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Agronomy, Volume 7, Issue 4 (December 2017)

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Research

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Open AccessArticle Geographic and Research Center Origins of Rice Resistance to Asian Planthoppers and Leafhoppers: Implications for Rice Breeding and Gene Deployment
Agronomy 2017, 7(4), 62; doi:10.3390/agronomy7040062
Received: 22 August 2017 / Revised: 18 September 2017 / Accepted: 18 September 2017 / Published: 21 September 2017
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Abstract
This study examines aspects of virulence to resistant rice varieties among planthoppers and leafhoppers. Using a series of resistant varieties, brown planthopper, Nilaparvata lugens, virulence was assessed in seedlings and early-tillering plants at seven research centers in South and East Asia. Virulence
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This study examines aspects of virulence to resistant rice varieties among planthoppers and leafhoppers. Using a series of resistant varieties, brown planthopper, Nilaparvata lugens, virulence was assessed in seedlings and early-tillering plants at seven research centers in South and East Asia. Virulence of the whitebacked planthopper, Sogatella furcifera, in Taiwan and the Philippines was also assessed. Phylogenetic analysis of the varieties using single-nucleotide polymorphisms (SNPs) indicated a clade of highly resistant varieties from South Asia with two further South Asian clades of moderate resistance. Greenhouse bioassays indicated that planthoppers can develop virulence against multiple resistance genes including genes introgressed from wild rice species. Nilaparvata lugens populations from Punjab (India) and the Mekong Delta (Vietnam) were highly virulent to a range of key resistance donors irrespective of variety origin. Sogatella furcifera populations were less virulent to donors than N. lugens; however, several genes for resistance to S. furcifera are now ineffective in East Asia. A clade of International Rice Research Institute (IRRI)-bred varieties and breeding lines, without identified leafhopper-resistance genes, were highly resistant to the green leafhopper, Nephotettix virescens. Routine phenotyping during breeding programs likely maintains high levels of quantitative resistance to leafhoppers. We discuss these results in the light of breeding and deploying resistant rice in Asia. Full article
(This article belongs to the Special Issue Plant Resistance for the Protection of Cereal Crops from Insect Pests)
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Open AccessArticle Vegetable Intercropping in a Small-Scale Aquaponic System
Agronomy 2017, 7(4), 63; doi:10.3390/agronomy7040063
Received: 15 August 2017 / Revised: 5 September 2017 / Accepted: 20 September 2017 / Published: 23 September 2017
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Abstract
This paper reports the results of the first study of an aquaponic system for Pangasianodon hypophthalmus production that uses Lactuca sativa L. (lettuce) and Cichorium intybus L. rubifolium group (red chicory) intercropping in the hydroponic section. The experiment was conducted in a greenhouse
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This paper reports the results of the first study of an aquaponic system for Pangasianodon hypophthalmus production that uses Lactuca sativa L. (lettuce) and Cichorium intybus L. rubifolium group (red chicory) intercropping in the hydroponic section. The experiment was conducted in a greenhouse at the Zurich University of Applied Sciences, Wädenswil, Switzerland, using nine small-scale aquaponic systems (each approximately 400 L), with the nutrient film technique (NFT). The intercropping of vegetables did not influence the water temperature, pH, electric conductivity (EC), oxidation–reduction potential, nor O2 content. Intercropping with red chicory increased the lettuce sugar content (+16.0% and +25.3% for glucose and fructose, respectively) and reduced the lettuce caffeic acid content (−16.8%). In regards to bitter taste compounds (sesquiterpene lactones), intercropping reduced the concentrations of dihydro-lactucopicrin + lactucopicrin (−42.0%) in lettuce, and dihydro-lactucopicrin + lactucopicrin (−22.0%) and 8-deoxy–lactucin + dihydro-lactucopicrin oxalate (−18.7%) in red chicory, whereas dihydro-lactucin content increased (+40.6%) in red chicory in regards to monoculture. A significantly higher organic nitrogen content was found in the lettuce (3.9%) than in the red chicory biomass (3.4%), following the intercropping treatment. Anion and cation contents in vegetables were affected by species (Cl, NO3, PO43−, SO42−, and Ca2+), intercropping (K+ and Mg2+), and species × intercropping interactions (NO2 and NH4+). Experimental treatments (monoculture vs