Biochemical Responses of Asparagus to Controlled Atmosphere Storage at 20 Degrees C

In seeking to understand the beneficial effects of controlled atmosphere (CA) storage at 20 degrees C on asparagus (Asparagus officinalis L.), biochemical responses of spear tips stored in air were compared with those of spears stored under CA (2% 02, 10% CO2). CA storage prevented the rapid loss of sucrose, increased acid invertase activity and asparagine accumulation observed in the tips of spears stored in air. CA storage also delayed changes in the levels of glutamine, malic, citric and fumaric acids, compared with those in tips of air-stored spears. Elongation observed in water-fed spears in air was reduced by CA. It is proposed that CA acted by depressing metabolism to such an extent that sucrose levels were maintained in the spear tip and this, in turn, prevented the cascade of metabolic events that contribute to spear deterioration in air

Deficit irrigation and reflective mulch effects on peach quality and storage performance

The effect of deficit irrigation and reflective mulch underneath the tree canopy on quality at harvest and during cold storage of ‘Royal Glory’ peaches (Prunus persica L.) was studied for two consecutive growing seasons. Four treatments were applied: 1) control, irrigation at 100% of crop evapotranspiration (ETc); 2) deficit irrigation (DI), irrigation at 75% of ETc in the last 3 weeks before harvest and 50% of ETc postharvest; 3) reflective mulch Extenday™ underneath the tree canopy; 4) the combined treatment of reflective mulch and deficit irrigation. Quality was assessed in fruit from the upper (sun-exposed) and lower (shaded) tree canopy at harvest and after 2, 4, and 6 weeks at 2°C plus 1 day of shelf life at 20°C. The quality parameters measured were fruit mass, skin color, flesh firmness and specific conductivity, juice acidity and soluble solids content (SSC), percent dry matter (DM) and total phenolic content in the edible part. Incidence and severity of chilling injury (CI) symptoms were also evaluated. Furthermore, tree fruit productivity and solar radiation (UV and PAR) above and underneath the tree canopy were measured. During cold storage, skin color changed slightly, fruit softened and the specific conductivity, SSC, acidity and percent dry matter decreased, while total phenolic content and CI symptoms increased. Reflective mulch application improved light availability and fruit quality, especially in the lower tree canopy. Peaches grown under DI had similar fruit quality and CI symptoms as control fruit, but decreased yield and fruit size. Peaches from the reflective mulch treatment were more mature at harvest than the fruit from other treatments, and reported better quality (especially the lower canopy fruit), and similar storage performance compared to control fruit. The fruit from the combined treatment behaved like the separate DI or reflective mulch treatments. © 2022 International Society for Horticultural Science. All rights reserved

‘Lemonato’ peach: A series of cultivated clones with high fruit quality

The ‘Lemonato’ peach is a series of clones cultivated in Magnesia, central Greece. These clones were selected locally from seedling populations characterized by different time of ripening and different fruit quality traits. The fruit are phenotypically discriminated from the other peach cultivars, as they have typical yellow skin colour when ripe, very little red hue and unique flavor and taste. The scope of the present work was the description of this series of clones based on morphological and agronomic characteristics, and fruit quality traits. Five trees of each ‘Lemonato’ clone in different locations throughout the cultivation area were selected based on ripening time. Presence of major stone fruit viruses was tested for each tree. For the morphological description of each clone, flowering time, shoot and fruit growth were followed in the field and shoots and fruit were described by UPOV. Specific leaf weight and leaf chlorophyll concentration were measured in late August. Fruit quality traits were also studied including fruit mass, skin colour, fruit firmness, soluble solids content, titratable acidity, total phenols and antioxidant activity. The results showed significant variation per clone and orchard for physiological leaf characteristics, shoot development, blooming and maturation time and fruit quality. We were able to separate trees with the best characteristics from each clone to initiate organized propagation, and, in the near future, to establish virus-free basic propagation material for each selection with different ripening times, to set up experimental farms and to exploit useful genetic traits through breeding programmes. These data will help spread the cultivation of this indigenous fruit clone series. © 2019 International Society for Horticultural Science. All rights reserved

Development and Evaluation of a Fuzzy Inference System and a Neuro-Fuzzy Inference System for Grading Apple Quality

In this research work, a fuzzy inference system (FIS) and an adaptive neuro-fuzzy inference system (ANFIS) were developed to classify apple total quality based on some fruit quality properties, i.e., fruit mass, flesh firmness, soluble solids content and skin color. The knowledge from experts was used to construct the FIS in order to be able to efficiently categorize the total quality. The historical data was used to construct an ANFIS model, which uses rules extracted from data to classify the apple total quality. The innovative points of this work are (i) a clear presentation of fruit quality after aggregating four quality parameters by developing a FIS, which is based on experts’ knowledge and next an ANFIS based on data, and (ii) the classification of apples based on the above quality parameters. The quality of apples was graded in five categories: excellent, good, medium, poor and very poor. The apples were also graded by agricultural experts. The FIS model was evaluated at the same orchard for data of three subsequent years (2005, 2006 and 2007) and it showed 83.54%, 92.73% and 96.36% respective average agreements with the results from the human expert, whereas the ANFIS provided a lower accuracy on prediction. The evaluation showed the superiority of the proposed expert-based approach using fuzzy sets and fuzzy logic

