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  • Open access
  • 131 Reads
Developing a subpopulation-based model for the olive fruit fly Bactrocera oleae (Diptera: Tephritidae): conceptual model outline
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Bactrocera oleae Rossi (olive fruit fly) is a dipteran of the family Tephritidae, considered the key pest of olives in Mediterranean countries, where it causes losses of great economic impact. Meanwhile, the intensification of olive tree mono-cultures has led to an increase in the use of pesticides against this pest, and consequently to several environmental problems. This way, and to comply with the increasing need of a more sustainable and resilient agriculture, it is urgent to integrate alternatives or complementary practices to the use of plant protection products, such as natural pest control. For the efficient enhancement of this ecosystem service, it is necessary to understand the interactions between pests, predators, agricultural management and climate, which can be done through models.

In here we present the conceptual model of a spatially explicit subpopulation-based model being developed for B. oleae in olive groves. In this modelling technique, the simulated dynamic landscape is segmented into non-overlapping cells, where the subpopulations of B. oleae are represented as separate but interacting entities. Our model is based on the Animal Landscape Man Simulation System (ALMaSS), which comprises a highly detailed and realistic landscape representation, incorporating data on different aspects of farm management, crop development, and climate, and where simulated entities operate. The presented conceptual model contains information on the different developmental stages of B. oleae’s life cycle, as well as on how these organisms interact with their environment, essential for the development of the final model and its implementation in ALMaSS.

This is a multidisciplinary study involving different research fields such as agronomy, entomology, ecology, mathematics, geophysics, and software engineering.

This work was funded by Fundação para a Ciência e Tecnologia through the project PTDC/ASP-PLA/30003/2017 - OLIVESIM - Managing ecosystem services in olive groves using advanced landscape agent-based Models; by Programa Operacional Regional do Centro, grant number Centro-01-0145-FEDER-000007; by project ReNATURE—Valorization of the Natural Endogenous Resources of the Centro Region—Centro 2020; and by the European Union’s Horizon 2020 Research and Innovation programme, under Grant Agreement No. 773554 (EcoStack).

  • Open access
  • 78 Reads
Results of oilseed poppy breeding and production potential of new varieties
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Published: 01 May 2021 by MDPI in The 1st International Electronic Conference on Agronomy session Posters

Breeding of poppy (Papaver somniferum L.) for food use of poppy seeds has a long tradition in Slovakia. Conventional breeding methods have brought several successes in the form of registration of new varieties with better yield parameters. In breeding process, the methods of crossing and selection of offspring were used. In the years 2016 – 2018, the testing of selected poppy seeds was performed at the Central Control and Testing Institute in Agriculture with the aim to register new varieties. Testing was carried out according to the valid methodology in 5 localities of the Slovak Republic. The experiments were based on the block method on plots with an area of ​​10 m2 in four replications. The obtained poppy seed yield and empty dry capsules were compared to the parameters of standard - control varieties ('Opal' and 'Major'). In the year 2019, 4 new food poppy varieties - 'Azurit', 'MS Diamant', 'MS Topas' and 'MS Zafir' were registered. On average, the reached poppy seed yield during 3 years from 5 experimental localities ranged from 1.77 t.ha-1 ± 0.16 ('Azurit') to 1.90 t.ha-1 ± 0.17 ('MS Diamant'). For comparison, the average yield of control varieties was 1.76 t.ha-1 ± 0.12. An important additional indication in evaluation of the variety economic value is the yield of empty dry capsules. It ranged from 0.98 t.ha-1 ± 0.12 and 0.98 t.ha-1 ± 0.09 ('Azurit' and 'MS Diamant', respectively) to 1.09 t.ha-1 ± 0.21 and 1.09 t.ha-1 ± 0.16 ('MS Topas' and 'MS Zafir', respectively). The average dry capsule yield of control varieties was 0.93 t.ha-1 ± 0.13. Statistical evaluation by analysis of variance didn't reveal significant differences in seed yield between tested and control varieties (p = 0.661). The difference was significant in the yield of dry capsules (p = 0.048). The locality had a statistically significant effect on the yield of seeds and capsules (p <0.001). A statistically significant difference on the yield of seeds (p = 0.050) and capsules (p <0.001) was also found in the experimental year. New poppy varieties showed generally a higher seed yield potential compared to standard varieties. Based on the knowledge on soil and climatic conditions of individual experimental localities and test years, it is possible to choose a suitable variety for specific growing conditions in order to be able to maximize its genetic potential.

