Showing papers in "The Journal of Agricultural Science in 2018"
TL;DR: The overall findings indicate that CNN constitutes a promising technique with high performance in terms of precision and classification accuracy, outperforming existing commonly used image-processing techniques.
Abstract: Deep learning (DL) constitutes a modern technique for image processing, with large potential. Having been successfully applied in various areas, it has recently also entered the domain of agriculture. In the current paper, a survey was conducted of research efforts that employ convolutional neural networks (CNN), which constitute a specific class of DL, applied to various agricultural and food production challenges. The paper examines agricultural problems under study, models employed, sources of data used and the overall precision achieved according to the performance metrics used by the authors. Convolutional neural networks are compared with other existing techniques, and the advantages and disadvantages of using CNN in agriculture are listed. Moreover, the future potential of this technique is discussed, together with the authors’ personal experiences after employing CNN to approximate a problem of identifying missing vegetation from a sugar cane plantation in Costa Rica. The overall findings indicate that CNN constitutes a promising technique with high performance in terms of precision and classification accuracy, outperforming existing commonly used image-processing techniques. However, the success of each CNN model is highly dependent on the quality of the data set used.
233 citations
TL;DR: In this paper, the authors examined the concept of integration in IPM and criteria for determining whether its control tactics have been integrated harmoniously, arguing that the agroecosystem must be understood and managed as a living system with the goal of enhancing and conserving agrobiodiversity and keeping ecosystem services intact.
Abstract: Hailed as the single most important paper published on crop protection in the 20th century, Stern et al. in 1959 formed the conceptual basis for modern integrated pest management (IPM) worldwide. The ecological foundation for IPM envisioned by its authors is as valid today as in 1959. However, adoption by developing country farmers has been low and its advances short-lived. The present paper examines the concept of integration in IPM and criteria for determining whether its control tactics have been integrated harmoniously. The effects of local and regional landscape patterns on pests and on the design of IPM are reviewed, arguing that the agroecosystem must be understood and managed as a living system with the goal of enhancing and conserving agrobiodiversity and keeping ecosystem services intact. Key to IPM adoption is convincing farmers to integrate non-chemical alternatives (e.g. biological control, plant diversification) as primary management components and to apply pesticides judiciously and only after non-chemical components fail to manage pests effectively. Research, extension and policy changes are identified to increase the efficiency, adoption and sustainability of IPM on resource-limited farms. The over-arching challenge is devising communication and support systems that allow resource-limited farmers to try, adopt and sustain IPM that enhances yields and profits in light of the many uncertainties and challenges. Use of information technology, media development, crowdsourcing and rural sociology is advocated to connect farmers to the technical sources required to enhance yields and profits and reduce risks to them, the farming community and the environment.
48 citations
TL;DR: Arbuscular mycorrhizal fungi can maintain and improve P/N uptake, WUE and growth of plants both at high/low P levels and under FI/DI, if this is also the case under field conditions, it should be implemented for sustainable potato production.
Abstract: Deficit irrigation (DI) improves water use efficiency (WUE), but the reduced water input often limits plant growth and nutrient uptake. The current study examined whether arbuscular mycorrhizal fungi (AMF) could alleviate abiotic stress caused by low phosphorus (P) fertilization and DI. A greenhouse experiment was conducted with potato grown with (P1) or without (P0) P fertilization, with AMF (M1+: Rhizophagus irregularis or M2+: Glomus proliferum) or AMF-free control (M−) and subjected to full irrigation (FI), DI or partial root-zone drying (PRD). Inoculation of M1+ and M2+ maintained or improved plant growth and P/nitrogen (N) uptake when subjected to DI/PRD and P0. However, the positive responses to AMF varied with P level and irrigation regime. Functional differences were found in ability of AMF species alleviating plant stress. The largest positive plant biomass response to M1+ and M2+ was found under FI, both at P1 and P0 (25% increase), while plant biomass response to M1+ and M2+ under DI/PRD (14% increase) was significantly smaller. The large growth response to AMF inoculation, particularly under FI, may relate to greater photosynthetic capacity and leaf area, probably caused by stimulation of plant P/N uptake and carbon partitioning toward roots and tubers. However, plant growth response to AMF was not related to the percentage of AMF root colonization. Arbuscular mycorrhizal fungi can maintain and improve P/N uptake, WUE and growth of plants both at high/low P levels and under FI/DI. If this is also the case under field conditions, it should be implemented for sustainable potato production.
44 citations
TL;DR: In this article, an overview of recent research aimed at verifying the role of arbuscular mycorrhizal fungi and chemical agents to improve plant tolerance to drought and to highlight the mechanisms involved in this improvement is presented.
Abstract: Drought represents one of the major constraints on agricultural productivity and food security and in future is destined to spread widely as a consequence of climate change. Research efforts are focused on developing strategies to make crops more resilient and to mitigate the effects of stress on crop production. In this context, the use of root-associated microbial communities and chemical priming strategies able to improve plant tolerance to abiotic stresses, including drought, have attracted increasing attention in recent years. The current review offers an overview of recent research aimed at verifying the role of arbuscular mycorrhizal fungi and chemical agents to improve plant tolerance to drought and to highlight the mechanisms involved in this improvement. Attention will be devoted mainly to current knowledge on the mechanisms involved in water transport.
43 citations
TL;DR: Intercropping IWG with a perennial legume such as alfalfa could benefit nutrient cycling while increasing agroecological diversity and mitigate the decline in yields as stands aged.
