Agronomy

22 pages, 4186 KiB

Open AccessEditor’s ChoiceArticle

The Influence of Bio-Stimulants and Foliar Fertilizers on Yield, Plant Features, and the Level of Soil Biochemical Activity in White Lupine (Lupinus albus L.) Cultivation

by Alicja Niewiadomska, Hanna Sulewska, Agnieszka Wolna-Maruwka, Karolina Ratajczak, Zyta Waraczewska and Anna Budka

Agronomy 2020, 10(1), 150; https://doi.org/10.3390/agronomy10010150 - 20 Jan 2020

Cited by 28 | Viewed by 6422

Abstract

The aim of this study is to assess the effect of two biostimulators (Titanit, Rooter) and six foliar fertilizers (Optysil, Metalosate Potassium, Bolero Bo, ADOB 2.0 Zn IDHA, ADOB B, ADOB 2.0 Mo) on white lupine. In addition, we evaluated the enzymatic activity [...] Read more.

The aim of this study is to assess the effect of two biostimulators (Titanit, Rooter) and six foliar fertilizers (Optysil, Metalosate Potassium, Bolero Bo, ADOB 2.0 Zn IDHA, ADOB B, ADOB 2.0 Mo) on white lupine. In addition, we evaluated the enzymatic activity of dehydrogenase, acid, and alkaline phosphatases, catalase, the level of biological nitrogen fixation, yield, plant biometric, chlorophyll fluorescence and chlorophyll content. A field experiment was conducted between 2016 and 2018 at the Gorzyń Experimental and Educational Station, Poznań University of Life Sciences in Poland. The best effects in plant yield were obtained after the application of Optysil or ADOB Zn IDHA. The three years results of dehydrogenase (DHA), alkaline phosphatase (PAL), and the biological index of soil fertility (BIF), show that the bio-stimulants and most of the foliar fertilizers used did not always stimulate the activity of these enzymes and index in the white lupine crops, as compared with the control treatment. Analysis of the results of the acid phosphatase activity (PAC) shows that during the entire white lupine growing season the foliar fertilizers and bio-stimulants decreased the activity of this enzyme. This effect was not observed when the Metalosate potassium foliar fertilizer was applied. The field analyses of biological nitrogen fixation showed that the fertilizers and bio-stimulants significantly stimulated nitrogenase activity under the white lupine plantation. The best effects in plant yield were obtained after application Optysil or ADOB Zn IDHA. Full article

(This article belongs to the Special Issue Toward a Sustainable Agriculture Through Plant Biostimulants: From Experimental Data to Practical Applications)

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11 pages, 894 KiB

Open AccessArticle

Designing a Sustainable Temporary Grassland System by Monitoring Nitrogen Use Efficiency

by Anamaria Mălinas, Ioan Rotar, Roxana Vidican, Vasile Iuga, Florin Păcurar, Cristian Mălinas and Cristina Moldovan

Agronomy 2020, 10(1), 149; https://doi.org/10.3390/agronomy10010149 - 19 Jan 2020

Cited by 7 | Viewed by 3767

Abstract

Assessing the efficiency of nitrogen application is a valuable first step in establishing an optimum N fertilizer management plan. The aim of this study was to elaborate a sustainable N management system for sown grassland installed in temperate regions, through manipulation of nitrogen [...] Read more.

Assessing the efficiency of nitrogen application is a valuable first step in establishing an optimum N fertilizer management plan. The aim of this study was to elaborate a sustainable N management system for sown grassland installed in temperate regions, through manipulation of nitrogen use efficiency and nitrogen response efficiency (NRE) indicators. Research was performed in western Romania. The biological material consists in two forage species of major importance for the forage base worldwide, namely Trifolium pratense L. and Lolium multiflorum Lam., in pure stands and in mixture. Both forage species were sown at two different spacings between rows (12.5 and 25.0 cm) and were fertilized with nitrogen (N) in three doses (N0-control, N50-fertilized with 50 kg N ha⁻¹ and N100-fertilized with 100 kg N ha⁻¹). The studies were made in 2016 and 2017, years very different from each other in matter of rainfalls. The results revealed a different behavior of the three sward types analyzed: while in Trifolium pratense monoculture and in the mixture of the two species studied, less N was removed than was applied; on the other hand Lolium multiflorum monoculture used a high proportion of the N applied, being at the limit to access N from the organic pool or residual N from fertilizer applications to a preceding crop. Full article

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16 pages, 2102 KiB

Open AccessEditor’s ChoiceArticle

Performance Evaluation of Two Commercially Available Portable Spectrometers to Non-Invasively Determine Table Grape and Peach Quality Attributes

by Irwin R. Donis-González, Constantino Valero, Md Abdul Momin, Amanjot Kaur and David C. Slaughter

Agronomy 2020, 10(1), 148; https://doi.org/10.3390/agronomy10010148 - 19 Jan 2020

Cited by 37 | Viewed by 6275

Abstract

Near-infrared (NIR) spectroscopy has been used to non-destructively and rapidly evaluate the quality of fresh agricultural produce. In this study, two commercially available portable spectrometers (F-750: Felix Instruments, WA, USA; and SCiO: Consumer Physics, Tel Aviv, Israel) were evaluated in the wavelength range [...] Read more.

Near-infrared (NIR) spectroscopy has been used to non-destructively and rapidly evaluate the quality of fresh agricultural produce. In this study, two commercially available portable spectrometers (F-750: Felix Instruments, WA, USA; and SCiO: Consumer Physics, Tel Aviv, Israel) were evaluated in the wavelength range between 740 and 1070 nm to non-invasively predict quality attributes, including the dry matter (DM), and total soluble solids (TSS) content of three fresh table grape cultivars (‘Autumn Royal’, ‘Timpson’, and ‘Sweet Scarlet’) and one peach cultivar (‘Cassie’). Prediction models were developed using partial least-square regression (PLSR) to correlate the NIR absorbance spectra with the invasive quality measurements. In regard to grapes, the best DM prediction models yielded an R² of 0.83 and 0.81, a ratio of standard error of performance to standard deviation (RPD) of 2.35 and 2.29, and a root mean square error of prediction (RMSEP) of 1.40 and 1.44; and the best TSS prediction models generated an R² of 0.97 and 0.95, an RPD of 5.95 and 4.48, and an RMSEP of 0.53 and 0.70 for the F-750 and SCiO spectrometers, respectively. Overall, PLSR prediction models using both spectrometers were promising to predict table grape quality attributes. Regarding peach, the PLSR prediction models did not perform as well as in grapes, as DM prediction models resulted in an R² of 0.81 and 0.67, an RPD of 2.24 and 1.74, and an RMSEP of 1.28 and 1.66; and TSS resulted in an R² of 0.62 and 0.55, an RPD of 1.55 and 1.48, and an RMSEP of 1.19 and 1.25 for the F-750 and SCiO spectrometers, respectively. Overall, the F-750 spectrometer prediction models performed better than those generated by using the SCiO spectrometer data. Full article

(This article belongs to the Special Issue Selected Papers from 10th Iberian Agroengineering Congress)

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17 pages, 1547 KiB

Open AccessArticle

Soil Pollution by Petroleum-Derived Substances and its Bioremediation: The Effect on Aphis fabae Scop. Infestation and Antioxidant Response in Vicia faba L.

by Milena Rusin, Janina Gospodarek and Aleksandra Nadgórska-Socha

Agronomy 2020, 10(1), 147; https://doi.org/10.3390/agronomy10010147 - 19 Jan 2020

Cited by 9 | Viewed by 3471

Abstract

In this study, the effects of soil contamination with petroleum-derived substances (PDSs) (petrol, diesel fuel and used engine oil) and its bioremediation using biopreparation ZB-01 on broad bean infestation by black bean aphid Aphis fabae Scop., as well as on the antioxidant enzymes [...] Read more.

