Quality Of Strawberries Research Articles

Strawberry preservation using combination of yam bean starch, agarwood Aetoxylon bouya essential oil, and calcium propionate edible coating during cold storage evaluated by TOPSIS-Shannon entropy

The effect of edible coatings made from yam bean starch (ST), agarwood bouya essential oil (ES), and calcium propionate (CP) on strawberry fruit in cold storage for 16 days was investigated. Strawberries coated with four different coating formulations and uncoated fruits were packed in sealed containers and stored at 4 °C with 85 % of humidity. Antifungal evaluation was conducted on the coating solution (membrane permeability and germination of Botrytis cinerea) and edible film (microstructure analyzed using atomic force microscopy), as well as testing at 4-day intervals on fresh fruit (weight loss, surface color, firmness, microstructure using scanning electron microscopy, and antifungal activity) and physicochemical analysis of strawberry juice (total soluble solid, citric acid, ascorbic acid, pH, and titratable acidity). Each result was then tested using TOPSIS-Shannon entropy analysis. From these tests, the edible coating treatment with ST-ES was the best treatment in this study (has Ci 0.839 as the highest of all untreated and treated sample) and better than fruit without coating, demonstrating that the coating was able to maintain the quality of strawberries during storage. At the final day of storage ST-ES samples has L* 30.9, a* 26.65, b* 16.36, total soluble solid 3.98 Brix/%.

Preharvest Application of Commercial Products Based on Chitosan, Phosphoric Acid Plus Micronutrients, and Orange Essential Oil on Postharvest Quality and Gray Mold Infections of Strawberry

Strawberry is a perishable fruit with a limited shelf life after harvest due to deterioration of quality and the development of gray mold, Rhizopus rot and other minor diseases. In this study, the effectiveness of commercial compounds based on chitosan, phosphoric acid plus micronutrients, and sweet orange essential oil (EO) in reducing decay and optimizing the quality of strawberries was analyzed. The plant canopy of a greenhouse crop was sprayed once and strawberry fruit were harvested three days later. Gray mold infections were evaluated after chilled storage for seven days at 4 ± 0.5 °C followed by five days shelf life. The qualitative parameters were recorded at harvest (initial day) and after three days of storage at room temperature (RT, 20 °C) or after cold storage and shelf life (CS, 4 °C). The application of sweet orange EO increased the antioxidant and flavonoid content at harvest, while a decrease was reported following three days of storage at RT. At the same time, increased ethylene production and weight loss were observed during CS three days after harvesting. Chitosan treatment maintained the harvest fruit quality and was effective in the control of postharvest decay. Our results suggest that the investigated natural compounds could improve strawberry quality after harvest. Since chitosan performed best in terms of maintaining quality and reducing postharvest decay, it could be considered as a good substitute for chemical-synthetic fungicides for the preservation of strawberry postharvest gray mold.

Cold chain storage for quality maintenance of strawberry fruits attacked by Drosophila suzukii (Matsumura) (Diptera: Drosophilidae)

Drosophila suzukii (Diptera: Drosophilidae) is a polyphagous pest that causes severe damage in strawberries and losses during postharvest. To reduce losses the effect of cold storage on development of D. suzukii and on quality of strawberries harvested at varying maturity stages was investigated. In this work, strawberry fruits infested with eggs and first instar larvae of D. suzukii were subjected (at 0.5 ºC, 3 ºC and 12.5 ºC for 24 h, 8 h and 5 days, respectively) or not (23 ºC for 7 days) to low temperatures, simulating the usual temperatures during the distribution chain. These fruits had partially (75%) or totally the red peel. Strawberries submitted to cold storage showed better maintenance of physicochemical characteristics (firmness, total soluble solids and titratable acidity) and visual aspect, regardless of the maturation stage, than the fruits not submitted to cold storage. The use of cold storage was efficient in reducing the development of eggs and larvae of D. suzukii to pupation. Since there is difficulty in identifying and separating fruits infested by D. suzukii in a lot of apparently healthy fruits, the use of cold storage is an alternative to market them and reduce losses during commercial sale processes.

Comprehensive responses of aroma production in 'Benihoppe' strawberry to low oxygen associated with the changes of key gene expressions and energy levels.