intercropping and distance from NFT inlet) did not exert significant effects on leaf SPAD (index of relative chlorophyll content) values, whereas the red coloration of the plants increased from the inlet to the outlet of the NFT channel. Intercropping of lettuce and red chicory affected the typical taste of these vegetables by increasing the sweetness of lettuce and changing the ratio among bitter taste compounds in red chicory. These results suggest intercropping as a possible solution for improving vegetable quality in aquaponics. Although the results are interesting, they have been obtained in a relatively short period, thus investigations for longer periods are necessary to confirm these findings. Further studies are also needed to corroborate the positive effect of the presence of red chicory in the system on fish production parameters. Full article
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Open AccessArticle Evaluating Agricultural Management Effects on Alachlor Availability: Tillage, Green Manure, and Biochar
Agronomy 2017, 7(4), 64; doi:10.3390/agronomy7040064
Received: 21 August 2017 / Revised: 6 September 2017 / Accepted: 20 September 2017 / Published: 23 September 2017
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Abstract
Agricultural and soil management practices have been reported to affect alachlor sorption–desorption and degradation rates. Though alachlor has been banned in the E.U. since 2006, it is still used in U.S. corn and soybean production. The objectives of this study were to: (a)
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Agricultural and soil management practices have been reported to affect alachlor sorption–desorption and degradation rates. Though alachlor has been banned in the E.U. since 2006, it is still used in U.S. corn and soybean production. The objectives of this study were to: (a) assess differences in alachlor sorption due to tillage treatments (chisel plow and ridge tillage) on soils from three midwestern U.S. locations; and (b) determine the effect of various soil amendments on the sorption–desorption and mineralization of alachlor. Soils were amended at a rate of 10% (w/w) with biochars derived from soybean stover, sugarcane bagasse, and wood chips, as well as the uncharred feedstock materials. Sorption–desorption studies were performed using the batch equilibration method, and alachlor mineralization was evaluated in a 30-day incubation. Tillage management did not affect alachlor sorption to soil across the three sites, despite the fact that the tillage operations were imposed for 4 years (p > 0.05). While the sorption coefficient (Kd) values for alachlor were relatively low in the three unamended soils (Kd = 1.76, 1.73, and 1.15 L·kg−1 for IL, MN, and PA soils, respectively), biochar amendments increased alachlor sorption between 4× and 33× compared to the unamended soil. The amendments also affected alachlor mineralization such that degradation was slower in both biochar- and raw feedstock-amended soils. Based on these results, biochar additions are expected to affect the availability of alachlor for transport and degradation. Furthermore, this study highlights the larger impact of biochar addition than tillage practices on altering immediate alachlor sorption capacities. Full article
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Open AccessArticle Effect of Vegetative Propagation Materials on Globe Artichoke Production in Semi-Arid Developing Countries: Agronomic, Marketable and Qualitative Traits
Agronomy 2017, 7(4), 65; doi:10.3390/agronomy7040065
Received: 31 August 2017 / Revised: 19 September 2017 / Accepted: 21 September 2017 / Published: 24 September 2017
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Abstract
In Tunisia, globe artichoke is mainly propagated by underground dormant axillary buds (ovoli), which are removed from the field in August during the quiescence period. The high cost of in vitro-plants and the absence of specialized nurseries were among the reasons for the
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In Tunisia, globe artichoke is mainly propagated by underground dormant axillary buds (ovoli), which are removed from the field in August during the quiescence period. The high cost of in vitro-plants and the absence of specialized nurseries were among the reasons for the rise of heterogeneity and spread of diseases. The aim was to help farmers to improve artichoke yield and quality by ameliorating their vegetative propagation technique with low cost methods. Three plant cuttings management methods were tested: summer ovoli (T0); spring offshoots nursery’s cuttings forced to pass a vegetative rest period by stopping irrigation (T1); and offshoots nursery’s cuttings not forced (T2). The cuttings management can affect both yield and qualitative traits of artichoke. T1 nursery plants produced the heaviest primary heads, 7% and 23% higher than T2 and T0, respectively. T1 plants exhibited the highest yield during the harvest season, with +17.7% and +12.2% compared to T0 and T2, respectively. T0 and T1 showed the highest total antioxidant capacity and inulin content; the propagation method also affected the short-chain sugars ratio. T1 is a viable and sustainable alternative to the traditional one that does not heavily impact on growing costs and improves yield and quality of artichoke. Full article
