High temperatures are considered the most important limiting factor for the productivity of beans, and the ongoing increase in global temperature is estimated to have a strong negative impact on its yield. With the aim of mitigating the effects of high temperatures that usually prevail during growing seasons, the efficacy of two novel biostimulants (not yet commercially available) based on amino acids supplemented with sulfur or silicon was tested in two consecutive growing seasons (early and late). During the early season (May 7-June 30), conditions of intense heat stress prevailed, and in combination with the cultivation of a relatively sensitive genotype, the marketable yield was reduced by 51%, compared to the yield in the late season (7,323 kg ha(-1)). The exogenous application of amino acid-based biostimulants supplemented with sulfur or silicon did not significantly mitigate yield reduction (7,143-7,693 kg ha(-1)). On the other hand, during the late season (August 5-October 19), conditions of milder heat stress prevailed, and in combination with the cultivation of a relatively resistant genotype, the marketable yield was high (14,915 kg ha(-1)). The exogenous application of amino acid-based biostimulants supplemented with sulfur or silicon did not significantly affect chlorophyll fluorescence parameters or yield (13,908-15,833 kg ha(-1)).

The effects of climate change could directly affect agricultural production. The related greenhouse-gas-emissions during agricultural production has negative impact on the agri-food sector, as well as the use of water resources. Broccoli is a widespread crop in eastern Mediterranean area, which is highly-valued due to its flavor and its nutritional values. The main aim of this study was to estimate agri-environmental indicators of broccoli crops in Pella, CentralMacedonia. Sixteen farms were selected and studied for three cultivation periods. The specific objectives of this study were to: i) apply an adjusted LCA-method to estimate the energy indicators and the carbon and water footprints of two different broccoli varieties (Parthenon and Triton), ii) compare the two different varieties per cultivation period and each cultivar between the different cultivation periods, and iii) identify the most-friendly to the environment broccoli cultivar, but also which cultivation period was the best for each cultivar. Fuel, fertilizers and irrigations represented the largest energy inputs for both varieties and for all the cultivation periods. Although the two varieties appear to have the same input requirements, there is a differentiation in their productivity through the cultivation periods, which led to increased use of blue water for the Triton F1 hybrid compared to that of Parthenon. Parthenon was more demanding in irrigation inputs than Triton when rainfall was low. High rainfall could have led to high fungicide inputs in some cultivation periods for both varieties. Cultivation periods with high fungal diseases led to low outputs for Triton F1 hybrid, while those with low fungal disease showed high outputs for Triton, which led to high energy use efficiency. It is concluded that the studied agri-environmental indicators could lead to the selection of the best broccoli cultivar to reduce the required inputs and the negative impact on the environment, without affecting crop yields.

The objective of this study was to evaluate the feasibility of using visible, near-infrared, and short-wave infrared (VIS/NIR/SWIR) spectroscopy coupled with chemometrics for non-destructive prediction of nutritional components in Galia-type melon fruit. A total of 175 fully ripened melons were analyzed for soluble solids content (SSC), dry matter (DM), pH, and titratable acidity (TA) using partial least squares regression (PLSR), principal components regression (PCR), and multilinear regression (MLR) models. Reflectance spectra were captured at three fruit locations (pedicel, equatorial, and blossom end) in the 350–2500 nm range. The PLSR models yielded the highest accuracy, particularly for SSC (R = 0.80) and SSC/TA (R = 0.79), using equatorial zone data. Variable selection using the genetic algorithm (GA) successfully identified the spectral regions critical for each nutritional parameter at the pedicel, equatorial, and blossom end areas. Key wavelengths for SSC were found around 670–720 nm and 900–1100 nm, with important wavelengths for pH prediction located near 1450 nm, and, for dry matter, in the ranges 1900–1950 nm. Variable importance in projection (VIP) analysis confirmed that specific wavelengths between 680 and 720 nm, 900 and 1000 nm, 1400 and 1500 nm, and 1900 and 2000 nm were consistently critical in predicting the SSC, DM, and SSC/TA ratio. The highest VIP scores for SSC prediction were noted around 690 nm and 950 nm, while dry matter prediction was influenced most by wavelengths in the 1450 nm to 1950 nm range. This study demonstrates the potential of VIS/NIR/SWIR spectroscopy for rapid, non-destructive melon quality assessment, with implications for commercial postharvest management.