In this study, the effects of soil contamination with petroleum-derived substances (PDSs) (petrol, diesel fuel and used engine oil) and its bioremediation using biopreparation ZB-01 on broad bean infestation by black bean aphid Aphis fabae Scop., as well as on the antioxidant enzymes activity (superoxide dismutase (SOD), catalase (CAT) and guaiacol peroxidase (POD)) and antioxidant (non-protein thiols and proline) content in plant leaves, were determined. Results showed that after three years from the moment of soil contamination PDSs limited infestation of broad bean by A. fabae. However, the adverse effects on aphids’ life cycles were not proven. The lowered infestation may result from the lower attractiveness of contaminated plants to pests. PDSs significantly affected the activities of enzymes and the antioxidants content, with that effect being diversified. The increased activity of SOD was found in plants exposed to diesel fuel, together with the lowest numbers of aphids accompanying it, which can suggest a certain role of the enzyme in pest response to the stress caused by this PDS. The ZB-01 biopreparation limited the adverse effect of PDSs on the degree of broad bean plant infestation by A. fabae. Its influence on the antioxidant response was diversified. In the plants exposed to EO, changes in antioxidant response were reduced under the influence of ZB-01. Full article

(This article belongs to the Special Issue Bioremediation of Contaminated Soil in Agriculture)

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14 pages, 1490 KiB

Open AccessArticle

Evaluation of Different Fall Dormancy-Rating Alfalfa Cultivars for Forage Yield in a Semiarid Environment

by Koffi Djaman, Curtis Owen, Komlan Koudahe and Michael O’Neill

Agronomy 2020, 10(1), 146; https://doi.org/10.3390/agronomy10010146 - 19 Jan 2020

Cited by 27 | Viewed by 5247

Abstract

Alfalfa is one of the most important, nutritive, and high yielding forage legumes planted across the US. Fall dormancy in alfalfa influences forage yield characteristics and the plants persistence mostly under the cold and temperate climate. The objective of this study was to [...] Read more.

Alfalfa is one of the most important, nutritive, and high yielding forage legumes planted across the US. Fall dormancy in alfalfa influences forage yield characteristics and the plants persistence mostly under the cold and temperate climate. The objective of this study was to evaluate alfalfa cultivars with different fall dormancy-ratings for their forage yield at each cut and the annual forage yield. Two sets of 24 alfalfa cultivars were evaluated in a field experiment conducted at the Agricultural Science Center at Farmington, NM. The first set of 24 cultivars was planted late fall 2007 at seeding rate of 22.4 kg ha⁻¹ and managed for the 2007–2011 period and the second set was planted late fall 2009 and managed during the 2009–2013 period. Average forage yield varied with years from 7.6 to 2.9 Mg ha⁻¹, 6.8 to 4.3 Mg ha⁻¹, 9.2 to 4.2 Mg ha⁻¹, and 7.9 to 3.2 Mg ha⁻¹ during the 1st, 2nd, 3rd, and 4th alfalfa cut, respectively. The results showed no statistical differences between the moderately dormant, dormant, and the non-dormant alfalfa cultivars while they showed higher forage yield than the very dormant and semi-dormant alfalfa cultivars. There was a decreasing trend in forage yield from the first cut to the fourth cut in each growing season. However, the very dormant cultivars showed the lowest forage yield. Alfalfa forage yield decreased from the cut 1 to the cut 4 which represented on average 33, 29, 22, and 16% of the annual yield. The semi-dormant cultivars obtained the lowest forage yield at the first and second cutting while there was no difference between the cultivars for the third and fourth harvests. Average forage yields per harvest were 5.7, 5.9, 6.0, 5.5, and 5.9 Mg ha⁻¹ for the very dormant, dormant, moderately dormant, semi-dormant, and non-dormant alfalfa cultivars, respectively. Annual forage yield varied with alfalfa fall dormancy-ratings and ranged from 15.5 to 29.9 Mg ha⁻¹ with the highest forage yield achieved during the third years of the production. The moderately dormant and the non-dormant cultivars showed the highest yield during the first harvest year while the very dormant cultivars and dormant cultivars had the lowest forage yield. Alfalfa cultivars with a fall dormancy range 4–5 may be considered for alfalfa production in northwest New Mexico however, the good agricultural practices (conservation tillage, fertilizer management based on soil residual available nutrient and crop requirement, recommended planting rate, weed and pest management, irrigation scheduling to match crop evapotranspiration) should be the most important to maximize alfalfa forage yield in the southwest US. Full article

(This article belongs to the Special Issue Breeding and Genetics of Forages for Semi-Arid and Arid Rangelands)

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17 pages, 15170 KiB

Open AccessArticle

Ultraviolet Index (UVI) inside an Almería-Type Greenhouse (Southeastern Spain)

by Rubén A. García-Ruiz, Javier López-Martínez, José L. Blanco-Claraco, José Pérez-Alonso and Ángel J. Callejón-Ferre

Agronomy 2020, 10(1), 145; https://doi.org/10.3390/agronomy10010145 - 19 Jan 2020

Cited by 2 | Viewed by 5685

Abstract

Greenhouse workers, despite being in a space beneath a plastic cover, may be susceptible to risks associated to ultraviolet (UV) radiation in skin and eyes. The present work focuses on experimentally analysing this risk throughout a complete year. For this purpose, a network [...] Read more.

Greenhouse workers, despite being in a space beneath a plastic cover, may be susceptible to risks associated to ultraviolet (UV) radiation in skin and eyes. The present work focuses on experimentally analysing this risk throughout a complete year. For this purpose, a network of sensors has been designed, comprising 12 UV radiation measuring stations inside the greenhouse and one outside. It is shown that the UVI risk limit established by World Health Organization (WHO) is exceeded for some particular dates and times, thus there exist risk of damage caused by UV radiation for greenhouse workers. The results allow to identify the UV risk periods for the location studied. A diagram called “UVIgram” has been created which offers weather and UV radiation information for a particular location, for each month, and also in general for the whole year. Finally, a series of recommendations and protection measures are given, highlighting the whitening of the plastic cover of the greenhouse and an alarm system which has been designed to alert workers when UV risk exists. Full article

(This article belongs to the Special Issue Greenhouse Technology)

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23 pages, 1445 KiB

Open AccessArticle

Mapping Agronomic and Quality Traits in Elite Durum Wheat Lines under Differing Water Regimes

by Rosa Mérida-García, Alison R. Bentley, Sergio Gálvez, Gabriel Dorado, Ignacio Solís, Karim Ammar and Pilar Hernandez

Agronomy 2020, 10(1), 144; https://doi.org/10.3390/agronomy10010144 - 19 Jan 2020

Cited by 10 | Viewed by 5681

Abstract

Final grain production and quality in durum wheat are affected by biotic and abiotic stresses. The association mapping (AM) approach is useful for dissecting the genetic control of quantitative traits, with the aim of increasing final wheat production under stress conditions. In this [...] Read more.

