Postharvest Period Research Articles

Pre- and Post-Harvest Conditions Affect Polyphenol Content in Strawberry (Fragaria × ananassa).

The strawberry fruit contains abundant polyphenols, such as anthocyanins, flavan-3-ol, and ellagitannin. Polyphenol enrichment improves the quality of strawberries and leads to a better understanding of the polyphenol induction process. We measured the total polyphenol content of strawberry fruits under different growth conditions, developmental stages, and treatment conditions during pre-harvest and post-harvest periods. High fruit polyphenol content was observed in cold treatment, which was selected for further analysis and optimization. A transcriptome analysis of cold-treated fruits suggested that the candidate components of polyphenols may exist in the phenylpropanoid pathway. Coverage with a porous film bag excluded the effects of drought stress and produced polyphenol-rich strawberry fruits without affecting quality or quantity. The degree of stress was assessed using known stress indicators. A rapid accumulation of abscisic acid was followed by an increase in superoxide dismutase and DPPH (2,2-Diphenyl-1-picrylhydrazyl) activity, suggesting that the strawberry fruits responded to cold stress immediately, reaching the climax at around 6 days, a trend consistent with that of polyphenol content. These findings enhance our understanding of the mechanism of post-harvest polyphenol accumulation and the value of strawberries as a functional food.

Factors affecting firmness loss in apples during postharvest handling and cold/controlled atmosphere storage in India: A review

Apples attract humans with their dominant appeal and eating quality. The most dominant properties are color and texture. This review paper discusses the scientifically published results of apple texture through understanding internal properties like structural, physiological, physical, mechanical, water and cell wall contributions and post-harvest handling and storage methods. A critical appraisal is made of factors responsible for inner texture and sustenance during post-harvest and storage periods. The status of research data available is discussed from a firmness point of view of Indian apple varieties vis-à-vis those grown in other countries. Most of the research work on Indian apples reported physico-chemical parameters like weight, diameter, firmness, bio-chemical and nutrient components. The latest literature did not find data for the long term behaviour in CAS (6 to 10 months). The research data on factors responsible for texture loss is also very limited for Indian-origin apples. There are still large gaps in research on firmness loss in apple. Hence, suggestions are made on the scope for future research on apples grown in India for the benefit of farmers, traders, and consumers.

Management of Iceberg Lettuce Quality

In this study, an attempt has been made to understand the quality deterioration of iceberg lettuce during its supply chain i.e. during the pre-harvesting, harvesting and post-harvesting period. Further, it was tried to identify the cost of cultivation of iceberg lettuce per hectare and the crop rotation followed by the farmers. The Nilgiris District of the Tamilnadu state was the study area for this research. For this study, 30 farmers were selected for data collection based on convenience sampling. From these farmers during the pre-harvesting, harvesting and post-harvesting period every 10 samples of iceberg lettuce heads were taken for inspection and observations were recorded during quality inspection. From the study, it was found that the major part of the quality deterioration takes place during the post-harvest period. This paper focused on the comparison of the quality parameters done before dispatch and after, the knowledge of iceberg lettuce growing farmers. It was identified for the chemical application the spraying techniques used for the growing of iceberg lettuce. These current practices of farmers for the chemical application and spraying techniques are compared with the standard practices to identify the loopholes in the current practices of the farmers. It was found that the total cost of cultivation was 66495 rupees/acre.

Fungistatic Films Containing Cinnamon Essential Oil: New Coatings to Preserve the Nutraceutical Content of Avocado Fruit against Fusariosis.

