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  • Open access
  • 95 Reads
Can we predict arbuscular mycorrhizal inoculation effects on vine plants?
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Scientific literature has demonstrated for more than 50 years the positive effect of arbuscular mycorrhiza (AM) on plant growth and stress resistance. But it has been in the last 10 years that its application was implemented in agricultural systems. Recent reviews point to AM as key to viticulture. In order to identify the most effective mycorrhizal species and detect the rootstocks most dependent on inoculation we reanalyzed published experiments were AM were inoculated in vine plants. . To do that, we created a database where we included all the results comparing the development of vine plants that have been inoculated with AM against a control. We calculated inoculation dependence ID= ((Mean of inoculate treatment - Mean of control)/ Mean of inoculate treatment)*100) to compare the effect of AM inoculation on the vine between very different experiments. Only two species of mycorrhiza (Rhizophagus irregularis and Funneliformis mosseae) have been studied on the same rootstock measuring the same variables in more than one study. If we analyze all the AM species used together, for the majority of measured response variables there are no differences in the ID of the different rootstocks. Without considering the different rootstocks, we did not find significant differences in the ID between the different mycorrhizal species used. The results obtained showed that plants cannot always benefit from AM inoculation, and the effect of mycorrhizae can be positive or negative. The effect of mycorrhizal inoculation in vineyards is context dependent. This study has shown the need for prior pilot testing to determine the effect of a specific mycorrhizal species on certain rootstocks under specific growing conditions before their use can be recommended.

  • Open access
  • 62 Reads
Diachronic mapping of invasive plants using airborne RGB imagery in a central Pyrenees landscape (South-West France)

The rapid spread of invasive plant species (IPS) over several decades has led to numerous impacts on biodiversity, landscape and human activities. Often, long-term invasions lead to a significant change in ecosystems due to significant competition with native species, but they also adversely affect diverse agro-ecosystems. Early detection and knowledge of the dynamics and spatio-temporal distribution of IPS is crucial to better understand invasion patterns and conduct appropriate activities for management. Therefore, high resolution remote sensing using aerial photos provides great potential for detecting and mapping the spatial spread of IPS.

To characterize the spatial dynamic of IPS, mapping on two study sites located along the Pique valley in the central Pyrenees in the southwest of France was performed. The targeted species included Reynoutria japonica and Impatiens glandulifera. The areas occupied by these species over the past decade were assessed from ortho-rectified RGB aerial photographs (2019, 2016, 2013, 2010, resolution 0.2 – 0.5 m).

A supervised classification based on the random forest algorithm was performed using pixel attributes. From previous aerial imagery obtained, the original spectral bands (R-G-B) was used, to which vegetation indices (CIVE, VDVI, NGRDI) and textures (Energy, Entropy) were added to improve target species detection. Ground truth data were also collected during field investigation and were randomly divided into two independent groups, one for learning (50%) and the other one for validation (50%).

The classification models yielded a mean prediction accuracy (F-score) of 0.90 with values ranging from 0.87 to 0.92 at site 1, and 0.87 at site 2 with values ranging from 0.81 to 0.91. The model’s ability to correctly detect IPS allowed further examination of the processes favoring their emergence. Classifications results show that the expansion of IPS in this region was closely related to the presence of roads and to environmental disturbance by human activity such as land clearing.

  • Open access
  • 186 Reads
Weed Detection using Computer Vision and Artificial Inteligence in the Raspberry Pi Plataform as an Edge Device

Keep the balance between high productivity, produce quality food and yet manage efficiently the resources available for production is one of the biggest challenges in the agricultural sector. As a possible solution to overcome these challenges and obstacles, precision agriculture emerged. Among the promising solutions that precision agriculture offers highlights the use of edge computing devices for monitoring and acquiring data in the rural environment, processing information locally and in real time. Computer Vision and Artificial Intelligence, more specifically Deep Learning, have also being applied recently in agriculture for different tasks such as image classification and object detection and semantic segmentation. However, there is a challenge and limitation of transferring this technology to more affordable platforms to process the data. Therefore, in this work, it was explored the use of computer vision and Deep Learning applied to the object detection task in edge devices, specifically the Raspberry PI 4 platform, without hardware acceleration. It was decided to apply this methodology for weed detection, once weeds are currently one of the pests that most cause loss of productivity in agriculture, also develop resistance for most of the herbicides used commercially. Also, in order to evaluate the performance gain for real-time weed detection on the Raspberry Pi platform, quantization of the deep neural network architecture using TensorFlow Lite was tested. The experimental results point out that the proposed methodology is functional, being possible to reproduce this experiment on similar edge devices, real time object detection was also achieved for the Raspberry Pi 4 platform.