Abstract: Intermediate wheatgrass (Thinopyrum intermedium; IWG) is a perennial cereal crop undergoing development for grain production; however, grain yield declines of >75% are often observed after year 2 of the perennial stand and may be linked to soil nutrient depletion. Intercropping IWG with a perennial legume such as alfalfa (Medicago sativa) could benefit nutrient cycling while increasing agroecological diversity. Intermediate wheatgrass was established at five environmentally diverse sites in Minnesota, USA in (1) bi-culture with alfalfa, (2) non-fertilized monoculture and (3) monoculture fertilized annually in the spring with 80 kg N/ha. At northern sites where alfalfa growth was favoured, IWG grain yields were reduced in year 2 by growing IWG in bi-culture with alfalfa, relative to the monoculture systems. Across all sites IWG grain yield decreased by 90% in the non-fertilized monoculture, 80% in the fertilized monoculture and 65% in the bi-culture from year 2 to 4 and plant macronutrient concentrations decreased by 25–70%. In year 4, IWG grain yield was similar or greater in the bi-culture than the fertilized monoculture at three of the five sites and alfalfa biomass was correlated positively with grain yield, harvest index and nutrient uptake in the year 4 bi-culture. Chemical-nitrogen fertilization increased grain yields in year 2 but did not mitigate the decline in yields as stands aged. Intermediate wheatgrass in the bi-culture had similar yields and nutrient uptake and lower yield declines than the chemically fertilized stand at sites where alfalfa growth was maintained throughout the life of the stand.
41 citations
TL;DR: It can be concluded that integrating very high- and high-resolution imagery with different VIs can be implemented effectively to produce large-scale crop maps even with a limited temporal-dataset.
Abstract: Remote sensing (RS) offers an efficient and reliable means to map features on Earth. Crop type mapping using RS at various temporal and spatial resolutions plays an important role spanning from environmental to economical. The main objective of the current study was to evaluate the significance of optical data in a multi-temporal crop type classification-based on very high spatial resolution and high spatial resolution imagery. With this aim, three images from WorldView-3 and Sentinel-2 were acquired over Coalville (UK) between April and July 2016. Three vegetation indices (VIs); the normalized difference vegetation index, the green normalized difference vegetation index and soil adjusted vegetation index were generated using red, green and near-infrared spectral bands; then a supervised classification was performed using ground reference data collected from field surveys, Random forest (RF) and decision tree (DT) classification algorithms. Accuracy assessment was undertaken by comparing the classified output with the reference data. An overall accuracy of 91% and κ coefficient of 0·90 were estimated using the combination of RF and DT classification algorithms. Therefore, it can be concluded that integrating very high- and high-resolution imagery with different VIs can be implemented effectively to produce large-scale crop maps even with a limited temporal-dataset.
34 citations
TL;DR: Use of manure and lime could result in improved soil pH for better uptake of nutrients, nodule formation and productivity of soybean in Western Kenya.
Abstract: Soybean is an important crop with nutrition, economic and soil fertility improvement benefits to farmers. However, its production in western Kenya is partly constrained by low soil pH and soil fertility levels. A greenhouse pot study was conducted to evaluate the effects of inorganic fertilizers, farmyard manure and lime application on soil pH, nutrient uptake, growth and nodulation of soybean grown in acidic soils from western Kenya. The experiment was set up in a randomized complete block design with eight treatments: control; NPK; manure; lime; manure+lime; NPK+manure; NPK+lime and manure+lime+NPK. Significant effects of inorganic fertilizers, manure and lime applications were observed on all the variables. Manure, lime and manure+lime treatments increased soil pH by 1.33, 2.19 and 2.28, respectively, above the control treatment. The shoot N was lower under control (1.71-1.81%), NPK (1.85-1.98%) and manure (2.00-2.11%) than under all other treatments. Treatments NPK+lime and manure+lime+NPK recorded higher uptake of P and K nutrients than all other treatments. The control and NPK treatments recorded shorter plants and low leaf area and above-ground biomass compared to other treatments. The NPK+lime and manure+lime+NPK treatments recorded higher plant height and aboveground biomass than other treatments. Lime+manure treatment recorded highest nodule numbers and dry weights per plant. Positive relationships were observed between pH and N, P and K nutrient uptake (R2 ranged between 0.30 and 0.77) and between biomass and N, P and K nutrient uptake (R2 ranged between 0.68 and 0.99). From this study, use of manure and lime could result in improved soil pH for better uptake of nutrients, nodule formation and productivity of soybean in Western Kenya.
28 citations
TL;DR: In this article, the authors compared two methods for estimating GC using a GC calculator (GENCALC) and generalized likelihood uncertainty estimation (GLUE) for three flooded rice (FDR) varieties.
