Tomato Fruit Quality Research Articles

Enhancement of Tomato Fruit Quality Through Moderate Water Deficit

In arid areas, water shortage has become a major bottleneck limiting the sustainable development of agriculture, necessitating improved water use efficiency and the full development of innovative water-saving irrigation management technologies to improve quality. In the present study, tomato (Solanum lycopersicum cv. Micro Tom) fruits were used as materials, and different irrigation frequencies were set during the fruit expansion stage. The normal treatment (CK) was irrigated every three days, while the water deficit treatments were irrigated at varying frequencies: once every 4 days (T1), 5 days (T2), 6 days (T3), 7 days (T4), and 8 days (T5). These corresponded to 80%, 70%, 60%, 50%, and 40% of the maximum field moisture capacity (FMC), respectively, with CK maintaining full irrigation at 90% of the maximum FMC. The water deficit treatment T3, with less stress damage to plants and the most significant effect on fruit quality improvement, was selected based on plant growth indices, photosynthetic characteristics, chlorophyll fluorescence parameters, and fruit quality indices, and its effects on carotenoids, glycolic acid fractions, and volatile compounds during tomato fruit ripening were further investigated. The outcome indicated that moderate water deficit significantly increased the carotenoid components of the tomato fruits, and their lycopene, lutein, α-carotene, and β-carotene contents increased by 11.85%, 12.28%, 20.87%, and 63.89%, respectively, compared with the control fruits at the ripening stage. The contents of glucose and fructose increased with the development and ripening of the tomato fruits, and reached their maximum at the ripening stage. Compared to the control treatment, the moderate water deficit treatment significantly increased the glucose and fructose levels during ripening by 86.70% and 19.83%, respectively. Compared to the control conditions, water deficit conditions reduced the sucrose content in the tomato fruits by 27.14%, 18.03%, and 18.42% at the mature green, turning, and ripening stages, respectively. The moderate water deficit treatment significantly increased the contents of tartaric acid, malic acid, shikimic acid, alpha ketoglutaric acid, succinic acid, and ascorbic acid, and decreased the contents of oxalic acid and citric acid compared to the control. The contents of total soluble sugar and total organic acid and the sugar–acid ratio were significantly increased by 48.69%, 3.71%, and 43.09%, respectively, compared with the control at the ripening stage. The moderate water deficit treatment increased the fruit response values to each sensor of the electronic nose, especially W5S, which was increased by 28.40% compared to the control at the ripening stage. In conclusion, during the ripening process of tomato fruit, its nutritional quality and flavor quality contents can be significantly improved under moderate (MD) deficit irrigation treatment. The results of this experiment can lay the foundation for the research on the mechanism of water deficit aiming to promote the quality of tomato fruit, and, at the same time, provide a theoretical basis and reference for tomato water conservation and high-quality cultivation.

Tomato MADS-RIN regulates GAME5 expression to promote non-bitter glycoalkaloid biosynthesis in fruit.

A well-known defense-associated steroidal glycoalkaloid (SGA) metabolic shift eliminates the bitterness and toxicity of ripe tomato fruits. This study was conducted to clarify the effects of MADS-RIN (RIN) and its cofactors on SGA metabolism in tomato fruits. Using a CRISPR/Cas9-based gene-editing system, we mutated RIN and two cofactor genes (FUL1 and FUL2). The observed changes to fruit color and size in the mutants reflected the overlapping and distinct effects of RIN, FUL1, and FUL2 on fruit ripening. According to a UPLC-MS/MS analysis, the RIN and cofactor mutants had decreased levels of the relatively non-toxic metabolite esculeoside A, but they accumulated toxic SGA pathway intermediates, suggesting RIN and its cofactors are directly involved in esculeoside A biosynthesis. Transcriptome and qPCR analyses detected the downregulated expression of GAME5, which encodes a key enzyme mediating esculeoside A biosynthesis. ChIP-seq and ChIP-qPCR analyses confirmed GAME5 is targeted by RIN. RIN was observed to activate GAME5 transcription by binding to two non-canonical CArG-boxes in the GAME5 promoter. Additionally, RIN promotes SGA metabolism independently of ethylene. Collectively, these findings enhance our understanding of the molecular mechanism governing tomato fruit ripening and SGA biosynthesis. Furthermore, they may be useful for improving tomato fruit quality and safety.