The influence of low oxygen on the biosynthesis of aroma-related esters and alcohols in strawberries has been well revealed. However, how low-oxygen conditions affect other volatile compounds, such as terpenes and furans, is still to be elucidated. The effects of 2 kPa O2 low oxygen on the biosynthesis of aroma in 'Benihoppe' strawberries were comprehensively investigated in this study. The results showed that, like esters, the accumulations of key terpene alcohols and furans in strawberries were also inhibited by 2 kPa O2 low oxygen during storage and subsequent shelf life, which was associated with the down-regulation of expression of FaNES1 (nerolidol synthase) and FaOMT (O-methyltransferase). However, no anaerobic fermentation occurred in 'Benihoppe' strawberries since no ethanol and acetaldehyde were produced under the 2 kPa O2 condition. As expected, the 2 kPa O2 condition suppressed the respiratory intensity and lowered the energy charge to maintain the quality of strawberries. The negative effects of low-oxygen storage on aroma accumulations and the energy charge of strawberries were more pronounced when transferred to the period of shelf life. The 2 kPa O2 condition caused a full-scale loss of aroma in 'Benihoppe' strawberries, including esters and alcohols as well as terpenes and furans, which was mainly reflected in the reduction of aroma emissions rather than the production of off-flavor, probably due to the reduced expressions of related genes and energy charge. © 2022 Society of Chemical Industry.

Effect of coating with co-product-based bionanocomposites on the quality of strawberries under refrigerated storage

This study evaluated the effect of cassava starch–based bionanocomposites reinforced with cellulose nanofibrils obtained from oat and wheat straw as edible coatings on the maintenance of postharvest strawberry quality during refrigerated storage. The coated strawberries were compared with uncoated strawberries stored in a sealed polyamide package and package with rigid polypropylene lids (control). The fruits were stored at 2 ± 1°C and evaluated every 3 days over 21 days for atmospheric modification, respiratory rate, mass loss, pH, titratable acidity, soluble solids, color, firmness, and cell wall enzymes, antioxidant activity, phenolic profile, and microbiological growth. The barrier properties of the coatings promoted a lower respiratory rate and slower fruit metabolism, delaying and minimizing events related to senescence, such as degradation of soluble solids and organic acids, tissue browning, synthesis of anthocyanins, the activity of softening enzymes, production of compounds with antioxidant activity, vanillin and resveratrol synthesis, and fungal growth. The coating with the bionanocomposites maintained the quality of strawberries under refrigerated storage, indicating that this material is a biodegradable alternative to conventional package used for fruits and vegetables postharvest.

Growth and Quality of Strawberry (Fragaria ananassa Dutch. cvs. ‘Kuemsil’) Affected by Nutrient Solution Supplying Control System Using Drainage Rate in Hydroponic Systems

Although hydroponic techniques enable intensive and effective crop management, controlling the watering for each crop type and growth stage is challenging using the commonly used timed watering system. Therefore, excessive and insufficient watering occurs frequently. Hydroponic technology that considers the drainage rate can minimize the amount of drainage, thereby reducing environmental pollution and fertilizer consumption. This study compared the drainage rate and the timed watering methods in a strawberry hydroponic system and determined the optimal drainage rate. As the drainage rate increased, the amount of water supplied increased. A significantly negative correlation was found between the amount of water supplied and the total nitrogen content. Drainage electrical conductivity (EC) level was the highest in the 10% drainage rate group. In the 20% drainage rate treatment, leaf length and width increased compared to the four applications timer-supplying method. The yield of fruits weighing more than 27 g was the highest in the 20% drainage rate treatment. Therefore, the 20% drainage rate treatment was the most appropriate. We propose that it is possible to reduce unnecessary fertilizer consumption and increase productivity by controlling the water supply using the drainage rate for precise water supply management of strawberries.

Silicon application improves strawberry plant antioxidation ability and fruit nutrition under both full and deficit irrigation