In order to study the effects of emerging climate change on the cultivation of broccoli (Brassica oleraceae var. italica Plenck), transplants of three F1 hybrids (‘Cigno’, ‘Principe’, and ‘Domino’ F1) were transplanted on three successive dates (7 June, 30 June, and 4 August) at the Experimental Farm of the Aristotle University of Thessaloniki, Greece. The last planting date (4 August) corresponds to the most common establishment time for the crop in the area, while the other two dates correspond to periods with higher temperatures. The number of leaves per plant was recorded on a weekly basis during the growing period, while the plant height, the number of head leaves, the number of lateral shoots, the head diameter, and the weight and quality of the head were recorded at harvest. The results showed that the average temperature and solar radiation during the first two growing periods (GP1 and GP2) were higher by 4.4–5.4 °C and 32–75%, respectively, compared to the third one (GP3). The consequences of the higher temperature were the shortening of the growing period between transplanting and harvest by 5–6 days in ‘Cigno’ F1 and its extension by 3–18 days in the ‘Principe’ and ‘Domino’ F1 ones, as well as the increase in the quantity of water required through irrigation by 14–61%. Higher temperatures induced a significant deterioration of the head quality and a reduction in marketable production by 42–92%.

Although the presence of anthocyanins in white asparagus is undesirable because it degrades its commercial quality, very little is known about their biosynthesis and regulation. The biosynthesis of anthocyanins in most plants is light dependent, but in white asparagus spears only a few studies have evaluated the effects of light and all of them focus mainly on the post-harvest period. There are no relevant reports on the effects of exposure of spears to solar and infrared radiation during their growth and development. For this purpose, white asparagus spears were grown in the dark under a low tunnel (100 cm wide and 60 cm high) for 7 days before being exposed to sunlight for 0, 2, 3, 4, 5, or 7 h. Subsequently, the spears were either harvested and kept in the dark or continued to grow in the dark for 0, 24, or 48 h. At the end of the treatments, the color and the anthocyanin and total phenol content of the top 7 cm of the spears were determined. The results showed that the infrared radiation that was trapped below the tunnel during the 7-day growing period of white asparagus spears induced anthocyanin biosynthesis only in the lower part (base) of the spears. Exposure to sunlight for at least 3 h was critical for significant anthocyanin biosynthesis in the epidermal cells of the top 7 cm part of white asparagus spears (0.48–0.95 μg g−1 FW). The amount of anthocyanins 24 h later was proportional to the exposure time (y = 0.1585x − 0.162, R2 = 0.9953) and was greater in the spears harvested and kept in the dark (up to 5.67 μg g−1 FW) than in the spears that continued to grow in dark conditions (up to 4.32 μg g−1 FW).

Heat stress is considered as the most important limiting factor for the productivity of beans and the emerging increase in global temperature is estimated to have a strong negative impact on its yield. In this context, the green bean industry is looking for means to mitigate these adverse effects. Foliar application of amino acids-based bi-ostimulants, supplemented with silicon or sulfur, has been reported to have beneficial effects on bean crops to mitigate the effects of various stresses but not of heat stress, yet. Amino16 is a commercial biostimulant with 16 L-amino acids and was used as a basis so that two novel products; Amino16+Si and Amino16+S were further produced. Their efficacy was tested upon foliar application in two consecutive growing seasons (early and late) of green beans. The mitigation of the effects of heat stress in green bean crops was not achieved upon the combined application of amino acids supplemented with sulfur or silicon at several rates. Obviously, higher concentrations of sulfur and silicon are required to induce beneficial effects, and probably through drench application, especially in crops with high sulfur demand, such as beans, while silicon requires another form, other than silicon dioxide, which is not easily absorbed by the plant’s roots.