Effect of Black Soldier Fly Larvae Frass as Organic Fertilizer on Postharvest Quality and Shelf Life of Open-field-grown Tomato (Solanum lycopersicon L.)

Open-field-grown tomatoes in Saudi Arabia are stressed by poor soil fertility because of the low organic matter content, low nutrient availability, and high pH. Thus, high chemical fertilizer inputs are crucial for commercial production; however, they cause economic loss as well as negatively affect environmental sustainability. The use of efficient organic fertilizers would be useful for developing more cost-effective, environmentally friendly, and sustainable agriculture. The current study evaluated the impact of Black soldier fly (Hermetia illucens L.) frass (BSFF) fertilizer applications as organic fertilizer on postharvest fruit quality and shelf life of open-field-grown F1 hybrid ‘Sinag Tala’ tomatoes compared with those grown under control treatment (received recommended doses of chemical fertilizers for tomato production under open field conditions). The experiment was conducted using a randomized complete block design with four replicates. The results showed that the application of BSFF fertilizer, especially at the higher rate (5 ton/ha; BSFF3), improved the overall quality of tomato fruit. The BSFF fertilizer treatments reduced weight loss, maintained higher firmness, antioxidants [vitamin C, total phenol content (TPC) and total flavinoid (TFC)], total soluble solids (TSS), and titratable acidity (TA) contents, and lowered the TSS/TA ratio of fruits during shelf life compared with those of the control. The decay incidence was only detected after 9 days of shelf life and was significantly lower in all the BSFF fertilizer treatments (range, 8.40%-12.05%) than in the control (15.9%). In addition, BSFF fertilizer treatments reduced both disease incidence and severity of gray mold following pathogen inoculation during shelf life compared with those of the control. These results might be attributable to the higher antioxidants content (vitamin C, TPC, and TFC) and higher polyphenol oxidase activity in BSFF-fertilized tomatoes. In conclusion, BSFF fertilizer could be used as a potential eco-friendly alternative to chemical fertilizers to improve tomato fruit quality during shelf life.

Amending clayey and sandy soils with nano - bio phosphorous for regulating tomato growth, biochemical, and physiological characteristics

Phosphorus is a critical nutrient that significantly enhances tomato production, so maintaining an adequate level of phosphorus plays an essential role in enhancing the growth of tomato by being present in the soil. This study assessed the impact of soil texture and phosphorus content on tomato plant properties using a factorial, complete, randomized design with four replications. Treatments included clayey and sandy soils with varying phosphorus sources: non-phosphorus (P0), calcium phosphate (CaP1 and CaP2), and nano-hydroxyapatite (PN1 and PN2), where 1 indicates a concentration of 0.12 g and 2 indicates a concentration of 0.23 g per 5-kilogram pot of fertilizer. Results indicated that treatments significantly influenced yield parameters such as average fruit weight, juice content, antioxidant activity, and fruit volume. In the clayey soil, CaP2 treatment had a superior effect on yield, average fruit weight, and shoot fresh weight. In comparison with sandy conditions, CaP2 produced a 50% increase in fruit number, 29% increase in average fruit weight, and 91% increase in fruit yield. The treatments then impacted the shoot fresh weight and root length, while the phosphorus concentration appeared to be more dependent on soil type than on phosphorus sources. Similar to the CaP1 and CaP2 treatments, the PN1 treatment in clay soil also resulted in the highest fresh and dry weights of tomato shoots when compared with the control group. Generally, the findings from this study suggest that the use of CaP2 can serve as a reliable method to improve the growth, yield, and fruit quality of tomatoes, especially in clayey soil environments. However, nano-based phosphorous sources need to be tested more to see if they can improve tomato performance in a range of soil conditions. Also, further research should look into the long-term effects of phosphorous interventions on soil health and sustainability.

