a service life of three months, presenting itself as a solid residue, whose characteristics provide high strength and longevity, and can be an alternative mulching product in agriculture. This research aimed to evaluate the technical viability of geotextile fabric and mulching (synthetic and organic) in the production of bell pepper, Kolima F1 cultivar, under three irrigation levels. The experiment was carried out in Arapiraca, Alagoas – Brazil, in subdivided plots, with three irrigation levels in the main plots (60, 100 and 150% ETc) and four mulches in subplots (geotextile blanket, uncovered soil, white and organic mulching), with five replicates. Four evaluation cycles were carried out between 10/2019 and 03/2020. In general, agronomic variables were influenced by irrigation levels and mulching. Soil temperature was the variable that most negatively influenced plants, while white mulching associated the 150% ETc water level reduced plant performance. Geotextile blanket showed maximum water use efficiency (average 28.8 kg m-3), average productivity (52.2 Mg ha-1) and higher profitability (R$ 180.33), being a solid residue soil cover alternative, which must be associated with a 100% Etc water level.

Agronomic behavior and fruit quality in habanero peppers (Capsicum chinense Jacq.) as a response to formative pruning

Objective: To evaluate the effect of pruning on the agronomic variables and fruit quality of habanero peppers (Capsicum chinense Jacq.). Methodology: Habanero peppers were pruned with two intensities, two shoots and three shoots. The control plants were not pruned. The experiment had a randomized block design with four replications. The experimental plots consisted of 50 plants established in rows at a distance of 1.2 m and 0.3 m among plants within a row. The evaluated variables were fruit yield, number of fruits per plant, fruit weight, fruit length and fruit diameter. Data were obtained from 10 harvests. For the analysis, the fruit quality, ash content, moisture, protein and crude fiber were determined. Results: Plants with two and three shoots produced fruits of 4 and 3.99 cm in length. Plants with two and three shoots produced 42 and 48 % first quality fruits, whereas control plants produced only 10 % first quality fruits. The highest protein content in fruits at physiological ripeness (14 %) and commercial maturity (12 %) was observed in plants pruned to two shoots. Implications: These results show the importance of crop management on the fruit quality of habanero peppers. Further studies are needed to have more information on the effects of crop management on the nutritional content of fruits. Conclusion: The pruning of habanero pepper plants significantly influenced the fruit size, crude fiber and protein content in their fruits

Characterization and Use of a Crop-Residue-Based Mat Mulch in the Production of Pepper (Capsicum annuum) during Dry Season

Agricultural mulches from plant waste constitute an ecological alternative due to their capacity to biodegrade and incorporate into the soil. This work aimed at evaluating, during a drought, the effects of a mat mulch, based on banana rachis and rice straw, on bell pepper (Capsicum annuum) production, and to characterize the material, both mechanically (traction resistance) and physical-chemically (water retention capacity, organic and inorganic components). Two contrasting irrigation regimes were used to determine the effect of the mat mulch on edaphic and productive parameters such as plant height, basal stem diameter, number of fruits and flowers, harvest, plant biomass, macro- and micronutrients in leaves, weeds/m2, and soil temperature. Treatments with the mat mulch resulted in increased height, number of fruits and flowers, biomass, and P, Zn and Cu concentrations. The mat mulch contributes to soil water retention, improves pepper agronomic variables response in plant’s height, basal stem diameter, and the number of flowers and fruits, especially with a low water irrigation regime. Furthermore, a 95% reduction in weed/m2, and soil temperature (18 °C) compared to air temperature (26.8 °C) was found. The characteristics of the waste-based mat mulch in soils offer new possibilities for environmentally friendly, efficient, and sustainable agricultural practices.

High‐throughput phenotyping of soybean genotypes under base saturation stress conditions

AbstractThe search for high‐yielding genotypes and that are tolerant to abiotic stresses has been a major goal in plant breeding. Thus, the use of technologies such as precision agriculture associated with remote sensing tools for plant phenotyping has increased. The hypothesis of this research was that soya bean genotypes respond differently to low and adequate base saturation levels in the soil and that vegetation indexes can be efficient auxiliary tools in plant phenotyping for this purpose. The objective of this study was to evaluate the nutritional status and agronomic performance of soya bean genotypes grown in low and recommended base saturation conditions using high‐throughput phenotyping. The research was carried out in 2017/2018 and 2018/2019 crop seasons, in which two field experiments in each season were installed. In experiment I, genotypes (P1, P2, P3, P4, P5, P6, P7, P8, P9 and P10) were evaluated without soil correction (low saturation condition). In experiment II, liming was performed three months before sowing of the genotypes to raise the base saturation to 60% (recommended saturation). Canopy spectral behaviour at the following wavelengths was evaluated: green (550 nm), red (660 nm), red edge (735 nm) and near‐infrared (790 nm), and the vegetation indices (Vis) NDVI, SAVI, EVI and MSAVI were calculated. The variables evaluated were leaf calcium and magnesium contents and grain yield. The use of VI’s was efficient in assessing the performance of genotypes soya bean at different base saturation levels. The EVI showed moderate correlation with the nutritional and agronomic variables measured in each base saturation level. The approach used enabled both to identify genotypes tolerant to low base saturation soils and the ones with better response to liming.

