Agronomy

20 pages, 3493 KiB

Open AccessArticle

Silicon and the Association with an Arbuscular-Mycorrhizal Fungus (Rhizophagus clarus) Mitigate the Adverse Effects of Drought Stress on Strawberry

by Narges Moradtalab, Roghieh Hajiboland, Nasser Aliasgharzad, Tobias E. Hartmann and Günter Neumann

Agronomy 2019, 9(1), 41; https://doi.org/10.3390/agronomy9010041 - 21 Jan 2019

Cited by 61 | Viewed by 7455

Abstract

Silicon (Si) is a beneficial element that alleviates the effects of stress factors including drought (D). Strawberry is a Si-accumulator species sensitive to D; however, the function of Si in this species is obscure. This study was conducted to examine the effect of [...] Read more.

Silicon (Si) is a beneficial element that alleviates the effects of stress factors including drought (D). Strawberry is a Si-accumulator species sensitive to D; however, the function of Si in this species is obscure. This study was conducted to examine the effect of Si and inoculation with an arbuscular mycorrhizal fungus (AMF) on physiological and biochemical responses of strawberry plants under D. Plants were grown for six weeks in perlite and irrigated with a nutrient solution. The effect of Si (3 mmol L⁻¹), AMF (Rhizophagus clarus) and D (mild and severe D) was studied on growth, water relations, mycorrhization, antioxidative defense, osmolytes concentration, and micronutrients status. Si and AMF significantly enhanced plant biomass production by increasing photosynthesis rate, water content and use efficiency, antioxidant enzyme defense, and the nutritional status of particularly Zn. In contrast to the roots, osmotic adjustment did not contribute to the increase of leaf water content suggesting a different strategy of both Si and AMF for improving water status in the leaves and roots. Our results demonstrated a synergistic effect of AMF and Si on improving the growth of strawberry not only under D but also under control conditions. Full article

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

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14 pages, 2763 KiB

Open AccessArticle

Near-Isogenic Lines of Japonica Rice Revealed New QTLs for Cold Tolerance at Booting Stage

by Zhenghai Sun, Juan Du, Xiaoying Pu, Muhammad Kazim Ali, Xiaomeng Yang, Chengli Duan, Meirong Ren, Xia Li and Yawen Zeng

Agronomy 2019, 9(1), 40; https://doi.org/10.3390/agronomy9010040 - 21 Jan 2019

Cited by 4 | Viewed by 3834

Abstract

Low temperature stress severely hampers rice productivity, and hence elaborating chilling-mediated physiochemical alterations and unravelling cold tolerance pathways will facilitate cold resilient rice breeding. Various cold tolerant Near-isogenic lines (NILs) selected at the booting stage through backcrossing of a japonica landrace Lijing2 (cold [...] Read more.

Low temperature stress severely hampers rice productivity, and hence elaborating chilling-mediated physiochemical alterations and unravelling cold tolerance pathways will facilitate cold resilient rice breeding. Various cold tolerant Near-isogenic lines (NILs) selected at the booting stage through backcrossing of a japonica landrace Lijing2 (cold tolerant) with cold sensitive Towada (a japonica cultivar). The cold tolerance attributes of NILs was validated over two years by evaluating the spikelet fertility followed by correlation of nineteen morphological traits with the rate of seed setting (RSS). Results revealed BG, FG, 1-2IL, RSLL, and UIL were significantly correlated with RSS and had nearer marker interval distance with cold tolerance in QTL analysis. Two QTLs, qCTB-7-a and qCTB-7-b, were found for RSS based on a mixed linear model. Alleles of two QTLs were contributed by Lijing2 and genetic distances between the peaks were 0.00 and 0.06cM, which explained 5.70% and 8.36% variation, respectively, One QTL for 1-2IL, RSLL, and ILBS, while two QTLs for FG, BG, and UIL were also identified. These findings can be exploited to engineer low temperature stress tolerant rice in times of climate change. Full article

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18 pages, 2854 KiB

Open AccessArticle

Optimizing Nitrogen Options for Improving Nitrogen Use Efficiency of Rice under Different Water Regimes

by Fazli Hameed, Junzeng Xu, Shah Fahad Rahim, Qi Wei, Anis ur Rehman Khalil and Qi Liao

Agronomy 2019, 9(1), 39; https://doi.org/10.3390/agronomy9010039 - 21 Jan 2019

Cited by 27 | Viewed by 6310

Abstract

Major challenge in rice production is to achieve the goal of enhancing both food production and fertilizer use efficiency. Rice growth simulation model, ORYZA (v3) was used in the present study to evaluate the model under continuous flooded (CF) and alternate wetting and [...] Read more.

Major challenge in rice production is to achieve the goal of enhancing both food production and fertilizer use efficiency. Rice growth simulation model, ORYZA (v3) was used in the present study to evaluate the model under continuous flooded (CF) and alternate wetting and drying (AWD) regimes with different fertilizer nitrogen (N) rates with different N splits using a historical data of past 45 years. The model satisfactorily simulated crop biomass and nitrogen uptake at both irrigation regimes and fertilizers N rates and splits. The yield differences among the years were large due to climate change, but enhanced by N rates. The response of N curves was different at both water regimes. At 0 N rate, the slope for agronomic efficiency (AE) was high which tends to decrease with increase in N rates. With the one split basal application of N, lowest yield was found with high physiological efficiencies (PE), lowest fertilizer recoveries (RE) and lowest agronomic efficiency (AE). For both water applications and fertilizer levels, high yield with high nitrogen uptake, AE, RE and partial factor productivity (PFP) were witnessed high at four split (3:3:3:1), while having low physiological efficiency. The water productivity (irrigation + rainfall) WP_I+R at basal in one N split for AWD at 150 kg N ha⁻¹ was 1.19 kg m⁻³ and for CF was 0.82 kg m⁻³, whereas for 225 kg N ha⁻¹ WP_I+R of AWD was 1.50 kg m⁻³ and 1.14 kg m⁻³ for CF. In general, AWD exhibited high WP_I+R with no rice yield penalty compared to CF. Splitting with the proper amount of fertilizer N resulted in good water productivity and nitrogen efficiencies, could lead to high rice yield. Full article

(This article belongs to the Section Soil and Plant Nutrition)

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19 pages, 1354 KiB

Open AccessArticle

Growth, Physiological, Biochemical, and Transcriptional Responses to Drought Stress in Seedlings of Medicago sativa L., Medicago arborea L. and Their Hybrid (Alborea)

by Eleni Tani, Evangelia G. Chronopoulou, Nikolaos E. Labrou, Effie Sarri, Μaria Goufa, Xristina Vaharidi, Alexia Tornesaki, Maria Psychogiou, Penelope J. Bebeli and Εleni M. Abraham

Agronomy 2019, 9(1), 38; https://doi.org/10.3390/agronomy9010038 - 19 Jan 2019

Cited by 35 | Viewed by 4979

Abstract

Medicago sativa L. is a tetraploid perennial forage legume of great agronomical interest. The increasing need for its use under water-deficit conditions as well as low-input systems demands further improvement of its drought tolerance. On the other hand, Medicagoarborea L. is a perennial [...] Read more.