Final grain production and quality in durum wheat are affected by biotic and abiotic stresses. The association mapping (AM) approach is useful for dissecting the genetic control of quantitative traits, with the aim of increasing final wheat production under stress conditions. In this study, we used AM analyses to detect quantitative trait loci (QTL) underlying agronomic and quality traits in a collection of 294 elite durum wheat lines from CIMMYT (International Maize and Wheat Improvement Center), grown under different water regimes over four growing seasons. Thirty-seven significant marker-trait associations (MTAs) were detected for sedimentation volume (SV) and thousand kernel weight (TKW), located on chromosomes 1B and 2A, respectively. The QTL loci found were then confirmed with several AM analyses, which revealed 12 sedimentation index (SDS) MTAs and two additional loci for SV (4A) and yellow rust (1B). A candidate gene analysis of the identified genomic regions detected a cluster of 25 genes encoding blue copper proteins in chromosome 1B, with homoeologs in the two durum wheat subgenomes, and an ubiquinone biosynthesis O-methyltransferase gene. On chromosome 2A, several genes related to photosynthetic processes and metabolic pathways were found in proximity to the markers associated with TKW. These results are of potential use for subsequent application in marker-assisted durum wheat-breeding programs. Full article

(This article belongs to the Special Issue Molecular Marker Technology for Crop Improvement)

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21 pages, 40290 KiB

Open AccessEditor’s ChoiceArticle

Deep Learning for Mango (Mangifera indica) Panicle Stage Classification

by Anand Koirala, Kerry B. Walsh, Zhenglin Wang and Nicholas Anderson

Agronomy 2020, 10(1), 143; https://doi.org/10.3390/agronomy10010143 - 18 Jan 2020

Cited by 33 | Viewed by 9113

Abstract

Automated assessment of the number of panicles by developmental stage can provide information on the time spread of flowering and thus inform farm management. A pixel-based segmentation method for the estimation of flowering level from tree images was confounded by the developmental stage. [...] Read more.

Automated assessment of the number of panicles by developmental stage can provide information on the time spread of flowering and thus inform farm management. A pixel-based segmentation method for the estimation of flowering level from tree images was confounded by the developmental stage. Therefore, the use of a single and a two-stage deep learning framework (YOLO and R²CNN) was considered, using either upright or rotated bounding boxes. For a validation image set and for a total panicle count, the models MangoYOLO(-upright), MangoYOLO-rotated, YOLOv3-rotated, R²CNN(-rotated) and R²CNN-upright achieved weighted F1 scores of 76.5, 76.1, 74.9, 74.0 and 82.0, respectively. For a test set of the images of another cultivar and using a different camera, the R² for machine vision to human count of panicles per tree was 0.86, 0.80, 0.83, 0.81 and 0.76 for the same models, respectively. Thus, there was no consistent benefit from the use of rotated over the use of upright bounding boxes. The YOLOv3-rotated model was superior in terms of total panicle count, and the R²CNN-upright model was more accurate for panicle stage classification. To demonstrate practical application, panicle counts were made weekly for an orchard of 994 trees, with a peak detection routine applied to document multiple flowering events. Full article

(This article belongs to the Special Issue In-Field Estimation of Fruit Quality and Quantity)

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14 pages, 1782 KiB

Open AccessArticle

Effect of UV Radiation and Salt Stress on the Accumulation of Economically Relevant Secondary Metabolites in Bell Pepper Plants

by Jan Ellenberger, Nils Siefen, Priska Krefting, Jan-Bernd Schulze Lutum, Daniel Pfarr, Maja Remmel, Lukas Schröder and Simone Röhlen-Schmittgen

Agronomy 2020, 10(1), 142; https://doi.org/10.3390/agronomy10010142 - 18 Jan 2020

Cited by 27 | Viewed by 6698

Abstract

The green biomass of horticultural plants contains valuable secondary metabolites (SM), which can potentially be extracted and sold. When exposed to stress, plants accumulate higher amounts of these SMs, making the extraction and commercialization even more attractive. We evaluated the potential for accumulating [...] Read more.

The green biomass of horticultural plants contains valuable secondary metabolites (SM), which can potentially be extracted and sold. When exposed to stress, plants accumulate higher amounts of these SMs, making the extraction and commercialization even more attractive. We evaluated the potential for accumulating the flavones cynaroside and graveobioside A in leaves of two bell pepper cultivars (Mavras and Stayer) when exposed to salt stress (100 mM NaCl), UVA/B excitation (UVA 4–5 W/m²; UVB 10–14 W/m² for 3 h per day), or a combination of both stressors. Plant age during the trials was 32–48 days. HPLC analyses proved the enhanced accumulation of both metabolites under stress conditions. Cynaroside accumulation is effectively triggered by high-UV stress, whereas graveobioside A contents increase under salt stress. Highest contents of secondary metabolites were observed in plants exposed to combined stress. Effects of stress on overall plant performance differed significantly between treatments, with least negative impact on above ground biomass found for high-UV stressed plants. The usage of two non-destructive instruments (Dualex and Multiplex) allowed us to gain insights into the ontogenetical effects at the leaf level and temporal development of SM contents. Indices provided by those devices correlate fairly with amounts detected via HPLC (Cynaroside: r² = 0.46–0.66; Graveobioside A: r² = 0.51–0.71). The concentrations of both metabolites tend to decrease at leaf level during the ontogenetical development even under stress conditions. High-UV stress should be considered as a tool for enriching plant leaves with valuable SM. Effects on the performance of plants throughout a complete production cycle should be evaluated in future trials. All data is available online. Full article

(This article belongs to the Special Issue Soilless Culture, Growing Media and Horticultural Plants)

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15 pages, 727 KiB

Open AccessArticle

Reaction of Sweet Maize to the Use of Polyethylene Film and Polypropylene Non-Woven Fabric in the Initial Growth Phase

by Katarzyna Adamczewska-Sowińska and Józef Sowiński

Agronomy 2020, 10(1), 141; https://doi.org/10.3390/agronomy10010141 - 18 Jan 2020

Cited by 8 | Viewed by 3388

Abstract

Sweet maize (Zea mays L. var. saccharata Bailey) is a valuable vegetable adapted to growing in temperate climate conditions. Temperature, especially in the beginning of the growing period, has a crucial effect on vegetation and yield. The best maize initial growth requires [...] Read more.

Sweet maize (Zea mays L. var. saccharata Bailey) is a valuable vegetable adapted to growing in temperate climate conditions. Temperature, especially in the beginning of the growing period, has a crucial effect on vegetation and yield. The best maize initial growth requires soil temperature above 10 °C. Maize covered by polyethylene film and polypropylene non-woven fabric leads to an increase in temperatures which accelerates crop growth. Three years (2012–2014) of field experiments were carried out at the Research and Didactic Station in Psary, belonging to the Department of Horticulture of Wroclaw University of Environmental and Life Sciences. A three-factorial experiment was established using the randomized subblock method in three repetitions in the years 2012–2014. Cobs were harvested in the milk-dough phase of grain maturity. Hybrid Rustler F1 produced, on average, 35.4% more marketable yield than Signet F1. On average, 10.2% more cobs and 22.7% more cobs (with Hybrid Rustler F1 and Signet F1, respectively) were harvested in cases when the sowing was performed in the third decade of April. The use of covers contributed to a significant increase in the yield compared to the yield of uncovered plants. Transparent foil also contributed to a significant increase in the number of cobs harvested in the marketable yield. Full article

(This article belongs to the Section Horticultural and Floricultural Crops)

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35 pages, 2864 KiB

Open AccessEditor’s ChoiceReview

A Review of Current and Potential Applications of Remote Sensing to Study the Water Status of Horticultural Crops

by Deepak Gautam and Vinay Pagay

Agronomy 2020, 10(1), 140; https://doi.org/10.3390/agronomy10010140 - 17 Jan 2020

Cited by 42 | Viewed by 8349

Abstract

With increasingly advanced remote sensing systems, more accurate retrievals of crop water status are being made at the individual crop level to aid in precision irrigation. This paper summarises the use of remote sensing for the estimation of water status in horticultural crops. [...] Read more.