Deficit irrigation has been widely studied on fruit quality improvement, but it also leads to yield losses, especially, fruit size reduction. The objective of this study was to investigate if the silicon application could offset the negative influence brought by deficit irrigation while enhancing fruit quality. A two-factor-three-level split plot greenhouse experiment was conducted where the Fragaria × ananassa cv. Kaorino plants were subjected to full irrigation (FI) or deficit irrigation (DI), and within each irrigation regime the plants were subjected to no silicon application (N), silicon foliar application (L) or silicon root application (R), resulting in 6 treatments in total, viz., FIN, FIL, FIR, DIN, FIL and DIR. The results showed that DI increased the fruit sugars and anthocyanins concentrations without reducing the fruit size. Compared to foliar application, silicon root application was more favorable for fruit quality improvement, especially under full irrigation, by which the anthocyanins, ascorbate and glutamate concentration were significantly increased. Under deficit irrigation, silicon root application also altered the leaf photosynthetic pigments composition, increasing carotenoids and reducing membrane peroxidation to protect the photosynthetic complexes. Also, only when plants were under deficit irrigation, the silicon foliar application could perform better on the improvement of antioxidant capacity and nitrogen assimilation, enhancing the ROS scavenging and amino acids synthesis. Collectively, exogenous silicon application is promising in alleviating the negative effects of DI on fruit yield while improving fruit quality of strawberry.

Cerium improves plant growth and fruit quality of strawberry plants under salt stress by changing the antioxidant capacity and water physiology

This study investigated the effects of cerium (Ce) on the growth and fruit quality of strawberries under salt stress. The findings revealed that salt stress markedly enhanced the activities of antioxidant enzymes and increased the contents of malonaldehyde (MDA) and hydrogen peroxide (H2O2) in leaves and the contents of anthocyanins, phenolic compounds, vitamin C (Vc), soluble sugar (SS) and titratable acid (TA) in fruits. Ce markedly improved the activities of ascorbate peroxidase, superoxide dismutase, peroxidase and catalase in leaves and the contents of anthocyanins, phenolic compounds, Vc and SS in fruits, but significantly decreased MDA and H2O2 levels in leaves and TA content in fruits under salt stress. However, salt stress significantly decreased the contents of chlorophyll (Chl) and carotenoids (Car), photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (gs), relative water content (RWC), plant height and biomass, and fruit weight and sugar-acid ratio (SAR). Compared with salt stress alone, Ce obviously increased Chl and Car contents, Pn, Tr, gs, RWC, plant height and biomass, as well as fruit weight and SAR. The above results suggested that Ce showed beneficial effects on the growth and fruit quality of strawberries under salt stress.

Effect of organic manure and bio-fertilizers on vegetative growth, yield and Quality of Strawberry (Fragaria Å~ ananassa Duch.) cv.Chandler

Studies were carried out to evaluate the effect of organic manure and bio-fertilizers on vegetative growth,yield and quality of Strawberry (Fragaria à ~ ananassa Duch.) cv. Chandler having twelve treatments withthree treatments replications during the year 2015-16. The treatments T2 R.D.F. 100% was found better overthe all treatments. This treatment recorded maximum height of plant (15.24 cm), number of leaf (15.55 cm),length of leaf with petiole (28.39 cm), length of leaf (13.62 cm), length of petiole (14.93 cm), width of leaf(13.16 cm),total number of fruit (16.77), length of fruit (52.82 mm), width of fruit (30.93 mm), weight/fruit (22.05 g), weight of fruit/plant (369.82 g) and weight of fruit/plot 8.15 kg).

Isolation of fecal Escherichia coli from fresh strawberries (fragaria ananassa) in Iran.

Microbial safety of the fresh fruits is a global concern. The production of strawberry (Fragaria ananassa) in Iran has grown 4.5% from 2016 to 2019. Little information is available about the microbiological quality of strawberry produced in Iran. The objective of this investigation was to assess the fecal Escherichia coli (FEC) contamination of fresh strawberries of south of Kerman province where is the centers of production and supply of strawberries to other parts of Iran. In this cross-sectional descriptive study, the FEC of a total number of 109 strawberry samples, which were collected from green-houses of strawberry of Kerman province during three months, were enumerated using the most probable number (MPN) as described by Iranian National Standards Organization, protocol No.2946, and interpreted using the latest statute released by Iran Veterinary Organization, Executive order number 2946, released in 2011. MPN of FEC counted in strawberries ranged between <0.3 (n=37) and >110 (n=19) per gram (g) having a mean, mode, and median value of 250.3, <0.3, and 9.4 MPN/g, respectively. More than one-fourth of the samples (28.44%) were polluted with FEC at a level of >100 MPN/g. Our findings may be resulted from the sanitary quality of the farm and strawberries of the study area, which indicated that the microbial safety of the strawberries in this survey was not satisfactory, alarming public health.