Abstract: Prior to applying the cropping system model-CERES-Rice model to deep water rice (DWR), it is important to estimate the rice genetic coefficients (GC). The goal of the current study was to compare two methods for estimating GC using a GC calculator (GENCALC) and generalized likelihood uncertainty estimation (GLUE) for three flooded rice (FDR) varieties. Data from a field experiment on the effect of planting date and variety on FDR production was conducted in 2009 on a DWR area in Bang Taen His Majesty's Private Development Project, Prachin Buri, Thailand. The experimental design was split-plot with four main plots (planting dates) and three sub-plots (FDR varieties) with four replications. The simulated values for anthesis date, maturity date and grain weight using GENCALC produced normalized root mean square errors (RMSEn) of 3.97, 3.69 and 3.68, while using GLUE produced RMSEn of 3.67, 2.50 and 3.68, respectively. The simulated grain number and grain yield under GENCALC GC were not significantly different from the observed values but were higher than simulated values for GLUE GC. Simulated values of above-ground biomass for both GENCALC (11 727 kg/ha) and GLUE GC (11 544 kg/ha) were overestimated compared to observed values (8512 kg/ha). In addition, good agreements of leaf N values were found with D-index values of 0.94 and 0.96 using GENACALC and GLUE GC simulations, respectively. Therefore, the GENCALC and GLUE GC estimators of DSSAT can both be used for estimating GC of FDR in the DWR area in Thailand and similar agro-ecosystems in Southeast Asia.
26 citations
TL;DR: The plant density required to obtain an ideal GY maize canopy structure should be increased by 10–18% from 9.72 plants/m2, taking into account the persistence time for maximum LAI.
Abstract: Good canopy structure is essential for optimal maize (Zea mays L.) production. However, creating appropriate maize canopy structure can be difficult, because the characteristics of individual plants are altered by changes in plant age, density and interactions with neighbouring plants. The objective of the current study was to find a reliable method for building good maize canopy structure by analysing changes in canopy structure, light distribution and grain yield (GY). A modern maize cultivar (ZhengDan958) was planted at 12 densities ranging from 1.5 to 18 plants/m2 at two field locations in Xinjiang, China. At the silking stage (R1), plant and ear height increased with plant density as well as leaf area index (LAI), whereas leaf area per plant decreased logarithmically. The fraction of light intercepted by the plant (F) increased with increasing plant density, but the light extinction coefficient (K) decreased linearly from 0.61 to 0.39. Taking the optimum value of F (95%) as an example, and using measured values of K for each plant density at R1 and the equation from Beer's law, the corresponding (theoretical) LAI for each plant density was calculated and optimum plant density (9.72 plants/m2) obtained by calculating the difference between theoretical LAIs and actual observations. Further analysis showed that plant density ranging from 10.64 to 11.55 plants/m2 yielded a stable GY range. Therefore, taking into account the persistence time for maximum LAI, the plant density required to obtain an ideal GY maize canopy structure should be increased by 10–18% from 9.72 plants/m2.
25 citations
TL;DR: In this paper, spatial-temporal variations of agricultural water demand in the Tarim River Basin were estimated using the Penman-Monteith equation and the crop coefficient approach, and the contributions of meteorological factors and planting structure to AWD variations were quantified based on traditional methods and numerical experiment.
Abstract: Agricultural water use accounts for more than 95% of the total water consumption in the extreme arid region of the Tarim River Basin. Understanding the variation of agricultural water demand (AWD) and its attributions is therefore vital for irrigation management and water resource allocation affecting the economy and natural ecosystems in this high water-deficit region. Here spatial–temporal variations of AWD based on weighted crop water requirement (ETc) were estimated using the Penman–Monteith equation and the crop coefficient approach. Then the contributions of meteorological factors and planting structure (i.e. proportions of crop acreages) to AWD variations were quantified based on traditional methods and numerical experiment (i.e. a series calculation of AWD based on different input data). Results indicated that AWD decreased during 1960–1988 at a rate of 2.76 mm/year and then started to increase at a high rate of 9.47 mm/year during 1989–2015. For the first period (1960–1988), wind speed (uz), maximum humidity (RHmax) and sunshine duration (n) were the most important factors leading to decreased AWD, while for the second period the evolution of planting structure was the most significant factor resulting in the rapid increase of AWD, followed by the minimum temperature (Tmin), uz and RHmax. The evolution of planting structure alone would lead to an increase rate for AWD of 7.1 mm/year while the climatic factor would result in an increase rate of 1.9 mm/year during 1989–2015.
25 citations
TL;DR: In this paper, the authors describe how valid inferences accounting for all relevant effects can be obtained using bivariate mixed linear model procedures, which allows bivariate correlations to be computed at the level of effects.
Abstract: Crop scientists occasionally compute sample correlations between traits based on observed data from designed experiments, and this is often accompanied by significance tests of the null hypothesis that traits are uncorrelated. This simple approach does not account for effects due to the randomization layout and treatment structure of the experiments and hence statistical inference based on standard procedures is not appropriate. The present paper describes how valid inferences accounting for all relevant effects can be obtained using bivariate mixed linear model procedures. A salient feature of the approach is that the bivariate model is commensurate with the model used for univariate analysis of individual traits and allows bivariate correlations to be computed at the level of effects. Heterogeneity of correlations between effects can be assessed by likelihood ratio tests or by graphical inspection of bivariate scatter plots of effect estimates. if heterogeneity is found to be substantial, it is crucial to focus on the correlation of effects, and usually, the main interest will be in the treatment effects. If heterogeneity is judged to be negligible, the marginal correlation can be estimated from the bivariate model for an overall assessment of association. The proposed methods are illustrated using four examples. Hints are given to alternative routes of analysis accounting for all treatment and design effects such as regression with groups and analysis of covariance.
TL;DR: An overview of Kompetitive Allele Specific PCR (KASP) genotyping platform requirements and its application that might be helpful in KASP marker development is provided.