Medicago sativa L. is a tetraploid perennial forage legume of great agronomical interest. The increasing need for its use under water-deficit conditions as well as low-input systems demands further improvement of its drought tolerance. On the other hand, Medicagoarborea L. is a perennial leguminous shrub, which is knownas a drought-tolerant species. In the present study, drought stress responses of the aforementioned medicago species, along with their hybrid, named Alborea, were comparatively assayed at the morphological, physiological, biochemical, and transcriptional levels. In particular, transcript abundance of representative genes that: (a) control ion transport, intracellular Na⁺/H⁺ antiporters(NHX1) and rare cold inducible2A (RCI2A); (b) have an osmotic function Δ1-pyrroline-5-carboxylate synthetase 1 (P5CS1); and (c) participate in signaling pathways and control cell growth and leaf function stress-induced mitogen-activated protein kinases kinases (SIMKK), Zinc Finger (ZFN), apetala2/ethylene-responsive element binding (AP2/EREB), basic leucine zipper (bzip) and Medicago sativa Helicase 1(MH1) were evaluated. Under well-watered conditions, the studied population of Alborea showed the highest stem elongation rate and photosynthetic rate that were dramatically reduced under drought conditions compared to M. sativa and M. arborea. Under drought conditions, the studied population of M. arborea showed less reduction of relative water content, all gas-exchange parameters, less lipid peroxidation, and more antioxidant capacity. Moreover, transcriptional analysis demonstrated that the population of M. arborea exhibited significantly higher transcript levels of drought-responsive genes in both leaves and roots under drought stress conditions. M. sativa has better antioxidant capacity than Alborea and had a higher induction of stress-related genes, thus it performs better than Alborea under drought conditions. Among the studied genes, it seems that AP2/EREB play a critical role in the response of the studied population to drought stress. Full article

(This article belongs to the Special Issue Gene Expression Regulation during Drought and Salt Stress in Crop Plants)

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15 pages, 976 KiB

Open AccessArticle

Subsoiling and Sowing Time Influence Soil Water Content, Nitrogen Translocation and Yield of Dryland Winter Wheat

by Yan Fei Liang, Shahbaz Khan, Ai-xia Ren, Wen Lin, Sumera Anwar, Min Sun and Zhi-qiang Gao

Agronomy 2019, 9(1), 37; https://doi.org/10.3390/agronomy9010037 - 16 Jan 2019

Cited by 24 | Viewed by 4390

Abstract

Dryland winter wheat in the Loess Plateau is facing a yield reduction due to a shortage of soil moisture and delayed sowing time. The field experiment was conducted at Loess Plateau in Shanxi, China from 2012 to 2015, to study the effect of [...] Read more.

Dryland winter wheat in the Loess Plateau is facing a yield reduction due to a shortage of soil moisture and delayed sowing time. The field experiment was conducted at Loess Plateau in Shanxi, China from 2012 to 2015, to study the effect of subsoiling and conventional tillage and different sowing dates on the soil water storage, Nitrogen (N) accumulation, and remobilization and yield of winter wheat. The results showed that subsoiling significantly improved the soil water storage (0–300 cm soil depth) and increased the contribution of N translocation to grain N and grain yield (17–36%). Delaying sowing time had reduced the soil water storage at sowing and winter accumulated growing degree days by about 180 °C. The contribution of N translocation to grain yield was maximum in glume + spike followed by in leaves and minimum by stem + sheath. Moreover, there was a positive relationship between the N accumulation and translocation and the soil moisture in the 20–300 cm range. Subsoiling during the fallow period and the medium sowing date was beneficial for improving the soil water storage and increased the N translocation to grain, thereby increasing the yield of wheat, especially in a dry year. Full article

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13 pages, 281 KiB

Open AccessArticle

Economic Evaluation of Biodegradable Plastic Films and Paper Mulches Used in Open-Air Grown Pepper (Capsicum annum L.) Crop

by Ana I. Marí, Gabriel Pardo, Alicia Cirujeda and Yolanda Martínez

Agronomy 2019, 9(1), 36; https://doi.org/10.3390/agronomy9010036 - 16 Jan 2019

Cited by 39 | Viewed by 5671

Abstract

Black polyethylene (PE) is the most common mulching material used in horticultural crops in the world but its use represents a very serious environmental problem. Biodegradable films and paper mulches are available alternatives but farmers are reluctant to adopt them because of their [...] Read more.

Black polyethylene (PE) is the most common mulching material used in horticultural crops in the world but its use represents a very serious environmental problem. Biodegradable films and paper mulches are available alternatives but farmers are reluctant to adopt them because of their high market prices. The aim of this paper is to evaluate the economic profitability of eight biodegradable mulching materials available for open-air pepper production. The economic evaluation is based on a four-year trial located in a semi-arid region of Spain. Three scenarios of PE waste management are examined: (i) absence of residues management, (ii) landfill accumulation, and (iii) total recycling. The inclusion of the costs of waste management and recycling under the current Spanish legislation only reduced the final net margin by 0.2%. The results show that an increase in subsidy rates of up to 50.1% on the market price would allow all biodegradable films to be economic alternatives to PE. The study supports the mandatory measures for the farmers to assume the costs of waste management and recycling. Despite savings in field conditioning costs, high market prices of biodegradable materials and papers are not compensated by the current level of subsidies, hampering their adoption in the fields. Full article

(This article belongs to the Special Issue Smart Management of Conservative, Organic and Integrated Agriculture)

20 pages, 663 KiB

Open AccessArticle

Ability of Modified Spectral Reflectance Indices for Estimating Growth and Photosynthetic Efficiency of Wheat under Saline Field Conditions

by Salah El-Hendawy, Nasser Al-Suhaibani, Yaser Hassan Dewir, Salah Elsayed, Majed Alotaibi, Wael Hassan, Yahya Refay and Muhammad Usman Tahir

Agronomy 2019, 9(1), 35; https://doi.org/10.3390/agronomy9010035 - 16 Jan 2019

Cited by 23 | Viewed by 4022

Abstract

Hyperspectral sensing offers a quick and non-destructive alternative for assessing phenotypic parameters of plant physiological status and salt stress tolerance. This study compares the performance of published and modified spectral reflectance indices (SRIs) for estimating and predicting the growth and photosynthetic efficiency of [...] Read more.

Hyperspectral sensing offers a quick and non-destructive alternative for assessing phenotypic parameters of plant physiological status and salt stress tolerance. This study compares the performance of published and modified spectral reflectance indices (SRIs) for estimating and predicting the growth and photosynthetic efficiency of two wheat cultivars exposed to three salinity levels (control, 6.0, and 12.0 dS m⁻¹). Results show that individual SRIs based on visible- and near-infrared (VIS/VIS, NIR/VIS, and NIR/NIR) estimate and predict measured parameters considerably more efficiently than those based on shortwave-infrared (SWIR/VIS and SWIR/NIR), with the exception of some modified indices (the water balance index (WABI-1_{(1550, 482)}, WABI-2_{(1640, 482)}, and WABI-3_{(1650, 531)}), normalized difference moisture index (NDMI_{(1660, 1742)}), and dry matter content index (DMCI_{(1550, 2305)}), which show moderate to strong relationships with measured parameters. Overall results indicate that modified SRIs can serve as rapid and non-destructive high-throughput alternative approaches for tracking growth and photosynthetic efficiency of wheat under salt stress field conditions. Full article

(This article belongs to the Section Farming Sustainability)

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19 pages, 1407 KiB

Open AccessArticle

Alley Cropping Increases Land Use Efficiency and Economic Profitability Across the Combination Cultivation Period

by Huasen Xu, Huaxing Bi, Lubo Gao and Lei Yun

Agronomy 2019, 9(1), 34; https://doi.org/10.3390/agronomy9010034 - 15 Jan 2019

Cited by 19 | Viewed by 4926

Abstract

Alley cropping allows the famer to effectively use available resources and yield more benefits. Choosing suitable associated crop and mitigating the competition between trees and crops are crucial for designing the alley cropping systems. We conducted a long-term experiment, including apple (Malus [...] Read more.

