Effect of Foliar Treatments with Calcium and Nitrogen on Oregano Yield

Oregano, Origanum vulgare L., is a perennial herbaceous plant belonging to the Lamiaceae family. Oregano shows variations in biomass yield and essential oil (EO) content due to the influence of abiotic and biotic factors. The aim of this study was to assess the effect of different foliar applications based on calcium (Ca) and nitrogen (N) on morphological and productive parameters in oregano. Tests were carried out in Sicily (Italy) in 2020–2021. In each year, eight foliar applications were applied. Only flowers and leaves were used for the extraction of the EO. For all parameters in the study, except for plant height and inflorescence length, the highest values were found in treated plants with respect to the control. In plants treated with calcium and nitrogen, an increase of between 0.6 and 1.6 t ha−1 was observed for fresh yield, and an increase of between 0.5 and 0.9 t ha−1 was observed for dry yield. The increase in biomass yield led to an increase in EO yield of between 4 and 12 kg ha−1. The results highlight that foliar treatments with Ca in combination with N enable growth in crop production in environments that show poor water availability

Effects of irrigation, peat-alternative substrate and plant Habitus on the morphological and production characteristics of Sicilian rosemary (Rosmarinus officinalis L.) biotypes grown in pot

Irrigation and growing substrate are considered as essential cultivation practices in order to obtain good productive and qualitative performance of potted rosemary plants. In pot growing, the chemical, physical and biological characteristics of the substrate must be stable over time in order to allow regular plant growth. However, the effects of cultivation techniques on the characteristics of potted rosemary are little known. Peat is traditionally used as the organic growing medium; however, despite numerous advantages, its use has determined a degradation of peatlands in the northern hemisphere and an increase in greenhouse gases in the atmosphere. The aim of the present study was to assess the effects of irrigation and peat-alternative substrates on the morphological, aesthetic and production characteristics of potted Sicilian rosemary biotypes with different habitus types. Two years, two different irrigation levels, three peat-alternative substrates and three types of rosemary plant habitus were tested in a split-split-split-plot design for a four-factor experiment. The results highlight that irrigation and substrate determined significant differences for all tested parameters. Rosemary plants demonstrated the best performances when irrigation was more frequent; vice versa, the greatest percent content in essential oil was obtained when irrigation events were less frequent. The chemical–physical characteristics of peat-alternative substrates changed with decreases in the peat content and increases in the compost content. The erect habitus biotype showed the best adaptation capacity to the various treatments. Our results suggest that irrigation and peat-alternative substrates significantly affect the growth of rosemary plants and should, therefore, be taken into consideration in order to improve the cultivation of this species in pots for ornamental purposes

Grafting Eggplant Onto Underutilized Solanum Species and Biostimulatory Action of Azospirillum brasilense Modulate Growth, Yield, NUE and Nutritional and Functional Traits

The grafting of vegetable crops is considered a valuable mean for ensuring the yield and quality under different cultivation conditions. Simultaneously, there are increasing research efforts in exploiting underutilised plants as potential rootstocks for vegetables to increase the sustainability of horticultural systems. In accordance with the European Green Deal, the application of biostimulants is a fashionable and ecological agronomic practice to enhance the production and quality of vegetables. Thus, the current research appraised the synergistic effect of grafting eggplant onto various allied potential rootstocks (Solanum torvum, S. aethiopicum and S. macrocarpon) and of applying a plant growth-promoting bacteria (Azospirillum brasilense DSM 2298) on eggplant growth, production, fruit quality traits (nutritional and functional features) and nitrogen use efficiency (NUE). The findings showed that ‘Gloria’ F1 plants grafted onto S. torvum or S. aethiopicum had a significant increase in plant height 50 DAT by 11.6% and 9%, respectively, compared with not grafted plants. Simultaneously, plants inoculated with A. brasilense DSM 2298 acquired a significant upsurge of plant height 50 DAT by 6% compared with the control. Our results revealed that S. torvum and S. aethiopicum-grafted plants improved their marketable yield by 31.4% and 20%, respectively, compared with not grafted ones. Furthermore, A. brasilense DSM 2298 significantly boosted the yield compared with the control plants. Plant type had no effect on fruit dry matter and firmness, whereas plants grafted onto S. macrocarpon showed a significant increase in the soluble solids content (SSC) and fruit K concentration compared with not grafted plants. Plants grafted onto S. torvum rootstock and inoculated with A. brasilense DSM 2298 had a significant increase in fruit protein concentrations compared with the combination not grafted × control. Moreover, S. torvum-grafted plants and those inoculated with the microbial biostimulant revealed the highest NUE values. The results evidenced that S. torvum and S. macrocarpon-grafted plants, inoculated with A. brasilense DSM 2298, had the highest ascorbic acid (average 7.33 and 7.32 mg 100 g−1 fw, respectively). Interestingly, S. torvum rootstock increased the chlorogenic acid concentration and reduced the glycoalkaloids concentration compared with not grafted plants. Our data also showed that A. brasilense DSM 2298 significantly increased SSC by 4.5%, NUE by 5.5%, chlorogenic acid concentration by 2.0% and the total anthocyanins by 0.2% compared to the control. Thus, our study underlined that S. aethiopicum rootstocks inoculated with A. brasilense DSM 2298 could represent a valid substitute to the common S. torvum rootstock