The market demand for baby leaf lettuce is constantly increasing, while safety has become one of the most important traits in determining consumer preference driven by human health hazards concerns. In this study, the performance of visible and near-infrared (vis/NIR) spectroscopy was tested in discriminating pesticide-free against pesticide-treated lettuce plants. Two commercial fungicides (mancozeb and fosetyl-al) and two insecticides (deltamethrin and imidacloprid) were applied as spray solutions at the recommended rates on baby leaf lettuce plants. Untreated-control plants were sprayed with water. Reflectance data in the wavelength range 400–2500 nm were captured on leaf samples until harvest on the 10th day upon pesticide application, as well as after 4 and 8 days during post-harvest storage at 5 °C. In addition, biochemical components in leaf tissue were also determined during storage, such as antioxidant enzymes’ activities (peroxidase [POD], catalase [CAT], and ascorbate peroxidase [APX]), along with malondialdehyde [MDA] and hydrogen peroxide [H2O2] content. Partial least square discriminant analysis (PLSDA) combined with feature-selection techniques was implemented, in order to classify baby lettuce tissue into pesticide-free or pesticide-treated ones. The genetic algorithm (GA) and the variable importance in projection (VIP) scores identified eleven distinct regions and nine specific wavelengths that exhibited the most significant effect in the detection models, with most of them in the near-infrared region of the electromagnetic spectrum. According to the results, the classification accuracy of discriminating pesticide-treated against non-treated lettuce leaves ranged from 94% to 99% in both pre-harvest and post-harvest periods. Although there were no significant differences in enzyme activities or H2O2, the MDA content in pesticide-treated tissue was greater than in untreated ones, implying that the chemical spray application probably induced a stress response in the plant that was disclosed with the reflected energy. In conclusion, vis/NIR spectroscopy appears as a promising, reliable, rapid, and non-destructive tool in distinguishing pesticide-free from pesticide-treated lettuce products.

Enzymatic browning, occurring on the cut surfaces of many popular fresh-cut fruit and vegetables due to wounding and the activity of endogenous polyphenyloxidase enzymes, is considered as the main reason for their rejection by consumers. In this study, water extracts were obtained from seeds of cabbage, sinapis, and wild rocket at 10 and 20% w/w seed:water ratios (SWE) and analyzed for total phenolic compounds (TPC) and antioxidant capacity (AC). The extract was then applied on cut surfaces of mid rib segments of lettuce leaves for 1 or 3 min. The segments were stored at 7 °C for 14 days. The SWE’s inhibitory capacity on enzymatic browning were measured by CIELAB color coordinates L* a* and b* and expressed as second derivatives, their % inhibition and different indices. An additional visual acceptance measurement and calculation of shelf life was also performed. The seed extracts of cabbage at 10–20% and wild rocket at 20% showed the highest anti-browning efficacy (comparable to 25 mM potassium metabisulfite control) along with TPC and AC. A high % of seed:water extract and increased exposure time led to a considerable increase in shelf life, visual score, % inhibition of browning or whitening index of the extracts of all seed sources. Chromatometric outcome data clearly showed that the visual data were more accurate than the chromatometric procedure (L*, a*, b* values, their derives ΔE, h°, C, Δh° and ΔC or calculated indices), although the latter could detect the differing degrees of browning development or its inhibition in treated and control segments during storage.

When transplanting vegetable plants in the field, the transplants undergo a small or large setback in growth, known as transplanting shock. Various practices are commonly applied to reduce the transplanting shock. In the past two decades, several studies have shown that the application of microbial and non-microbial biostimulants can enhance plant tolerance against abiotic stresses. However, there is no information on the effect of applying biostimulants at the time of transplanting in mitigating the transplanting shock of lettuce transplants in the field. Lettuce seedlings transplanted into the soil of an unheated plastic greenhouse were treated with two biostimulants, one microbial (Bactiva®) and one non-microbial (Isabion®), on the day of transplanting and after 14 and 21 days. During production, plant growth, and development, chlorophyll fluorescence and compositional parameters were determined. According to the results, the application of the non-microbial biostimulant had a significant effect on some measured parameters, with the leaves of the treated plants having a higher chlorophyll index (CCI) by 8%, as well as higher fluorescence parameters Fm/Fo, Fv/Fo, and Fv/Fm and area by 7, 10, 3, and 27%, respectively, but fewer total soluble phenols and lower fluorescence parameter ABS/RC by 7 and 26%, respectively, compared to the control untreated ones. The above may constitute some effects on the transplanting shock, without, however, being accompanied by significant effects on the number of leaves/plant, the leaf color parameters (L*, a*, b*, C*, and ho), and the chlorophyll (a, b, a + b), total carotenoid, dry matter, and nitrate content, along with the antioxidant capacity and plant fresh weight at harvest. However, a notable effect was that a greater percentage of plants at harvest had a fresh weight in the 351–400 class, while the greatest percentage of the control plants had a fresh weight in the 301–350 g class. In contrast, the application of the microbial biostimulant had no significant effect on any of the parameters determined compared to the control. Therefore, under the conditions of the present study, the effectiveness of biostimulant application at the time of transplanting on lettuce transplants is questionable.