The effect of postharvest application of O3 and 1-MCP on 'Red Chief' apple quality during prolonged air cold storage

The effects of postharvest application of 1-MCP and air storage in the presence of low O3 concentration on 'Red Chief' apple fruit quality were studied during prolonged storage. Apple fruit were harvested from two commercial orchards from 300 and 700 m elevation in the Zagora region, central Greece, during September 2012. The next day, the fruit were treated or not with 600 nl L-1 1-MCP and stored at two commercial rooms at 0°C (90-95% RH) with or without 50-60 nl L-1 O3. Apple quality was evaluated at harvest and after 2.5, 5 and 7.5 months immediately after storage and after 7 days shelf-life (20-22°C, 50-60% RH). Quality evaluation included skin color, flesh firmness, juice soluble solids content (SSC) and titratable acidity, and superficial scald incidence. Apples from the orchard at high elevation had darker redder skin color were firmer, and had lower SSC, acidity and scald incidence at harvest and during storage, than the apples from the orchard at low elevation. Fruit treated with 1-MCP kept their high quality with minor scald incidence and firmness loss even after 7.5 months cold storage in the presence or not of O3. Fruit stored with low O3 without 1-MCP treatment at harvest were of similar quality to control fruit, but had higher scald incidence. It is concluded that 1-MCP treatment at harvest, satisfactorily maintained apple fruit quality without the addition of O3 in air cold storage, while fruit not treated with 1-MCP should not be stored in the presence of low O3 concentration

Development and Evaluation of a Fuzzy Inference System and a Neuro-Fuzzy Inference System for Grading Apple Quality

In this research work, a fuzzy inference system (FIS) and an adaptive neuro-fuzzy inference system (ANFIS) were developed to classify apple total quality based on some fruit quality properties, i.e., fruit mass, flesh firmness, soluble solids content and skin color. The knowledge from experts was used to construct the FIS in order to be able to efficiently categorize the total quality. The historical data was used to construct an ANFIS model, which uses rules extracted from data to classify the apple total quality. The innovative points of this work are (i) a clear presentation of fruit quality after aggregating four quality parameters by developing a FIS, which is based on experts’ knowledge and next an ANFIS based on data, and (ii) the classification of apples based on the above quality parameters. The quality of apples was graded in five categories: excellent, good, medium, poor and very poor. The apples were also graded by agricultural experts. The FIS model was evaluated at the same orchard for data of three subsequent years (2005, 2006 and 2007) and it showed 83.54%, 92.73% and 96.36% respective average agreements with the results from the human expert, whereas the ANFIS provided a lower accuracy on prediction. The evaluation showed the superiority of the proposed expert-based approach using fuzzy sets and fuzzy logic. © 2018 Taylor & Francis

Nutrient inputs and outputs in commercial clingstone peach orchards in Greece based on conventional or sustainable fertilization practices

Clingstone peach production is important in Greece as large amounts of processed peaches are being exported throughout the world. Fertilization of peach farms is still conducted empirically with substantial amounts of N, P and K applied in late winter with basic composite fertilizers rarely followed by additional N and K or Ca applications in spring and summer. A more sustainable fertilization program was followed using <50% N, minor quantities of P, and similar or higher quantities of K than that applied with the local regime and with a different schedule compared to local practices in a number of farms and commonly grown cultivars. Inorganic nutrients were measured in fruits and prunings after two years of sustainable fertilization practices. Fruit yield and prunings volume were measured. The macronutrient inputs in the sustainable program were (in kg/ha): in 2019 <70 N, <30 P2O5, <100 K2O, and in 2020 <85 N, <40 P2O5, <155 K2O. Outputs with fruit normalized for 40 Mg ha-1 (most farms during the two years had lower yield) in 2020 were (in kg ha-1): <50 N, <11 P2O5, <4.3 CaO, <4.4 MgO, <80 K2O. Outputs with prunings in 2020 were (in kg ha-1): <25 N, <4 P2O5, <30 CaO, <3 MgO, <11 K2O. The balance between inputs and outputs was improved using the sustainable fertilization program, while fertilizer cost was variably affected and the possible environmental and economic burden due to nutrient losses decreased. © 2022 International Society for Horticultural Science. All rights reserved