  • Open access
  • 72 Reads
Oak barrel effects on Chardonnay wine composition
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Published: 01 May 2021 by MDPI in The 1st International Electronic Conference on Agronomy session Posters

The quality of a wine depends mainly on its chemical composition. Chardonnay wine is a flexible variety, which could be adapted to different growth regions, weather or soil characteristics. Oak barrels are used in the winemaking due to the oak size and shape of the annual circles insuring its durability. The purpose was to examine the effects of two types of oak and short ageing periods on Chardonnay white wine composition by using gas chromatography coupled to mass spectrometry (GC–MS), focusing on the identification of the volatile profile. It can be conclude that the time and method of ageing significantly influenced the concentration of alcohols in the samples. During ageing, the esters have interesting trends, most of them increasing in concentration compared with the initial wine, only hexyl acetate and trimethylene acetate decreasing. For white Chardonnay wine, the use of oak could prevent the oxidation of aromatic volatile compounds, in the same inducing oak notes to the wine without decreasing the fresh and fruity characteristics.

  • Open access
  • 48 Reads
Comparison LAI estimates from of high resolution satellite observations using different biophysical processors

Earth observation provides timely and spatially explicit information on crop phenology and vegetation dynamics that can support decision making and sustainable agricultural land management. Vegetation spectral indices calculated from optical multispectral satellite sensors have been largely used to monitor vegetation status. Besides, techniques to retrieve biophysical parameters from satellite acquisitions, like the Leaf Area Index (LAI), allowed to assimilate Earth observation time series in numerical modelling for the analysis of several land surface processes related to agroecosystem dynamics. More recently, biophysical processors used to estimate biophysical parameters from satellite acquisitions have been calibrated for the retrieval from sensors with different high spatial resolution and spectral characteristics. Virtual constellations of satellite sensors allow the generation of denser LAI time series, contributing to improve vegetation phenology estimation accuracy and consequently enhancing agroecosystems monitoring capacity. This research study compare LAI estimates over croplands using different biophysical processors from Sentinel-2 MSI and Landsat-8 OLI satellite sensors. Results are used to demonstrate the capacity of virtual satellite constellation to strengthen LAI time series to derive important cropland use information over large areas.

  • Open access
  • 109 Reads
The influence of climatic factors on the elemental composition of Feteasca Regala wine from three southern regions
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Published: 01 May 2021 by MDPI in The 1st International Electronic Conference on Agronomy session Posters

The research targeted the investigation of the aromatic profile for 2019 Feteasca Regala wine resulted from three romanian traditional wineyards: Samburesti, Corcova and Avincis Dragasani. After the liquid / liquid extraction, 42 aroma compounds were identified and quantified by gas chromatography coupled with mass spectrometry (GC-MS), the obtained results differentiating them based on the area of origin and climatic factors. The higher alcohols varyed between 28644.53 µg /L and 33969.27 µg / L, while the esters showed values between 4221.10 µg /L and 7901.25 µg /L. Significant amounts were also observed for fatty acids, between 5310.99 µg /L and 6045.15 µg /L, while lactones showed values starting from 727.39 µg /L and accumulated up to 988.01 µg/L. The most significant results were noticeable in the case of Feteasca Regală wine from Avincis Dragasani, where the climatic indicators were in an optimal ratio, imposing specific quantifiable elements.

Acknowledgements. This work was supported by the project ANTREPRENORDOC, in the framework of Human Resources Development Operational Programme 2014-2020, financed from the European Social Fund under the contract number 36355/23.05.2019 HRD OP /380/6/13 – SMIS Code: 123847.