Alley cropping allows the famer to effectively use available resources and yield more benefits. Choosing suitable associated crop and mitigating the competition between trees and crops are crucial for designing the alley cropping systems. We conducted a long-term experiment, including apple (Malus pumila)/peanut (Arachis hypogaea), apple/millet (Setaria italica) and apple/maize (Zea mays) alley cropping systems with conventional intercropping distance, and corresponding monocultures (Exp.1), and a short-term experiment with improved intercropping distance in the same three combinations (Exp.2) in the Loess Plateau, China. The results showed crop yields in three alley cropping systems were lower than the corresponding monocultures. Apple yields were significantly constrained by millet and maize in the alley cropping systems, but not sensitive to the presence of peanut. Land equivalent ratios (LERs) ranged from 0.44 to 0.89 before the tree bore fruit. The LERs were greater than 1.0 after the tree bore fruit, and the apple trees made a decisive contribution to the land use advantage. Net present values of three alley cropping systems were on average 60.1% higher than the corresponding monocultures across the alley cropping period. The maximum annual present value in the first–fifth, sixth and seventh–ninth years after the alley cropping establishment was observed in the apple/maize, apple/millet and apple/peanut system, respectively. These results highlight that choosing the optimal alley cropping management and suitable associated crops at different years after establishment may allow farmers to increase the land use efficiency and economic profitability. Full article

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11 pages, 624 KiB

Open AccessArticle

Delivery of Inoculum of Rhizophagus irregularis via Seed Coating in Combination with Pseudomonas libanensis for Cowpea Production

by Ying Ma, Aleš Látr, Inês Rocha, Helena Freitas, Miroslav Vosátka and Rui S. Oliveira

Agronomy 2019, 9(1), 33; https://doi.org/10.3390/agronomy9010033 - 15 Jan 2019

Cited by 29 | Viewed by 6091

Abstract

Cowpea (Vigna unguiculata L. Walp) is an important legume grown primarily in semi-arid area. Its production is generally inhibited by various abiotic and biotic stresses. The use of beneficial microorganisms (e.g., plant growth promoting bacteria (PGPB) and arbuscular mycorrhizal fungi (AMF)) can [...] Read more.

Cowpea (Vigna unguiculata L. Walp) is an important legume grown primarily in semi-arid area. Its production is generally inhibited by various abiotic and biotic stresses. The use of beneficial microorganisms (e.g., plant growth promoting bacteria (PGPB) and arbuscular mycorrhizal fungi (AMF)) can enhance agricultural production, as these microorganisms can improve soil fertility and plant tolerance to environmental stresses, thus enhancing crop yield in an eco-friendly manner. Application of PGPB and AMF in large scale agriculture needs to be improved. Thus, the use of seed coating could be an efficient mechanism for placement of inocula into soils. The aim of this study was to evaluate the effects of the AMF Rhizophagus irregularis BEG140 and the PGPB Pseudomonas libanensis TR1 alone or in combination on the biomass and physiological traits of cowpea. Four treatments were set: (i) non-inoculated control; (ii) PGPB; (iii) AMF applied via seed coating; and (iv) PGPB + AMF applied via seed coating. Cowpea plants inoculated via seed coating with R. irregularis and those inoculated with R. irregularis + P. libanensis showed root mycorrhizal colonization of 21.7% and 24.2%, respectively. PGPB P. libanensis was efficient in enhancing plant biomass and seed yield. There was no benefit of single (AMF) or dual (PGPB + AMF) inoculation on plant growth or seed yield. The application of beneficial soil microorganisms can be a viable approach for sustainable cowpea production in precision agriculture scenarios. Full article

(This article belongs to the Special Issue Symbiotic Associations of Plants with Beneficial Microbes: Perspectives and Challenges for Agronomical Applications)

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21 pages, 8702 KiB

Open AccessArticle

Development of a Mushroom Growth Measurement System Applying Deep Learning for Image Recognition

by Chuan-Pin Lu, Jiun-Jian Liaw, Tzu-Ching Wu and Tsung-Fu Hung

Agronomy 2019, 9(1), 32; https://doi.org/10.3390/agronomy9010032 - 14 Jan 2019

Cited by 40 | Viewed by 9937

Abstract

In Taiwan, mushrooms are an agricultural product with high nutritional value and economic benefit. However, global warming and climate change have affected plant quality. As a result, technological greenhouses are replacing traditional tin houses as locations for mushroom planting. These greenhouses feature several [...] Read more.

In Taiwan, mushrooms are an agricultural product with high nutritional value and economic benefit. However, global warming and climate change have affected plant quality. As a result, technological greenhouses are replacing traditional tin houses as locations for mushroom planting. These greenhouses feature several complex parameters. If we can reduce the complexity such greenhouses and improve the efficiency of their production management using intelligent schemes, technological greenhouses could become the expert assistants of farmers. In this paper, the main goal of the developed system is to measure the mushroom size and to count the amount of mushrooms. According to the results of each measurement, the growth rate of the mushrooms can be estimated. The proposed system also records the data of the mushrooms and broadcasts them to the mobile phone of the farmer. This improves the effectiveness of the production management. The proposed system is based on the convolutional neural network of deep learning, which is used to localize the mushrooms in the image. A positioning correction method is also proposed to modify the localization result. The experiments show that the proposed system has a good performance concerning the image measurement of mushrooms. Full article

(This article belongs to the Special Issue Deep Learning Techniques for Agronomy Applications)

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20 pages, 2809 KiB

Open AccessArticle

Prospects of Forage Production in Northern Regions under Climate and Land-Use Changes: A Case-Study of a Dairy Farm in Newfoundland, Canada

by Marcos R. C. Cordeiro, Alan Rotz, Roland Kroebel, Karen A. Beauchemin, Derek Hunt, Shabtai Bittman, Karen M. Koenig and David B. McKenzie

Agronomy 2019, 9(1), 31; https://doi.org/10.3390/agronomy9010031 - 12 Jan 2019

Cited by 16 | Viewed by 5473

Abstract

Forage production in northern latitudes is challenging and uncertain in the future. In this case-study, the integrated farm system model (IFSM) was used to assess the impact of climate change and cropland expansion scenarios on forage production in a dairy farm in Newfoundland, [...] Read more.