Abstract: Single nucleotide polymorphism (SNP) can be detected by mining sequence databases or by using different singleplex or multiplex SNP genotyping platforms. Development of high-throughput genotyping molecular markers can be instrumental towards maximizing genetic gain. In this review we provide an overview of Kompetitive Allele Specific PCR (KASP) genotyping platform requirements and its application that might be helpful in KASP marker development. This literature further illustrates the possibilities to design KASP primers. Several research institutes routinely using KASP platform, producing in excess of humungous data points yearly for breeding cultivars and as well as for medical and commercial purposes. KASP genotyping technology offers cost effectiveness and high throughput molecular marker development platform. Conventional molecular markers can be converted into more robust and high throughput KASP markers. More than 2000 published references clearly show the popularity of KASP technology among the researchers.
TL;DR: The nitrogen, potassium, phosphorus, and calcium are the most pronounced macronutrients in soybean seeds, while iron, manganese and zinc are those with more evidence.
Abstract: The objective of this work was to evaluate the chemical composition of the macronutrients: nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and sulfur (S), and micronutrients: boron (Cu), iron (Fe), manganese (Mn), molybdenum (Mo) and zinc (Zn), and the elements aluminum (Al) and sodium (Na) measured in soybean seeds from different producing regions of Brazil. This work was carried out by sampling 2543 lots of soybean seeds produced in the 2009, 2010, 2011 and 2012 growing seasons. There is high variability of macro and micronutrients concentration in soybean seeds produced in several regions of Brazil. The nitrogen, potassium, phosphorus, and calcium are the most pronounced macronutrients in soybean seeds. Among the micronutrients, iron, manganese and zinc are those with more evidence. Understanding macro and micronutrients variability is critical for improving management and fertility treats in soybean seed production fields.
TL;DR: Results of a cross-validation indicate that the root mean square prediction error and mean absolute error as % of the observed mean are encouraging and reflect that the concepts encoded capture many of the underlying biological mechanisms that drive the diurnal pattern and daily UN excretion, as well as thirst, acceptable.
Abstract: Measurement of water consumption and urinary nitrogen (UN) excretion of individual grazing ruminants is difficult, time-consuming and expensive. Therefore, prediction and modelling are critical for research to improve N and water use efficiency. The objective of the current work was to use a mechanistic model of a grazing ruminant, MINDY, to represent drinking and urination diurnal patterns, and the resulting pattern of UN excretion. This work is primarily an integration of existing knowledge of basic urination physiology and water dynamics in ruminants. MINDY reproduces observed patterns of urination achieving the correct temporal occurrence, relative volumes and nitrogen (N) concentration of individual urination events for a grazing dairy cow, comparable with those reported in the literature. The model simulates daily water imbibed and UN realistically, as well as ingestion rates for herbages with different protein content and contrasting grazing managements. Results of a cross-validation indicate that the root mean square prediction error and mean absolute error as % of the observed mean, respectively, were 26 and 23% for daily water imbibed, 26 and 27% for urination volume, and 25 and 19% for the frequency of urination. Although further parameterization and validation are needed, for a new development in an exploratory model like MINDY, these numbers are encouraging and reflect that the concepts encoded capture many of the underlying biological mechanisms that drive the diurnal pattern and daily UN excretion, as well as thirst, acceptable.
TL;DR: It was concluded that under frequent and tight grazing management, the management strategy applied may be capable of alleviating the detrimental effect of N fertilizer on clover, to a point between 60 and 120 kg N/ha.
Abstract: A 4-year (2010–2013) plot study was undertaken to evaluate the effect of nitrogen (N) fertilizer rate (0, 60, 120, 196 and 240 kg N/ha/year) on seasonal responses and species persistency in frequently and tightly grazed (⩽4 cm) grass-only (GO) and grass white clover swards (GWc). Increasing N application rate increased herbage removed and pre-grazing sward height. Cows frequently grazed the GWc tighter than the GO. Increasing N rate reduced clover content, especially during the warmest months of the year, but less so up to 120 kg N/ha/year. The GWc had greater amounts of herbage removed than GO in the May–September period but the effect was less as N rate increased. Cumulative herbage removed from GWc was greater than GO swards receiving the same N rate and herbage quality was better in GWc than GO. Such effects were reduced as swards aged and with increasing N rate. It was concluded that under frequent and tight grazing management: (1) clover inclusion increased annual herbage removed; (2) herbage removed from GWc swards receiving no N was the same as the GO sward receiving 240 kg N/ha, and greater for the 240 GWc swards than the 240 GO swards; (3) clover inclusion benefits were mainly from summer onwards; (4) the management strategy applied in the current experiment may be capable of alleviating the detrimental effect of N fertilizer on clover, to a point between 60 and 120 kg N/ha.
TL;DR: Application of AgNPs improved plant growth and reduced nematode infection in comparison to silver nitrate and control treatments, and showed the highest increment of fresh weight as well as the lowest numbers of galls and egg-masses when tomato plants was treated with AgNP produced by ginger extract at 1 mM.