Effect of lemongrass and chili pepper oils on the quality of ripe tomato fruits stored under tropical ambient temperature

Postharvest quality of tomato (Solanum lycopersicum L.) fruits treated with lemongrass (Cymbopogon citratus L.) and chili pepper (Capsicum annuum L.) oil was evaluated. Tomato variety Roma fruits of uniform size and weight at the red stage of ripening were overlaid with lemongrass oil only (L1P0), chili pepper oil only (L0P1), or mixtures in a ratio 1:1 (L1P1), and 1:2 (L1P2 and L2P1). Control (L0P0) was not treated with any oil. Treated and untreated fruits were stored at 280±20C and 46%±2 RH for 12 days. Treatments L1P0 and L2P1 oil inhibited postharvest tomato fruit rot for 12 days, whereas L1P2, L0P1, and L1P1 oil and the control showed rot within the range of 86.6% - 100% in 12 days. L1P0 and L2P1 also slowed fruit softening and significantly reduced weight loss, though L1P0 was the most protective. Total soluble solid content of fruit was not affected by both L1P0 and L2P1 throughout storage, but the parameter reduced significantly (p<0.05) in fruits treated with L1P1, L1P2, L0P1 and in control. Reduction in titratable acidity during storage was least in fruits treated with L1P0 followed by L2P1, compared to that in other treatments and the control. This study showed that lemongrass oil applied as surface coating preserved tomato fruit quality in tropical ambient storage conditions for 12 days.

Effect of Tapioca and Tragacanth based edible coatings on the physiological, chemical, microbial, and phytochemical quality of Tomato fruits

AbstractIn recent years, edible coatings have emerged as a promising solution to extend the shelf life, and maintain the quality of fruits and vegetables. The purpose of the study was the development and application of gum Tragacanth and Tapioca‐based edible coatings to extend the storability and quality of tomato (Solanum Lycopersicum L). Different treatments were prepared with combinations of Tragacanth gum (0.5, 1, 1.5 g) and Tapioca (1, 1.5, 2 g). Parameters such as weight loss, sugars, decay percentage, pH, titratable acidity, total soluble solids, antioxidant capacity, phenolic and flavonoid contents, microbial counts, and sensory evaluation were measured during 14 days storage. Results revealed that the application of gum Tragacanth and Tapioca‐based coatings significantly reduced weight loss, decay percentage, and microbial counts of treated tomatoes as compared to the control group. The coated tomatoes exhibited improved sensory features, with a slower rate of softening, during the storage. There was a significant increment in total phenolic and flavonoid contents and antioxidant capacity of coated fruits during 7 days of storage. The observed improvements in the postharvest quality attributes suggest that the gum Tragacanth and Tapioca‐based edible coatings have the potential to retain and enhance the nutritional and bioactive contents and shelf life of tomato.

Hydroxycinnamic Acid Oligomers-Based Biostimulant Nurspray® Enhances Tomato Yield, Fruit Quality, and Reduces Blossom-End Rot

Tomato production faces challenges such as high input costs, pests, diseases, and climate change. Biostimulants like Nurspray®, based on hydroxycinnamic acid oligomers, offer a promising solution. This study evaluated the impact of different application timings of Nurspray® on tomato yield and fruit quality under open-field conditions. Four treatments were tested: T1 (control), T2 (Nurspray® at BBCH 19–51), T3 (Nurspray® at BBCH 19–51–61), and T4 (Nurspray® at BBCH 19–23–51). The results showed significant improvements in root development, canopy cover, and flowering for T3 and T4, with root systems increasing by up to 103% in T4 compared to the control. Fruit yield and quality were enhanced, with a reduction in blossom-end rot (BER) incidence to 0% in T3 and T4, compared to 5% in the control. Additionally, T4 produced the highest dry matter content in fruits. The optimal application strategy was three doses of Nurspray® at BBCH 19–23–51, enhancing both yield and fruit quality. This study highlights the potential of Nurspray® as an organic biostimulant in sustainable tomato farming.