Avocadoes are a rich source of nutrients and nutraceuticals that preserve human health. Nevertheless, this fruit is susceptible to phytopathogen infection during the postharvest period causing severe economic losses. Herein, we report on the in situ antifungal assessment of biodegradable films impregnated with the essential oil of Cinnamomum verum (CvEO) as natural fungistatic coatings to extend postharvest quality of Hass avocadoes (Persea americana cv. Hass). These coatings were evaluated on fruits previously infected with a native strain of Fusarium verticillioides. The cytotoxic assessment of CvEO on F. verticillioides revealed a minimum inhibitory concentration of 0.3±0.0 g L-1 whereas its chemical profiling showed (E)-cinnamaldehyde (45.9 %) 1,3,8-p-menthatriene (7.9 %) and linalool (6.8 %) as the major bioactive compounds. Four coatings (FC1-FC4) were made using chitosan (1 %) and a diverse quantity of CvEO (0.4-1.3 % w/v). The physicochemical properties demonstrated that the films FC3 and FC4 have the optimal characteristics of a food coating. Avocadoes preserved with the films FC3 and FC4 substantially kept (p<0.01) fruit firmness and the nutraceutical content of infected avocados at least for 21 d. The results of the present investigation suggest that our hybrid materials can conserve basic nutritional parameters such as fiber, protein, reducing sugars, as well as the content of unsaturated fatty acids which are the main nutraceuticals of this fruit.

Root Reserves Ascertain Postharvest Sensitivity to Water Deficit of Nectarine Trees

This work studied the sensitivity of the postharvest period of early maturing nectarine trees (Prunus persica L. Batsch, cv. Flariba) to water stresses. Along with a well-irrigated treatment (T-0), three water deficit treatments (by withholding irrigation) were applied: T-1: early postharvest (June–July), T-2: late postharvest (August–September), and T-3: the whole postharvest period (June–September). Soil water content (θv) and midday stem water potential (Ψstem) were measured throughout the study. During winter dormancy, L-arginine, starch, and phosphorus content in the roots were analyzed. Yield, fruit quality, and metabolites were determined at harvest. Ψstem reached −1.7 and −2.3 MPa at the end of the early and late postharvest periods, respectively. Total yield and number of fruits per tree were significantly reduced in all deficit treatments with respect to T-0, while no significant differences were observed in physicochemical fruit quality. The T-2 treatment showed the highest percentage of cracked fruits. Significantly, lower values of L-arginine and phosphorus were observed in the roots of T-2 trees, with respect to T-0, while they were similar in T-1 trees. Although the early postharvest stage is key for the application of RDI strategies, our results indicated that the late postharvest period was also a sensitive period to severe drought, as the accumulation of winter root reserves (L-arginine and phosphorus) was reduced, which limited yield.

Functional identification of the DHN melanin synthesis gene cluster and its role in UV-C tolerance in citrus postharvest pathogenic fungus Penicillium digitatum

The filamentous fungus Penicillium digitatum brings out great losses in citrus fruits by causing citrus green mold disease during the postharvest period. Previously, we obtained a T-DNA insertion mutant N2130 of P. digitatum, which produced albino conidia. To understand the role of green-grey conidial pigment in P. digitatum, we identified the insertion site and deeply explored the 1,8-dihydroxynaphtsalene (DHN)-melanin synthesis gene cluster in this phytopathogen. In this study, we deleted five genes in P. digitatum, PdPksP, PdAbr1, PdArp1, PdArp2, and PdAyg1, and the experiments were further performed on phenotype analyses, including pigmentation, UV-C tolerance, virulence, growth rate, conidiation, stress (osmotic-, oxidative-, cell wall disturbing-, and high temperature-) tolerance, fungicide resistance, and conidial hydrophobicity. The results showed that the five deletion mutants (ΔPdPksP, ΔPdAbr1, ΔPdArp1, ΔPdArp2 and ΔPdAyg1) produced albino, brownish, brown, reddish-brown, and Yellowish green conidia, respectively. In addition, the survival colony forming units (CFUs) of the deletion mutants, under the treatment of UV-C radiation (261.4 mJ/cm2), were 0.3- to 0.6-fold of those surviving in wild-type strain N1. Moreover, after 522.8 mJ/cm2-UV-C-irradiation on conidia, the deletion mutants showed a larger decrease in pathogenicity on Valencia Orange fruits compared with strain N1. However, there were no significant differences among other phenotypes tested in this study. Collectively, our research reported the DHN-melanin synthesis pathway in P. digitatum for the first time, and revealed that DHN-melanin is important for P. digitatum to tolerate UV-C irradiation.