  • Open access
  • 72 Reads
Sustainability issues and consumption requirements, agricultural land production practices from a climate change perspective

The paper provides an overview of the agricultural economy regarding the development of agriculture and rural space. Prioritizing an action behavior in terms of vulnerabilities favors the orientation of agriculture through more environmentally responsible methods. One of the main objectives in the field of agriculture and rural development is to maintain a low level of greenhouse gas emissions generated by the agricultural sector. The role of research in the field and studies have shown an important factor in the fact that a reduction of the carbon footprint per ton of food produced from organic farming compared to conventional agriculture, in principle, due to the abandonment of the use of chemical fertilizers and pesticides. The purpose of the following research is to collect data and information on the most efficient management models that will create the premises for the production of production models that will respond in the future to climate change challenges, especially from the perspective of reducing greenhouse gases, in depending on soil quality. During the research we tried to highlight issues that, in our opinion, are important for the development of the agricultural sector as part of the economy. An important role is played by the implementation of best practices in the proper management of the land and the promotion of organic production models can significantly contribute to increasing the carbon absorption in the soil and, at the same time, indicating the possible improvements in their performance.

  • Open access
  • 142 Reads
Mapping macro and micronutrients in leaves of wheat colonized by intact arbuscular mycorrhiza extraradical mycelium through Laser Ablation-Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS)

Arbuscular mycorrhizal fungi (AMF) are obligate symbionts of over 80% of land plants. A mutualistic relation that grants colonized plants privileged access to water, nutrients and protection against biotic and abiotic stress. However, their use in intensive agriculture has been limited as result of an incomplete understanding of the complex ecological dynamics that drive plant–microbe interactions. Under Mn toxicity, in acidic soils, the development of an intact AMF extraradical mycelium (ERM) by stress-adapted native plants (Developers), can promote earlier AMF colonization, increased growth and protection against metal toxicity in the subsequent crop. In a previous study, the ERM developed from Ornithopus compressus (ORN) more than doubled wheat shoot weight and increased P contents while decreasing toxic shoot Mn. This beneficial effect was promoted by ORN-mediated soil microbial enrichment, which selected the AMF that colonized the succeeding wheat crop. The biochemical mechanisms promoting improved wheat growth are not yet fully understood but may involve the enzymatic management of oxidative stress and subcellular redistribution of nutrients and of excess Mn. In the present work, shoot Ca, Fe, Mg, Mn, P, K, Si, Na and Zn were mapped through Laser Ablation-Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS), in wheat grown for 3 weeks in undisturbed soil where ORN previously developed an extensive ERM network. Element mapping allowed the detection of higher levels of Fe, Mg, Mn, P, K, Na and Zn in the interveinal parts of wheat leaves while Ca and Si showed higher levels in vascular zones in the adaxial leaf side. This preliminary work is part of an ongoing project which aims at identifying biochemical mechanisms responsible for the protective properties of an early AM colonization of crops by ERM previously developed in association with native plants under Mn toxicity. Future research will determine the subcellular apoplastic or symplastic location of these elements as well as of excess Mn.

  • Open access
  • 58 Reads
Essential oils as potential biopesticides in the control of the genus Meloidogyne: A review

Root-knot nematodes (RKN), Meloidogyne spp., are among the most economically damaging phytoparasites. The pathogenic effects of these obligate biothrophs dramatically increase under mass monoculture of horticultural and field crops, causing significant economic losses for farmers. Pest management is usually a complex task given RKN worldwide distribution and wide host range. Control of RKN infestation is performed through the application of commercial synthetic nematicides that kill or disrupt the feeding or reproductive behavior of nematodes, commonly broad-spectrum fumigants and nervous system toxins. Despite their high efficiency, synthetic nematicides can cause extremely negative environmental and public health impacts, and are feared to lead to the development of resistance and immunity. Phytochemical based strategies for RKN control have been successfully employed and many essential oils (EOs) have shown remarkable activities, in some cases even surpassing those of commercial nematicides. EOs offer the advantage of being natural, biodegradable and subjected to less strict regulatory approval mechanisms for their exploration, due to a long history of use. The present work reviews the existing bibliography on the direct biological activity of EOs against Meloidogyne spp. A total of 49 publications were found reporting on the RKN antinematodal activity of EOs, from 1995 up to 2020. Plants from Lamiaceae and Compositae families make up more than 50% of the source material for EO extraction. The highest activities were reported for EOs extracted from plants of genus Monarda, Artemisia, Filipendula and Satureja. These taxa show potential to be further explored as highly active anti-RKN phytochemicals with practical applications in sustainable pest management strategies.