The role of SlCHRC in carotenoid biosynthesis and plastid development in tomato fruit

Chromoplasts are specialized plastids in plants involved in carotenoid synthesis, accumulation, and stress resistance. In tomatoes (Solanum lycopersicum), the Chromoplast-associated carotenoid binding protein (CHRC) regulates chromoplast development and carotenoid accumulation, although its precise mechanisms are not yet fully understood. To investigate the role of SlCHRC in carotenoid biosynthesis, we generated transgenic tomatoes using overexpression (oe-SlCHRC) and CRISPR/Cas9-mediated gene editing (cr-SlCHRC) techniques. The results demonstrated inhibited fruit ripening and delayed onset of color break in both transgenic lines. The oe-SlCHRC lines exhibited increased carotenoid accumulation, particularly (E/Z)-phytoene, lycopene, and γ-carotene, with abundant plastoglobules and carotenoid crystals observed via TEM. In contrast, cr-SlCHRC mutants showed a greener phenotype, reduced carotenoid content, and fewer plastoglobules at the BK + 10 stage. Transcriptome analysis indicated that SlCHRC influences key genes in carotenoid biosynthesis, such as SlNCED2, as well as genes related to chloroplast development, photosynthesis, and plastoglobule formation. Additionally, SlCHRC enhances heat stress tolerance in tomato fruits by upregulating heat shock proteins (HSPs), antioxidants, and proline accumulation. These findings indicate that SlCHRC plays a crucial role in improving tomato fruit quality under heat stress conditions.

A vacuolar invertase gene SlVI modulates sugar metabolism and postharvest fruit quality and stress resistance in tomato

Abstract Sugars act as signaling molecules to modulate various growth processes and enhance plant tolerance to various abiotic and biotic stresses. Moreover, sugars contribute to the post-harvest flavor in fleshy fruit crops. To date, the regulation of sugar metabolism and its effect in plant growth, fruit ripening, postharvest quality and stress resistance remains not fully understood. In this study, we investigated the role of tomato gene encoding a vacuolar invertase, hydrolyzing sucrose to glucose and fructose. SlVI is specifically expressed during the tomato fruit ripening process. We found that overexpression of SlVI resulted in increased leaf size and early flowering, while knockout of SlVI led to increased fruit sucrose content, enhanced fruit firmness, and elevated resistance of postharvest fruit to Botrytis cinerea. Moreover, the content of naringenin and total soluble solids was significantly increased in SlVI knockout fruit at postharvest stage. Transcriptome analysis showed a negative feedback regulation triggered by sucrose accumulation in SlVI knockout fruit resulting in a downregulation of BAM3 and AMY2, which are critical for starch degradation. Moreover, genes associated with cell wall, cutin, wax, and flavonoid biosynthesis and pathogen resistance were upregulated in SlVI knockout fruit. Conversely, the expression levels of genes involved in cell wall degradation were decreased in knockout fruit. These results are consistent with the enhanced postharvest quality and resistance. Our findings not only provide new insights into the relationship between tomato fruit sucrose content and postharvest fruit quality, but also suggest new strategies to enhance fruit quality and extend postharvest shelf life.

Exogenous p-coumaric acid treatment improves phenolic compounds biosynthesis of postharvest cherry tomatoes by regulating physiological metabolism.

To investigate the effect of p-coumaric acid (p-CA) on postharvest cherry tomatoes, breaker stage fruits were treated with p-CA to analyze the physiological metabolism during storage. The results showed that exogenous p-CA treatment improved the sensory quality of tomato fruits. Transcriptomics results indicated that 782 genes (339 up-regulated and 443 down-regulated) were differentially expressed between p-CA treated and control fruits. Results suggested that p-CA treatment regulated the synthesis of phenolic compounds and inhibited the fruit ripening through the pathways of mangiferic acid biosynthesis and phenylalanine metabolism. Key enzymes activities of the phenylpropane metabolic pathway of tomato fruits were increased, including phenylalanine ammonia lyase (PAL), cinnamic acid 4-hydroxylase (C4H), and 4-coumarate-CoA ligase (4CL). In addition, the total phenols content, flavonoids content and antioxidant capacities of tomato fruits were improved with p-CA treatment. Overall, these findings showed that p-CA treatment could be a potential strategy for fruit and vegetable preservation.

Comparative Effects of Calcium, Boron, and Zinc Inhibiting Physiological Disorders, Improving Yield and Quality of Solanum lycopersicum.