Abstract: Root-knot nematode, Meloidogyne incognita is the most economically important plant parasitic nematode species that cause serious damage to most agricultural crops including tomato worldwide. Nematicides do not provide long-term suppression of root-knot nematodes, and environmental and human health concerns are resulting in increased restrictions on their use. A greenhouse experiment was conducted to evaluate the effect of silver nanoparticles (AgNPs) at concentrations of 0.25, 0.5 and 1 mM as a potential nematicide on M. incognita infecting tomato. AgNP was biologically and chemically synthesized by a reaction of silver nitrate with ginger ( Zingiber officinale ) rhizomes aqueous extract and sodium borohydride, respectively. Results indicated that application of AgNPs improved plant growth and reduced nematode infection in comparison to silver nitrate and control treatments. The highest increment of fresh weight as well as the lowest numbers of galls and egg-masses was obtained when tomato plants was treated with AgNP produced by ginger extract at 1 mM.
TL;DR: Overall, the tested pea + cereal intercrops did not increase DMY over the respective monocrops, but they indicated several nutritional quality benefits, which present opportunities to substitute some grain or supplements in the beef cattle diet with better quality forage by interCrops.
Abstract: Spring barley (Hordeum vulgare L.), oat (Avena sativa L.) and triticale (x Triticosecale Wittmack) monocrops and their intercrops with two forage varieties (40-10 and Tucker) and one seed variety (Cooper) peas (Pisum sativum L.) were evaluated for forage production, nutrition quality and suitability in the beef cattle diet. Pea + cereal intercrops were compared to respective cereal monocrops in 2009, 2010 and 2011. Plant height of cereals tended to be reduced in intercrops compared to respective monocrops. Taller 40-10 forage type pea tended to cause lodging in 2009 and 2011, not observed with other pea varieties. Fresh forage of pea + cereal intercrops had higher moisture than respective cereal monocrops. Fourteen of the 18 intercrops had less dry matter yield (DMY) than respective cereal monocrops. Shorter Tucker pea had less negative impact on DMY than taller 40-10 pea. Treatments with barley had lower DMY than respective oat and triticale systems. Intercrops improved forage crude protein (CP) content over the respective monocrops, which was enough to overcome the DMY penalty and produce more CP yield than their monocrops. The forage Ca and Mg contents were improved by intercrops over their monocrops, and they were greater with 40-10 pea than other pea varieties and with barley than oat or triticale. The forage P content also tended to be higher in intercrops than corresponding monocrops, without a consistent effect of cereal type or pea variety. The forage K and S contents were not consistently influenced by the cereal types, pea varieties or intercrops. Forage Na content was greater from oat than respective barley and triticale treatments. The monocrops and intercrops had similar forage Cu content, and treatments with barley had more Cu than with oat or triticale. Forage Zn content tended to be intercrops > monocrops; and barley > triticale > oat. Treatments had no influence on the forage Fe and Mn contents. Levels of acid (ADF) and neutral (NDF) detergent fibres in the forage were similar for the corresponding intercrops and monocrops, and greater for oat than barley or triticale treatments. Some of the intercrops improved total digestible nutrients (TDN) content in forage over their monocrops. Monocrop of oat had less TDN than barley or triticale. Drought reduced the ADF, NDF and TDN contents. The forage NEL, NEM and NEG as well as RFV and NFC showed similar trend as the TDN. Overall, the tested pea + cereal intercrops did not increase DMY over the respective monocrops, but they indicated several nutritional quality benefits. These improvements present opportunities to substitute some grain or supplements in the beef cattle diet with better quality forage by intercrops.
TL;DR: In this article, an innovative system for forecasting crop potential evapotranspiration (ETp) has been implemented recently in the Campania region (southern Italy) by coupling the visible and near-infrared crop imagery with numerical weather prediction outputs.
Abstract: Irrigation according to reliable estimates of crop water requirements (CWR) is one of the key strategies to ensure long-term sustainability of irrigated agriculture. In southern Mediterranean regions, during the irrigation season, CWR is almost totally controlled by the potential evapotranspiration of the irrigated crop. An innovative system for forecasting crop potential evapotranspiration (ETp) has been implemented recently in the Campania region (southern Italy). The system produces ETp forecasts with a lead time of up to 5 days, by coupling the visible and near-infrared crop imagery with numerical weather prediction outputs of a limited area model. The forecasts are delivered to farmers with a simple and intuitive web app interface, which makes daily real-time ETp maps accessible from desktop computers, tablets and smartphones. Forecast performances were evaluated for maize fields of two farms in two irrigation seasons (2014–2015). The mean absolute bias of the forecasted ETp was <0.3 mm/day and the RMSE was <0.6 mm/day, both for lead times up to 5 days.
TL;DR: The data presented here are meant to introduce to the breeding community the use of these two research stations along the Senegal River for assessing heat tolerance of wheat or other winter cereals, as well as presenting two new ideal germplasm sources for heat tolerance, and the identification of spike fertility as the key trait controlling adaptation to heat stress.