The Quality and Productivity of Strawberry (Fragaria × ananassa Duch.) Improved by the Inoculation of PGPR Bacillus velezensis BS89 in Field Experiments

Efficient plant-growth-promoting rhizobacteria (PGPR) used as biofertilizers and biological control agents are promising substitutes for minimizing the application of synthetic agrochemicals in crop production. We studied the effect of PGPR strain Bacillus velezensis BS89 alone and in combination with three forms of nitrogen fertilizers (ammonium nitrate, carbamide, and ammonium sulfate) on the productivity of two strawberry varieties in three-year field experiments. We first showed that the application of PGPR Bacillus velezensis BS89 on strawberries demonstrated the same effect as the application of nitrogen fertilizers. Use of the strain BS89 increased the chlorophyll content in plant leaves by 2.7–6.8%, and also increased the yield of berries by 6.7–36.4% for cv. Rusich and 7.5–19.3% for cv. Troitskaya depending on the form of nitrogen fertilizer. The best results in the yield of strawberry plants of the cv. Rusich were achieved in the variant BS89 + ammonium nitrate (41.9–57.4%), and the cv. Troitskaya—in the BS89 + carbamide variant (8.1–38.8%). Three-year use of strain BS89 for cv. Rusich resulted in an increase of runner’s weight by 212.1%, and also the weight of the roots by 120%, thereby significantly improving the mineral nutrition of plants. This is mainly associated with the plant growth-promoting activity of Bacillus velezensis BS89, which was able to produce a high amount of IAA—494.1 µg/mL. We believe that the PGPR strain BS89 can be successfully used for growing strawberries. However, each variety requires careful selection of the composition of nitrogen fertilizers and analysis of the compatibility of fertilizers and the PGPR strain.

Green Tea Incorporated Edible Coating Extends the Postharvest Life of Strawberry Fruits (Fragaria ananassa)

In this study, the effects of green tea incorporated edible coating (EC) on the postharvest quality of strawberries were evaluated. EC was prepared by solubilizing carboxymethyl cellulose (0.75 % w/v), glycerol (2% v/v), and green tea concentrate (14% v/v) in distilled water at 80°C. Coated strawberries were packed in perforated polyethylene terephthalate boxes (10 fruits per box) and kept in refrigerated conditions (6±1°C). Uncoated strawberries were used as the control. Significant differences were observed in weight loss, visual quality, titratable acidity, and total soluble solids between the coated and uncoated fruits. The EC significantly reduced the total aerobic plate count and yeast and mold count of the stored fruits (p&lt;0.05). EC exhibited decent in vitro inhibitory activity against Botrytis cinerea. The sensory properties of the coated fruits were comparable with fresh strawberries even on the 15th day of storage. In conclusion, green tea incorporated edible coating can be introduced as an effective coating material for the extension of the postharvest life of strawberry fruits.

Effect of Some Sanitizing Treatments on Strawberry Fruit Quality during Cold Storage

The present research was conducted to evaluate the effect of dipping treatments with 2% citric acid, 0.2% benzoic acid, 0.2% sorbic acid and acidic electrolyzed water on the quality of strawberries ("Malvina" cultivar) during 21 days storage at 8 °C. The following analyses were performed on the control and sanitized strawberry fruits at 1, 7, 14 and 21 days of storage: weight loss, firmness, decay incidence, soluble solids content, titratable acidity, total phenolics content, total anthocyanins content and DPPH antioxidant activity. All sanitizing treatments significantly (P&lt;0.05) reduced weight loss and fruit decay during strawberry storage. Dipping strawberries in 0.2% sorbic acid or 0.2% benzoic acid aqueous solutions were the most effective treatments for maintaining firmness and phytochemical content and for delaying the decay of strawberries during cold storage.