Localized calcium deficiency at the tomato flower end causes a physiological disorder called blossom end rot, resulting in yield losses of up to 50 percent. Fruit cracking is another physiological disorder of tomatoes that most often occurs when the movement of water and solutes to the tomato is protracted or rapid, but the underlying cause of fruit cracking is, again, calcium deficiency. Therefore, the present field experiment was conducted with the aim of increasing yield and reducing physiological disorders in tomatoes with a foliar application of calcium and micronutrients (zinc and boron). Four levels of calcium (0, 0.3, 0.6, and 0.9%), three levels of boron (0, 0.25, and 0.5%), and three levels of Zinc (0, 0.25, and 0.5%) were applied foliarly three times (starting at flowering, the 2nd application was repeated when the fruits set, and the 3rd after a period of 15 days from the fruits set). An addition of 0.6% calcium increased yield and associated traits with a decreased flower drop. Likewise, a 0.9% calcium addition increased fruit Ca content and decreased blossom end rot, fruit cracking, and Zn content. Foliar spraying with 0.25% boron (compound B) improved flowering and production while reducing flower drop and tomato fruit cracking. Similarly, an application of 0.5% B significantly increased Ca and B content with minimal blossom end rot and Zn content. Likewise, a 0.5% Zn application resulted in yield and yield-related traits with increased fruit B and Zn contents while blossom end rot, fruit cracking, and fruit Ca content were lower when 0.5% of foliar Zn was applied. Therefore, it is concluded that a foliar application of Ca, B, and Zn can be used alone or in combination to minimize the physiological disorders, increase production, and improve tomato fruit quality.

Jasmonate and salicylic sprays improve cherry tomato fruit productivity and quality in unheated greenhouses

Introduction. Arable regions often have insufficient soil nutrients, which means that fertilizers must be used. However, using fertilizers excessively can harm the environment, human health, and food safety. Natural growth regulators derived from plants are environmentally friendly and reasonably priced. Salicylic acid (SA) and methyl jasmonate (MeJA) phytohormones are crucial for enhancing plant biomass, quality, productivity, and resistance to environmental stresses. Objective. To evaluate the foliar effect of MeJA and SA on fruit quality and production of cvs. colorful tomato under greenhouse conditions. Materials and methods. The trial was carried out in the University of Diyala, Iraq, from 1 December, 2022 to 5 June 2023. Foliar of 0, 200 mg/L SA and or 200 mg/L MeJA was evaluated to determine effects on fruit quality and production of colorful cherry tomato cultivars indeterminate: LA4013, LA353, LA2921, LA3899 and IQ2, with a randomized complete block design with each treatment having three replicates. Results. The cv. IQ2 had the heaviest fruit (82.13 g), highest yield (4.56 kg/plant), total yield (4.56 t/house) and highest treatable acidity (0.62 %). The cv. LA4013 had a higher fruit number (612.88 fruit/plant) and the highest total soluble solids (2.933 %). Foliar of SA at 200 mg/L had the highest chlorophyll index (36.68 SPAD) highest fruits per plant (373.73), highest yield (3.15 kg/plant) and total yield (3.93 t/house). Conclusion. When considering all variables together, the best genotypes were IQ2 and LA4013, which were found to be superior to the other genotypes in quality and yield trials. The 200 mg/L foliar SA improved the yield and quality of cherry tomatoes under greenhouse conditions.

Physiological and Biochemical Effects of Intermittent Warming on 'Marmandi' Turning Tomato Fruits During Low-Temperature Storage

This experiment was conducted on the variety 'Marmandi' turning tomato fruits to investigate the effect of intermittent warming temperatures during extended low chilling temperature storage (21 days) on the subsequent ripening quality of tomato fruits. The quality was measured by assessing the quantitative amount of total phenolic compounds, chlorogenic acid, and ascorbic acid, as well as the development of fruit color and the evaluation of chilling injury (CI) symptoms. The results indicated that the amounts of total phenolic compounds and chlorogenic acid increased significantly during continuous low-temperature storage and after subsequent transfer to room temperature, with this increase being associated with significant loss of ascorbic acid. More frequent periods of intermittent warming (IW) during low-temperature storage were very effective in significantly decreasing the rate of accumulation of phenolic compounds, chlorogenic acid, and ascorbic acid losses. A significant reciprocal relationship between the amounts of chlorogenic acid and ascorbic acid was observed. Additionally, the results showed that as IW time increased, its effectiveness in retarding CI significantly improved.