Abstract: The Senegal River basin (Guinea, Mali, Mauritania, and Senegal) is a key agricultural production area in sub-Saharan Africa. Here, rice fields are left fallow during the cooler winter season, when the night temperatures reach 16 °C but the maximum daily temperatures remain above 30 °C. This season was used for the first time to conduct multi-environmental trials of durum wheat. Twenty-four elite breeding lines and cultivars were tested for adaptation during seasons 2014-15 and 2015-16 at two stations: Kaedi, Mauritania and Fanaye, Senegal. Phenological traits, grain yield and its components were recorded. Top grain yield was recorded at 5,330 kg ha -1 and the average yield at 2,484 kg ha -1 . The season lasted just 90 days from sowing to harvest. Dissection of the yield in its components revealed that biomass and spike fertility ( i.e. number of seeds produced per spike) were the most critical traits for adaptation to these warm conditions. This second trait was confirmed in a validation experiment conducted in 2016-17 at the same two sites. Genotype × environment interaction was dissected by AMMI model, and the derived IPC values used to derive an ‘AMMI wide adaptation index’ (AWAI) to asses yield stability. The use of a selection index that combined adjusted means of yield and AWAI identified three genotypes as the most stable and high yielding: ‘Bani Suef 5’, ‘DAWRyT118’, and ‘DAWRyT123’. The last two genotypes were also confirmed among the best in a validation trial conducted in season 2016-17. The data presented here are meant to introduce to the breeding community the use of these two research stations along the Senegal River for assessing heat tolerance of wheat or other winter cereals, as well as presenting two new ideal germplasm sources for heat tolerance, and the identification of spike fertility as the key trait controlling adaptation to heat stress.
TL;DR: The results demonstrate that crop rotation and grazing management exhibited interactive effects on the determination of weed outcomes in an ICLS during a 12-year period under no-tillage in sub-tropical southern Brazil.
Abstract: Effective integrated weed management in agricultural landscapes depends on the ability to identify and manage processes that drive weed dynamics. The current study reports the effects of grazing management and crop rotation strategies on the seedbank and emerged weed flora in an integrated crop-livestock system (ICLS) experiment during a 12-year period under no-tillage in sub-tropical southern Brazil. During winter, Italian ryegrass cover crops were grazed by sheep: grazing management treatments included two stocking methods (continuous and rotational) and two forage allowances (10 and 20 kg of herbage dry matter available per 100 kg animal live weight). During summer, the crop rotation treatments involved either soybean-maize or soybean-soybean in succession with winter-grazed cover crops. The treatments were part of a factorial randomized complete block design. Treatment effects were evaluated on the weed seedbank and emerged weed flora populations during winter-grazed cover crop and summer crop growth as well as during the harvest phase. The current results demonstrate that crop rotation and grazing management exhibited interactive effects on the determination of weed outcomes in an ICLS. However, overall, compared with moderate forage allowance, high forage allowance during the winter-grazed cover crop caused lower emerged weed flora in subsequent crops (20% reduction during crop growth and 90% reduction at crop harvest) and 48% reduction in seedbank size. High forage allowance promoted more residue from winter-grazed cover crop biomass, which remained during the summer crop phases and probably resulted in a physical barrier to weed emergence.
TL;DR: In this paper, the authors used a Murashige and Skoog (MS) liquid medium supplemented with 1.5 mg/L 2,4-D, 0.5 µg/L kinetin and 30 g/L sucrose to extract vinblastine and vincristine from C. roseus.
Abstract: Catharanthus roseus (L.) G. Don is an important herbal plant. There are two important alkaloids, vinblastine and vincristine, use in anti-cancer drugs. In this study production of the two alkaloids was enhanced in C. roseus cell cultures, in a Murashige and Skoog (MS) liquid medium supplemented with 1.5 mg/L 2,4-D, 0.5 mg/L kinetin and 30 g/L sucrose, by adding 0, 50, 100, 250 or 500 mg/L medium molecular weight chitosan or chitosan derived from shrimp shell. After 14 days of culture, the cell suspension at stationary phase in the 100 mg/L medium molecular weight chitosan could produce the highest amounts of vinblastine and vincristine at 4.15 and 5.48 µg/mg cell dry weight, respectively. At the same time, the controls (0 mg/L chitosan) produced the two alkaloids at only 2.43 and 2.49 µg/mg cell dry weight, respectively. For chitosan from shrimp shell, it was found that 100 mg/L chitosan could lead to the highest quantity of 4.09 µg vinblastine/mg cell dry weight. The highest amount of 5.47 µg vincristine/mg cell dry weight was obtained when 250 mg/L chitosan was added.
TL;DR: The biological characteristics and reproduction of T. podisi were impacted by adult mating prior to parasitism and by different temperatures, and it may be affected when unmated females are released.
Abstract: We evaluated the effects of adult mating and temperature on the biological potential and parasitism of Telenomus podisi (Ashmead) (Hymenoptera: Platygastridae) on Euschistus heros (Fabricius) (Hemiptera: Pentatomidae). Females were isolated and the characteristics of the F1 generation were compared with those of females previously copulated. The parasitism capacity of T. podisi on E. heros eggs at 20, 25, 30, 35, and 40 °C was evaluated. The longevity of parental females (days), egg-adult period (days) of the F1 generation, parasitism of parental females (%), and parasitoid emergence (%) were not influenced by the lack or not of the copulation. The offspring of non-copulated females were males, and arrhenotokous parthenogenesis occurred. The temperatures most favorable to the parasitoid were 25 and 30 °C. Even previously copulated females generated mostly males after a few days of oviposition. Therefore, the biological characteristics and reproduction of T. podisi were impacted by adult mating prior to parasitism and by different temperatures. Although parasitism of T. podisi was not affected by mating parasitoid permanence in the field, it may be affected when unmated females are released.
TL;DR: In this paper, the potential for glycine betaine (GB) treatment of seeds to increase the chilling tolerance of cotton at the seedling stage was examined and the experimental results suggested that although GB was only used to treat cotton seed, the beneficial effect caused by the preliminary treatment of GB could play a significant role during germination that persisted to at least the four-leaf seedling.