Efficiency of nanoemulsion of essential oils to control Botrytis cinerea on strawberry surface and prolong fruit shelf life

Strawberry fruit is highly susceptible to decay by fungi. The objective of this study was to determine if essential oils (EOs) or nano-emulsions (Nano-EM) of EOs from Thymus vulgaris (Th), Matricaria chamomilla (Mc), Pistacia atlantica (Pa), or Mentha longifolia (Me) could inhibit growth of strawberry spoilage fungi Botrytis cinerea and their effect, if any, on strawberry quality parameters. An In vitro study showed that Th and Me EOs had the same minimal inhibitory concentrations (MIC) of 0.021 % while the MICs for Mc and Pa EOs were 0.9 % and 1.5 %, respectively. Th and Me EOs were used for subsequent experiments. In the second experiment, the application of Th and Me EOs and their nano-EM at 0.021, 0.1, 0.5 and 1 % were studied to control B. cinerea growth on the fruit surface. Nano-EM of EOs had higher antifungal activity in the control of B. cinerea than EOs on fruit surface. Generally, antifungal activity was increased at higher concentrations of Nano-EM, but in the case of EOs, their antifungal activity was not increased by increasing concentration. Nano-EM of EOs with 0.5 % was selected for further study. Finally, the quality changes and postharvest losses of fruit treated with Nano-EM of EOs of Th and Me at 4 °C were studied. The results of third experiment showed that Nano-EM of both EOs reduced microbial load, decay index, weight loss and induced greater firmness, vitamin C, total flavonoid and antioxidant activity in strawberry during storage. NanoEM-ThEO 0.5 % was more effective than NanoEM-MeEO 0.5 % to retain strawberry firmness, vitamin C and total flavonoid.

Detection of powdery mildew on strawberry leaves based on DAC-YOLOv4 model

Strawberry powdery mildew (PM) is the main disease affecting the yield and quality of strawberries in recent years, which always appears on the back side of leaves in the early stage. Traditional methods of disease detection are labor-intensive and time-consuming. In this paper, we proposed a computer vision algorithm for strawberry leaf PM and infected leaves (IL) detection in complex background. Then we additionally proposed the estimation index of strawberry leaf PM for disease assessment. The original YOLOv4 backbone and neck are replaced by the proposed backbone and neck with depthwise convolution and hybrid attention mechanism, and the improvement can be made to decrease the size of the model and retain the performance. By combining the proposed backbone and neck, four new network structures are designed and evaluated, and the best one was named DAC-YOLOv4. Compared with YOLOv4, the mean average precision (mAP) of DAC-YOLOv4 reaches 72.7%, while the size is greatly compressed. To confirm the effectiveness of the proposed model, we compare DAC-YOLOv4 with five algorithms, and experimentally show that DAC-YOLOv4 performs well. We also deploy the algorithm on the Jetson Xavier NX and Jetson Nano, and the speed of DAC-YOLOv4 is 43 and 20 FPS, respectively, which can meet the real-time detection requirements. In summary, the experimental results indicate that the DAC-YOLOv4 proposed in this paper has good performance in strawberry leaf PM detection on the embedded platform, and the method to attain the disease index provides a solution for the early detection and prevention of strawberry PM.

Furaneol Detection with Molecularly Imprinted Polymer (MIP)-Based Polyaniline (PANI) Gas Sensor