It is well known that the harvesting period and the storage duration have a significant effect on the quality characteristics of cherry tomato fruits. On the other hand, the effect of the fruit position in the truss has not been studied, as well as the relative contribution of each one of these factors on fruit quality. For this purpose, cherry tomato (Genio F1) whole trusses were harvested at the fruit red ripe stage during three periods. At each harvesting period, the first four (at the base of the truss) and the last four (at the top) fruits from each truss that was previously trimmed to 10 fruits, were stored at 12 °C for 0, 4 and 10 days. At the end of each storage duration, the external color, firmness, antioxidant capacity, pH and titratable acidity, as well as dry matter, soluble solid, total soluble phenol, lycopene, total carotenoid and β-carotene content, were determined. Analysis of variance (ANOVA) indicated that the harvesting period had the most significant effect on skin color parameters L * and C * and β-carotene, as well as on antioxidant capacity, total soluble phenols, dry matter and total soluble solids, while it also had an appreciable effect on titratable acidity. The storage duration had a dominant effect on firmness, total carotenoids and lycopene, while it had an appreciable effect on skin color parameter L * as well. On the other hand, the fruit position in the truss exerted an exclusive effect on ho and a */b * ratio skin color parameters and pH and an appreciable effect on titratable acidity.

Propagation of watermelon is mainly carried out through grafting. The period of healing is critical for the development of healthy grafted seedlings of high quality. In this study the grafted seedlings were grown in a chamber with controlled conditions and artificial light during healing. The aim of the present study was to test the effect of LED lights with various wavelengths on several morphological characteristics of grafted watermelon seedlings during healing. In the healing chamber, temperature was set at 25 degrees C, relative air humidity at 89-98%, photoperiod at 16 h and PPFD was maintained at 85 +/- 5 mu mol m(-2) s(-1). Seedlings were irradiated either by FL lamps (control) or by LED lights with various wavelengths (different B/R ratios). Determinations included overground and root system parameters. It should be noted that at the time of grafting the entire root system was removed and its re-growth was enhanced by the abovementioned LEDs. Red LED and red supplemented with blue enhanced several morphological characteristics such as leaf area, stem diameter, as well as root development, which are an indicator of the seedlings' quality. On the contrary, blue LED alone did not perform as good as the abovementioned LEDs. Moreover, traditional FL lamps reduced seedling quality both overground and underground. The results indicate that blue light is needed in addition to red light during the healing of grafted watermelon seedlings.

In many countries of Europe and Eastern Asia, watermelon production is mainly based on the use of grafted seedlings. Upon grafting, seedlings undergo a period of healing where artificial lighting is provided by light-emitting diodes in controlled chambers in order to accelerate and improve the healing process. The objective of our study was to test the effect of light quality on the final product (i.e., seedlings ready for transplanting) in the nursery, as well as to evaluate the possible implications on fruit quality after field cultivation. Narrow-band blue (B) and red (R) wavelengths, 64–36% R-B (36B), 76–24% R-B (24B), 88–12% R-B (12B), and 83–12% R-B plus 5% far-red (12B+FR) wavelengths were tested. 12B+FR enhanced the root dry weight, root architecture, and maximum photosynthetic rate, while RB combinations generally showed better root system development with increased blue portion. R light induced inferior root dry weight and quality indices (root/shoot and shoot–dry–weight/length ratios), lower gas exchange parameters, and chlorophyll content, but high shoot length and leaf area. B light led to inferior root architecture, lower stem diameter, leaf area, and maximum photosynthetic rate. Both R and B wavelengths showed decreased concentration of macronutrients and trace elements. After field cultivation, fruit quality (i.e., morphology and color), and valuable nutritive characteristics (i.e., phenolics, carotenoids, lycopene, antioxidants) maintained high quality irrespective of light treatments. Overall, 12B+FR performed well in almost all qualitative parameters including the morphology, the root development, and photosynthesis, while also maintaining high fruit quality.