Influência da adubação bórica na cultura do feijoeiro

A cultura do feijão em nosso país além de participar de maneira expressiva no cenário econômico que engloba a cadeia do agronegócio, exerce uma função cultural bastante intensificada por ser um dos símbolos básicos da alimentação da população e importante fonte de proteína. O Brasil destaca-se no ranking mundial como um dos principais países produtores e consumidores de feijão (Phaseolus vulgares L). Esta cultura pode ter sua produtividade limitada pelo baixo teor de Boro (B) encontrada em parte dos solos brasileiros cultivados, onde os níveis adequados deste nutriente varia de 1,0 a 1,2 mg dm-3. Com isso, pode existir a necessidade de se fazer a adubação para superar a limitação na produtividade por deficiência de Boro no solo e na planta. As plantas absorvem B na forma de ácido bórico. Ao longo dos anos o nível tecnológico empregado na produção do feijão vêm aumentando significativamente, neste sentido diversas pesquisas tem sido direcionadas para práticas de manejo que gerem rentabilidade e produtividade dessa cultura. Essa revisão tem por objetivo discorrer sobre a relevância da adubação bórica na cultura do feijoeiro e identificar em quais estádios de desenvolvimento essa adubação seria crucial para o ciclo da planta, assim como levantar a resposta à adubação bórica das principais variáveis agronômicas estudadas.

High-Resolution Airborne Hyperspectral Imagery for Assessing Yield, Biomass, Grain N Concentration, and N Output in Spring Wheat

Remote sensing allows fast assessment of crop monitoring over large areas; however, questions regarding uncertainty in crop parameter prediction and application to nitrogen (N) fertilization remain open. The objective of this study was to optimize of remote sensing spectral information for its application to grain yield (GY), biomass, grain N concentration (GNC), and N output assessment, and decision making on spring wheat fertilization. Spring wheat (Triticum turgidum L.) field experiments testing two tillage treatments, two irrigation levels and six N treatments were conducted in Northwest Mexico over four consecutive years. Hyperspectral images were acquired through 27 airborne flight campaigns. At harvest, GY, biomass, GNC and N output were determined. Spectral exploratory analysis was used to identify the best wavelength combinations, the most suitable vegetation indices (VIs) and the best growth stages to assess the agronomic variables. The relationship between the spectral information and the agronomic measurements was evaluated by the coefficient of determination (R2) and the root mean square error (RMSE). The ability of the indices to guide fertilizer recommendation was assessed through an error analysis based on the N sufficiency index. GY was better assessed from the end of flowering to the early milk stage by VIs based on the combination of bands from near infrared radiation/visible and from near infrared radiation/red-edge regions (R2 > 0.6; RMSE < 700 kg ha−1). N output was efficiently assessed by a combination of bands from near infrared radiation/red-edge at booting (R2 > 0.7; RMSE < 9 kg N ha−1). The GNC was better estimated by VIs combining bands in near infrared radiation/red-edge at early milk, but with great variability among the years studied. Some VIs were promising for guiding fertilizer recommendation for increasing GNC, but there was not a single index providing reliable recommendations every year. This study highlights the potential of remote sensing imagery to assess GY and N output in spring wheat, but the identification of GNC responsive sites needs to be improved.

Impacto de cubierta, ecotipo y endomicorriza en morfología y calidad de chile piquín