  • Open access
  • 54 Reads
The response of baby leaf lettuce to selenium biofortification under different lighting conditions

Selenium (Se) is an essential microelement for a human having antioxidant and anticancerous properties. One of the ways to increase its concentration in plants is biofortification through various agronomic practices including artificial lighting. The aim of the study was to determine the responses of baby leaf lettuce to various Se content in hydroponic solution at different ratio of blue (B) and red (R) light of light-emitting diodes (LED) lighting Lettuce (Lactuca sativa, ‘Little Gem’) were grown hydroponically under B: R light ratios - 10B:90R%, 75B:25R% 21 days after sowing (DAS). The photon flux density (PFD), photoperiod, temperature, and relative humidity in the growth chamber were maintained at 220 mol m-2 s-1, 18 h, 21/17±2oC, and 60±5%, respectively. Two experiments with Se were performed using natrium selenate (Na2SeO4). Results of the first experiment (Se - 0, 1, 3 ppm) showed that the content of Se in lettuce was about 15 times higher at 3 ppm compared to 1 ppm. Similar trends were observed for both B and R ratios. However, even the lowest dose of Se inhibited lettuce growth and reduced chlorophyll content. Therefore, a second experiment was performed with lower Se doses (0, 0.5, 1 ppm) at different growth stages (11th and 17thDAS). It was found that when Se exposure was initiated at 17th DAS, lettuce accumulated lower Se content compared to 11th DAS, but this did not have a negative effect on their growth. B:R ratios 10B:90R% resulted in higher Se content in the leaves. Overall, these results suggest that properly composed doses of Se and LED lighting could be a suitable way for the cultivation of selenium-biofortified baby leaf lettuces without any adverse effects on growth. Acknowledgements: This project has received funding from the Research Council of Lithuania (LMTLT), agreement No. S-MIP-19-2.

  • Open access
  • 70 Reads
Forest species of ecological importance in tropical dry forest fragments associated with a cultivation matrix of Gossypium herbaceum L. (La Guajira, Colombia)

The tropical dry forest is a dynamic ecosystem that develops in warm areas between 0-1000 meters of altitude with high genetic variability and supply of ecosystem services. The objective of the work was to identify forest species of conservation interest present in two remnants of tropical dry forest associated with a cultivation matrix of Gossypium herbaceum in the department of Guajira, Colombia. Ten transects of 100 m2 were established in each of the remnants and ad libitum trails to record the tree species and their abundances. Also, data on repetition height, total height, diameter at breast height (DAP), cover, and phenological notes (vegetative state, presence of flowers, presence of fruits) of each individual were taken; the specimens were determined with specialized bibliography and database. The families with greater species richness were Leguminosae, Anacardiaceae, Euphorbiaceae, and Moraceae; the species with greater abundance were Albizia saman, Leucaena leucocephala, Gliricidia sepium, Anacardium excelsum, Astronium graveolens, Hura crepitans, Ficus sp, Guazuma ulmifolia, and Casearia corymbosa; in the neighboring tree vegetation, the following species were registered: Mangifera indica, Persea americana, Annona muricata, Azadirachta indica and palms such as Attalea butyracea and Cocos nucifera; the remnants showed a relatively homogeneous species composition, but with variable dominances; in the agricultural matrix of cotton cultivation, forest species have emerged that provide shade and maintenance of the humidity of the agricultural system. The forest inventory of the zone contributes to the knowledge of the diversity of the tropical dry forest that is drastically reduced in the south of La Guajira and represents inputs for the formulation of environmental management and conservation plans.

  • Open access
  • 71 Reads
Garlic mimicks nitric oxide (NO) effects on ripening of pepper (Capsicum annuum L.) fruits and improves their commercial and nutritional properties.