Main criteria and parameters in selecting strawberry varieties suitable for integrated fruits production

The researches were held in 2011-2019 on the base of strawberry experimental sites in the Experimental Production Association of the I. V. Michurin Federal Scientific Center (Michurinsk, Tambov Region, RF). The purpose of the research was to identify criteria and parameters for evaluating strawberry varieties suitable for integrated cultivation technology, and to improve the commercial assortment. Plants of 45 introduced varieties were studied in strawberry plantations established in 2010-2016. The results of the analysis of the Register of strawberry varieties allowed for use on the territory of the Russian Federation and the region are presented. The principal problems of improving the assortment of strawberry are shown taking into account different cultivation systems. On the base of system analysis of experiment results main criteria and parameters were indicated. They allow us to evaluate the strawberry varieties suitable for the system of integrated production. The folloving sequence for evaluating strawberry varieties is recommended: adaptive capacity (abiotic, biotic and edaphic factors), commercial quality, transportability, productivity, consumption qualities marketability at post-harvest period, season of ripening; simultaneous ripening and number of harvesting. Introduced strawberry varieties have been identified that meet the parameters of the developed assessment, which formed the basis of an commercial assortment suitable for the integrated fruit production system. These are varieties with ripening dates: very early ('Flair', 'НФ311), early ('Elianneу', 'Maya', 'НФ 421', 'Fleurette'), medium ('Isaritsa', 'НФ 205', 'Marmolada', 'Vima Xima'), late ('Florence', 'Malwina'), very late ('Flamenko', 'Monterey', 'San Andreas'). They make it possible to significantly expand the period of strawberry production with high marketability, which is expressed in an increase in the share of the output of products of the highest and first commercial varieties during the life of the plantations (65-90 %).

Effects of Plant Growth Regulators on Plum (Prunus domestica L.) Grown on Two Rootstocks at Harvest and at the Postharvest Period

Plant growth regulators (PGRs), such as cytokinins (6-benzyladenine; BA) and gibberellins (GAs), are widely used in fruit production. This study focused on the plum cultivar “Čačanska rodna” (P. domestica L.) grafted on vegetative rootstock “WaVit” and generative rootstock Prunus cerasifera, with interstock Prunus spinosa. PGR treatments included 50 mg L−1 and 100 mg L−1 of BA and 200 mg L−1 of gibberellin A3 (GA3) and non-treated control. Pomological characteristics of plum fruits were examined at harvest, while physicochemical properties were analyzed at harvest and after 28 days of cold storage and 4 days of shelf life. GA3 and BA application changed the fruit morphological traits, improved skin strength, and increased carotenoid, anthocyanin and sucrose content while decreasing the titratable acidity at harvest. The beneficial effects of higher sucrose, anthocyanin and carotenoid levels persisted in all PGR-treated fruits after cold storage and shelf life. GA3-treated fruits had firmer flesh, stronger skin and higher total soluble solids (TSS) content, while in BA-treated plums, these effects were rootstock-dependent. The physical properties and chemical composition of plum fruit in the postharvest period suggest beneficial effects of the applied PGR treatments. Moreover, these chemical treatments might have prolonged the beneficial impact on fruit storability, nutritional profile and sensory properties. Based on our results, GA3 preharvest treatment can be included in standard cultivation practices within contemporary production systems of European plums not only to improve fruit quality at harvest but also to improve the storage potential and nutritional value, regardless of the rootstock used.