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Open AccessArticle Investigating the Combined Effect of Tillage, Nitrogen Fertilization and Cover Crops on Nitrogen Use Efficiency in Winter Wheat
Agronomy 2017, 7(4), 66; doi:10.3390/agronomy7040066
Received: 14 August 2017 / Revised: 19 September 2017 / Accepted: 20 September 2017 / Published: 27 September 2017
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Abstract
A field study was conducted in northern France over two consecutive years to evaluate the combined effect of conventional tillage (CT) vs no till (NT) with or without cover crops (cc) and nitrogen (N) fertilization on various agronomic traits related to N use
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A field study was conducted in northern France over two consecutive years to evaluate the combined effect of conventional tillage (CT) vs no till (NT) with or without cover crops (cc) and nitrogen (N) fertilization on various agronomic traits related to N use efficiency in winter wheat. Five years after conversion of CT to NT, significant increases in N use efficiency, N utilization efficiency, N agronomic efficiency, N partial factor productivity, N apparent recovery fraction and N remobilization were observed under three N fertilization regimes (0, 161, 215 kg ha−1). It was also observed that grain yield and grain N content were similar under CT and NT. The N nutrition index was higher under NT at the three rates of N fertilization. Moreover, N use efficiency related traits were increased in the presence of cc both under NT and CT. Thus, agronomic practices based on continuous NT in the presence of cc, appear to be promising strategies to increase N use efficiency in wheat, while reducing both the use and the loss of N-based fertilizers. Full article
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Open AccessArticle Performance of Precision Mobile Drip Irrigation in the Texas High Plains Region
Agronomy 2017, 7(4), 68; doi:10.3390/agronomy7040068
Received: 14 September 2017 / Revised: 13 October 2017 / Accepted: 19 October 2017 / Published: 20 October 2017
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Abstract
Mobile drip irrigation (MDI) technology adapts driplines to the drop hoses of moving sprinkler systems to apply water as the drip lines are pulled across the field. There is interest in this technology among farmers in the Texas High Plains region to help
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Mobile drip irrigation (MDI) technology adapts driplines to the drop hoses of moving sprinkler systems to apply water as the drip lines are pulled across the field. There is interest in this technology among farmers in the Texas High Plains region to help sustain irrigated agriculture. However, information on the performance of this system and its benefits relative to common sprinkler application technologies in the region are limited. A two-year study was conducted in 2015 and 2016 to compare grain yields, crop water use (ETc) and water use efficiency (WUE) of corn (Zea Mays L.) irrigated with MDI, low elevation spray application (LESA) and low energy precision application (LEPA) methods. Irrigation amounts for each application method were based on weekly neutron probe readings. In both years, grain yield and yield components were similar among application treatment methods. Although WUE was similar for the MDI treatment plots compared with LEPA and LESA during the wet growing season (2015), MDI demonstrated improved WUE during the drier year of 2016. Additional studies using crops with less than full canopy cover at maturity (sorghum and cotton) are needed to document the performance of MDI in the Texas High Plains region. Full article
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Open AccessArticle Reducing Severity of Late Blight (Phytophthora infestans) and Improving Potato (Solanum tuberosum L.) Tuber Yield with Pre-Harvest Application of Calcium Nutrients
Agronomy 2017, 7(4), 69; doi:10.3390/agronomy7040069
Received: 7 August 2017 / Revised: 18 September 2017 / Accepted: 19 September 2017 / Published: 21 October 2017
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Abstract
The efficiency of pre-harvest application of calcium chloride alone, calcium nitrate alone, and combined application of calcium chloride and calcium nitrate (1:1) was evaluated in reducing the severity of P. infestans and improving potato tuber yield. Pot experiment was conducted in randomized complete