Ripening of pepper (Capsicum annuum L.) fruits is characterized a shift in the fruit color from green to red, yellow, orange or purple depending on the variety. This event implies chlorophyll breakdown and synthesis of new carotenoids and anthocyanins, emission of organic volatiles, new protein synthesis and cleavage of existing ones and cell wall softening, among others [1]. From a metabolic point of view, this physiological process is accompanied by an increase of the lipid peroxidation, the activity of some enzymes such the superoxide-generating respiratory burst oxidative homolog (Rboh) and NADP-dehydrogenases, as well as by higher NADPH levels and some post-translational modification of proteins. Conversely, during ripening nitric oxide (NO) content and catalase activity lower [2]. NO has been proved to delay pepper fruit ripening and to enhance about 40% the ascorbate concentration [3,4]. Recent research carried out in our laboratory found that garlic (Allium sativum L.) clove samples release considerable amounts of NO. In this work, incubation of pepper fruits in the presence of garlic preparations was achieved. Then, diverse biochemical, nutritional and commercial parameters such as ascorbate, glutathione, carotenoids and flavonoids, among others, were determined in treated pepper fruits. Our data indicate that garlic preparations exerted similar effects as NO in pepper fruits, delaying ripening and increasing some trait values such as ascorbate, glutathione and flavonoids. These results suggest that this experimental design could be up-scaled for agro-biotechnological purposes with the circular economy being promoted.

[1] Palma et al., 2020, Antioxidants 9, 878.

[2] Chu-Puga et al., 2019, Antioxidants 8, 9.

[3] Chaki et al., 2015, Ann. Bot. 116: 637-647.

[4] Rodríguez-Ruiz et al., 2017, Redox Biol. 12, 171-181.

[Supported by grants PID2019-103924GB-I00 and P18-FR-1359 from MICINN and PAIDI-Junta de Andalucía, Spain]

  • Open access
  • 37 Reads
Higher Yield and Fruit Quality of a Solanum pennellii Introgression Line

Nowadays, the growing interest for well-being, is influencing the choices of consumers addressing them to eat functional foods that have high antioxidant potential. Cultivated tomato (Solanum lycopersicum L.) is an important source of antioxidants, such as ascorbic acid (vitamin C), carotenoids and phenolic compounds. Epidemiological results confirm that these antioxidant molecules are associated with a reduced risk of cancer, inflammation and cardiovascular diseases. Recently, one Introgression Line (IL) population deriving from Solanum pennellii has been exploited to identify favorable alleles that can improve fruit quality traits in commercial varieties, including antioxidants content. The aim of this work was to evaluate growth, final yields and the content of nutraceutical compounds at the ripe red fruit stage in one sub-line coded R182 which carries only a small region (448 Kbp) of wild genome in the cultivated genetic background (M82). Analyses carried out on R182 and on the parental line M82, demonstrated that the sub-line showed better performances in terms of yield and fruit qualitative traits most considered in industry. Indeed, higher yield (+28.99%), content of soluble sugars (+34.64%) and titratable acidity (+78.94%) were demonstrated for R182 compared to M82. Also, for the nutritional traits analyzed, an increase in the content of phenols (+ 69.96%), ascorbic acid (+ 48.55%), carotenoids (+ 29.66%), lycopene (+ 31.22%) and β-carotene (+31.67%) was observed. Therefore, it is possible to assert that the sub-line R182 may be considered as a good candidate to be used as parental genotype in breeding programs.

  • Open access
  • 137 Reads
Can Organic Farming development be driven by Remote Sensing technology?