Forage production in northern latitudes is challenging and uncertain in the future. In this case-study, the integrated farm system model (IFSM) was used to assess the impact of climate change and cropland expansion scenarios on forage production in a dairy farm in Newfoundland, Canada. Climatic projections indicated increases in temperature in the recent past (1990–2016) and under any future climate (2020–2079), thus enhancing agronomic performance. Temperature increases ranged from 2.8 °C to 5.4 °C in winter and from 3.2 °C to 6.4 °C in spring. Small precipitation increases (<10%) create narrower time windows to perform farm operations in the already stringent condition of excess moisture in the region. Results of land use scenarios including expansions of 20, 30, and 40% in cropland area, out of which 5% was dedicated to corn silage and the remainder to grass-legume mixtures, indicated increased yield and total production. Improvements in grass-legume yield ranged from 8% to 52%. The full range of production increases ranged from 11% to 105%. Increments in corn silage yield ranged from 28% to 69%. Total farm corn silage production increases ranged from 29% to 77%. An attainable cropland expansion of 20% would enable the farm to become self-sufficient in forage production under any climate scenario. Full article

(This article belongs to the Section Farming Sustainability)

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16 pages, 2795 KiB

Open AccessArticle

Assessment of the Persistence of Avena sterilis L. Patches in Wheat Fields for Site-Specific Sustainable Management

by Isabel Luisa Castillejo-González, Ana Isabel De Castro, Montserrat Jurado-Expósito, José-Manuel Peña, Alfonso García-Ferrer and Francisca López-Granados

Agronomy 2019, 9(1), 30; https://doi.org/10.3390/agronomy9010030 - 10 Jan 2019

Cited by 6 | Viewed by 4351

Abstract

This paper aims to evaluate the spatial persistence of wild oat patches in four wheat fields over time to determine the economic feasibility of using late-season wild oat maps for early site-specific weed management (SSWM) next season. The spatial persistence of wild oat [...] Read more.

This paper aims to evaluate the spatial persistence of wild oat patches in four wheat fields over time to determine the economic feasibility of using late-season wild oat maps for early site-specific weed management (SSWM) next season. The spatial persistence of wild oat patches was analyzed by three tests: land use change detection between years, spatial autocorrelation, and analysis of spreading distance. The temporal trend of wild oat patch distribution showed a clear persistence and a generalized increase in the infested area, with a noticeable level of weed aggregation and a tendency in the new weed patches to emerge close to older ones. To economically evaluate the SSWM, five simulations in four agronomic scenarios, varying wheat yields and losses due to wild oat, were conducted. When yield losses due to wild oat were minimal and for any of the expected wheat yields, some SSWM simulations were more economically profitable than the overall application in most of the fields. Nevertheless, when the yield losses due to wild oat were maximal, all SSWM simulations were less profitable than overall treatment in all the analyzed fields. Although the economic profit variations achieved with SSWM treatments were modest, any of the site-specific treatments tested are preferred to herbicide broadcast over the entire field, in order to reduce herbicide and environmental pollution. Full article

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

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9 pages, 737 KiB

Open AccessArticle

Sensitivity of Three Phosphate Extraction Methods to the Application of Phosphate Species Differing in Immediate Plant Availability

by Tobias Edward Hartmann, Iris Wollmann, Yawen You and Torsten Müller

Agronomy 2019, 9(1), 29; https://doi.org/10.3390/agronomy9010029 - 10 Jan 2019

Cited by 13 | Viewed by 4287

Abstract

Extractive tests for determining the plant-availability of soil phosphorus (P) give varying results due to the inherently different characteristics of the extraction solution. Generally, classical soil P tests such as the Olsen or calcium acetate/lactate (CAL) method do not give an indication on [...] Read more.

Extractive tests for determining the plant-availability of soil phosphorus (P) give varying results due to the inherently different characteristics of the extraction solution. Generally, classical soil P tests such as the Olsen or calcium acetate/lactate (CAL) method do not give an indication on the total amount of plant available P, but merely give an indication of the equilibrium between soil and extraction solution. It is also not entirely clear which fractions of P are directly determined through the various methods of extraction, i.e., determined P must not be immediately plant available, as is the case for rock phosphate. It is therefore possible that extraction methods either over or under estimate the amount of P available for plant consumption. In this research, we compared three methods of soil P determination (CAL, Olsen and diffusive gradients in thin films (DGT)) with regards to their ability to determine P species (Ca(H₂PO₄)₂, CaHPO₄, Ca₃(PO₄)₂ and Inositol-6-hexakisphosphate) added to soils of high sorption capacity, immediately after as well as two weeks after application. For each of the methods, it could be shown that sorption processes in the soil immediately (0 days incubation) fix P to a point where it is not extractable through any of the described methods. These sorption processes continue over time, leading to a further decrease of determined P. The acidic CAL extraction method gives higher results of extractable P compared to the Olsen method. Due to the extraction of Ca₃(PO₄)₂, the CAL method may overestimate immediately plant-available P. The most suitable methods for the determination of immediately plant available P may therefore be the Olsen and DGT methods. Organic IP6 is not determined by any of the extraction methods. At low concentrations of soil P, the DGT method may fail to give results. Full article

(This article belongs to the Section Soil and Plant Nutrition)

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16 pages, 1950 KiB

Open AccessArticle

A Novel Biostimulant, Belonging to Protein Hydrolysates, Mitigates Abiotic Stress Effects on Maize Seedlings Grown in Hydroponics

by Sara Trevisan, Alessandro Manoli and Silvia Quaggiotti

Agronomy 2019, 9(1), 28; https://doi.org/10.3390/agronomy9010028 - 09 Jan 2019

Cited by 49 | Viewed by 6535

Abstract

The main challenge to agriculture worldwide is feeding a rapidly growing human population, developing more sustainable agricultural practices that do not threaten human and ecosystem health. An innovative solution relies on the use of biostimulants, as a tool to enhance nutrient use efficiency [...] Read more.

The main challenge to agriculture worldwide is feeding a rapidly growing human population, developing more sustainable agricultural practices that do not threaten human and ecosystem health. An innovative solution relies on the use of biostimulants, as a tool to enhance nutrient use efficiency and crop performances under sub-optimal conditions. In this work a novel biostimulant (APR®, ILSA S.p.A., Arzigano VI, Italy), belonging to the group of protein hydrolysates, was supplied to maize seedlings in hydroponic and its effects were assessed in control conditions and in the presence of three different kinds of stresses (hypoxia, salt and nutrient deficiency) and of their combination. Our results indicate that APR® is soluble and is able to influence root and shoot growth depending on its concentration. Furthermore, its effectiveness is clearly increased in condition of single or combination of abiotic stresses, thus confirming the previously hypothesised action of this substance as enhancer of the response to environmental adversities. Moreover, it also regulates the transcription of a set of genes involved in nitrate transport and ROS metabolism. Further work will be needed to try to transfer this basic knowledge in field experiments. 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, 831 KiB

Open AccessArticle

Evaluation of the Antioxidant and Wound-Healing Properties of Extracts from Different Parts of Hylocereus polyrhizus

by Yu Tsai, Ching-Gong Lin, Wei-Lin Chen, Yu-Chun Huang, Cheng-Yu Chen, Keh-Feng Huang and Chao-Hsun Yang

Agronomy 2019, 9(1), 27; https://doi.org/10.3390/agronomy9010027 - 09 Jan 2019

Cited by 19 | Viewed by 5841

Abstract

Hylocereus polyrhizus cultivation started in Taiwan around the 1980s. The pulp of the fruit is edible and contains small, black, and soft seeds. The peel of the fruits are covered with bracts. The H. polyrhizus fruit is known to be rich in nutrients [...] Read more.