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The efficiency of pre-harvest application of calcium chloride alone, calcium nitrate alone, and combined application of calcium chloride and calcium nitrate (1:1) was evaluated in reducing the severity of P. infestans and improving potato tuber yield. Pot experiment was conducted in randomized complete block design with four replications. The treatments consisted of combination of two potato varieties (Shenkola and Gera) and three types of calcium nutrients (calcium chloride alone, calcium nitrate alone, and calcium chloride mixed with calcium nitrate), each at three levels (5, 10, and 15 g per liter per plant) and the control treatment (0 g of calcium nutrients). In comparison to the control treatment, the application of calcium nutrients significantly decreased the severity of late blight disease and improved potato tuber yield. The effect of calcium nutrients on the severity of late blight disease and potato tuber yield differed among the two potato varieties. The maximum severity reduction (60%) was noticed in the Gera potato variety with the application of calcium chloride mixed with calcium nitrate (1:1), supplied at 15 g per plant. However, the highest average tuber yield was obtained with the application of calcium nitrate at 15 g per plant, and average tuber yield was increased by 77% in both potato varieties. Hence, foliar application of either calcium nitrate alone or calcium nitrate mixed with calcium chloride was found to be more efficient than the application of calcium chloride alone. This result suggests that the nitrate ion present in the calcium nitrate may make a difference in terms of reducing the severity of late blight disease and improving potato tuber yield. The lowered severity of late blight disease and the increased tuber yield in potato plants sprayed with calcium nutrients may be because of the higher accumulation of calcium in the plant tissue. Full article
(This article belongs to the Special Issue Role of Plant Nutrients in Agronomic Crops)
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Open AccessArticle Prospects for Genetic Improvement in Internal Nitrogen Use Efficiency in Rice
Agronomy 2017, 7(4), 70; doi:10.3390/agronomy7040070
Received: 13 September 2017 / Revised: 24 October 2017 / Accepted: 26 October 2017 / Published: 30 October 2017
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Abstract
While improving the efficiency at which rice plants take up fertiliser nitrogen (N) will be critical for the sustainability of rice (Oryza sativa L.) farming systems in future, improving the grain yield of rice produced per unit of N accumulated in aboveground
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While improving the efficiency at which rice plants take up fertiliser nitrogen (N) will be critical for the sustainability of rice (Oryza sativa L.) farming systems in future, improving the grain yield of rice produced per unit of N accumulated in aboveground plant material (agronomic N use efficiency; NUEagron) through breeding may also be a viable means of improving the sustainability of rice cropping. Given that NUEagron (grain yield/total N uptake) is a function of harvest index (HI; grain yield/crop biomass) × crop biomass/total N uptake, and that improving HI is already the target of most breeding programs, and specific improvement in NUEagron can only really be achieved by increasing the crop biomass/N uptake. Since rice crops take up around 80% of total crop N prior to flowering, improving the biomass/N uptake (NUEveg) prior to, or at, flowering may be the best means to improve the NUEagron. Ultimately, however, enhanced NUEagron may come at the expense of grain protein unless the N harvest index increases concurrently. We investigated the relationships between NUEagron, total N uptake, grain yield, grain N concentration (i.e., protein) and N harvest index (NHI) in 16 rice genotypes under optimal N conditions over two seasons to determine if scope exists to improve the NHI and/or grain protein, while maintaining or enhancing NUEagron in rice. Using data from these experiments and from an additional experiment with cv. IR64 under optimum conditions at an experimental farm to establish a benchmark for NUE parameters in high-input, high yielding conditions, we simulated theoretical potential improvements in NUEveg that could be achieved in both low and high-input scenarios by manipulating target NHIs and grain protein levels. Simulations suggested that scope exists to increase grain protein levels in low yielding scenarios with only modest (5–10%) reductions in current NUEagron by increasing the current NHI from 0.6 to 0.8. Furthermore, substantial scope exists to improve NUEveg (and therefore NUEagron) in high-yielding scenarios if maintaining current grain protein levels of 7.3% is not essential. Full article