Application of Magnetic Resonance Imaging (MRI) as a Safe &amp; Non-Destructive Method for Monitoring of Fruit &amp; Vegetable in Postharvest Period

To investigate and control quality, one must be able to measure quality-related attributes. Quality of produce encompasses sensory attributes, nutritive values, chemical constituents, mechanical properties, functional properties and defects. MRI has great potential for evaluating the quality of fruits and vegetables. The equipment now available is not feasible for routine quality testing. The image and resolution produced by MRI is quite detailed and can detect tiny changes of structures within the body. For some procedures, contrast agents, such as gadolinium, are used to increase the accuracy of the images. MRI additionally quality, can even examine the histology, histochemistry and structural characteristics of samples. He also mentioned that MRI is used as an on-line sensor in postharvest sorting and processing situations. The equipment now available is not feasible for routine quality testing; however, costs and capabilities are rapidly improving. Each sensor method is based on the measurement of a given constituent or property; therefore, its ability to measure overall quality is only as good as the relationship of that constituent or property to quality as defined for a particular purpose. Improved statistical methods for combining the inputs from several measurements into classification algorithms are being developed

Equilibrium Moisture Content Modeling and Study of Circulating-Bed Drying Kinetics of Non-Fragrant and Fragrant Paddy Varieties

Due to maintaining good quality of rice grain kernel varieties during post-harvesting and in-store period, the thermos-physical properties which relate to surrounding conditions (temperature and relative humidity) of each rice variety are essential, especially on its moisture content and diffusion mechanism. Therefore, the main objectives of this research are to determination of the thermo-physical properties (in terms of equilibrium moisture content (EMC) and effective diffusivity (Deff)) of local non-glutinous GorKhor55 (RD55) and Hom Thammasat (HT) paddy varieties and to field experiment study of the small-scale circulating-bed dryer with capacity of 1 - 1.5 ton. The EMC experiment using gravitational method is carried on and the experimental results are simulated by non-linear regression analysis. The results show that the predicted data using Modified Oswin model is the most suitable fitting to the exact EMC data for both paddy varieties. The effective diffusivity of both paddy varieties is the function of inlet drying temperature. For the last purpose of this work, the drying kinetics of RD55 and HT paddy varieties with initial moisture content (MC) of 20.1 and 24.6 % dry-basis, respectively are studied using the circulating-bed technique. The inlet drying temperature is set as 45 and 55 °C including operation conditions of 1 stage and 2 stages circulating-bed drying. The inlet air velocity is fixed at 0.41 m/s and the grain mass flow rate of circulation is 0.23 kg/s. The desired final MC after drying of each experiment is in ranges of 16.5 - 16.8 % dry-basis. All of experimental data are non-linear regression analyzed by conventional drying equation models and the simulation results stated that the most suitable model for the circulating-bed drying of RD55 variety with inlet drying temperature of 45 and 55 °C is the Logarithmic and Approximation of diffusion model, respectively.&#x0D; HIGHLIGHTS&#x0D; &#x0D; The special parameter of equilibrium moisture content value of these two rice varieties have been firstly determined&#x0D; The compact circulating-bed dryer with LPG fuel source for farmer community has been tested and run. The drying kinetics models for both rice varieties were evaluated among drying temperature of 45 - 50 deg. Celsius&#x0D; From the Fick’s law of diffusion, the effective diffusion coefficient of the rice varieties were determined and formulated the relationship between this coefficient and drying temperature&#x0D;

Evaluation of the Egg Predator Blattisocius tarsalis (Mesostigmata: Blattisociidae) for the Biological Control of the Potato Tuber Moth Tecia solanivora under Storage Conditions