Abstract: Chilling injury is an important natural stress that can threaten cotton production, especially at the sowing and seedling stages in early spring. It is therefore important for cotton production to improve chilling tolerance at these stages. The current work examines the potential for glycine betaine (GB) treatment of seeds to increase the chilling tolerance of cotton at the seedling stage. Germination under cold stress was increased significantly by GB treatment. Under low temperature, the leaves of seedlings from treated seeds exhibited a higher net photosynthetic rate (PN), higher antioxidant enzyme activity including superoxide dismutase, ascorbate peroxidase and catalase, lower hydrogen peroxide (H2O2) content and less damage to the cell membrane. Enzyme activity was correlated negatively with H2O2 content and degree of damage to the cell membrane but correlated positively with GB content. The experimental results suggested that although GB was only used to treat cotton seed, the beneficial effect caused by the preliminary treatment of GB could play a significant role during germination that persisted to at least the four-leaf seedling stage. Therefore, it is crucial that this method is employed in agricultural production to improve chilling resistance in the seedling stage by soaking the seeds in GB.
TL;DR: Combining ability analysis and heterosis was conducted to identify yield associated traits from nine male indicas and three female japonicas, together with their 27 F1 hybrids, suggesting that they could be good breeding donors.
Abstract: Understanding genetic variability and mode of gene action for agronomic and yield related traits is important in formulation of effective rice breeding program for genetic enhancement of grain yield. Combining ability analysis and heterosis was conducted to identify yield associated traits from nine male indicas and three female japonicas, together with their 27 F1 hybrids. Four parental lines, including Basmati 370, Basmati 217, K2-54 and Komboka showed good general combining ability in days to 50% flowering, days to maturity, number of tillers plant-1, number of spikelet’s panicle-1, number of panicles plant-1, number of filled grains panicle-1, and grain yield. While the combine K2-9 × Komboka, K2-9 × Basmati 370, K2-54 × Dourado Precoce and K2-54 × Basmati 217 showed specific good for grain yield. The hybrids K2-9 × Basmati 370, K2-8 × Basmati 217, K2-54 × Basmati 217 and K2-9 × Komboka showed 20% excess in standard check variety, suggesting that they could be good breeding donors.
TL;DR: Among the four products tested, Biodoz seemed the best product for inoculation under cool growing conditions, while strains of other products were identified as Bradyrhizobium japonicum, which might be a possible explanation for the better performance of Biodzin in Belgium.
Abstract: Bacterial inoculation of soybean seeds to improve biological nitrogen fixation is a well-known practice to achieve higher seed and protein yield with reduced fertilization. The optimal inoculation strategy in temperate regions is unknown because soybeans are rarely cultivated under colder growing conditions. The aim of the present work was to determine the most suitable inoculation strategy for soybean cultivation in Belgium. Field trials were set up with four Bradyrhizobium inoculants (HiStick, Force 48, Biodoz and Optimize) at two locations over 2 years (2014–2015) and compared with a non-inoculated control treatment. In addition, HiStick was tested at three doses and Optimize at two time periods prior to sowing. Under Belgian conditions, all inoculants were effective in establishing rhizobial symbiosis, resulting in increased yield, protein content, protein yield and thousand-grain weight compared with the non-inoculated control. A single dose of HiStick was sufficient to establish symbiosis. Pre-inoculation with Optimize 2 weeks before sowing gave an intermediate performance for most parameters between the non-inoculated control treatment and inoculation with Optimize 24 h prior to sowing. Among the four products tested, Biodoz seemed the best product for inoculation under cool growing conditions. Based on the atpD gene, the bacterial strain of Biodoz showed complete similarity with Bradyrhizobium diazoefficiens, while strains of other products were identified as Bradyrhizobium japonicum. In vitro growing capacity of the Biodoz strain at 8 °C was higher compared with the other strains. Better cold adaptation of the Biodoz strain might be a possible explanation for the better performance of Biodoz in Belgium.
TL;DR: In this paper, the effects and possible mechanisms of chitooligosaccharides on improving the cold resistance of rice (II YOU 1259) seedlings were investigated, and a novel Deg/HtrA family serine endopeptidase (DegQ) gene related to COS enhanced rice cold resistance, was identified.
Abstract: Chitooligosaccharides (COS) are multi-functional foods and nutrients and environmentally friendly biological abiotic-resistance inducing agents for plants. In the current study, the effects and possible mechanisms of COS on improving the cold resistance of rice (II YOU 1259) seedlings were investigated. Compared with the control, a COS pre-soaking treatment enhanced photosynthesis, reduced oxidation damage and led to accumulation of more osmotic regulation substances under chilling treatment. In addition, a novel Deg/HtrA family serine endopeptidase (DegQ) gene, related to COS enhanced rice cold resistance, was identified. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis revealed that transcription of DegQ and psbA (D1 protein encoding gene) were up-regulated in a time-dependent manner by COS treatment under cold stress. With increasing expression of the D1 protein, chlorophyll b content was enhanced correspondingly. The current results suggest that COS could enhance cold stress tolerance of rice by repairing the photodamaged photosystem II, altering osmotic regulation and reducing oxidation damage.