La investigación se realizó con ecotipos de chile piquín de Coahuila, Nuevo León y Zacatecas. Se evaluaron plantas de chile piquín del segundo año de producción. Se utilizaron dos ambientes: a) macro túneles de malla blanca, roja azul, negra tipo raschel con 30% de sombreo; y b) campo abierto con 100% de transmisión de luz. Se inocularon 50 esporas de un conglomerado de hongos micorrízicos arbusculares (Glomus mosseae, Rhizophagus intraradices, Sclerocystis coremioides y Gigaspora albida), directamente al sistema radical. Se utilizó un arreglo factorial 5 x 6 x 2 (cubiertas, ecotipos y micorrizas) y su distribución fue un diseño bloques al azar con cuatro repeticiones. Se evaluó el rendimiento y algunos caracteres morfológicos como altura de planta (AP), diámetro de tallo (DT), longitud de raíz (LR), peso fresco de planta (PFP), peso fresco de planta (PSP), peso fresco de raíz (PFR), peso seco de raíz (PSR), rendimiento por planta (RPP). Los resultados indicaron que la malla blanca favoreció los caracteres morfológicos de la planta con 320% en AP, 322.7% en DT, 235.8% la LR, 8 veces el PFP, 8.5 veces el PSP, 327.2% el PFR, 5 veces el PSR, 6.8 veces el RPP, en comparación a las plantas desarrolladas en campo abierto. Además, la calidad de chile piquín proporciona condiciones para el desarrollo de endomicorrizas (esporas y porcentaje de colonización). La malla azul con la menor radiación fotosintéticamente activa (RFA) influyó positivamente en las variables agronómicas, de calidad y la inoculación (número de esporas y porcentaje de colonización). El ecotipo que influyó en los SST, VitC, fenoles y NE fue el de SNL y el RTZ en variables agronómicas y % colonización. La inoculación con el consorcio de micorrizas mejoró los caracteres agronómicos y calidad del fruto de chile piquín.

Genotype × trait biplot and canonical correlations for spectral and agronomic traits in corn

AbstractThe current challenge of corn (Zea mays L.) crops is to reach high yield to supply the world's demand for food, especially under different fertilization regimes and using the latest technology. We hypothesized that wavelengths and vegetation indices have a linear relationship with agronomic variables in corn. Our objectives were to verify the formation of super‐traits and to study the association between wavelengths and vegetation indices with agronomic traits in corn cultivated under high and low topdressing N. The experiments were carried out in two crop seasons using a randomized block design with three replicates in a factorial scheme (11 genotypes × 2 contrasting levels of N: low, 60 kg ha–1 and high, 180 kg ha–1). At full bloom, the spectral variables green (550 nm), red (660 nm), red‐edge (735 nm), and near‐infrared (790 nm) and the vegetation indices normalized difference vegetation index (NDVI), normalized difference red‐edge index (NDRE), green normalized difference vegetation index (GNDVI), and soil‐adjusted vegetation index (SAVI) were evaluated. Agronomic traits evaluated were leaf N, plant height, first pod height, stem diameter, cob length, rows per cob, grains per row, and grain yield. Results showed that SAVI, GNDVI, NDVI, and NDRE and red‐edge and red were associated with agronomic traits in corn. The association between the agronomic traits evaluated here can be used to estimate the leaf N content and corn yield.

Bokashi, Boiled Manure and Penergetic Applications Increased Agronomic Production Variables and May Enhance Powdery Mildew Severity of Organic Tomato Plants

Research on organic fertilizers are of crucial importance for sustainable production systems with high efficiency of natural resource use. The objective of this study was to evaluate organic sources of fertilization (boiled manure (BM), effective microorganism (EM) Bokashi, and Penergetic) for their effects on agronomic variables (fruit size and yield, total soluble solids) and on foliar powdery mildew severity of tomato (Solanum lycopersicum L.). The crops were grown during two cropping cycles in protected cultivation. The treatments were: Control (water only); 50 g per plant of EM Bokashi compost in two applications; Penergetic at 1.5 g L−1 applied to the substrate before planting or sprayed on the plants 14 days after transplanting; and BM at 2.5%, 5.0%, 7.5%, and 10% concentrations (vol/vol) in water, via fertigation. Fruit production and quality were assessed. The effects of treatments on powdery mildew (Leveillula taurica Lév. G. Arnaud) were analyzed by using a diagrammatic scale. Bokashi, 10% BM, and Penergetic increased fruit production of the first three fruit trusses. Bokashi treatment increased tomato fruit diameter. The effects on fruit length and total soluble solids varied with each crop cycle. Powdery mildew severity increased with 10% BM, compared to the control. Both 10% BM and Penergetic presented similar fruit production to Bokashi and are good candidates as substitutes for Bokashi as organic fertilizers/amendments while maintaining tomato yield.