Tecia solanivora is the most prevalent pest causing damage to potato crops in fields in the Canary Islands, but even more so in the postharvest storage period. However, currently, there are no authorised chemical insecticides for potato storage facilities. Analysis of the viability of the predator mite Blattisocius tarsalis as a biological control agent for this moth was carried out. A study of the temperature effect showed B. tarsalis maintains predatory capacity in the range of 10–27 °C. Though predatory activity increases with temperature, no differences in mortality rates were observed between 10 and 20 °C (33.52 ± 2.44 and 40.14 ± 3.54% efficacy rate, respectively), nor between 25 and 27 °C (59.26 ± 4.59 and 75.19 ± 4.64% efficacy rate, respectively). Under microcosm conditions, at low pest infestation (10 eggs), B. tarsalis achieved the highest mortality of eggs at a density of 5 mites, with an efficacy rate of 91.67 ± 8.33%. At high infestation levels (50 eggs), maximum mortality was achieved with a density of 10 mites and efficacy of 98.52 ± 1.48%. The choice-assay showed no preference of B. tarsalis between T. solanivora and Phthorimaea operculella, suggesting this mite could be useful in mixed infestations of potato moths. The results show B. tarsalis is a very good candidate as a control agent in storage conditions and even in mixed infestations of T. solanivora and P. operculella.

Early-Summer Deficit Irrigation Increases the Dry-Matter Content and Enhances the Quality of Ambrosia™ Apples At- and Post-Harvest

Ambrosia™ is an apple that naturally has limited post-harvest quality retention, which is accompanied by relatively low dry-matter content (DMC). This trial was proposed to improve the DMC of this apple by scheduling deficit irrigation (DI) conducted in a semi-arid orchard in the Similkameen Valley (British Columbia, Canada) in 2018 and 2019. Two irrigation regimes were implemented in the orchard: commercial irrigation (CI) and DI, which was defined as irrigation for 2/5 of the timespan of CI. Five irrigation treatments were conducted: 1—adequate irrigation (AI), which used CI for the whole season; 2—early-summer DI (ED), which used DI from 20 June to 20 July; 3—middle-summer DI (MD), which used DI from 20 July to 20 August; 4—late-summer DI (LD), which used DI from 20 August to 10 days before harvest; and 5—double-period DI (DD), which covered the interval of MD and LD. The DI treatments resulted in a significant decrease from AI −1.0 to −1.5 MPa in stem water potential (SWP), followed by subsequent recovery. Conversely, SWP did not recover, and instead reached a critical low of −2.5 MPa under continued deficit conditions (DD). This, in turn, correlated with significant differences in the DMC among the treatments. Specifically, ED resulted in a rapid and sustained increase in DMC throughout the summer. At the time of harvest, ED resulted in a five-fold increase in the proportion of fruit, with greater than 16% DMC and 15% DMC in 2018 and 2019, respectively, compared to AI. DD resulted in similar levels of DMC elevation compared to ED, but also caused irregular maturation and the increased incidence of soft scald disorder in the post-harvest period. MD and LD had variable effects on DMC, and also increased the incidence of soft scald disorder. Consequently, fruit collected from the ED resulted in the best blush color attributes, higher soluble solid content, and a significant improvement in the post-harvest retention of both fruit firmness and acidity. The ED irrigation model would be recommended as a practical way for Ambrosia™ growers in semi-arid regions to decrease water usage, and to ensure high fruit quality for superior marketing and sustainable production.

The effectiveness of Xanthium strumamrium L. extract and Trichoderma spp. against pomegranate isolated pathogenic fungi in Taif, Saudi Arabia