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Open AccessArticle A Dynamic Decision-Making Tool for Calculating the Optimal Rates of N Application for 40 Annual Crops While Minimising the Residual Level of Mineral N at Harvest
Agronomy 2017, 7(4), 73; doi:10.3390/agronomy7040073
Received: 20 July 2017 / Revised: 16 October 2017 / Accepted: 7 November 2017 / Published: 14 November 2017
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Abstract
Adequate nitrogen (N) fertilisation is an important component of sustainable management in agricultural systems because it reduces the environmental impacts of agriculture. However, taking into account the varied sources of soil N remains a challenge, and farmers require robust decision-making tools to manage
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Adequate nitrogen (N) fertilisation is an important component of sustainable management in agricultural systems because it reduces the environmental impacts of agriculture. However, taking into account the varied sources of soil N remains a challenge, and farmers require robust decision-making tools to manage increasingly diverse growing conditions. To address these issues, we present the AzoFert® decision support system for farmers and extension services. This tool is capable of providing N recommendations at the field scale for 40 main field crops. It is based on a full inorganic N balance sheet and integrates the dynamic modelling of N supply from soil and various organic sources. Because of the choice of formalisms and parameters and the structure and modularity of the computer design, the tool is easily adaptable to new crops and cropping systems. We illustrate the application of Azofert® through a range of N fertilisation experiments conducted on cereals, sugar beet and vegetables in France. Full article
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Open AccessArticle Resistance to Wheat Curl Mite in Arthropod-Resistant Rye-Wheat Translocation Lines
Agronomy 2017, 7(4), 74; doi:10.3390/agronomy7040074
Received: 29 September 2017 / Revised: 4 November 2017 / Accepted: 8 November 2017 / Published: 15 November 2017
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Abstract
The wheat curl mite, Aceria toschiella (Keifer), and a complex of viruses vectored by A. toschiella substantially reduce wheat yields in every wheat-producing continent in the world. The development of A. toschiella-resistant wheat cultivars is a proven economically and ecologically viable method
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The wheat curl mite, Aceria toschiella (Keifer), and a complex of viruses vectored by A. toschiella substantially reduce wheat yields in every wheat-producing continent in the world. The development of A. toschiella-resistant wheat cultivars is a proven economically and ecologically viable method of controlling this pest. This study assessed A. toschiella resistance in wheat genotypes containing the H13, H21, H25, H26, H18 and Hdic genes for resistance to the Hessian fly, Mayetiola destructor (Say) and in 94M370 wheat, which contains the Dn7 gene for resistance to the Russian wheat aphid, Diuraphis noxia (Kurdjumov). A. toschiella populations produced on plants containing Dn7 and H21 were significantly lower than those on plants of the susceptible control and no different than those on the resistant control. Dn7 resistance to D. noxia and H21 resistance to M. destructor resulted from translocations of chromatin from rye into wheat (H21—2BS/2RL, Dn7—1BL/1RS). These results provide new wheat pest management information, indicating that Dn7 and H21 constitute resources that can be used to reduce yield losses caused by A. toschiella, M. destructor, D. noxia, and wheat streak mosaic virus infection by transferring multi-pest resistance to single sources of germplasm. Full article
(This article belongs to the Special Issue Plant Resistance for the Protection of Cereal Crops from Insect Pests)
Open AccessArticle Assessment of Soil Aggradation through Soil Aggregation and Particulate Organic Matter by Riparian Switchgrass Buffers
Agronomy 2017, 7(4), 76; doi:10.3390/agronomy7040076
Received: 6 October 2017 / Revised: 1 November 2017 / Accepted: 13 November 2017 / Published: 17 November 2017
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Abstract
The restoration of riparian zones has been an important issue in many regions for the recovery of ecosystem functions. The objective of this study was to assess soil aggradation in a 7-year established riparian switchgrass buffer (SGB) and in a non-buffered riparian zone