Hylocereus polyrhizus cultivation started in Taiwan around the 1980s. The pulp of the fruit is edible and contains small, black, and soft seeds. The peel of the fruits are covered with bracts. The H. polyrhizus fruit is known to be rich in nutrients and minerals. To evaluate the potential applications of the agricultural wastes of H. polyrhizus, the stem, peel, and flower of H. polyrhizus were extracted with solutions of ethanol and water mixed in different ratios. Data was collected for the H. polyrhizus extract including the yield of total phenolics, the total flavonoids, and antioxidant activity, as determined by the 2-2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging assay. The protective effects of H. polyrhizus extract on DNA was investigated using an assay with the pUC19 plasmid. The cell proliferation and migration effects were evaluated in the NIH-3T3 fibroblast cell line. The greatest yield of extract from the stem of H. polyrhizus was 44.70 ± 1.77% which was obtained using 50% aqueous ethanol and the greatest yield of extract from the peel was 43.47% using distilled water. The stem extract, which was prepared with 95% aqueous ethanol, had the highest composition of phenolics and flavonoids as well as the best DPPH radical scavenging activity. The stem extract had excellent ABTS radical scavenging activity as well. The stem, peel, and flower extracts, which were prepared using 95% aqueous ethanol, showed excellent results in protecting themselves from DNA damage, similar to the effect of 0.3 mg/mL ferulic acid. None of the extracts were able to promote cell proliferation at concentrations of 250 μg/mL to 2,000 μg/mL in a 24 h period. The 1000 μg/mL stem and flower extracts in 95% aqueous ethanol promoted considerable cell migration after a 24 h period. Full article

(This article belongs to the Special Issue Bioactives from Plants: Content, Accumulation and Means to Reach Higher Levels)

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11 pages, 228 KiB

Open AccessReview

Progress in Developing Bacterial Spot Resistance in Tomato

by Sadikshya Sharma and Krishna Bhattarai

Agronomy 2019, 9(1), 26; https://doi.org/10.3390/agronomy9010026 - 09 Jan 2019

Cited by 16 | Viewed by 7969

Abstract

Bacterial spot (BS), caused by four species of Xanthomonas: X. euvesicatoria, X. vesicatoria, X. perforans and X. gardneri in tomato (Solanum lycopersicum L.) results in severe loss in yield and quality by defoliation and the appearance of lesions on fruits, [...] Read more.

Bacterial spot (BS), caused by four species of Xanthomonas: X. euvesicatoria, X. vesicatoria, X. perforans and X. gardneri in tomato (Solanum lycopersicum L.) results in severe loss in yield and quality by defoliation and the appearance of lesions on fruits, respectively. The combined industry standard for BS control (foliar applications Actigard^® rotated with copper plus mancozeb) does not offer sufficient protection, especially when weather conditions favor disease spread. Development of tomato cultivars with BS resistance is thus an important measure to minimize losses. Hypersensitive and non-hypersensitive resistance has been identified in different wild accessions and cultivated tomato relatives and has been transferred to cultivated tomato. However, complete resistance is yet to be obtained. With the advent of next generation sequencing and precise genome editing tools, the genetic regions that confer resistance to bacterial spot can be targeted and enriched through gene pyramiding in a new commercial cultivar which may confer higher degree of horizontal resistance to multiple strains of Xanthomonas causing bacterial spot in tomato. Full article

(This article belongs to the Special Issue Genetics and Genomics of Tomato and Solanaceae)

17 pages, 5430 KiB

Open AccessTechnical Note

The Prognostic Breeding Application JMP Add-In Program

by Vasilia A. Fasoula, Kevin C. Thompson and Andy Mauromoustakos

Agronomy 2019, 9(1), 25; https://doi.org/10.3390/agronomy9010025 - 09 Jan 2019

Cited by 6 | Viewed by 4491

Abstract

Prognostic breeding is a crop improvement methodology that utilizes prognostic equations to enable concurrent selection for plant yield potential and stability of performance. There is a necessity for plant breeders to accurately phenotype plants in the field and select effectively for high and [...] Read more.

Prognostic breeding is a crop improvement methodology that utilizes prognostic equations to enable concurrent selection for plant yield potential and stability of performance. There is a necessity for plant breeders to accurately phenotype plants in the field and select effectively for high and stable crop yield in the absence of the confounding effects of competition. Prognostic breeding accomplishes this goal by evaluating plants for (i) plant yield potential and (ii) plant stability, in the same generation. The plant yield index, stability index and the plant prognostic equation are the main criteria used for the selection of the best plants and the best entries grown in honeycomb designs. The construction of honeycomb designs and analysis of experimental data in prognostic breeding necessitate the development of a computer program to ensure accurate measurement of the prognostic equations. The objective of this paper is to introduce the Prognostic Breeding Application JMP Add-In, a program for constructing honeycomb designs and analyzing data for the efficient selection of superior plants and lines. The program displays powerful controls, allowing the user to create maps of any honeycomb design and visualize the selected plants in the field. Multi-year soybean data are used to demonstrate key features and graphic views of the most important steps. Full article

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10 pages, 244 KiB

Open AccessEditorial

Acknowledgement to Reviewers of Agronomy in 2018

by Agronomy Editorial Office

Agronomy 2019, 9(1), 24; https://doi.org/10.3390/agronomy9010024 - 09 Jan 2019

Viewed by 2585

Abstract

Rigorous peer-review is the corner-stone of high-quality academic publishing [...] Full article

13 pages, 2270 KiB

Open AccessArticle

Development of Allergenicity and Toxicity Assessment Methods for Evaluating Transgenic Sugarcane Overexpressing Sucrose–Phosphate Synthase

by Intan Ria Neliana, Widhi Dyah Sawitri, Netty Ermawati, Tri Handoyo and Bambang Sugiharto

Agronomy 2019, 9(1), 23; https://doi.org/10.3390/agronomy9010023 - 08 Jan 2019

Cited by 4 | Viewed by 5114

Abstract

Sugarcane is considered as an industrial crop that produces sugar. The number of transgenic sugarcane on the market is currently increasing. Therefore, investigation of the potential allergens and toxics in transgenic sugarcane is necessary, since there is less information regarding food safety for [...] Read more.

Sugarcane is considered as an industrial crop that produces sugar. The number of transgenic sugarcane on the market is currently increasing. Therefore, investigation of the potential allergens and toxics in transgenic sugarcane is necessary, since there is less information regarding food safety for human consumption. Bioinformatics and experimental analysis were used for the validation of the allergenic potential of transgenic sugarcane overexpressing sucrose–phosphate synthase (SPS). Bioinformatics analysis showed that SPS has no homology with any known allergenic proteins. However, eight-residues identical contiguous sequence was detected, and further specific assessment is required to confirm the potential of allergenicity. The results of protein stability evaluation showed that SPS gradually decreased at 28 °C and rapidly inactivated at 60 °C and 90 °C by heat treatment. In addition, total protein was degraded by simulated gastric fluids (SGF), and simulated intestine fluid (SIF) assays for one-minute incubation. The level of specific IgE in the transgenic sugarcane and controls also showed no potential risk of allergy. An acute oral toxicity assay was performed by oral gavage of transgenic sugarcane juice in mice. The LD₅₀ for transgenic sugarcane juice was >25 gr/kg body weight. We propose a development method for allergenicity and toxicity assessment in transgenic sugarcane. Full article

(This article belongs to the Special Issue Breeding and Genetics of Sugarcane and Other Sugar Crops)

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13 pages, 2814 KiB

Open AccessArticle

Exploiting Genetic and Genomic Resources to Enhance Heat-Tolerance in Tomatoes

by Valentino Ruggieri, Roberta Calafiore, Carlo Schettini, Maria Manuela Rigano, Fabrizio Olivieri, Luigi Frusciante and Amalia Barone

Agronomy 2019, 9(1), 22; https://doi.org/10.3390/agronomy9010022 - 08 Jan 2019

Cited by 40 | Viewed by 7011

Abstract

High temperature is one of the most detrimental abiotic stresses in tomatoes. Many studies highlighted that even small increases in temperature can alter the plant reproductive system, causing a significant reduction in tomato yield. The aim of this study was to exploit the [...] Read more.