Strawberry is one of the beloved fruits worldwide due to its exquisite flavor with highly nutritious compounds which give promising health benefits. [1] With dragging the great attention, efforts to monitor the quality of strawberries and strawberry derivatives are becoming significant to obtain better flavor and nutrition. 2,5-Dimethyl-4-hydroxy-3(2H)-furanone(furaneol) is one of the compounds which plays an important role in a flavor that can be naturally found in various fruits such as strawberry, pineapple, raspberry, and mango. Especially, furaneol composition is reported as a significant factor for maturity condition monitoring of strawberries due to the different amounts at the ripening stage. [2] Furaneol is also known to be an essential signature for controlling the food production process, verifying the food production origin, and regulating the quality of products.Currently, furaneol detection is conducted with time-consuming techniques, such as gas chromatography (GC) and high-performance liquid chromatography (HPLC). For example, Yuan et al. [3] showed the identification of furaneol with HPLC. Also, Buttery et al. [4], and Lopez et al. [5], used GC for the determination of furaneol in foods. Developing a real-time gas sensor for fast, cheap, stable, sensitive detection of furaneol is a significant challenge in the area of the food industry.Chemo-resistive gas sensors can be an attractive approach due to their miniaturization, simple operation, ease of fabrication, and low production cost. For utilizing resistive gas sensors, polyaniline (PANI) got great attention because of its environmental stability, simple synthesis, and ease of tailoring the surface charge characteristics by changing the dopants. However, PANI-based gas sensors are reactive to numerous gases which limits the selective detection of target gas molecules. Many compounds in strawberries may restrict the use of PANI-based sensors. [6] Molecular imprinting technology (MIT), which can create molecularly imprinted polymers (MIPs) obtaining specific binding sites for target molecules, is utilized to achieve selective gas sensing similar to biological antibodies. [7] The improved affinity not only provides selective detection but also enhances response to target gas molecules.In this study, a resistive gas sensor based on synthesized molecularly imprinted polymer and polyaniline is demonstrated for the detection of furaneol gas molecules for its operation in food packaging. Herein, we developed a unique method to synthesize molecularly imprinted polymer and polyaniline (MIP-PANI) nanocomposites with an interfacial polymerization technique. Aniline monomer is polymerized and oxidized simultaneously to tailor the surface charge characteristics forming polyaniline. Then, the molecularly imprinting process on polyaniline is conducted with methacrylic acid (MAA) as a functional monomer, ethylene glycol dimethacrylate (EGDMA) as a crosslinker, furaneol as a template, and benzoyl peroxide as a radical initiator. After the furaneol template was constructed, MIP-PANI presented a high affinity to furaneol target molecules and showed a high sensing response. Their response signals are enhanced tens of times compared to the pure PANI. Furthermore, selective detection of the target furaneol molecules was observed. This study may broaden the application of resistive gas sensors for selective and sensitive detection of volatile organic compounds in food industries. Reference [1] S. Afrin, M. Gasparrini, T.Y. Forbes-Hernandez, P. Reboredo-Rodriguez, B. Mezzetti, A. Varela-Lopez, F. Giampieri, M. Battino, Promising Health Benefits of the Strawberry: A Focus on Clinical Studies, J Agric Food Chem 64 (2016) 4435-4449. [2] C. Aubert, S. Baumann, H. Arguel, Optimization of the analysis of flavor volatile compounds by liquid-liquid microextraction (LLME). Application to the aroma analysis of melons, peaches, grapes, strawberries, and tomatoes, Journal of Agricultural and Food Chemistry 53 (2005) 8881-8895. [3] J.P. Yuan, F. Chen, Separation and identification of furanic compounds in fruit juices and drinks by high-performance liquid chromatography photodiode array detection, Journal of Agricultural and Food Chemistry 46 (1998) 1286-1291. [4] R.G. Buttery, G.R. Takeoka, M. Naim, H. Rabinowitch, Y. Nam, Analysis of furaneol in tomato using dynamic headspace sampling with sodium sulfate, Journal of Agricultural and Food Chemistry 49 (2001) 4349-4351. [5] R. Lopez, M. Aznar, J. Cacho, V. Ferreira, Determination of minor and trace volatile compounds in wine by solid-phase extraction and gas chromatography with mass spectrometric detection, Journal of Chromatography A 966 (2002) 167-177. [6] A.T. Oz, G. Baktemur, S.P. Kargi, E. Kafkas, Volatile Compounds of Strawberry Varieties, Chemistry of Natural Compounds 52 (2016) 507-509. [7] L. Chen, X. Wang, W. Lu, X. Wu, J. Li, Molecular imprinting: perspectives and applications, Chem Soc Rev 45 (2016) 2137-2211.

Dynamic Prediction of Preharvest Strawberry Quality Traits as a Function of Environmental Factors

Fruit quality is of increasing importance for consumers but is a complex trait for growers, as it is affected by environment, genotype, and crop management interactions. Decision support tools, such as computer models that simulate crop growth and development can help optimize production but require further improvement to simulate quality aspects. The goal of this study was to apply the newly developed CROPGRO-Strawberry model in the Decision Support System for Agrotechnology Transfer (DSSAT) model framework and develop a module for the dynamic prediction of quality traits for strawberry. Experimental data from Florida with quality measurements from multiple harvests were correlated with indices based on preharvest weather conditions (temperature, radiation, rainfall) and simulated model parameters (evapotranspiration) during fruit development. Two quality relationships based on linear equations were identified and integrated into the model to simulate strawberry fruit soluble solids content (r2 = 0.89, d = 0.97) and titratable acidity (r2 = 0.55, d = 0.85) based on preharvest temperature. A strategic analysis with historical weather data for a subtropical growing region over a 10-year period showed the importance of seasonal climate variability for simulated strawberry yield and fruit quality across different harvest months. The improved CROPGRO-Strawberry model is the first process-based crop model to predict selected quality traits across multiple harvests throughout the season and can be extended to other crop models for which quality traits are important.