With increasingly advanced remote sensing systems, more accurate retrievals of crop water status are being made at the individual crop level to aid in precision irrigation. This paper summarises the use of remote sensing for the estimation of water status in horticultural crops. The remote measurements of the water potential, soil moisture, evapotranspiration, canopy 3D structure, and vigour for water status estimation are presented in this comprehensive review. These parameters directly or indirectly provide estimates of crop water status, which is critically important for irrigation management in farms. The review is organised into four main sections: (i) remote sensing platforms; (ii) the remote sensor suite; (iii) techniques adopted for horticultural applications and indicators of water status; and, (iv) case studies of the use of remote sensing in horticultural crops. Finally, the authors’ view is presented with regard to future prospects and research gaps in the estimation of the crop water status for precision irrigation. Full article

(This article belongs to the Special Issue Increasing Agricultural Water Productivity in a Changing Environment)

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21 pages, 8869 KiB

Open AccessArticle

Interactive Effects of the CO₂ Enrichment and Nitrogen Supply on the Biomass Accumulation, Gas Exchange Properties, and Mineral Elements Concentrations in Cucumber Plants at Different Growth Stages

by Xun Li, Jinlong Dong, Nazim S. Gruda, Wenying Chu and Zengqiang Duan

Agronomy 2020, 10(1), 139; https://doi.org/10.3390/agronomy10010139 - 17 Jan 2020

Cited by 16 | Viewed by 4678

Abstract

The concentration changes of mineral elements in plants at different CO₂ concentrations ([CO₂]) and nitrogen (N) supplies and the mechanisms which control such changes are not clear. Hydroponic trials on cucumber plants with three [CO₂] (400, 625, and [...] Read more.

The concentration changes of mineral elements in plants at different CO₂ concentrations ([CO₂]) and nitrogen (N) supplies and the mechanisms which control such changes are not clear. Hydroponic trials on cucumber plants with three [CO₂] (400, 625, and 1200 μmol mol⁻¹) and five N supply levels (2, 4, 7, 14, and 21 mmol L⁻¹) were conducted. When plants were in high N supply, the increase in total biomass by elevated [CO₂] was 51.7% and 70.1% at the seedling and initial fruiting stages, respectively. An increase in net photosynthetic rate (Pn) by more than 60%, a decrease in stomatal conductance (Gs) by 21.2–27.7%, and a decrease in transpiration rate (Tr) by 22.9–31.9% under elevated [CO₂] were also observed. High N supplies could further improve the Pn and offset the decrease of Gs and Tr by elevated [CO₂]. According to the mineral concentrations and the correlation results, we concluded the main factors affecting these changes. The dilution effect was the main factor driving the reduction of all mineral elements, whereas Tr also had a great impact on the decrease of [N], [K], [Ca], and [Mg] except [P]. In addition, the demand changes of N, Ca, and Mg influenced the corresponding element concentrations in cucumber plants. Full article

(This article belongs to the Special Issue Soilless Culture, Growing Media and Horticultural Plants)

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14 pages, 480 KiB

Open AccessEditor’s ChoiceArticle

Using Digestate and Biochar as Fertilizers to Improve Processing Tomato Production Sustainability

by Domenico Ronga, Federica Caradonia, Mario Parisi, Guido Bezzi, Bruno Parisi, Giulio Allesina, Simone Pedrazzi and Enrico Francia

Agronomy 2020, 10(1), 138; https://doi.org/10.3390/agronomy10010138 - 17 Jan 2020

Cited by 68 | Viewed by 6685

Abstract

The principal goal of the organic farming system (OFS) is to develop enterprises that are sustainable and harmonious with the environment. Unfortunately, the OFS yields fewer products per land than the non-organic farming system in many agricultural products. The objective of our study [...] Read more.

The principal goal of the organic farming system (OFS) is to develop enterprises that are sustainable and harmonious with the environment. Unfortunately, the OFS yields fewer products per land than the non-organic farming system in many agricultural products. The objective of our study was to assess the effects of digestate and biochar fertilizers on yield and fruit quality of processing tomato produced under the OFS. The experiment was carried out in Po Valley, during the 2017 and 2018 growing seasons. Liquid digestate (LD), LD + biochar (LD + BC) and pelleted digestate (PD) were evaluated and compared to biochar (BC) application and unfertilized control. The results showed that plants fertilized with LD + BC recorded the maximum marketable yield (72 t ha⁻¹), followed by BC (67 t ha⁻¹), PD (64 t ha⁻¹) and LD (59 t ha⁻¹); while the lowest production (47 t ha⁻¹) was recorded in unfertilized plants. Over the two cropping seasons, LD + BC, BC, PD, and LD, increased fruit number per plant (+15%), fruit weight (+24%), Brix t ha⁻¹ (+41%) and reduced Bostwick index (−16%), if compared to the untreated control. Considering the overall agronomic performances, digestate and biochar can be useful options for increasing yield and quality of processing tomato production in the OFS. Hence, these fertilizers can be assessed in future research both on other crops and farming systems. Full article

(This article belongs to the Special Issue Herbaceous Field Crops Cultivation)

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25 pages, 359 KiB

Open AccessEditorial

Acknowledgement to Reviewers of Agronomy in 2019

by Agronomy Editorial Office

Agronomy 2020, 10(1), 151; https://doi.org/10.3390/agronomy10010151 - 16 Jan 2020

Viewed by 3286

Abstract

The editorial team greatly appreciates the reviewers who have dedicated their considerable time and expertise to the journal’s rigorous editorial process over the past 12 months, regardless of whether the papers are finally published or not [...] Full article

16 pages, 1083 KiB

Open AccessEditor’s ChoiceArticle

Chlorophyll Fluorescence, Photosynthesis and Growth of Tomato Plants as Affected by Long-Term Oxygen Root Zone Deprivation and Grafting

by Rosario Paolo Mauro, Michele Agnello, Miriam Distefano, Leo Sabatino, Alberto San Bautista Primo, Cherubino Leonardi and Francesco Giuffrida

Agronomy 2020, 10(1), 137; https://doi.org/10.3390/agronomy10010137 - 16 Jan 2020

Cited by 40 | Viewed by 5283

Abstract

A greenhouse experiment was conducted to study the effects of the O₂ root zone level and grafting on chlorophyll fluorescence, photosynthesis and growth of cherry tomato grown in a hydroponic system. Two O₂ concentrations in the root zone, namely Ox (saturation [...] Read more.