Broccoli (Brassica oleracea L. var. italica Plenck.) is nowadays one of the most important vegetable crops worldwide, with an increasing demand by the market, due to its high nutritional value. Based on the optimal temperature range, its cultivation in the temperate regions takes place from late summer to late spring. Broccoli cultivation nowadays faces many challenges, such as the profitable production throughout the year, as well as during conditions of an increased temperature, induced by the emerging climate change, as well as the possibility of introducing the cultivation to subtropical and tropical areas. The modern genotypes (F1 hybrids) differ significantly among themselves in terms of the requirements for the head’s formation, which, however, has not been fully elucidated. In this direction, breeders have been developing programs internationally since the early 1990s, in order to create genotypes that will be adapted to temperatures higher than the optimal range, having, however, a relatively limited initial germplasm pool. The purpose of this review is to present extensively the temperature requirements in the broccoli crop production and to highlight the impacts of the emerging climate change.

Watermelon is a worldwide cultivated crop and most of the cultivated area use grafted seedlings. The first stage of grafted watermelon seedling production is the growth of seedlings to-be-grafted which can be achieved with controlled environment agriculture (greenhouses and growth chambers). These seedlings are essential to be of certain status in order for the grafting to be successful and the grafted seedlings to be of high quality. Quality categories for watermelon seedlings to-be-grafted have already been established. Controlled environment agriculture is practiced as a way of crop production which is unaffected by seasons and external environmental conditions. The use of artificial light sources (fluorescent-FL lamps and light-emitting diodes-LEDs) is absolutely necessary in controlled environment agriculture. The aim of the study was to test the potential of broad spectra LEDs to reduce the growth cycle of watermelon seedlings to-be-grafted. Temperature in the growth chamber was set at 22/20 degrees C (day/night), photoperiod was 16 h and PPFD was 85 +/- 5 mu mol m(-2) s(-1). Light treatments included FL lamps (control) or two LED light sources with broad spectra (L20AP67 with 11% blue, 26% green, 49% red, 14% far-red; AP673L with 12% blue, 19% green, 61% red, 8% far-red; Valoya Oy, Helsinki, Finland). Seedlings were grouped in categories namely "not acceptable" and "acceptable" depending on their potential to develop into high quality final products. After 11 days in the growth chamber, all seedlings of the three light treatments were characterized as "not acceptable". After 12 and 13 days, all seedlings of FL and AP673L were also "not acceptable", while L20AP67 developed 13 and 38% "acceptable" seedlings, respectively. The results indicate the ability of white LEDs to efficiently replace traditionally used FL lamps and potentially reduce the growth cycle of watermelon seedlings to-be-grafted.

BACKGROUND Nutritional quality in bell pepper is related to the ripening stage of the fruit at harvest and postharvest storage. Its determination requires time-consuming, tissue-destructive, analytical laboratory techniques. The objective of this study was to investigate the effect of ripening stage and of postharvest storage period on fruit nutritional quality, and whether it is feasible to develop reliable models for assessing the nutritional components in peppers using non-destructive methods. The dry matter, soluble solids, ascorbic acid, phenolics, chlorophylls, carotenoids and the total antioxidant capacity were determined in bell pepper fruits at six ripening stages, from green to full red, during storage at 10 degrees C for 8 days. Color, chlorophyll fluorescence, visible/near infrared (Vis/NIR) spectroscopy, red-green-blue (R-G-B) and red-green-near infrared (R-G-NIR) digital imaging were tested for assessing the nutritional quality of peppers. RESULTS The nutritional composition was mainly affected by the ripening stage of bell pepper fruits at harvest and only to a small degree by the storage period. Indeed, the more advanced ripening stage of fruit at harvest resulted in superior nutritional quality. Most of the non-destructive techniques reliably predicted the internal quality of the fruit. The genetic algorithm (GA), the variable importance in projection (VIP) scores, and the variable inflation factor (VIF) tests identified nine distinct regions and four specific wavelengths on the whole visible/NIR electromagnetic spectrum that exhibited the most significant effect in the assessment of the nutritional components. CONCLUSION It is possible to predict individual nutritional components in bell pepper fruit reliably and non-destructively, and irrespective of the ripening stage of fruits at harvest. (c) 2021 Society of Chemical Industry.