  • Open access
  • 87 Reads
Effect of shungite application on the temperature sensitivity of Allium cepa respiration under two soil water regime

For agricultural soils with low natural fertility, the possibility of using rock powders as an alternative source of nutrients and/or improver of soil physical parameters is under discussion and study. Shungite rocks, volcanic sedimentary rock formed mainly on a silicate basis, are characterized by the high content of carbon and nutrients. This study aimed to evaluate if shungite application to Umbric Podzols may affect leaf and root mitochondrial respiratory pathways, and leaf response to a temperature change. A pot culture experiment was conducted with Allium cepa L. seedlings, using soil shungite concentrations of 0, 5, 10, and 20 g kg-1 and two soil water regimes: well-watered (WW) and drying-wetting (DW) cycles. Soil water deficit increased total respiration (Vt) of onion leaves, but not roots, under low (13°C) and high (33°C) measurement temperature. Shungite application affected leaf Vt only at 13°C: it increased the Vt rate under WW and decreased one under DW. An increase in measurement temperature enhanced the sensitivity of leaf respiration to the inhibitor of the alternative respiratory pathway (salicylhydroxamic acid, SHAM). Shungite application increased the contribution of SHAM-sensitive pathway to the leaf Vt rate under WW, but not DW regime, regardless of the leaf temperature. In contrast to SHAM-resistant pathway, the temperature sensitivity of the SHAM-sensitive rate decreased following the decrease in soil water availability. Shungite application increased the temperature sensitivity of both SHAM-sensitive and SHAM-resistant pathways under DW, and significantly decreased these parameters under WW. In summary, the decrease of temperature sensitivity of alternative SHAM-sensitive respiratory pathway with a decrease of soil water availability or shungite-related decrease of both SHAM-sensitive and SHAM-resistant leaf respiration may play an important role in enhancing the resistance of plant respiration to stress temperature.

  • Open access
  • 81 Reads
Nematodicidal activity of essential oils and volatiles on the cyst nematodes Globodera and Heterodera

Plant parasitic nematodes (PPN) cause 11-14% yearly yield losses in worldwide agricultural crops. Establishment of efficient pest management practices is challenged by their diverse parasitic habits, either freely moving and feeding on root tissues or sedentary in feeding sites inside susceptible roots. The cyst nematodes of the genera Heterodera (HET) and Globodera (GLO), are among the most damaging obligate PPNs that parasitize cereals, rice, potatoes and soybean. The adult females body wall dries and hardens into a cyst (cutinization) that protects the embryonated eggs and can persist in the soil for many years until hatching. In the absence of resistant crops, soil fumigation of pesticides provides a good strategy for population control. However, synthetic nematicides can cause negative environmental and public health impacts, and are feared to lead to the development of resistance and immunity. The use of essential oils (EOs) can be a viable environment friendly alternative that has been poorly explored on cyst nematodes but has showed very good results on other PPNs. The present work reviews the existing bibliography on the biological activity of EOs against GLO and HET. One work reported a patented EO formulation claiming successful control of both genera, using EOs from Tagetes erecta, Ocimum basilicum and Cymbopogon martini. Seven works reported on the activity of EOs from 17 plant species against HET and only two against GLO, with EOs from 7 species. The EC50 values reported varied between 0.1 and 4 mg/mL, with the most successful belonging to Kaempferia galanga EO. Ethyl p-methoxycinnamate, a phenylpropanoid ester, was the EO volatile with the highest toxicity against HET, showing lower EC50 values than the nematodicide fosthiazate. The study of EOs against cyst nematodes is still preliminary in comparison to other PPNs. Future works must expand this research line and explore greener practices in cyst nematode pest management.