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The restoration of riparian zones has been an important issue in many regions for the recovery of ecosystem functions. The objective of this study was to assess soil aggradation in a 7-year established riparian switchgrass buffer (SGB) and in a non-buffered riparian zone with an annual row crop (ARC). We measured the aggregate size distribution and stability of macroaggregates, aggregate-associated soil organic carbon, soil organic matter fractions and the chemical composition of light particulate organic matter to monitor soil aggregation in a riparian soil following the conversion of agricultural row crops to switchgrass filters. Aggregate size fractions were separated by wet sieving using the aggregate size-stability protocol. The proportion of soil and total organic C was quantified for each aggregate size class. Soil organic matter fractions were isolated by size and density into light particulate organic matter and heavy particulate organic matter and mineral fraction organic matter. The categorization of aggregates by size and water stability (slaking resistance) showed a significantly larger (p < 0.001) proportion of water-unstable large macroaggregates (>2000 µm) under SGB (34%) compared to that under ARC (29%), while the proportion of water-unstable small macroaggregates (250–2000 µm) was significantly higher under ARC (14%) than under SGB (10%). Our results showed that the amounts of light and heavy particulate organic matter did not change in the short-term (7 years) after SGB establishment. It appears that the lower soil stabilization and soil organic C storage under SGB is related to (i) the large number of coarse roots; (ii) lower inputs of light and heavy particulate organic matter; (iii) no changes in the alkyl-C/O-alkyl-C ratio over time; and (iv) light particulate organic matter with a high C/N ratio. Full article

Review

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Open AccessReview Arsenic Accumulation in Rice and Probable Mitigation Approaches: A Review
Agronomy 2017, 7(4), 67; doi:10.3390/agronomy7040067
Received: 21 August 2017 / Revised: 15 September 2017 / Accepted: 30 September 2017 / Published: 12 October 2017
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Abstract
According to recent reports, millions of people across the globe are suffering from arsenic (As) toxicity. Arsenic is present in different oxidative states in the environment and enters in the food chain through soil and water. In the agricultural field, irrigation with arsenic
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According to recent reports, millions of people across the globe are suffering from arsenic (As) toxicity. Arsenic is present in different oxidative states in the environment and enters in the food chain through soil and water. In the agricultural field, irrigation with arsenic contaminated water, that is, having a higher level of arsenic contamination on the top soil, which may affects the quality of crop production. The major crop like rice (Oryza sativa L.) requires a considerable amount of water to complete its lifecycle. Rice plants potentially accumulate arsenic, particularly inorganic arsenic (iAs) from the field, in different body parts including grains. Different transporters have been reported in assisting the accumulation of arsenic in plant cells; for example, arsenate (AsV) is absorbed with the help of phosphate transporters, and arsenite (AsIII) through nodulin 26-like intrinsic protein (NIP) by the silicon transport pathway and plasma membrane intrinsic protein aquaporins. Researchers and practitioners are trying their level best to mitigate the problem of As contamination in rice. However, the solution strategies vary considerably with various factors, such as cultural practices, soil, water, and environmental/economic conditions, etc. The contemporary work on rice to explain arsenic uptake, transport, and metabolism processes at rhizosphere, may help to formulate better plans. Common agronomical practices like rain water harvesting for crop irrigation, use of natural components that help in arsenic methylation, and biotechnological approaches may explore how to reduce arsenic uptake by food crops. This review will encompass the research advances and practical agronomic strategies on arsenic contamination in rice crop. Full article
(This article belongs to the Special Issue Further Metabolism in Plant System)
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Open AccessReview Artificial Seeds (Principle, Aspects and Applications)
Agronomy 2017, 7(4), 71; doi:10.3390/agronomy7040071
Received: 20 September 2017 / Revised: 23 October 2017 / Accepted: 27 October 2017 / Published: 3 November 2017
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Abstract
Artificial seeds are artificially encapsulated somatic embryos (usually) or other vegetative parts such as shoot buds, cell aggregates, auxiliary buds, or any other micropropagules which can be sown as a seed and converted into a plant under in vitro or in vivo conditions.