A floating system was established in a heated glass greenhouse in order to investigate whether the effect of amino acids (0.25 or 0.50% of a commercial amino acid (AA) solution Amino16®) during peppermint and spearmint production on plant developmental and nutritional status may be in part attributed to salinity induced osmotic stress. For this reason, in some nutrient solutions, three levels of salinity were induced by adding 0, 10, or 20 mM NaCl. According to the results, it can be concluded that spearmint is mostly favored by the highest amino acid supplement of the nutrient solution (0.50%) in terms of a substantial improvement of the antioxidant nutritional quality (by up to 130%) at the expense of a reduced biomass production (by <30%). Enzymic antioxidant defense mechanism (APX and POD) was efficiently activated, preventing severe lipid peroxidation and the accumulation of reactive oxygen species such as H2O2 and maintaining the proline content at the normal levels. The osmotic stress that was induced by the excessive AA concentration and confirmed by the chlorophyl fluorescence variations was probably related to NH4+ excess supply in the growing media and was not associated with the elevated electrical conductivity in the solution. The absence of any adverse stressful consequences upon the addition of 20 mM NaCl may be attributed to the high salt tolerance of peppermint and spearmint species.

Seven winter and five summer vegetables produced under organic and conventional systems were collected from a supermarket seven times between January and April and between July and October for winter and summer vegetables, respectively, and their ascorbic acid and total phenolic content (compounds with proven antioxidant activity) as well as total antioxidant capacity, soluble solids and nitrates were determined. The results clearly indicated that, from the three factors studied (vegetable species, cropping system and sampling time), vegetable species made the highest contribution to ascorbic acid, phenolics, antioxidant capacity, soluble solids and nitrates. Results for each vegetable species showed that most organic vegetables appear to have lower nitrate content, some have higher phenolics, antioxidant capacity and soluble solids, and only few have higher ascorbic acid compared with conventional vegetables. The significance of the differences in nutritional and antioxidant value between organic and conventional vegetables is questionable, since vegetable species and sampling time can affect their nutritional value to a great or greater extent than the cropping system.

In Greece, among vegetables, watermelon is exclusively cultivated with the use of grafted plants while high percentages (>30-50%) of other vegetables (tomato, cucumber, etc.) are also grafted. The production of grafted vegetable seedlings is mainly carried out by modern nurseries and the healing of seedlings is considered as the most critical stage during their production process. Previously, beds inside the greenhouse were used for healing while nowadays they are replaced by chambers with fluorescent (FL) lamps as supplemental light. The aim of the present study was to find the efficacy of LED lamps in the healing chamber as an alternative lighting source for grafted watermelon seedling production. Apart from FL lamps (control treatment with photosynthetic photon flux density (PPFD) of 45 mu mol m(-2) s(-1)), LEDs employed were 12B (12% blue and 88% red), 12B+FR (12B with 5% supplemental far-red) and AP673L (wide spectra with 12% blue), all providing PPFD of 85 mu mol m(-2) s(-1) over plants. The characteristics evaluated were stem length, leaf area, root and shoot weights and their ratio (R/S) as well as leaf colour. According to the results, seedlings treated with 12B and 12B+FR were taller (+11 and +14%, respectively), had larger leaves (+21 and +8%, respectively), greater shoot (+24 and +22%, respectively) and root (+111 and +89%, respectively) biomass, as well as R/S ratio (+65 and +49%, respectively) compared to those treated with FL. On the other hand, seedlings treated with AP673L had higher dry root weight (+46%) and R/S ratio (+32%) compared to those treated with FL. It is concluded that red light supplemented with 12% blue and optionally far-red is ideal for the production of high quality seedlings, while a wide spectrum slightly improved seedling quality.