Effects of Alternative Fertilization and Irrigation Practices on the Energy Use and Carbon Footprint of Canning Peach Orchards

Throughout peach orchards in Greece, plant protection, fertilization and irrigation are often conducted empirically, negatively affecting energy use efficiency and greenhouse gas emissions (GHG emissions). The aim of this study was to apply alternative fertilization and irrigation practices in canning peach orchards to improve nutrient and irrigation water management and to assess yield, energy input–output and the carbon footprint of the alternative cultivation practices for three important clingstone cultivars of different ripening periods. Energy use analysis revealed that the cultivation practice with the highest energy use was almost always irrigation, followed by fertilization, plant protection, weed control and pruning. Electricity, fuels, fertilizers and machinery presented the highest energy requirements. Alternative fertilization, in combination with deficit irrigation (DI), was more energy efficient compared to farmers’ practices in all cultivars based on energy use efficiency, energy productivity and specific energy. Irrigation was the cultivation practice with the highest impact on GHG emissions due to electricity and, secondly, to fuel consumption. Alternative fertilization and DI decreased the intensity (kg CO2eq kg−1) of the emitted GHG compared to farmers’ practices. In conclusion, alternative fertilization and irrigation practices improved energy use efficiency and decreased the carbon footprint of the canning peach orchards by improving yield and decreasing fertilizer and irrigation water input. © 2022 by the authors

Alternative fertilization effects on peach and nectarine plant and fruit characteristics

Over- or under-fertilization is a common farmers’ practice in Greek peach orchards. During 2019 and 2020, 160% K were applied to ‘Onora’ peach and ‘Big Top’ nectarine mature trees, based on leaf and soil analyses, vegetative growth and expected yield, compared to farmer’s traditional practice (Control). Even though both cultivars were grown in the same orchard, soil properties were different with higher clay and pH in ‘Big Top’ compared to the ‘Onora’ planting area. All leaf macronutrients were at sufficiency levels and were not affected from the changes in fertilization practice. Soil surface temperature on tree row increased probably due to reduced vegetative growth and increased light penetration. Alternative fertilization had no effects on fruit size and yield of the two cultivars and differently affected fruit quality and antioxidant characteristics compared to control. Plant (Fv/Fm, crop water stress index, stem water potential) and leaf (specific leaf weight, chlorophyll, carotenoid and proline concentrations, relative water content, total phenols, antioxidant activity) response were differently affected from the alternative fertilization in each cultivar studied and each period of measurements (late June, early October). Reduced N and P and increased K fertilization differently affected fruit quality, and showed various positive or negative effects on plant and leaf characteristics studied. © 2022 International Society for Horticultural Science. All rights reserved

Effects of foliar calcium applications and maturity stage on ‘Lemonato’ peach fruit quality and bruising severity

‘Lemonato’ peach is a traditional Greek series of clones particularly valued by the consumers because of its high fruit quality, flavor and aroma. The main problem of ‘Lemonato’ peach is flesh softening during ripening and the susceptibility of ripe fruit to bruising. Our hypothesis was that harvesting the fruit earlier than its commercial maturity could reduce fruit quality losses during postharvest handling. Secondly, innovative Ca formulations could reduce bruising incidence by strengthening cell walls and reducing flesh softening. In this work, two clones of ‘Lemonato’ peach (a mid-season ‘Andrea’ and a late-season ‘Mytera’) were used in order to study the effects of maturity stage, such as early harvest (EH) and commercial maturity (CM) on fruit quality. Moreover, the influence of foliar Ca applications on fruit quality with two formulations containing calcium-silicate in nanoparticles (CaSi) and organic Ca (OrCa) were also tested. Estimated fruit quality parameters included total phenols content (TPC), total antioxidant activity (TAA), and bruising severity. Compared to ‘Andrea’ clone, ‘Mytera’ fruit had better quality traits, higher TPC and TAA in both maturity stages, whereas at EH it had fruit mass similar to ‘Andrea’ and higher browning index (BI) fruit because of differences in tree fruit load. In all treatments and clones, CM fruit improved organoleptic characteristics compared to EH fruit. ‘Andreas’ fruit harvested at CM had higher fruit mass and significantly softer flesh than EH fruit without any effect from Ca applications. ‘Mytera’ fruit at CM had higher TPC and TAA than EH fruit in all treatments. Flesh browning caused by mechanical bruising increased with time mainly during the first 10 min after bruising in all treatments and maturity stages of both clones. Ca-treated fruit had slightly increased TPC and TAA, except of CM OrCa ‘Mytera’ fruit, which had lower quality parameters compared to control. Hovewer, this was not associated with BI. In both ‘Lemonato’ clones, Ca applications did not improve flesh firmness and BI at any maturity stage. © 2021 International Society for Horticultural Science. All rights reserved