A greenhouse experiment was conducted to study the effects of the O₂ root zone level and grafting on chlorophyll fluorescence, photosynthesis and growth of cherry tomato grown in a hydroponic system. Two O₂ concentrations in the root zone, namely Ox (saturation level) and Ox- (2–3 mg L⁻¹), were applied for 30 days on self-grafted cherry tomato Dreamer or grafted onto the hybrids Arnold, Beaufort, Maxifort and Top Pittam. Root hypoxia increased minimum fluorescence (by 10%) while it decreased variable fluorescence and the maximum quantum yield of PSII (up to 16 and 8%, respectively). Moreover, it reduced leaf photosynthesis, transpiration and stomatal conductance (by 12, 17 and 13%, respectively), whereas it increased leaf electrolyte leakage (by 2.1%). The graft combinations showed a different ability in buffering the effects of root hypoxia on plant growth and related components, and these differences were related to their root biomass. The minimum fluorescence was negatively correlated to plant growth, so it may be a useful indicator to select tolerant rootstocks to root hypoxia. Our results suggest the occurrence of both diffusive and metabolic constraints to tomato photosynthesis under root hypoxia, a condition that can be mitigated by selecting rootstocks with a more developed root system. Full article

(This article belongs to the Special Issue Recent Advances in Rootstock of Vegetable Plants)

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18 pages, 1786 KiB

Open AccessArticle

Allelic Variation for Prolamins in Spanish Durum Wheat Landraces and Its Relationship with Quality Traits

by Efraín A. Chacón, Francisco J. Vázquez, Patricia Giraldo, José M. Carrillo, Elena Benavente and Marta Rodríguez-Quijano

Agronomy 2020, 10(1), 136; https://doi.org/10.3390/agronomy10010136 - 16 Jan 2020

Cited by 22 | Viewed by 4201

Abstract

Wheat landraces are currently being explored mainly as a source of allelic variation related to crop resilience and low-input adaptation. Characterization of their high- and low-molecular weight glutenin subunits can aid breeders to select as donor local materials those ensuring good end-use properties [...] Read more.

Wheat landraces are currently being explored mainly as a source of allelic variation related to crop resilience and low-input adaptation. Characterization of their high- and low-molecular weight glutenin subunits can aid breeders to select as donor local materials those ensuring good end-use properties in the derived elite cultivars. By using protein electrophoretic methods, we have determined the prolamin allelic profile of 116 Spanish durum wheat landraces. Their quality properties (as defined by grain protein content, sodium dodecyl sulfate (SDS) sedimentation volume and mixograph behavior) have also been assessed. The study has identified six novel glutenin alleles plus some other rare alleles some of which have been associated with improved durum wheat quality. Most of the novel variation detected needs to be characterized in a wider sample of varieties to establish any eventual beneficial effect on functional quality. Further analysis of the quality properties associated to specific allele combinations of Glu-A3, Glu-B3, and Glu-A1 has disclosed some clues on the influence on quality of certain non-allelic interactions between these main prolamin-encoding loci. Some of the landraces, showing outstanding values for the gluten quality parameters analyzed, might be directly used by farmers interested in the cultivation of traditional varieties for specialized food markets. Full article

(This article belongs to the Special Issue Analysis of Crop Genetic and Germplasm Diversity)

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17 pages, 560 KiB

Open AccessArticle

The Impacts of Flowering Time and Tillering on Grain Yield of Sorghum Hybrids across Diverse Environments

by Xuemin Wang, Colleen Hunt, Alan Cruickshank, Emma Mace, Graeme Hammer and David Jordan

Agronomy 2020, 10(1), 135; https://doi.org/10.3390/agronomy10010135 - 16 Jan 2020

Cited by 12 | Viewed by 4380

Abstract

Sorghum in Australia is grown in water-limited environments of varying extent, generating substantial genotype × environment interactions (GEIs) for grain yield. Much of the yield variation and GEI results from variations in flowering time and tillering through their effects on canopy development. The [...] Read more.

Sorghum in Australia is grown in water-limited environments of varying extent, generating substantial genotype × environment interactions (GEIs) for grain yield. Much of the yield variation and GEI results from variations in flowering time and tillering through their effects on canopy development. The confounding effects of flowering and tillering complicate the interpretation of breeding trials. In this study, we evaluated the impacts of both flowering time (DTF) and tillering capacity (FTN) on the yield of 1741 unique test hybrids derived from three common female testers in 21 yield testing trials (48 tester/trial combinations) across the major sorghum production regions in Australia in three seasons. Contributions of DTF and FTN to genetic variation in grain yield were significant in 14 and 12 tester/trial combinations, respectively. The proportion of genetic variance in grain yield explained by DTF and FTN ranged from 0.2% to 61.0% and from 1.4% to 56.9%, respectively, depending on trials and genetic background of female testers. The relationship of DTF or FTN with grain yield of hybrids was frequently positive but varied across the genetic background of testers. Accounting for the effects of DTF and FTN using linear models did not substantially increase the between-trial genetic correlations for grain yield. The results suggested that other factors affecting canopy development dynamics and grain yield might contribute GEI and/or the linear approach to account for DTF and FTN on grain yield did not capture the complex non-linear interactions. Full article

(This article belongs to the Special Issue Breeding Sorghum for Adaptation to Abiotic Stress through Use of Heterosis)

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17 pages, 864 KiB

Open AccessArticle

Effects of Low Water Availability on Root Placement and Shoot Development in Landraces and Modern Barley Cultivars

by Ridha Boudiar, Ana M. Casas, Tania Gioia, Fabio Fiorani, Kerstin A. Nagel and Ernesto Igartua

Agronomy 2020, 10(1), 134; https://doi.org/10.3390/agronomy10010134 - 16 Jan 2020

Cited by 22 | Viewed by 5757

Abstract

Early vigor has been proposed as a favorable trait for cereals grown in drought-prone environments. This research aimed at characterizing early stage shoot and root growth of three Spanish barley landraces compared with three modern cultivars. Genotypes were grown in an automated phenotyping [...] Read more.

Early vigor has been proposed as a favorable trait for cereals grown in drought-prone environments. This research aimed at characterizing early stage shoot and root growth of three Spanish barley landraces compared with three modern cultivars. Genotypes were grown in an automated phenotyping platform, GrowScreen-Rhizo, under well-watered and drought conditions. Seminal and lateral root length, root system width and depth were recorded automatically during the experiment. Drought induced greater growth reduction in shoots (43% dry weight reduction) than in roots (23% dry weight). Genotypic differences were larger under no stress, partly due to a more profuse growth of landraces in this treatment. Accession SBCC146 was the most vigorous for shoot growth, whereas SBCC073 diverted more assimilates to root growth. Among cultivars, Cierzo was the most vigorous one and Scarlett had the least root dry weight of all genotypes, under both conditions. Root growth was redirected to lateral roots when seminal roots could not progress further in dry soil. This study reveals the presence of genetic diversity in dynamics of early growth of barley. The different patterns of growth observed for SBCC073 and SBCC146 should be explored further, to test if they affect field performance of barley in drought-prone environments. Full article

(This article belongs to the Special Issue Crop Genetic Adaptation to Changing Climate Conditions)

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19 pages, 724 KiB

Open AccessArticle

Plant Biostimulant Effects of Baker’s Yeast Vinasse and Selenium on Tomatoes through Foliar Fertilization

by Stefan-Ovidiu Dima, Constantin Neamțu, Malina Desliu-Avram, Marius Ghiurea, Luiza Capra, Elena Radu, Rusăndica Stoica, Victor-Alexandru Faraon, Valentin Zamfiropol-Cristea, Diana Constantinescu-Aruxandei and Florin Oancea

Agronomy 2020, 10(1), 133; https://doi.org/10.3390/agronomy10010133 - 16 Jan 2020

Cited by 20 | Viewed by 6745

Abstract

The application of selenium (Se) to tomatoes enhances accumulation of bioactive compounds. The physiological window of Se is very narrow, and Se overdose reduces the yield. Glycine betaine was shown to reduce Se’s negative effects on plants and to potentiate its beneficial effects. [...] Read more.