ObjectivesPomegranate (Punica granatum L.) is frequently affected by fungal infections during the pre-and post-harvesting periods, resulting in severe losses to the farming economy. The common pre-and post-harvest pomegranate pathogens affecting the final yield and quality of the fruits are Botrytis cinerea, Alternaria alternata, Penicillium implicatum, and Aspergillus niger. This study aimed to isolate and identify the pathogens causing pomegranate rot diseases. Also, the values of Xanthium strumarium extracts as eco-friendly control agents and three Trichoderma strains as biological control agents against the pomegranate fungal pathogen were determined. MethodsThe plate dilution method was used to isolate fungi populations from pomegranate plants. The pathogens fungi were identified by the morphological and molecular method by sequenced of internal transcript spacer (ITS) region. The antifungal activities of X. strumarium extracted either by both ethanol or methanol and Trichoderma were investigated. Results and conclusionsThe isolated and identified pathogens were P. implicatum, A. alternata, A. niger, Fusarium oxysporum, and F. chlamydosporum. The obtained sequences of these fungi were deposited in NCBI gene bank with accession numbers OK562113–OK562125. The efficiency of X. strumarium extract against pomegranate fungal pathogens ranged from 40.32 to 69.53% for ethanol extract and from 44.40 to 70.28% for methanol extract compared to 44.43%–85.71% for the antifungal Nystatin. Moreover, the efficiency of Trichoderma was 42.22%–72.50%, 42.30%–70.21%, and 44.54%–72.50% for strains ABSA-16, TSA-17, and ABSA-18, respectively. It could be concluded that the isolated pomegranate's pathogenic fungi in Taif were P. implicatum, A. alternata, A. niger, F. oxysporum, and F. chlamydosporum. The extract of X. strumarium obtained from the Taif region and Trichoderma can successfully assist control the pomegranate's pathogenic fungi at pre-and post-harvest, and hence can be successfully included in the IPM programs.

Long-term stream chemistry response to harvesting in a northern hardwood forest watershed experiencing environmental change

Previous studies of harvest impacts on stream chemistry from deciduous forests with seasonal snow cover have shown variable responses and recovery times. We hypothesized that this variability in response and recovery was due to the interactive effects of forest harvesting with regional and global environmental changes. We investigated harvest impacts on stream solute (K+, Na+, Ca2+, Mg2+, Cl–, SO42–, DOC, Si, NO3–, NH4+, total P) concentrations, pH and conductivity under clearcut, selection, and shelterwood harvesting using a before-after control-impact experimental approach. The experiment was conducted at the Turkey Lakes Watershed, a shade-tolerant sugar maple forest within the Boreal Shield Ecozone, over a 36 year period (15 year pre-harvest and 21 year post-harvest) that has experienced climate change and acidification recovery. Harvest impacts on stream chemistry were greatest in the clearcut, moderate in the selection cut, and least in the shelterwood cut. The largest impacts on stream solutes typically lasted one to six years following harvest, although some solutes were impacted during the entire 21 year post-harvest period. Different patterns in the response of stream solute concentrations included: initial deviations (increase or decrease) followed by a return to pre-harvest levels within two to four years (Na+, Ca2+, Mg2+, conductivity); initial increase followed by a decrease but still not recovered (K+); initial increase followed by a decrease to below pre-harvest levels (NO3–, Na+, Cl-); sustained elevated concentrations (dissolved organic carbon [DOC], Si); and a noisy response (TP, SO42-, pH). The different patterns were consistent with expected changes in nutrient demand, sources, and transport (including changes in hillslope-stream hydrologic connectivity due to harvesting). Comparing harvest impacts to long-term climate change and acidification recovery showed that harvesting had antagonistic (mitigative) effects to environmental changes for some solutes (e.g., cations), while for others (e.g., DOC) harvesting had agonistic (synergistic) effects to environmental changes. These results emphasize the need for long-term monitoring to accurately interpret the consequences of forest harvesting practices on the resilience of forests experiencing environmental change.