Stand-Alone or Combinatorial Effects of Grafting and Microbial and Non-Microbial Derived Compounds on Vigour, Yield and Nutritive and Functional Quality of Greenhouse Eggplant

The current research investigated the effects of endophytic fungi such as Trichoderma atroviride (Ta) or Ascophyllum nodosum seaweed extract (An) and their combination on growth, yield, nutritive and functional features, and mineral profile of ‘Birgah’ F1 eggplant either ungrafted, self-grafted or grafted onto the Solanum torvum rootstock. Eggplant exposed to An or An+Ta had a significant increase in root collar diameter 50 days after transplanting (RCD50), total yield (TY), marketable yield (MY), ascorbic acid (AA) content, Mg, Cu, and Zn concentration, and a reduction in glycoalkaloids (GLY) compared with the control. Furthermore, grafted plants had a higher TY, MY, number of marketable fruits (NMF), RCD50, AA, Cu, and Zn and a lower SSC, GLY, and Mg than the ungrafted plants. The combination of grafting and An+Ta significantly improved mean weight of marketable fruits (MF), plant height 50 days after transplanting (PH50), number of leaves 50 days after transplanting (NL50), fruit dry matter (FDM), chlorogenic acid (ClA), proteins, and K and Fe concentration. This combination also produced fruits of high premium quality as evidenced by the higher AA and ClA concentration, the lower GLY concentration, and an overall improved mineral profile

Agro-Morphological Characterization of Sicilian Chili Pepper Accessions for Ornamental Purposes

The species belonging to the genus Capsicum have been widely used as decorative vegetables, however only a few genotypes are available for this purpose. The goal of the present work was the agro-morphological characterization of several chili pepper accessions cultivated into different pot sizes (10, 14, 18 or 20 cm diameters). The agro-morphological characterization of 19 accessions was performed following IPGR (International Plant Genetic Resources Institute) descriptors: plant height (PH), plant canopy width (PCW), PH/PCW ratio, plant growth habit, plant visual quality, first flower emission, fruiting start, end of harvest, fruit number, fruit length, fruit width, fruit color at mature stage and fruit shape. Analysis of Variance (ANOVA) for all observed traits showed statistical significant differences among the genotypes tested. Results of the heat map complementarily secured the frequency of multiplicity highlighted from the ANOVA analysis. Furthermore, the present study pointed out that A33, A27, G1 and A1 chili pepper accessions achieved optimal performances in terms of plant visual quality, which is a crucial trait for ornamental purposes

Planting Date and Different N-Fertilization Rates Differently Modulate Agronomic and Economic Traits of a Sicilian Onion Landrace and of a Commercial Variety