TL;DR: Some biological and chemical properties of a Gleysol were examined after 24 years of soil tillage (chisel plough -CP, mouldboard plough-MP, no-till -NT) and that of ploughing the 24-yr NT (P-NT) once, in two cropping systems applied over 4 years (2007-2010) of a long-term experiment (autumn 1987-autumn 2011) at La Pocatiere, Quebec, Canada as mentioned in this paper.
Abstract: Some biological and chemical properties of a Gleysol were examined after 24 years of soil tillage (chisel plough – CP, mouldboard plough – MP, no-till – NT) and that of ploughing the 24-yr NT (P-NT) once, in two cropping systems (conventional – CONV, organic – ORG) applied over 4 years (2007–2010) of a long-term experiment (autumn 1987–autumn 2011) at La Pocatiere, Quebec, Canada The 0–10, 10–20 and 20–30 cm soil depths were sampled in autumn 2011 after a maize trial Tillage affected light fraction organic carbon (LFOC), light fraction organic nitrogen (LFON) and mineralizable N (Nmin) in soil, with the lowest LFOC, LFON and Nmin values in the MP treatment No-till had lower soil pH than the other tillage systems in the 10–20 and 20–30 cm soil depths Tillage affected the amounts of nitrate-N in 0–10 and 10–20 cm soil depths, with the lowest amounts for MP (43 kg nitrate-N/ha) compared with NT (72 or 85 kg nitrate-N/ha) or CP (77 kg nitrate-N/ha) The P-NT had no negative impact on organic C and N, or available nutrients in soil Cropping system had no effect on soil organic C and N, available nutrients or pH Findings suggest that long-term NT or CP may result in greater storage of organic C and N in soil and improve available nutrients compared with MP Ploughing 25-year-old NT plots redistributed available nutrients in the profile but had no negative effect on soil organic C or N
TL;DR: An up-to-date overview of the adaptation mechanisms of weed species commonly found in Southern Europe is provided, in order to expand the available knowledge regarding their response to drought and elevated temperatures.
Abstract: It is challenging to predict the changes in weed flora that may occur because of changes in global climate. Limited data are available on the effect of climate change and drought conditions on weed flora and their competitiveness in Southern Europe. Future predictions by scientists indicate reduced and untimely rainfall, along with increased temperatures in this region. Weeds possess a variety of developmental and physiological mechanisms, including senescing, increased leaf cuticular wax deposition, well-developed palisade parenchyma in the leaves, high root/shoot ratio, stomatal closure, peroxidase accumulation and symbiosis with endophytes that enable them to adapt to drought and high temperatures. Because of high adaptability of weeds to adverse environmental conditions, it can be assumed that under future warmer and drier environmental conditions, their growth will be favoured, while the competitiveness of vegetable crops against weeds will be decreased. It is important to highlight that the predicted decrease in overall rainfall levels throughout the year may lead to increased problems of herbicide residues (carryover effects) to following crops. The current paper provides an up-to-date overview of the adaptation mechanisms of weed species commonly found in Southern Europe, in order to expand the available knowledge regarding their response to drought and elevated temperatures. Emphasis is placed on revealing the effects of drought and increased temperatures on vegetable–weed competition and, most importantly, its effect on vegetable crop yield.
TL;DR: The overall Principal Components Analysis results in both cuts indicate that the accessions CE7 and CE14 presented great Reb-A yield, height and lodging, and the stevia accessions showed characteristics of the interest for crop improvement for both biomass and SGs production.
Abstract: Stevia, a native species of South America, is commercially important as a source of the non-caloric diterpene glycosides stevioside and rebaudioside-A. Although it has been cultivated in southern Brazil, the production is not enough to meet the domestic market demand. This study evaluated biomass accumulation, morphological and physiological characters, and steviol glycosides yield of seven stevia accessions after two cuts. A great variation for the different plant characteristics was found between the first and second cuts. There was a positive correlation between biomass production and SGs content and productivity. The overall Principal Components Analysis results in both cuts indicate that the accessions CE7 and CE14 presented great Reb-A yield, height and lodging (%). The accessions CE4 and CE12 produced high Ste yield and accessions CE6, CE8 and CE9 the highest leaf:stem ratio and low SGs. The stevia accessions showed characteristics of the interest for crop improvement for both biomass and SGs production.
TL;DR: It is affirm that salicylic acid can be used up to the dose of 1.0 mM with no further damage to basil seeds’ quality, and the highest correlations were obtained amongst the germination variables.
Abstract: The quality of the seeds is of great importance for the cultivation of plants, however, the quality can be altered by the abiotic effects, amongst such, saline stress. Salinity is one of the great obstacles faced by modern agriculture, however, alternatives have been researched to mitigate its effects, where it is possible to mention the use of salicylic acid. The objective of this study was to evaluate the quality of basil (Ocimum basilicum L.) seeds cultivated using applications of salicylic acid to attenuate the irrigation water salinity. The experimental design was a completely randomized complete block design in incomplete factor scheme, with five conductivities for irrigation water (0.5, 1.3, 3.25, 5.2, 6.0 dS m-1) and five salicylic acid doses (0.0, 0.29, 1.0, 1.71 and 2.0 mM), with five and four replicates, respectively. The electrical conductivity presented an effect on germination, while the salicylic acid presented an effect on the germination speed index, emergence speed index, shoot length, root and seedling length, and seedlings dry mass. The highest correlations were obtained amongst the germination variables. Therefore, it is possible to affirm that salicylic acid can be used up to the dose of 1.0 mM with no further damage to basil seeds’ quality.