Evaluación del rendimiento, características morfológicas y químicas de variedades del maíz morado (Zea mays L.) en la región Cajamarca-Perú

El Perú tiene una gran diversidad de productos agrícolas, debido a la variedad de climas y diversidad geográf ica, por lo que cuenta con siete principales razas del maíz morado. Por tanto, el objetivo del presente trabajo de investigación fue evaluar el rendimiento, las características morfológicas y químicas de cinco variedades del maíz morado, las cuales fueron el INIA-601, maíz morado mejorado MMM (variedad experimental), UNC-47, INIA-615 y PM-581 y la raza Canteño como control en dos niveles altitudinales de 2770 m (Llollón) y a 3140 m (Llanupacha), ambos pertenecientes al Distrito de Ichocán, Provincia de San Marcos y Región Cajamarca en Perú, en las campañas agrícolas 2017/18 y 2018/19. Se evaluaron las variables agronómicas y el contenido de antocianinas. Los resultados muestran que el mejor rendimiento en promedio fue para el INIA-601 con 5.3 Mg ha-1 en Llanupacha y de 4.5 Mg ha-1 en Llollón. Las variedades con mayor altura de planta y mazorca fueron para el MMM (2.33 y 1.2 m) e INIA-601 (2.35 y 1.25 m) en Llollón; mientras que en Llanupacha, resaltaron el MMM (1.93 y 0.88 m) y el INIA-601 (1.9 y 0.88 m), respectivamente. La variedad INIA-615 logró ser la variedad más precoz en el florecimiento femenino y masculino en ambos niveles altitudinales, con 101.5 y 93.3 días en Llollón y con 125.6 y 118.3 días en Llanupacha, respectivamente; además, esta variedad obtuvo el menor porcentaje de pudrición de 2.3% en Llanupacha y 5.9% en Llollón. La variedad INIA-601, se destacó por tener la mayor cantidad de antocianinas tanto en el olote como en las brácteas, presentando (6.7 y 7.5 mg g-1) y (2.9 y 2.5 mg g-1), en Llanupacha y Llollón, respectivamente.

Response of tomato varieties (Solanum lycopersicum L.) to water stress

Background and Objectives: Water scarcity is limiting for tomato (Solanum lycopersicum L) production, due to its sensitive to drought in the different phases of development, so irrigation should be done in an optimal way; because of this, the objective was to evaluate four levels of irrigation in greenhouse tomato varieties. Methods: A completely randomized experimental design with factorial arrangement was used and various agronomic variables, fruit quality and biomass were measured as response variables. Results: Tomatoes were significantly affected (P?0.05) by variety factors (V), irrigation (R), and their interaction. 100% of variety P presented fruits of greater weight (122 g); while weight decreased to 84, 90, 34 and 18 g when reducing water up to 25%, in varieties Cid, P, E and C, respectively. However, in terms of yield and leaf area, 100% of the Cid variety presented the highest values, around 3.3 kg/plant and 8.6 m-2. Conclusions: Variety c was tolerant to water stress and also does not present apical rotting (calcium deficiency) in the fruit.

The main drivers of methane emissions differ in the growing and flooded fallow seasons in Mediterranean rice fields

PurposeTo assess 1) the cumulative greenhouse gas emissions –GHG- and global warming potential (methane – CH4- and nitrous oxide) from rice fields in the growing and fallow seasons, and 2) the environmental and agronomic drivers of CH4 emissions, and their relative capacity to explain CH4 variation.MethodsA two-year multisite field experiment covering the agronomic and environmental variability of a rice growing area in NE Iberian Peninsula was conducted with monthly samplings of GHG and monitoring of both environmental and agronomic factors. Information-theoretic framework analysis was used to assess the relative contribution of the environmental and agronomic variables on methane emissions.ResultsTwo thirds of the CH4 is emitted in the fallow season. Edaphic factors exert more influence during the growing season whereas agronomic factors have a higher impact in the fallow. The implications of these findings on the design of improved mitigation options rice are discussed.ConclusionsSoils with higher soil sulphate concentration, bulk density and clay content emit less CH4 in growing season. In the fallow season, the rates of both straw input and nitrogen fertilization stimulate CH4 emissions.Graphical abstract

Influence of the environment and production components on the protein content of green cowpea grain

The protein content of the cowpea has proved to be very variable, especially of the green grain. The aim of this study, therefore, was to obtain information on the influence of the environment and genetic variability on the total protein content (TPC) of green cowpea grain, as well as to evaluate the effects of production components on this variable. Sixteen cowpea genotypes were evaluated in two environments (Pentecoste and Acarau) in the state of Ceara, in a simple factorial scheme (16 x 2) for eight production components and protein content. The grain was collected while still green (after filling was complete - stage R5) and protein quantification was carried out using the Bradford method. Path analysis was performed in order to identify possible relationships between the agronomic variables and the protein content. There was a different response from the genotypes for each environment and in the interaction between genotype and environment. In Pentecoste, the MNC00-303-09E strain was highlighted, with a TPC of 6.602%, while in Acarau, the Paulistinha cultivar stood out with a TPC content of 15.154%. For the genotypes under evaluation, selection for total protein content should be made in Acarau via direct selection of the green-pod-grain weight, 100-grain weight and green-pod weight, and in Pentecoste, via indirect selection of the green-pod weight and green-grain yield.