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Artificial seeds are artificially encapsulated somatic embryos (usually) or other vegetative parts such as shoot buds, cell aggregates, auxiliary buds, or any other micropropagules which can be sown as a seed and converted into a plant under in vitro or in vivo conditions. An improved artificial seed production technique is considered a valuable alternate technology of propagation in many commercially important crops and a significant method for mass propagation of elite plant genotypes. The production of plant clones multiplied by tissue culture and distributed as artificial seeds could be a useful alternative to the costly F1 hybrids for different plant crops. The delivery of artificial seeds also facilitates issues such as undertaking several ways for scaling up in vitro cultures and acclimatization to ex vitro conditions. The development of an artificial seed technique also provides a great approach for the improvement of various plant species such as trees and crops. Full article
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Open AccessReview Trade-Offs in Arbuscular Mycorrhizal Symbiosis: Disease Resistance, Growth Responses and Perspectives for Crop Breeding
Agronomy 2017, 7(4), 75; doi:10.3390/agronomy7040075
Received: 5 October 2017 / Revised: 30 October 2017 / Accepted: 30 October 2017 / Published: 16 November 2017
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Abstract
There is an increasing need to develop high-yielding, disease-resistant crops and reduce fertilizer usage. Combining disease resistance with efficient nutrient assimilation through improved associations with symbiotic microorganisms would help to address this. Arbuscular mycorrhizal fungi (AMF) form symbiotic relationships with most terrestrial plants,
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There is an increasing need to develop high-yielding, disease-resistant crops and reduce fertilizer usage. Combining disease resistance with efficient nutrient assimilation through improved associations with symbiotic microorganisms would help to address this. Arbuscular mycorrhizal fungi (AMF) form symbiotic relationships with most terrestrial plants, resulting in nutritional benefits and the enhancement of stress tolerance and disease resistance. Despite these advantages, arbuscular mycorrhizal (AM) interactions are not normally directly considered in plant breeding. Much of our understanding of the mechanisms of AM symbiosis comes from model plants, which typically exhibit positive growth responses. However, applying this knowledge to crops has not been straightforward. In many crop plants, phosphate uptake and growth responses in AM-colonized plants are variable, with AM plants exhibiting sometimes zero or negative growth responses and lower levels of phosphate acquisition. Host plants must also balance the ability to host AMF with the ability to resist pathogens. Advances in understanding the plant immune system have revealed similarities between pathogen infection and AM colonization that may lead to trade-offs between symbiosis and disease resistance. This review considers the potential trade-offs between AM colonization, agronomic traits and disease resistance and highlights the need for translational research to apply fundamental knowledge to crop improvement. Full article
(This article belongs to the Special Issue Disease Resistance Trade-offs in Crop Breeding for Disease Resistance)
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