International standards for leguminous crops and methods of microbiological validation of laboratory researches

The article presents an analysis of the current international standards for leguminous crops and methods of microbiological validation based on laboratory studies. Quality and safety standards are considered at different stages of the food chain - from producer to consumer. Standards containing technical recommendations on optimal storage, loss prevention, preservation of product quality (ISO 6322 “Cereals and legumes. Storage”); standards for the detection of pests of legumes, including sampling methods and rapid methods for determining the time of infection (ISO 663 “Cereals and legumes - Determination of latent insect infestation”); determination of contaminants and impurities and suitability for use (ISO 605 “Leguminous crops - Determination of impurities, sizes, odors, insects, species and varieties - Test methods”); Determination of moisture content of legumes during the post-harvest period and storage period (ISO 24557 Legumes - Determination of moisture content). Analyzed a new series of international standards ISO 16140, consisting of 6 parts, in the field of microbiological validation of the food chain. A comparative assessment of the standards providing for procedures and criteria for selecting methods of microbiological testing in laboratories is given. The protocols for checking reference methods of standards and validated alternative methods, protocols for laboratory studies to identify qualitative and quantitative microbiological indicators, as well as methods for confirmation and typing are described in detail. The procedures for the practical application of laboratory quality control of the tests performed have been comprehensively analyzed.

Gene Expression, Activity and Localization of Beta-Galactosidases during Late Ripening and Postharvest Storage of Tomato Fruit

Beta-galactosidases (β-GALs) hold a key role in both fruit softening and the increase of total soluble solids during maturation. Despite determining both quality and potential postharvest longevity, β-GAL activity during ripening, with a special focus on the postharvest period, has not been adequately addressed in a spatial and temporal manner. This study focused on the regulation of gene expression in relation to the total β-GAL enzyme activity during the ripening of tomato fruit attached on the plant, as well as harvested fruit ripened for 5 d at 4, 10, or 25 °C. The transcription of genes coding for β-GAL isoenzymes was significantly affected by both the fruit maturation stage (unripe vs. red ripe) and postharvest storage temperature. Cold stressed tomatoes (4 °C) exhibited a remarkably higher transcription of most β-GAL genes compared to on-plant red ripe fruit and to fruit exposed to either 10 or 25 °C, indicating a low temperature response. However, enzymatic activity and water-soluble pectin content increased with elevated temperature exposure, peaking in fruit stored at 25 °C. β-GAL activity was present in the pericarp, while it was less detected in locular parenchyma. These findings highlight the dual role of β-GAL not only in maturation, but also in the metabolism during postharvest homeostasis and cold acclimation of tomato fruit.

Improving the Shelf Life of Avocado Fruit against Clonostachys rosea with Chitosan Hybrid Films Containing Thyme Essential Oil.

Hass avocadoes are one of the most popular fruits consumed worldwide because of their nutritional and nutraceutical content. Nevertheless, these fruits are susceptible to phytopathogen attacks that decrease fruit quality during the postharvest period. Herein we present the results of the in situ fungistatic activity of four hybrid films (FT1–FT4) manufactured with chitosan and different concentrations of the essential oil of thyme (TvEO). The films were evaluated as biodegradable materials to prevent fruit decay triggered by Clonostachys rosea which is considered an emergent phytopathogen of this crop. The in situ fungistatic strength, spectroscopic properties (FT-IR), optical features (transmittance/opacity), and consistency obtained by microscopic analysis (SEM), indicated that the films FT3 and FT4 possessed the best physicochemical properties to protect Hass avocadoes against the soft rot produced by C. rosea. Avocadoes treated with the films FT3 and FT4 significantly (p < 0.01) conserved fruit firmness and nutritional composition (protein, fat, fiber, and reducing sugars) as well as the nutraceutical content (oleic, palmitoleic, linoleic, and palmitic acids) of infected avocados for 21 days. Our results validate the potential use of the films FT3 and FT4 to prevent the soft rot caused by C. rosea and to improve the shelf life of Hass avocadoes.