High temperature is one of the most detrimental abiotic stresses in tomatoes. Many studies highlighted that even small increases in temperature can alter the plant reproductive system, causing a significant reduction in tomato yield. The aim of this study was to exploit the phenotypic and genomic variations of a tomato landrace collection grown at high temperatures. Fifteen genotypes were selected as the best performing in two experimental fields. The selection was based on six yield-related traits, including flower earliness, number of flowers per inflorescence, fruit set, number of fruit per plant, fruit weight and yield per plant. In order to identify markers targeting traits that could be highly influenced by adverse climate conditions, such as flowering and fruit setting, an association mapping approach was undertaken exploiting a tomato high-throughput genomic array. The phenotypic variability observed allowed us to identify a total of 15 common markers associated with the studied traits. In particular, the most relevant associations co-localized with genes involved in the floral structure development, such as the style2.1 gene, or with genes directly involved in the response to abiotic stresses. These promising candidate genes will be functionally validated and transferred to a cultivated tomato to improve its performance under high temperatures. Full article

(This article belongs to the Special Issue Genetics and Genomics of Tomato and Solanaceae)

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12 pages, 2358 KiB

Open AccessArticle

Preparation and In Vitro Characterization of Chitosan Nanoparticles and Their Broad-Spectrum Antifungal Action Compared to Antibacterial Activities against Phytopathogens of Tomato

by Jae-Wook OH, Se Chul Chun and Murugesan Chandrasekaran

Agronomy 2019, 9(1), 21; https://doi.org/10.3390/agronomy9010021 - 08 Jan 2019

Cited by 119 | Viewed by 10899

Abstract

The present study was to prepare chitosan nanoparticles (CNPs) from chitosan (CS) to evaluate their in vitro antimicrobial activities against phytopathogens of tomato. We prepared and characterized CNPs for their particle size, polydispersity index, and structures. The antifungal properties of CS and CNPs [...] Read more.

The present study was to prepare chitosan nanoparticles (CNPs) from chitosan (CS) to evaluate their in vitro antimicrobial activities against phytopathogens of tomato. We prepared and characterized CNPs for their particle size, polydispersity index, and structures. The antifungal properties of CS and CNPs against phytopathogenic fungi namely Colletotrichum gelosporidies, Phytophthora capsici, Sclerotinia sclerotiorum, Fusarium oxysporum, Gibberella fujikuori were investigated. CNPs showed the maximum growth inhibitory effects on mycelial growth of F. oxysporum followed by P. capsici. We also studied antibacterial activities against phytopathogenic bacteria, such as three strains of Erwinia carotovora subsp. carotovora and one strain of Xanthomonas campestris pv. vesicatoria. Our results showed that both CS and CNPs markedly inhibited the growth of the both Xanthomonas and Erwinia strains. From our study, it is evident that both CS and CNPs have tremendous potential against phytopathogens of tomato for further field screening towards crop protection. Full article

(This article belongs to the Special Issue Nanotechnology Applications in Agriculture System)

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10 pages, 1543 KiB

Open AccessArticle

Influence of Temperature on the Development of Peach Fruit in a Subtropical Climate Region

by Filipe Souza, Eduardo Alves, Rafael Pio, Elisa Castro, Gregory Reighard, Ana Izabella Freire, Newton Alex Mayer and Róberson Pimentel

Agronomy 2019, 9(1), 20; https://doi.org/10.3390/agronomy9010020 - 07 Jan 2019

Cited by 17 | Viewed by 3620

Abstract

Understanding the growing process and fruit size differences among peach cultivars is extremely important in the technological domain of the crop and can provide information to improve the proper crop management (thinning and harvesting seasons) and the crop breeding of fruits with a [...] Read more.

Understanding the growing process and fruit size differences among peach cultivars is extremely important in the technological domain of the crop and can provide information to improve the proper crop management (thinning and harvesting seasons) and the crop breeding of fruits with a larger caliber. However, this information is still incipient in subtropical regions and requires further research, especially in Brazil. The aim of this study was to determine the influence of temperature on the growing of four peach cultivars (Tropical, Aurora-2, Ouro Mel-4, and Biuti) under subtropical conditions of field cultivation. Fruit development was determined every two weeks throughout the cycle with 30 fruits from previously identified branches from six different plants of each cultivar. Regarding the thermal accumulation in growing degree-days (GDD), the cultivar ‘Tropical’ showed the lowest agronomic fruit properties (size and mass) and required a lower GDD accumulation during the development stages of the fruits, whereas the cultivar ‘Biuti’ showed higher thermal requirements and higher agronomic properties. The number of cells had greater influence on the final fruit size than the cell area. Full article

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15 pages, 2010 KiB

Open AccessArticle

The Impact of Seasonal Environments in a Tropical Savanna Climate on Forking, Leaf Area Index, and Biomass of Cassava Genotypes

by Phanupong Phoncharoen, Poramate Banterng, Nimitr Vorasoot, Sanun Jogloy, Piyada Theerakulpisut and Gerrit Hoogenboom

Agronomy 2019, 9(1), 19; https://doi.org/10.3390/agronomy9010019 - 05 Jan 2019

Cited by 15 | Viewed by 4247

Abstract

Information on the forking, leaf area index, and biomass of cassava for different growing seasons could help design appropriate management to improve yield. The objective was to evaluate the forking date, leaf growth, and storage root yield of different cassava genotypes grown at [...] Read more.

Information on the forking, leaf area index, and biomass of cassava for different growing seasons could help design appropriate management to improve yield. The objective was to evaluate the forking date, leaf growth, and storage root yield of different cassava genotypes grown at different planting dates. Four cassava genotypes (Kasetsart 50, Rayong 9, Rayong 11, and CMR38–125–77) were evaluated using a randomized complete block design with four replications. The cassava genotypes were planted on 20 April, 25 May, 30 June, 5 October, 10 November, and 15 December 2015, and 19 May and 3 November 2016. The soil properties prior to the planting, forking date, leaf area index (LAI), dry weights, harvest index (HI), starch content, and weather data were recorded. The forking date patterns for all of the growing seasons varied depending on the cassava genotypes. The weather caused occurring in the first forking for the Rayong 11 and CMR38–125–77 and the second forking for Rayong 11, but not for Kasetsart 50. The forking CMR38–125–77 had a higher LAI, leaf dry weight, biomass, and storage root dry weight than the non-forking Rayong 9. The higher storage root yields in Rayong 9 compared with Rayong 11 were due to an increased partitioning of the storage roots. Full article

(This article belongs to the Section Crop Breeding and Genetics)

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15 pages, 6968 KiB

Open AccessArticle

Characterization of Chromosomal Rearrangement in New Wheat—Thinopyrum intermedium Addition Lines Carrying Thinopyrum—Specific Grain Hardness Genes

by Zhihui Yu, Hongjin Wang, Yunfang Xu, Yongshang Li, Tao Lang, Zujun Yang and Guangrong Li

Agronomy 2019, 9(1), 18; https://doi.org/10.3390/agronomy9010018 - 03 Jan 2019

Cited by 25 | Viewed by 3983

Abstract

The wild species, Thinopyrum intermedium. (Genome StStJ^SJ^SJJ), serves as a valuable germplasm resource providing novel genes for wheat improvement. In the current study, non-denaturing fluorescence in situ hybridization (ND-FISH) with multiple probes and comparative molecular markers were applied to [...] Read more.

