Molecular Hallmarks, Agronomic Performances and Seed Nutraceutical Properties to Exploit Neglected Genetic Resources of Common Beans Grown by Organic Farming in Two Contrasting Environments.

Common bean (Phaseolus vulgaris L.) is an essential source of food proteins and an important component of sustainable agriculture systems around the world. Thus, conserving and exploiting the genetic materials of this crop species play an important role in achieving global food safety and security through the preservation of functional and serependic opportunities afforded by plant species diversity. Our research aimed to collect and perform agronomic, morpho-phenological, molecular-genetic, and nutraceutical characterizations of common bean accessions, including lowland and mountain Venetian niche landraces (ancient farmer populations) and Italian elite lineages (old breeder selections). Molecular characterization with SSR and SNP markers grouped these accessions into two well-separated clusters that were linked to the original Andean and Mesoamerican gene pools, which was consistent with the outputs of ancestral analysis. Genetic diversity in the two main clusters was not distributed equally the Andean gene pool was found to be much more uniform than the Mesoamerican pool. Additional subdivision resulted in subclusters, supporting the existence of six varietal groups. Accessions were selected according to preliminary investigations and historical records and cultivated in two contrasting Venetian environments: sea-level and mountain territories. We found that the environment significantly affected some nutraceutical properties of the seeds, mainly protein and starch contents. The antioxidant capacity was found significantly greater at sea level for climbing accessions and in the mountains for dwarf accessions. The seed yield at sea level was halved than mountain due to a seeds reduction in weight, volume, size and density. At sea level, bean landraces tended to have extended flowering periods and shorter fresh pod periods. The seed yield was positively correlated with the length of the period during which plants had fresh pods and negatively correlated with the length of the flowering period. Thus, the agronomic performance of these genetic resources showed their strong connection and adaptation to mountainous environments. On the whole, the genetic-molecular information put together for these univocal bean entries was combined with overall results from plant and seed analyses to select and transform the best accessions into commercial varieties (i.e., pure lines) suitable for wider cultivation.

Rainfall increasing offsets the negative effects of nighttime warming on GHGs and wheat yield in North China Plain.

The effects of nighttime warming and rainfall increasing on crop productivity and soil greenhouse gas emissions are few studied. This study was conducted with a field experiment to investigate the effects of nighttime warming, rainfall increasing and their interaction on wheat grain yield, methane (CH4) and nitrous oxide (N2O) emissions during a winter wheat growing season in the North China Plain (NCP). The results showed that nighttime warming and rainfall increasing significantly altered soil temperature and moisture, and thus the CH4 and N2O emissions from the soil. Nighttime warming significantly promoted soil CH4 uptake by 21.2% and increased soil N2O emissions by 22.4%. Rainfall increasing stimulated soil N2O emissions by 15.7% but decreased soil CH4 uptake by 18.6%. Nighttime warming significantly decreased wheat yield by 5.5%, while rainfall increasing enhanced wheat yield by 4.0%. The results indicate that the positive effect of nighttime warming on CH4 uptake and negative effect on wheat yield can be offset by rainfall increasing in the NCP. Generally, rainfall increasing significantly raised the global warming potential and greenhouse gas intensity induced by CH4 and N2O emissions. Overall, this study improves our understanding of agroecosystem C and N cycling in response to nighttime warming and rainfall increasing under future climate change.

Green walls to treat kitchen greywater in urban areas: Performance from a pilot-scale experiment.

An increase in water use in urban areas is forcing scientists and policy makers to find alternative solutions for freshwater management, aimed at attaining integrated water resources management. Here, we tested in a 2-year experiment (June 2017-April 2019) the treatment performance of an innovative wall cascade constructed wetland (WCCW) system. The aim was to combine the multifunctional benefits of green walls (e.g. aesthetic, surface area requirements) with those of constructed wetland systems (e.g. high pollutants removal efficiencies, water recycling) to treat kitchen greywaters. The WCCW was a terraced system of six phytoremediation lines, each of which was composed of three plastic tanks (3 × 0.04 m3), filled with lightweight porous media, and vegetated with different ornamental species, namely Mentha aquatica L., Oenanthe javanica (Blume) DC., and Lysimachia nummularia L. Physicochemical (temperature, pH, electrical conductivity, dissolved oxygen, turbidity) and chemical parameters (chemical oxygen demand, biochemical oxygen demand, anionic surfactants, Kjeldahl, ammonium and nitric nitrogen, total orthophosphate) were monitored at a frequency of at least 15 days, depending on the season and WCCW management. Results showed that the WCCW significantly reduced the main water pollutants (e.g. organic compounds, nutrients), suggesting its potential application in urban environments for water recycling in the context of green infrastructures and ecological sanitation. A culture-independent taxonomic assessment of suspended bacterial communities before and after the treatment showed clear treatment-related shifts, being the functional ecology attributes changed according to changes in greywater chemical parameters. Future research should attempt to optimize the WCCW system management by regulating the nutrients balance to avoid macronutrients deficiency, and setting the most suitable water flow dynamics (hydraulic retention time, saturation-desaturation cycles) to improve the greywater treatment.

Composition and quality traits of vegetables grown in a low-tech aquaponic system at different fish stocking densities.