Studies on the Effect of Different Biofertilizers and Organic Manures on Yeild and Quality of Strawberry (Fragaria ananasa Duch.) cv. Chandler under Allahabad Agro Climatic Condition

The present investigation entitled “Effect of Different Biofertilizers and Organic Manures on Growth, Yield and Quality of Strawberry (Fragaria×ananassa Duch.) cv. Chandler.” An experiment was conducted at the research field, Department of Horticulture, Allahabad School of Agriculture, Sam Higgibottom Institute of Agriculture, Technology &amp; Sciences, Allahabad during the year 2015-2016, the experiment was laid out in a Randomized Block Design having 12 treatments three replications of bio-fertilizers and organic manure at different levels. The result revealed that treatment T12 (Phosphobacter 5kg/ha + Azatobacter 5 kg/ha + FYM 6 ton/ha + Vermicompost 3 ton/ha + Poultry Manure 3 ton/ha) was found to be best in terms of maximum plant height (19.67 cm), plant spread (26.43cm), number of leaves (18.13), petiole length (4.96 cm), day to first flowering (67.33), number of flowers per plant (16.80), fruit yield per plant (75.94 g), fruit yield per plot (683.46gm), fruit yield per hectare(6.83 t), TSS (8.54 0 B), acidity (0.46%), pH of juice (4.40). Similarly the maximum gross return (1079250 rupees), net return (696022.95 rupees) and benefit cost ratio (2.77:1) for cultivation of strawberry under Allahabad agro- climatic condition. However, since these findings are based on a one-year experiment, additional trials may be required to support them.

PERFORMANCE OF STRAWBERRY IN A CLOSED LOOP AQUAPONICS SYSTEM

Aquaponics is an innovative technology and a sustainable source of organic food in agriculture that combines aquaculture (fish farming) and hydroponics (soilless plant cultivation). To determine the performance of strawberry in closed loop aquaponics system, an experiment was carried out at newly established aquaponics system at Ornamental plants nursery, Department of Horticulture, The University of Agriculture Peshawar in 2019.Strawberry cv. Chandler was raised from runners in peat moss and seedlings were transplanted at different times in the Aquaponics system i.e., 15th January, 15th February and 15th March. The Experiment was laid out in Randomized complete block design (RCBD) with single factor i.e. Transplantation times with five replications. The analysis of data showed that different transplantation times significantly affected the growth, yield and quality of strawberry. However transplantation of plants on 15th February, resulted in maximum number of leaves plant-1 (7.79), fresh &amp; dry leaves weight plant-1 (29.39 &amp; 4.04 g ), number of fruits plant-1 (20.0), fruit weight plant-1 (140 g), root length (16.69 cm) with maximum fresh &amp; dry root weight (35.74 &amp; 6.32 g). Whereas transplantation of strawberry plants on 15th January took maximum days (100.20) to fruit maturity and produced fruits with minimum fruit weight plant-1 (4.66).However transplantation of strawberry plants on 15th march took maximum days to first flowering (35.00) and produced minimum root length (10.51 cm). It was concluded from the results of experiment that Strawberry cv. Chandler could be transplanted in growing beds of aquaponics system on 15th February for better production under the agro-climatic conditions of Peshawar.

THE EFFECT OF DIFFERENT MOLECULAR WEIGHTS OF CHITOSAN ON THE YIELD, QUALITY, AND HEALTH-PROMOTING PROPERTIES OF STRAWBERRIES

Chitosan could be an alternative to synthetic plant protection chemicals commonly used in strawberry cultivation. The aim of this study was to determine the effect of chitosan with different molecular weights on the yield, health, and quality of Korona cultivar strawberries. The largest number of strawberries was harvested from plants sprayed with chitosan with a molecular weight of 50k kDa (611 g/plant). On the other hand, the largest (1017 g/100 fruit) and the firmest (225 G mm) strawberries were harvested from plants sprayed with chitosan125k kDa. Compared with the control, chitosan with a molecular weight &gt;50 kDa also increased the contents of l-ascorbic acid and polyphenols and the antioxidant activity and improved fruit colour compared with the control. The plants were also more resistant to grey mould infestation. The experiment has shown that how chitosan interacts with fruit depends on its molecular weight, and chitosan with a higher molecular weight has a better effect on most traits determining fruit quality.