The wild species, Thinopyrum intermedium. (Genome StStJ^SJ^SJJ), serves as a valuable germplasm resource providing novel genes for wheat improvement. In the current study, non-denaturing fluorescence in situ hybridization (ND-FISH) with multiple probes and comparative molecular markers were applied to characterize two wheat-Th. intermedium chromosome additions. Sequential ND-FISH with new labeled Th. intermedium specific oligo-probes were used to precisely determine the chromosomal constitution of Th. intermedium, wheat—Th. intermedium partial amphiploids and addition lines Hy36 and Hy37. The ND-FISH results showed that the added J^S-St translocated chromosomes in Hy36 had minor Oligo-5S ribosomal DNA (rDNA) signals at the short arm, while a pair of J-St chromosomes in Hy37 had major Oligo-pTa71 and minor Oligo-5S rDNA signals. The 90K SNP array and PCR-based molecular markers that mapped on wheat linkage group 5 and 3 facilitated the identification of Thinopyrum chromosome introgressions in the addition lines, and confirmed that added chromosomes in Hy36 and Hy37 were 5J^SS.3StS and 5JS.3StS, respectively. Complete coding sequences at the paralogous puroindoline-a (Pina) loci from Th. intermedium were cloned and localized on the short arm of chromosome 5J^S of Hy36. Line Hy36 showed a reduction in the hardness index, which suggested that Th. intermedium-specific Pina gene sequences may be associated with the softness trait in wheat background. The molecular cytogenetic identification of novel wheat—Th. intermedium derivatives indicated that the frequent chromosome rearrangement occurred in the progenies of wheat-Thinopyrum hybridization. The new wheat-Thinopyrum derived lines may increase the genetic diversity for wheat breeding. Full article

(This article belongs to the Special Issue Advanced Genetic Technology Application towards the Improvement of Agricultural and Food Product Quality)

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19 pages, 2885 KiB

Open AccessArticle

Application of Logistic Regression Models for the Marketability of Cucumber Cultivars

by Manuel Díaz-Pérez, Ángel Carreño-Ortega, José-Antonio Salinas-Andújar and Ángel-Jesús Callejón-Ferre

Agronomy 2019, 9(1), 17; https://doi.org/10.3390/agronomy9010017 - 03 Jan 2019

Cited by 7 | Viewed by 7420

Abstract

The aim of this study is to establish a binary logistic regression method to evaluate and select cucumber cultivars (Cucumis sativus L.) with a longer postharvest shelf life. Each sample was evaluated for commercial quality (fruit aging, weight loss, wilting, yellowing, chilling [...] Read more.

The aim of this study is to establish a binary logistic regression method to evaluate and select cucumber cultivars (Cucumis sativus L.) with a longer postharvest shelf life. Each sample was evaluated for commercial quality (fruit aging, weight loss, wilting, yellowing, chilling injury, and rotting) every 7 days of storage. Simple and multiple binary logistic regression models were applied in which the dependent variable was the probability of marketability and the independent variables were the days of storage, cultivars, fruit weight loss, and months of evaluation. The results showed that cucumber cultivars with a longer shelf life can be selected by a simple and multiple binary logistic regression analysis. Storage time was the main determinant of fruit marketability. Fruit weight loss strongly influenced the probability of marketability. The logistic model allowed us to determine the cucumber weight loss percentage over which a fruit would be rejected in the market. Full article

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15 pages, 631 KiB

Open AccessArticle

Weather During Key Growth Stages Explains Grain Quality and Yield of Maize

by Carrie J. Butts-Wilmsmeyer, Juliann R. Seebauer, Lee Singleton and Frederick E. Below

Agronomy 2019, 9(1), 16; https://doi.org/10.3390/agronomy9010016 - 02 Jan 2019

Cited by 45 | Viewed by 7060

Abstract

Maize (Zea mays L.) grain yield and compositional quality are interrelated and are highly influenced by environmental factors such as temperature, total precipitation, and soil water storage. Our aim was to develop a regression model to account for this relationship among grain [...] Read more.

Maize (Zea mays L.) grain yield and compositional quality are interrelated and are highly influenced by environmental factors such as temperature, total precipitation, and soil water storage. Our aim was to develop a regression model to account for this relationship among grain yield and compositional quality traits across a large geographical region. Three key growth periods were used to develop algorithms based on the week of emergence, the week of 50% silking, and the week of maturity that enabled collection and modeling of the effect of weather and climatic variables across the major maize growing region of the United States. Principal component analysis (PCA), stepwise linear regression models, and hierarchical clustering analyses were used to evaluate the multivariate relationship between weather, grain quality, and yield. Two PCAs were found that could identify superior grain compositional quality as a result of ideal environmental factors as opposed to low-yielding conditions. Above-average grain protein and oil levels were favored by less nitrogen leaching during early vegetative growth and higher temperatures at flowering, while greater oil than protein concentrations resulted from lower temperatures during flowering and grain fill. Water availability during flowering and grain fill was highly explanatory of grain yield and compositional quality. Full article

(This article belongs to the Special Issue Environmental and Management Factor Contributions to Maize Yield)

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12 pages, 888 KiB

Open AccessArticle

Diallel Analysis of Early Leaf Spot (Cercospora arachidicola Hori) Disease Resistance in Groundnut

by Adama Zongo, Abdourasmane K. Konate, Kadidia Koïta, Mahamadou Sawadogo, Philippe Sankara, Bonny R. Ntare and Haile Desmae

Agronomy 2019, 9(1), 15; https://doi.org/10.3390/agronomy9010015 - 01 Jan 2019

Cited by 11 | Viewed by 4424

Abstract

Early leaf spot (ELS) is one of the major biotic constraints of groundnut production in West and Central Africa. A study using 6 × 6 F2 full diallel populations from six parents (NAMA, B188, PC79-79, QH243C, TS32-1, and CN94C) was conducted to assess [...] Read more.

Early leaf spot (ELS) is one of the major biotic constraints of groundnut production in West and Central Africa. A study using 6 × 6 F2 full diallel populations from six parents (NAMA, B188, PC79-79, QH243C, TS32-1, and CN94C) was conducted to assess the mode of inheritance of ELS resistance traits. The F2 and parents were grown in a randomized complete block design with three replications. Data was collected on ELS disease severity, and an area under disease progress curve (AUDPC) was estimated. The results revealed that additive and non-additive gene actions were involved in the inheritance of the ELS resistance traits, but additive gene action was predominant. Significant reciprocal cross effect was observed, suggesting cytoplasmic effect on ELS resistance. Graphical analysis also revealed the predominance of additive gene action for ELS resistance. The results suggest that early generation selection should be effective for ELS resistance. Looking at the distribution of array points along with the regression line, parental lines NAMA, PC79-79, and B188 would be suitable as good donors in an ELS disease resistance breeding program. Full article

(This article belongs to the Section Crop Breeding and Genetics)

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13 pages, 2738 KiB

Open AccessArticle

Dynamics of Bacterial Communities in a 30-Year Fertilized Paddy Field under Different Organic–Inorganic Fertilization Strategies

by Yadong Yang, Peixin Wang and Zhaohai Zeng

Agronomy 2019, 9(1), 14; https://doi.org/10.3390/agronomy9010014 - 01 Jan 2019

Cited by 31 | Viewed by 4759

Abstract

Fertilization plays important roles in improving soil fertility and in increasing crop yield. Soil microbial communities are sensitive indicators of soil quality and health, which could be affected by fertilization strategy. However, our knowledge on how organic–inorganic fertilizers application affects soil bacterial communities [...] Read more.