Organic Farming (OF) is a form of production that uses a diverse set of methods and techniques focused on product quality, conservation of natural resources and biodiversity, and then seeking to ensure the sustainability of ecosystems and the health of farmers and consumers. The role of OF in rural development has been characterized by a great dynamic in the diversity of goods produced, good adaptation to the condition of smallholdings, family agriculture and local production. It has ensured a good compromise between the achievement of food security and nature conservation goals. The modernization of agriculture is increasingly dependent on the application of Precision Agriculture (PA) technologies, and Remote Sensing (RS) techniques become an essential tool for their effective application. PA technologies can deal with some crop production issues linked to OF, related to water and soil management, plant protection, and mechanization. These problems have limited the expansion of OF, due to the greater demands in technical knowledge and the accessibility to specific equipment, and farmers reticence for investments. This work addresses this critical issue for OF, analyzing the potential of RS-based PA techniques to face these problems. Different technologies are explored, based on the information provided by multispectral and thermal sensors on board satellite platforms and drones, as well as handheld devices. Data provided with the required frequency and spatial resolution allows a continuous monitoring of the crop growing and can be very helpful in several processes of OF vegetal production. Here are some examples, to assess: i) plant water stress to determine irrigation timing; ii) crop development vigor, to plan fertilization, irrigation needs, cultivation operations, or harvesting; iii) signs of biotic and abiotic diseases, to assess pesticide treatments or micronutrient application and iv) weeds, to determine quantity and typology and stablish timing and control processes. Successful examples reported in the bibliography and a specific study case focused on the Lis Valley, Portugal will be presented. This study will contribute to a better understanding on how the OF development could be driven by RS technology.

  • Open access
  • 63 Reads
Carotenoids determination of carrot cultivars
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Carotenoids play an essential role in human health and they also affect the perception of taste and flavour that influence consumer preference. Carrot is one of the most important and consumed vegetables in the world, and a critical source of α- and β-carotene accumulated in root tissues. The carotenoid content of carrots is mainly influenced by cultivar and growing sites. Commonly grown carrot cultivars (hybrids) were obtained from Begeč location (Vojvodina, Serbia): Maestro, Bolero, Natuna and Naval. The objectives of this study were to determine: 1) the carotenoid profile of the carrot cultivars by using the Raman spectroscopy and spectrophotometry, 2) are there any differences among selected cultivars regarding carotenoid content. Raman spectra of the root of four carrot cultivars exhibited three dominant carotenoid signals, mainly related to α- and β-carotene, in the three distinct regions: from 1509-1517 cm-1, 1146-1157 cm-1 and 998-1009 cm-1. According to the PCA analysis of the Raman spectra it is indicated that the first and second principal components are responsible for 94.06% of the total data variance and it suggested the existence of two groups of objects along PC1 axis. The loading plots showed variables with the highest positive and negative contribution along PC1 and PC2, indicating the differences between Maestro and Bolero on the one side and Natuna and Naval on the other, that are mainly based on carotenoid content and in the lower extend in carbohydrates. Raman spectroscopy was applied as a fast tool for the chemical evaluation which provided information about the carrot cultivars differences, mainly contributed to carotenoid content. Spectrophotometric analysis revealed that total carotenoid content was in range from 24.14 to 31.12 μg/g of dry mass (Naval and Bolero).

  • Open access
  • 71 Reads
Effects of the exogenous supplementation of natural and synthetic auxins on tomato transplant production

The research aimed to evaluate the use of synthetic or natural auxins on the growth of tomato seedlings. The seeds of Solanum lycopersicum "Marmande" were sown in polystyrene plug plant trays (104 cells). Two doses of natural or synthetic exogenous auxins (200 ppm and 100 ppm) were supplied to the substrate through the irrigation water with an ebb and flow system 3, 11, and 17 days after sowing (05, 11, and 13th BBCH growth stage, respectively). A commercial biostimulant based on Ecklonia maxima extracts (Basfoliar® Kelp SL Compo) was used as a source of natural auxin while 1-naphthaleneacetic acid NAA was used as a synthetic auxin. Seedlings supplied only with water were used as a control. The treatments had significant effects on many morphological and physiological parameters (plant height, stem diameter, plant fresh and dry weight, leaf number and area, stomatal conductance, plant water use, and water use efficiency). Seedlings treated with both doses of exogenous auxin provided via Ecklonia maxima extracts increased their fresh and dry weight by 31% and 37% respectively and were taller and leafier than the control seedlings. The use of NAA had a negative effect on plant height and stem fresh and dry weight but did not alter the other morpho-physiological parameters as compared to the control seedlings. The treatments with auxins from algae extract during nursery growth improved the performance of tomato seedlings but the benefits could be probably ascribed not only to auxins themselves but to the synergic effect of the other organic compounds contained in the product (amino acids, proteins, carbohydrates, and vitamins).