The application of selenium (Se) to tomatoes enhances accumulation of bioactive compounds. The physiological window of Se is very narrow, and Se overdose reduces the yield. Glycine betaine was shown to reduce Se’s negative effects on plants and to potentiate its beneficial effects. In this study, baker’s yeast vinasse (BYV), as an affordable source of glycine betaine, was tested for its interaction with Se in an optimized foliar fertilizer. The application dose was selected after a laboratory experiment, wherein assays on plant height, leaves surfaces, stomatal conductance, and chlorophyll fluorescence were done. The Se and BYV supplemented foliar fertilizers were tested for their effects on accumulation of bioactives in drip-irrigated tomatoes cultivated in a greenhouse. Under laboratory conditions, assays demonstrated Se and BYV induced effects on tomatoes plants. Both the stomatal conductance and photosynthesis efficiency increased compared to a water treated control. The greenhouse experiment demonstrated that BYV and Se addition increases the number of tomato fruits in the “extra” marketable class and enhances the accumulation of ascorbic acid, carotenes, polyphenols, and flavonoids. The effects depend on the composition of the foliar fertilizer, the most significant effects being recorded for the foliar applied product with the highest BYV and nitrogen content. Full article

(This article belongs to the Special Issue Effects of Biostimulants and Bioeffectors on Plant Growth)

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13 pages, 2002 KiB

Open AccessArticle

Combined Application of Organic and Inorganic Nitrogen Fertilizers Affects Soil Prokaryotic Communities Compositions

by Liyuan Liu, Chuanzong Li, Shuhao Zhu, Yan Xu, Houyu Li, Xiangqun Zheng and Rongguang Shi

Agronomy 2020, 10(1), 132; https://doi.org/10.3390/agronomy10010132 - 16 Jan 2020

Cited by 30 | Viewed by 4981

Abstract

As a fundamental part of the soil ecosystem, prokaryotes are involved in the preservation of soil functions. However, little is known of how the combined application of long-term organic and inorganic nitrogen fertilizer affects the prokaryotic communities’ dynamics at a paddy field. A [...] Read more.

As a fundamental part of the soil ecosystem, prokaryotes are involved in the preservation of soil functions. However, little is known of how the combined application of long-term organic and inorganic nitrogen fertilizer affects the prokaryotic communities’ dynamics at a paddy field. A long-term positioning experiment initiated in 2013 with four treatments (NO: no N fertilizer, CN: 100% urea N with no organic fertilizer, PM: 80% urea N plus 20% N with pig manure, CM: 80% urea N plus 20% N with compost) were applied to detect the differential responses of soil physicochemical properties, and prokaryotic community structure and composition in different fertilization regimes. The results indicated that the long-term combined application of organic and inorganic nitrogen fertilizers altered the physicochemical properties to some extent and, simultaneously, established unique prokaryotic communities. In detail, the treatment of PM and CM significantly increased the content of soil organic carbon (SOC) and total nitrogen (TN) compared to NO. Moreover, a total of 31 indicator taxa were screened across the four treatments by LDA Effect Size (LEfSe) analysis following the principle of the greatest differences, which suggests that these indicator taxa were more sensitive to the fertilization. This research suggested that the combined application of long-term organic and inorganic nitrogen fertilizers not only contributed to the soil’s physicochemical properties but also changed the prokaryotic community composition. Full article

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14 pages, 1802 KiB

Open AccessArticle

Floral Scent Evaluation of Three Cut Flowers Through Sensorial and Gas Chromatography Analysis

by Danilo Aros, Nicole Garrido, Constanza Rivas, Marcela Medel, Carsten Müller, Hilary Rogers and Cristina Úbeda

Agronomy 2020, 10(1), 131; https://doi.org/10.3390/agronomy10010131 - 16 Jan 2020

Cited by 23 | Viewed by 7016

Abstract

The main function of floral scent is to attract and guide pollinators, but it is also an important character in the ornamental plant industry. Several studies have considered the chemical evaluation of floral scent during vase life, but only a few have considered [...] Read more.

The main function of floral scent is to attract and guide pollinators, but it is also an important character in the ornamental plant industry. Several studies have considered the chemical evaluation of floral scent during vase life, but only a few have considered sensorial analysis of this character, which is a very important quality trait for the marketing of ornamental plants. This study focused on assessing the floral scent of three fragrant cut flowers of high economic importance: Lilium, chrysanthemum, and freesia. Eighty individuals were included in a sensorial analysis where the attributes of floral scent liking and intensity were evaluated. The composition of the floral scent was analyzed through the collection of headspace followed by gas chromatography-mass spectrometry (GC-MS). The floral scents of oriental lily and freesia were perceived as more intense, compared to chrysanthemum. A total of 28 volatile compounds were detected and the monoterpenes β-pinene (40.7 ± 1.8 μg·L⁻¹), β-cis-ocimene (5552 ± 990 μg·L⁻¹), and linalool (11,800 ± 220 μg·L⁻¹) were the major volatile organic compounds (VOCs) present in chrysanthemum, lilium, and freesia, respectively. The results presented in this study confirm that the concentration and abundance of volatile compounds is not directly related to the human perception of floral scent. Full article

(This article belongs to the Special Issue Postharvest Physiology of Ornamentals: Processes and Their Regulation)

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14 pages, 834 KiB

Open AccessArticle

Identifying the Critical Stage Near Anthesis for Waterlogging on Wheat Yield and Its Components in the Yangtze River Basin, China

by Jinfeng Ding, Peng Liang, Peng Wu, Min Zhu, Chunyan Li, Xinkai Zhu and Wenshan Guo

Agronomy 2020, 10(1), 130; https://doi.org/10.3390/agronomy10010130 - 16 Jan 2020

Cited by 19 | Viewed by 3521

Abstract

Frequent waterlogging near anthesis is a primary constraint for wheat production in the Yangtze River Basin, China. This study aimed to identify the critical stage for waterlogging on wheat yield and its components and identify the possible factors determining this stage. In the [...] Read more.

Frequent waterlogging near anthesis is a primary constraint for wheat production in the Yangtze River Basin, China. This study aimed to identify the critical stage for waterlogging on wheat yield and its components and identify the possible factors determining this stage. In the first experiment (E1), we evaluated three varieties and initiated a 10-day waterlogging starting at the stem elongation (S1), booting (S2), and anthesis (S3) stages. In the second experiment (E2), waterlogging was applied at the stem elongation (S1) and anthesis (S3) stages and for three durations (five, 10, and 15 days). In E1, waterlogging at S1 and S2 resulted in a lower grain yield than at S3. In the second year of E1, grain yield under waterlogging at S1 and S3 was similar but significantly lower than under waterlogging conditions at S2. Waterlogging at S1 and S2 greatly decreased the kernel number per spike and 1000-kernel weight, but waterlogging at S3 only decreased the 1000-kernel weight. Moreover, different varieties did not change the stages mostly reducing grain yield and yield components. In E2, grain yield decreased with prolonged exposure to waterlogging and was significantly lower under 15-day conditions than the five-day conditions. There was no significant interaction between the stage and duration of waterlogging. Finally, our results indicate that in yield formation, a greater reliance on kernel weight instead of the kernel number per spike can contribute to a reduction in yield loss for waterlogging at S1 and S2. This study, therefore, indicates that the stem elongation stage is the most affected by waterlogging. Full article

(This article belongs to the Special Issue Impacts of Climate Change on Sustainable Agricultural Development)

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15 pages, 4931 KiB

Open AccessArticle

Flaming, Glyphosate, Hot Foam and Nonanoic Acid for Weed Control: A Comparison

by Luisa Martelloni, Christian Frasconi, Mino Sportelli, Marco Fontanelli, Michele Raffaelli and Andrea Peruzzi

Agronomy 2020, 10(1), 129; https://doi.org/10.3390/agronomy10010129 - 15 Jan 2020

Cited by 19 | Viewed by 11320

Abstract

Synthetic herbicides are commonly used in weed management, however, 70 years of use has led to weed resistance and environmental concerns. These problems have led scientists to consider alternative methods of weed management in order to reduce the inputs and impacts of synthetic [...] Read more.