Fertilization plays important roles in improving soil fertility and in increasing crop yield. Soil microbial communities are sensitive indicators of soil quality and health, which could be affected by fertilization strategy. However, our knowledge on how organic–inorganic fertilizers application affects soil bacterial communities remains largely poorly understood. In this study, we investigated the long-term effects of different organic–inorganic fertilization strategies: without fertilizer (CK), fertilizers NPK (CF), fertilizers NPK, plus 30% organic manure (CFM1), and fertilizers NPK plus 60% organic manure (CFM2) on soil bacterial communities in paddy fields. Results showed that the bacterial 16S ribosomal DNA (rDNA) gene abundances in treatments CF, CFM1, and CFM2 were 1.44, 1.54, and 1.28 times higher than that in CK and the ACE index in treatment CFM1 was 9.0% greater than that in treatment CFM2, respectively. Fertilization strategy significantly changed the relative abundance of Nitrospirae, Gemmatimonadetes, and unclassified bacteria at the phylum level and bacteria belonging to order Nitrospira, candidate bacterium SBR2076, unclassified bacteria, Syntrophobacterales, and Solibacterales at the order level, respectively. High organic–inorganic fertilizer application rates inhibited the growth of Nitrospirae by 20–35%, and stimulated the growth of Gemmatimonadetes by 14–77%, relative to the rest of the treatments, respectively. Hierarchical cluster and principal coordinate analysis (PCoA) showed that the fertilization strategy affected the bacterial community structures, and the organic–inorganic fertilized treatments possessed similar bacterial community structures. Furthermore, soil pH, total nitrogen (TN), and soil organic carbon (SOC) were the main driving factors altering the bacterial communities. Our results suggested that combined organic–inorganic fertilizers application increased soil nutrient contents and bacterial abundances, and this could be an optimized fertilization strategy in regulating soil bacterial communities for rice production. Full article

(This article belongs to the Special Issue Soil Microbial Diversity in Prairie and Agricultural Ecosystems)

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20 pages, 1906 KiB

Open AccessArticle

Evaluating Soybean Cultivars for Low- and High-Temperature Tolerance During the Seedling Growth Stage

by Firas Ahmed Alsajri, Bhupinder Singh, Chathurika Wijewardana, J. Trenton Irby, Wei Gao and Kambham Raja Reddy

Agronomy 2019, 9(1), 13; https://doi.org/10.3390/agronomy9010013 - 01 Jan 2019

Cited by 58 | Viewed by 7611

Abstract

Soybean (Glycine max L.) seedlings may be exposed to low or high temperatures under early or conventional soybean production systems practiced in the US Midsouth. However, a wide range of soybean cultivars commonly grown in the region may inherit diverse tolerance to [...] Read more.

Soybean (Glycine max L.) seedlings may be exposed to low or high temperatures under early or conventional soybean production systems practiced in the US Midsouth. However, a wide range of soybean cultivars commonly grown in the region may inherit diverse tolerance to degrees of temperatures. Therefore, a study was conducted in a controlled-environment facility to quantify 64 soybean cultivars from Maturity Group III to V, to low (LT; 20/12 °C), optimum (OT; 30/22 °C), and high (HT; 40/32 °C) temperature treatments during the seedling growth stage. Several shoot, root, and physiological parameters were assessed at 20 days after sowing. The study found a significant decline in the measured root, shoot, and physiological parameters at both low and high temperatures, except for root average diameter (RAD) and lateral root numbers under LT effects. Under HT, shoot growth was significantly increased, however, root growth showed a significant reduction. Maturity group (MG) III had significantly lower values for the measured root, shoot, and physiological traits across temperature treatments when compared with MG IV and V. Cultivar variability existed and reflected considerably through positive or negative responses in growth to LT and HT. Cumulative stress response indices and principal component analysis were used to identify cultivar-specific tolerance to temperatures. Based on the analysis, cultivars CZ 5225 LL and GS47R216 were identified as most sensitive and tolerant to LT, while, cultivars 45A-46 and 5115LL identified as most tolerant and sensitive to HT, respectively. The information on cultivar-specific tolerance to low or high temperatures obtained in this study would help in cultivar selection to minimize stand loss in present production areas. Full article

(This article belongs to the Section Crop Breeding and Genetics)

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15 pages, 332 KiB

Open AccessArticle

Saffron Cultivation in Marginal Alpine Environments: How AMF Inoculation Modulates Yield and Bioactive Compounds

by Matteo Caser, Íris Marisa Maxaieie Victorino, Sonia Demasi, Andrea Berruti, Dario Donno, Erica Lumini, Valeria Bianciotto and Valentina Scariot

Agronomy 2019, 9(1), 12; https://doi.org/10.3390/agronomy9010012 - 31 Dec 2018

Cited by 39 | Viewed by 6396

Abstract

Arbuscular mycorrhizal fungi (AMF) establish mutualistic symbiotic associations with plant roots and act as biofertilizers by enhancing plant nutrient and water uptake. Moreover, AMF colonization may influence the biosynthesis of plant bioactive compounds in medicinal and aromatic plants. There is limited information on [...] Read more.

Arbuscular mycorrhizal fungi (AMF) establish mutualistic symbiotic associations with plant roots and act as biofertilizers by enhancing plant nutrient and water uptake. Moreover, AMF colonization may influence the biosynthesis of plant bioactive compounds in medicinal and aromatic plants. There is limited information on AMF associations with Crocus sativus L. (saffron) roots and their effect on crop performances and spice quality. In the present work we verified the efficiency of root mycorrhization in potted conditions, and then we evaluated the yield and quality of the saffron produced in two Alpine sites during two cultivation cycles with the application of AMF. Two inocula were applied, either a single-species (Rhizophagus intraradices) or a multispecies mixture (R. intraradices and Funneliformis mosseae). The trial conducted in potted conditions confirmed that both AMF commercial inocula established symbiotic relationships with saffron roots. The multispecies inoculation yielded the highest content of arbuscules in colonized portions of the root (100%), while the single-species was slightly less (82.9%) and no AMF were recorded in untreated control corms. In open-field conditions, AMF colonization of the root systems, flower production, and saffron yields were monitored, and bioactive compounds contents and antioxidant activity in the dried spice were analyzed using spectrophotometry and high performance liquid chromatography. Overall, the saffron produced was high quality (ISO category) and had high contents of bioactive compounds, with very high total polyphenol content and elevated antioxidant activity. The use of arbuscular mycorrhizal symbionts as biostimulants positively affected saffron cultivation, improving the crop performances and the content of important nutraceutical compounds. In particular, the inoculum composed by R. intraradices and F. mosseae increased flower production and the saffron yield. R. intraradices alone enhanced the spice antioxidant activity and the content of bioactive compounds such as picrocrocin, crocin II, and quercitrin. Since saffron is the world’s highest priced spice, the increases in yield and quality obtained using AMF suggests that farms in marginal areas such as alpine sites can increase profitability by inoculating saffron fields with arbuscular mycorrhiza. 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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