BACKGROUND: Aquaponics is considered a sustainable system for the production of fish and vegetables. However, little is known about the effects of different system variables on vegetable quality. Hence, the aims of this study were to evaluate the influence of aquaponics on the composition and quality traits of three vegetable species in relation to stocking density of the common carp (Cyprinus carpio L.), in comparison with those of plants grown in hydroponics. RESULTS: The highest cumulative vegetable marketable yield was obtained in low-density aquaponics (APL), followed by hydroponics (HP) and high-density aquaponics (APH). Vegetable quality traits showed species-specific responses. In general, phosphorus concentration was higher in plants grown in APH and lower in those grown in HP, while the opposite was observed for nitrate concentration. In lettuce (Lactuca sativa L.), sugar content was the highest in APH, whereas for Swiss chard (Beta vulgaris L. subsp. vulgaris Cicla group), the aquaponics treatments increased only glucose content. No differences in sugar content were observed in Catalogna (Cichorium intybus L. Catalogna group). The lowest and highest phenolic acid concentrations in the aboveground biomass of Catalogna and lettuce were observed in HP and APH treatments, respectively. For Swiss chard, APH treatment resulted in the highest caffeic acid content, whereas ferulic acid was the highest in HP. CONCLUSIONS: Aquaponics at low stocking density increased plant yield, compared to HP, without compromising vegetable quality, whereas aquaponics at high stocking density improved vegetable quality, but at the expense of yield. © 2020 Society of Chemical Industry.

Effect of stocking density of fish on water quality and growth performance of European Carp and leafy vegetables in a low-tech aquaponic system.

Aquaponics (AP) is a semi-closed system of food production that combines aquaculture and hydroponics and represents a new agricultural system integrating producers and consumers. The aim of this study was to test the effect of stocking densities (APL, 2.5 kg m-3; APH, 4.6 kg m-3) on water quality, growth performance of the European Carp (Cyprinus carpio L.), and yield of leafy vegetables (catalogna, lettuce, and Swiss Chard) in a low-technology AP pilot system compared to a hydroponic cultivation. The AP daily consumption of water due to evapotranspiration was not different among treatments with an average value of 8.2 L d-1, equal to 1.37% of the total water content of the system. Dissolved oxygen was significantly (p < 0.05) different among treatments with the lowest median value recorded with the highest stocking density of fish (5.6 mg L-1) and the highest median value in the hydroponic control (8.7 mg L-1). Marketable yield of the vegetables was significantly different among treatments with the highest production in the hydroponic control for catalogna (1.2 kg m-2) and in the APL treatment for Swiss Chard (5.3 kg m-2). The yield of lettuce did not differ significantly between hydroponic control and APL system (4.0 kg m-2 on average). The lowest production of vegetables was obtained in the APH system. The final weight (515 g vs. 413 g for APL and APH, respectively), specific growth rate (0.79% d-1 vs. 0.68% d-1), and feed conversion (1.55 vs. 1.86) of European Carp decreased when stocking density increased, whereas total yield of biomass was higher in the APH system (4.45 kg m-3 vs. 6.88 kg m-3). A low mortality (3% on average) was observed in both AP treatments. Overall, the results showed that a low initial stocking density at 2.5 kg m-3 improved the production of European Carp and of leafy vegetables by maintaining a better water quality in the tested AP system.

Comparison of carbon balance in Mediterranean pilot constructed wetlands vegetated with different C4 plant species.

This study investigates carbon dioxide (CO2) and methane (CH4) emissions and carbon (C) budgets in a horizontal subsurface flow pilot-plant constructed wetland (CW) with beds vegetated with Cyperus papyrus L., Chrysopogon zizanioides (L.) Roberty, and Mischantus × giganteus Greef et Deu in the Mediterranean basin (Sicily) during the 1st year of plant growing season. At the end of the vegetative season, M. giganteus showed the higher biomass accumulation (7.4 kg m(-2)) followed by C. zizanioides (5.3 kg m(-2)) and C. papyrus (1.8 kg m(-2)). Significantly higher emissions of CO2 were detected in the summer, while CH4 emissions were maximum during spring. Cumulative CO2 emissions by C. papyrus and C. zizanioides during the monitoring period showed similar trends with final values of about 775 and 1,074 g m(-2), respectively, whereas M. giganteus emitted 3,395 g m(-2). Cumulative CH4 bed emission showed different trends for the three C4 plant species in which total gas release during the study period was for C. papyrus 12.0 g m(-2) and ten times higher for M. giganteus, while C. zizanioides bed showed the greatest CH4 cumulative emission with 240.3 g m(-2). The wastewater organic carbon abatement determined different C flux in the atmosphere. Gas fluxes were influenced both by plant species and monitored months with an average C-emitted-to-C-removed ratio for C. zizanioides, C. papyrus, and M. giganteus of 0.3, 0.5, and 0.9, respectively. The growing season C balances were positive for all vegetated beds with the highest C sequestered in the bed with M. giganteus (4.26 kg m(-2)) followed by C. zizanioides (3.78 kg m(-2)) and C. papyrus (1.89 kg m(-2)). To our knowledge, this is the first paper that presents preliminary results on CO2 and CH4 emissions from CWs vegetated with C4 plant species in Mediterranean basin during vegetative growth.