Synthetic herbicides are commonly used in weed management, however, 70 years of use has led to weed resistance and environmental concerns. These problems have led scientists to consider alternative methods of weed management in order to reduce the inputs and impacts of synthetic herbicides. The aim of this experiment was to test the level of weed control using four weeding methods: glyphosate applied at an ultra-low volume, the organic herbicide nonanoic acid, flaming, and hot foam. The results showed that weed control was effective only when flaming and hot foam were applied (99% and 100% weed control, respectively). Nonanoic acid at a dose of 11 kg a.i. ha⁻¹ diluted in 400 L of water did not control developed plants of Cyperus esculentus (L.), Convolvulus arvensis (L.) and Poa annua (L.). Glyphosate at a dose of 1080 g a.i. ha⁻¹ (pure product) only controlled P. annua (L.), but had no effect on C. esculentus (L.) and C. arvensis (L.). After the aboveground tissues of weeds had died, regrowth began earlier after flaming compared to hot foam. There was no regrowth of P. annua (L.) only after using hot foam and glyphosate. Hot foam was generally better at damaging the meristems of the weeds. In one of the two experiment sites, significantly more time was needed after the hot foam to recover 10% and 50% of the ground compared to flaming. The time needed to recover 90% of the ground was on average 26–27 days for flaming and hot foam, which is the time that is assumed to be required before repeating the application. A total of 29 days after the treatments, weeds were smaller after flaming, glyphosate and hot foam compared to nonanoic acid and the control, where they had more time to grow. Full article

(This article belongs to the Special Issue Weed Management & New Approaches)

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13 pages, 5361 KiB

Open AccessArticle

CitrusYield: A Dashboard for Mapping Yield and Fruit Quality of Citrus in Precision Agriculture

by María Gyomar González-González, Juan Gómez-Sanchis, Jose Blasco, Emilio Soria-Olivas and Patricia Chueca

Agronomy 2020, 10(1), 128; https://doi.org/10.3390/agronomy10010128 - 15 Jan 2020

Cited by 14 | Viewed by 6601

Abstract

The application of new technologies in precision agriculture offers the possibility to link information to very specific crop locations. The spatial representation of these agricultural data through yield and fruit quality maps allows for crop management in a precise way that means that [...] Read more.

The application of new technologies in precision agriculture offers the possibility to link information to very specific crop locations. The spatial representation of these agricultural data through yield and fruit quality maps allows for crop management in a precise way that means that agricultural operations may be carried out considering intraorchard variability, thus resulting in greater efficiency. The aim of this work was to advance the development of new tools for the generation of yield and quality maps for precision agriculture. A new tool was implemented for citrus through a dashboard called CitrusYield that integrates the requirements demanded by technicians and farmers in terms of spatial distribution and the quality of their citrus production. The data for testing were collected by a prototype of a citrus harvest-assist platform. In order to obtain maps showing heterogeneity of production, an experimental plot with different varieties and variable production was chosen. The maps, tables and graphs showing different crop data were generated automatically by CitrusYield from the analysis of the data collected. The main advantage of knowing the differences in production between the swaths and areas inside the crop is to provide the grower with precise information to make accurate decisions for localised crop management, such as fertilisation, irrigation, pest and disease control, etc. Full article

(This article belongs to the Special Issue Selected Papers from 10th Iberian Agroengineering Congress)

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15 pages, 2934 KiB

Open AccessEditor’s ChoiceArticle

Comparison of Biochemical, Anatomical, Morphological, and Physiological Responses to Salinity Stress in Wheat and Barley Genotypes Deferring in Salinity Tolerance

by Muhammad Zeeshan, Meiqin Lu, Shafaque Sehar, Paul Holford and Feibo Wu

Agronomy 2020, 10(1), 127; https://doi.org/10.3390/agronomy10010127 - 15 Jan 2020

Cited by 158 | Viewed by 12472

Abstract

A greenhouse hydroponic experiment was performed using salt-tolerant (cv. Suntop) and -sensitive (Sunmate) wheat cultivars and a salt-tolerant barley cv. CM72 to evaluate how cultivar and species differ in response to salinity stress. Results showed that wheat cv. Suntop performed high tolerance to [...] Read more.

A greenhouse hydroponic experiment was performed using salt-tolerant (cv. Suntop) and -sensitive (Sunmate) wheat cultivars and a salt-tolerant barley cv. CM72 to evaluate how cultivar and species differ in response to salinity stress. Results showed that wheat cv. Suntop performed high tolerance to salinity, being similar tolerance to salinity with CM72, compared with cv. Sunmate. Similar to CM72, Suntop recorded less salinity induced increase in malondialdehyde (MDA) accumulation and less reduction in plant height, net photosynthetic rate (Pn), chlorophyll content, and biomass than in sensitive wheat cv. Sunmate. Significant time-course and cultivar-dependent changes were observed in the activities of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) in roots and leaves after salinity treatment. Higher activities were found in CM72 and Suntop compared to Sunmate. Furthermore, a clear modification was observed in leaf and root ultrastructure after NaCl treatment with more obvious changes in the sensitive wheat cv. Sunmate, rather than in CM72 and Suntop. Although differences were observed between CM72 and Suntop in the growth and biochemical traits assessed and modified by salt stress, the differences were negligible in comparison with the general response to the salt stress of sensitive wheat cv. Sunmate. In addition, salinity stress induced an increase in the Na⁺ and Na⁺/K⁺ ratio but a reduction in K⁺ concentrations, most prominently in Sunmate and followed by Suntop and CM72. Full article

(This article belongs to the Special Issue Physiological and Molecular Characterization of Crop Resistance to Abiotic Stresses)

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13 pages, 2452 KiB

Open AccessArticle

Fittonia verschaffeltii Response to Artificial Light Treatments: BIOMASS, Nutrient Concentrations and Physiological Changes

by Pedro García-Caparros, Eva María Almansa, Francisco Javier Barbero, Rosa María Chica and María Teresa Lao

Agronomy 2020, 10(1), 126; https://doi.org/10.3390/agronomy10010126 - 15 Jan 2020

Cited by 2 | Viewed by 3730

Abstract

The purpose of the present study was to evaluate the effects of different light treatments on biomass, nutrient concentrations and physiological parameters of Fittonia verschaffeltii (Lem) Van Houtte. The aim was to establish a methodology to evaluate the effect of photosynthetically active radiation [...] Read more.