I AD values of apricot (Prunus armeniaca L.) at harvest in relation to fruit quality and sensory properties during cold storage and shelf life

ABSTRACT DA-meter enables quick and non-invasive determination of fruit ripeness in different types of fruit, including apricots. In order to examine the postharvest physiology of apricots, fruits were divided into five I AD categories (0.00; 0.01−0.40; 0.41−0.80; 0.81−1.20; and >1.20) and were analyzed in terms of the physicochemical and sensory properties at harvest, after 21 days of cold storage and after 3 days of shelf life. The specified I AD categories differed in terms of ethylene production, flesh firmness, skin colour, composition and sensory properties at harvest. After cold storage and shelf life, ethylene production and respiration patterns, sensory properties, colour and fruit composition were affected by the I AD value. Fruit assigned to the categories I AD 0.81−1.20 and I AD >1.20 categories maintained higher firmness compared with the remaining three groups. Carotenoid, phenol, fructose, sucrose, citric and succinic acid content were affected by the I AD value during storage. Apricots attained optimal properties for consumption in different postharvest periods, depending on their maturity stage. These findings suggest that I AD-based segregation can support apricot fruit management during storage and shelf life.

Water use of intercropped species: Maize-soybean, soybean-wheat and wheat-maize

Plant-plant interactions in the intercropping system can significantly affect crop productivity. However, it is poorly understood how the interactions affect the land equivalent ratios (LER) in the cereal-legumes and cereal-cereal intercropping systems in semi-arid agroecosystems. A two-year (2019–2020) field experiment was conducted in the Dryland Agricultural Experimental Station of Lanzhou University, a semiarid rainfed site of northwest China, to quantify the impact of crop diversification on land equivalent ratio, and its moisture-dependent mechanisms in three intercropping systems of maize-wheat, maize-soybean and wheat-soybean. The soybean-involved intercropping systems showed positive interactions, which substantially promoted crop productivity of maize and wheat by 18.1–20.9%. The soil water in soybean strips can be used by intercropped wheat or maize, which in turn promoted soil water storage (SWS) in maize or wheat strips by 0.6% and 11.0% respectively, during the co-growth period. This further improved the photosynthetic rate (Pn), instantaneous growth rate (IGR), and water use efficiency (WUE) for each species and thereafter elevated the land equivalence ratio (LER>1). However, in the wheat-maize intercropping system, interspecific competition was dominated with wheat as dominant species and maize as inferior one respectively. The competition plundered available water of maize strips (SWS decreased by 10.5%), and thus decreased its Pn and WUE by 12.7% and 20.0% (P < 0.05), respectively. Importantly, maize yield and LER were not improved via the compensation effect during the post-harvest period of wheat. While soil water was to some extent restored, the Pn and IGR of intercropped maize were still lower than those of monoculture maize. This trend resulted in maize yield loss during the reproductive period, and ultimately lower LER. For the first time, we found a rarely reported phenomenon, i.e. negative relationships between crop diversity and land equivalent ratios in semiarid agroecosystem, since the yield loss caused by competition was not compensated during the co-growth period. Therefore, a positive relationship between crop diversification and land equivalent ratio required rational crop species configuration, in terms of the tradeoff between crop diversity and its productivity at agricultural landscape scale.

The Effects of Post-Harvest Drying Period on the Yield and Chemical Composition of leaf Essential Oil from Cymbopogon citratus (DC.) Stapf

Lemongrass (Cymbopogon citratus) is an aromatic, medicinal oil-bearing grass that grows spontaneously in tropical regions like Malaysia and India. The effects of drying periods (fresh sample, 1 day, 2 days, and 3 days of drying) on essential oil yield and chemical composition of C. citratus was investigated. The chemical composition of the oils was analyzed using gas chromatography flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC/MS). The post-harvest drying periods were found to be beneficial for improving oil yield of C. citratus. The highest essential oil concentration (0.392% v/w) was obtained from samples dried for 2 days post-harvest compared to 1 day (0.28%) and 3 days (0.31%) post-harvest periods. The major components were α-citral and β-citral followed by myrcene for both fresh and dried samples. Drying periods had no significant effect on the main components of the lemongrass essential oil. Nevertheless, the post-harvest drying periods had a marked effect on the proportions of monoterpenes.