The onion is one of the most widespread bulb vegetables worldwide. Onion cultivation is common in Sicily, as is the use of local genotypes. Cultivation practices are of particular interest in optimizing yield, quality, and profits. The aim of this study was to assess the agronomic response of a Sicilian landrace (Bianca Calda di Comiso, coded L1) and a commercial variety (Bianca di Maggio, coded V1) to different planting dates and N fertilization rates. An economic appraisal was also performed. The two genotypes were assessed using an experimental split-split-plot design with four levels of nitrogen rates (0, 80, 160, and 220 kg N ha−1) and two different planting dates (8 October 2005 to 9 October 2006 for the early planting date, and 27 December 2005 to 30 December 2006 for the traditional planting date). The marketable yield and production parameters were significantly influenced by the nitrogen dose: higher doses led to a higher total yield, with yield peaks above 60 t ha−1 and the marketable yield ranging from 23% to 54%. Simultaneously, decreases in the firmness (from 7% to 19%) and scale content (from 1% to 3%) were also reported. The L1 landrace showed a higher production than the V1 variety. The crop year did not significantly affect the results, and the traditional planting date appeared to be the most suitable choice in obtaining the best agronomic response. Economic analysis showed that the L1 landrace, with high-N application treatments, produced greater net benefits and marginal rates of return. Thus, the L1 landrace exposed to the highest dosages of nitrogen (160 or 220 kg ha−1) and transplanted during the traditional planting period is the best choice from agronomic and economic points of view

Application of PGPB Combined with Variable N Doses Affects Growth, Yield-Related Traits, N-Fertilizer Efficiency and Nutritional Status of Lettuce Grown under Controlled Condition

Nitrogen (N) fertilization is a crucial agricultural practice for boosting production traits in vegetables. However, N synthetic fertilizers—commonly adopted by farmers—have several counterproductive effects on the environment and on humans. The research was performed to assess the combined influence of plant growth promoting bacteria (PGPB) (Azospirillum brasilense DSM 1690, A. brasilense DSM 2298 and Pseudomonas sp. DSM 25356) and various N fertilization doses (0, 30, 60 or 120 kg ha−1) on growth, yield, quality and nitrogen indices of lettuce in protected cultivation. Plant height, root collar diameter, number of leaves and fresh weight were enhanced by A. brasilense DSM 2298 inoculation and N at 30 or 60 kg ha−1. Overall, soluble solids content (SSC), ascorbic acid, total phenolics, carotenoids, total chlorophyll and total sugars were augmented by the combined effect of A. brasilense strains and 30, 60 or 120 kg N ha−1. Furthermore, PGBP inoculation improved potassium (K) and magnesium (Mg) concentrations in leaf tissues. PGPB inoculation increased N leaf concentration; however, it hastened N indices. These results suggest that the PGPB tested can be considered an eco-friendly tool to improve lettuce yield, particularly when combined with N at 30 or 60 kg ha−1

Agronomic performance and fruit quality in greenhouse grown eggplant are interactively modulated by iodine dosage and grafting

Iodine (I) is considered an indispensable trace element for humans due to its capacity to promise a normal functions of thyroid hormones, preventing cretinism, goiter, reproductive failure, and diverse types of brain injury. Vegetable grafting is a technique for securing yield constancy and/or improving fruit quality. The study evaluated the combined effect of I-dosages and grafting onto Solanum torvum rootstock on 'Birgah' eggplant. Iodine at 100 or 300 mg L-1 enhanced marketable yield by 28.8% and 8.5%, respectively, compared with the control. Plants grafted onto S. torvum and self-grafted plants increased marketable yield by 53.0% and 45.8%, respectively compared with the ungrafted plants. I-biofortification determined a linear decrease in SSC as I dosage increased. I-enrichment at 300 and 600 mg L-1 improved fruit dry matter and ascorbic acid compared with the control. The combinations of self-grafting x I-biofortification at 600 mg L-1 and ungrafting x I-biofortification at 600 mg L-1 improved total anthocyanins concentration by 8.5% and 9.1%, respectively, compared with the ungrafting x 0 I-biofortification combination. Exposing ungrafted plants to 600 mg I L-1 resulted in a significantly higher chlorogenic acid content compared to the control. Glycoalkaloids concentration in the fruits was always below the suggested safety value (200 mg 100 g(-1) DW). Grafting enhanced proteins, K, Fe and Zn by 22.9%, 7.2%, 20.0% and 2.4%, respectively compared with ungrafting. I concentration in fruit of grafted plants varied from 0.67 mg kg(-1) DW at 0 mg I L-1 to 188.67 mg kg(-1) DW in plant biofortified with the highest I-dosage. The pulp browning potential was significantly dependent upon I-dosage and grafting with the lowest values found in fruits from grafted plants supplied with 0 or 100 mg I L-1. The present results suggested that I-biofortification at 300 or 600 mg L-1 and grafting, successfully boosted nutritional and functional traits of 'Birgah' eggplant, securing satisfactory yield and yield-related traits