The purpose of the present study was to evaluate the effects of different light treatments on biomass, nutrient concentrations and physiological parameters of Fittonia verschaffeltii (Lem) Van Houtte. The aim was to establish a methodology to evaluate the effect of photosynthetically active radiation (PAR) emitted by lamps on biomass. The light treatments used were tube luminescent Dunn (TL-D), tube luminescent Dunn + light emitting diodes (LEDs) and Tube luminescent 5 (TL-5). At the end of the experimental period, biomass, nutritional, biochemical, and physiological parameters were assessed. A clear reduction in total plant dry weight under TL-D + LEDs at the end of the experiment was recorded. With respect to nutrient concentration in the different organs assessed, there was no clear response under the different light treatments. The growth under TL-D lamps resulted in the highest concentration of total soluble sugars and starch in leaves, whereas the highest value of indole 3-acetic acid concentration was under TL-5 lamps. Plants grown under TL-D + LEDs showed the lowest values of chlorophyll a, b and a + b. The relationship proposed between integrated use of spectral energy (IUSE) and total dry weight (TDW) showed a good correlation with an R² value of 0.86, therefore we recommend this methodology to discern the effects of the different spectral qualities on plant biomass. Full article

(This article belongs to the Special Issue Control of LED Lighting Based on Plant Physiological Principles)

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17 pages, 1441 KiB

Open AccessArticle

Effects of Exogenous Application of Osmotic Adjustment Substances on Growth, Pigment Concentration, and Physiological Parameters of Dracaena sanderiana Sander under Different Levels of Salinity

by Pedro García-Caparrós, Alfonso Llanderal, Elodie Hegarat, María Jiménez-Lao and María Teresa Lao

Agronomy 2020, 10(1), 125; https://doi.org/10.3390/agronomy10010125 - 15 Jan 2020

Cited by 21 | Viewed by 4596

Abstract

We evaluated two osmotic adjustment substances (glycine betaine (GB) and glycine (G) and a combination of both glycine + glycine betaine (G + GB) using two modes of application; irrigation and foliar sprays with Dracaena sanderiana plants. The plants were grown in containers [...] Read more.

We evaluated two osmotic adjustment substances (glycine betaine (GB) and glycine (G) and a combination of both glycine + glycine betaine (G + GB) using two modes of application; irrigation and foliar sprays with Dracaena sanderiana plants. The plants were grown in containers and subjected to two levels of NaCl concentrations (2.0 and 7.5 dS m⁻¹) over 8 weeks. Growth, pigment concentrations, and physiological parameters were assessed at the end of the trial. The foliar application of GB resulted in most optimal plant growth and biomass production in the presence of NaCl. The chlorophyll and carotenoid concentrations showed different trends depending on the osmotic adjustment substance applied and the mode of application. Stomatal density and dimensions varied considerably with respect to the osmotic adjustment substance supplied. The concentration of soluble sugars in leaves did not show a clear trend under the different treatments assessed. The exogenous application of G resulted in the highest concentration of free proline and proteins in leaves. The antioxidant capacity in leaves increased with both osmotic adjustment substances, and both means of application, under low and high saline conditions. We concluded that the foliar application of GB can be recommended in order to achieve cost-effective growth of D. sanderiana under saline conditions. Full article

(This article belongs to the Special Issue Roles of Glycine Betaine in Improving Plant Abiotic Stress Resistance)

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9 pages, 1603 KiB

Open AccessArticle

Soil Type and Zinc Doses in Agronomic Biofortification of Lettuce Genotypes

by Hilário Júnior de Almeida, Victor Manuel Vergara Carmona, Maykom Ferreira Inocêncio, Antônio Eduardo Furtini Neto, Arthur Bernardes Cecílio Filho and Munir Mauad

Agronomy 2020, 10(1), 124; https://doi.org/10.3390/agronomy10010124 - 15 Jan 2020

Cited by 19 | Viewed by 4268

Abstract

The incidence of many malnutrition-related diseases among the populations of developing countries is closely related to low dietary zinc (Zn) intakes. This study evaluated the potential of agronomic biofortification of lettuce genotypes with Zn in different soils. We evaluated the ability to biofortify [...] Read more.

The incidence of many malnutrition-related diseases among the populations of developing countries is closely related to low dietary zinc (Zn) intakes. This study evaluated the potential of agronomic biofortification of lettuce genotypes with Zn in different soils. We evaluated the ability to biofortify three lettuce genotypes (‘Grand Rapids’, ‘Regina de Verão’, and ‘Delícia’) in two soils (Red-Yellow Latosol and Dystroferric Red Latosol) using five doses of Zn (0, 5, 10, 20, and 30 mg kg⁻¹). At 55 days after sowing, the plants were harvested. There was an interaction among the soils, genotypes, and Zn doses. Regardless of the soil and genotype, the increase in Zn supply promoted a linear increase in shoot Zn concentration. However, shoot and root dry matter yields were differentially affected by Zn supply according to the genotype and soil type. Overall, the Red-Yellow Latosol provided a higher shoot Zn concentration but also caused greater growth damage, especially in ‘Regina de Verão’ and ‘Delícia’. ‘Grand Rapids’ was biofortified the most in Red-Yellow Latosol. Full article

(This article belongs to the Special Issue Biofortification of Crops)

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12 pages, 1297 KiB

Open AccessArticle

A Comparative Study of Field Nematode Communities over a Decade of Cotton Production in Australia

by Oliver Knox, David Backhouse and Vadakattu Gupta

Agronomy 2020, 10(1), 123; https://doi.org/10.3390/agronomy10010123 - 15 Jan 2020

Cited by 3 | Viewed by 3523

Abstract

Soil nematode populations have the potential to indicate ecosystem disturbances. In response to questions about nematode interactions with soilborne diseases and whether genetically modified cotton altered nematode populations, several fields in the Namoi cotton growing area of Australia were sampled between 2005 and [...] Read more.

Soil nematode populations have the potential to indicate ecosystem disturbances. In response to questions about nematode interactions with soilborne diseases and whether genetically modified cotton altered nematode populations, several fields in the Namoi cotton growing area of Australia were sampled between 2005 and 2007. No significant interactions were observed, but nematodes numbers were low and postulated to be due to the use of the nematicide aldicarb. Aldicarb was removed from the system in 2011 and in 2015 funding allowed some fields to be resampled to determine if there had been a change in the nematode numbers following aldicarb removal. No significant changes in the total nematode numbers were observed, implying that the removal of aldicarb had little impact on the total nematode population size. However, an increase in plant parasitic nematodes was observed in both fields, but the species identified and the levels of change were not considered a threat to cotton production nor driven solely by altered pesticide chemistry. Additionally, greater numbers of higher order coloniser-persisters in the 2015 samples suggests that the current cotton production system is less disruptive to the soil ecosystem than that of a decade ago. Full article

(This article belongs to the Special Issue Impact of Agricultural Practices on Biodiversity of Soil Invertebrates)

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11 pages, 1019 KiB

Open AccessReview

Chromosome Engineering in Tropical Cash Crops

by Pablo Bolaños-Villegas

Agronomy 2020, 10(1), 122; https://doi.org/10.3390/agronomy10010122 - 15 Jan 2020

Cited by 3 | Viewed by 5339

Abstract

Tropical and subtropical crops such as coffee, cacao, and papaya are valuable commodities, and their consumption is a seemingly indispensable part of the daily lives of billions of people worldwide. Conventional breeding of these crops is long, and yields are threatened by global [...] Read more.

Tropical and subtropical crops such as coffee, cacao, and papaya are valuable commodities, and their consumption is a seemingly indispensable part of the daily lives of billions of people worldwide. Conventional breeding of these crops is long, and yields are threatened by global warming. Traditional chromosome engineering and new synthetic biology methods could be used to engineer new chromosomes, facilitate the transmission of wild traits to improve resistance to stress and disease in these crops, and hopefully boost yields. This review gives an overview of these approaches. The adoption of these approaches may contribute to the resilience of agricultural communities, lead to economic growth and secure the availability of key resources for generations to come. Full article

(This article belongs to the Special Issue Chromosome Manipulation for Plant Breeding Purposes)

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