Enhancing fruit quality and yield in tomato through cyanobacterium mediated nutri-fertigation

Protected cultivation of high-value crops such as tomato, with several health benefits, is gaining global significance. This study explored the influence of aqueous formulations of cyanobacteria-Anabaena laxa (C11), Nostoc carneum (BF2), and Anabaena doliolum (BF4), applied as soil drench at pre-flowering and fruiting stages, on the dynamics of soil and plant attributes important for growth, productivity, and quality of fruits in an indeterminate tomato variety (NS4266) under protected cultivation. Drenching with the BF2 formulation resulted in a significant fold-increase in soil dehydrogenase activity and an increase of 40–45% in soil nitrogen availability; positively impacted glutamine synthetase activity, fruit weight, lycopene content, skin elasticity, in comparison to control. C11 drenching led to a 17% elevation in soil microbial biomass carbon, besides bringing about a 24 and 54% enhancement in available phosphorus and iron content. Additionally, it also enhanced chlorophyll a, b and total pigments by 54–65% over control. Principal Component Analysis (PCA) and Multivariate analysis showcased the distinct effects of cyanobacterial formulations on crop growth and soil fertility, as well as the significant and positive correlations among quality, plant, soil, and yield attributes contributed through cyanobacterial drenching. This investigation highlighted cyanobacterial drench as a promising organic option to augment soil nutrient availability, bolster overall productivity, and enhance fruit quality in tomato grown under protected cultivation.

Enhancing tomato (Solanum lycopersicum) yield and nutrition quality through hydroponic cultivation with treated wastewater

Utilizing treated wastewater for crop cultivation is essential in regions with scarce freshwater resources for irrigation. This study evaluated the growth, fruit yield, nutritional and phytochemical quality of tomato fruits cultivated using a treated wastewater-based hydroponics system developed for the Trans Himalaya, India. Tomatoes grown with treated wastewater exhibited better growth, yield, nutritional content, phytochemical properties, and antioxidant activities than those grown in soil. Specifically, the lycopene and β carotene were significantly (p < 0.05) higher in tomato fruits cultivated in treated wastewater (0.05 ± 0.00 and 0.09 ± 0.00 mg/g) than soil (0.02 ± 0.00 and 0.01 ± 0.00 mg/g). Also, significantly (p < 0.05) higher carbohydrate and protein contents (55.91 ± 1.19 and 21.34 ± 0.31 mg/g, respectively) were obtained under-treated wastewater than soil (39.48 ± 0.07 and 18.52 ± 0.10 mg/g). Similar trends were also obtained in phytochemicals and mineral analysis. However, morphological, proximate, and phytochemical characteristics of tomatoes in nutrient and wastewater-based hydroponics were comparable. Treated wastewater offers eco-friendly benefits for quality crop production.

Pararhizobium sp. strains enhancing chilling stress tolerance and yield in tomato plants

In temperate climates, low temperatures represent a significant stressor that adversely affects crop yield and production. Tomato (Solanum lycopersicum L.) is a subtropical crop cultivated in temperate regions. However, most tomato cultivars are sensitive to chilling temperatures, which limit their cultivation in colder regions. Some microorganism-based plant biostimulants have been reported to enhance abiotic stress tolerance in crops. In this study, we isolated two Pararhizobium sp. strains (44 and 128) and tested their potential to trigger chilling stress tolerance in tomato. Through transcriptional, metabolic and biochemical analyses we demonstrate that inoculation with strains 44 and 128 enhance chilling stress tolerance by stimulating the ICE1-CBF-COR cold stress signaling pathway at transcriptional level, improving reactive oxygen species (ROS) detoxifying capacity and boosting the biosynthesis of stress-protective metabolites, such as polyamines and reduced glutathione (GSH). Treatment of tomato plants with these strains under non-stress conditions also increased tomato fruit weight and quality attributes. These findings suggest that Pararhizobium strains 44 and 128 could be valuable biostimulants for improving chilling stress tolerance and crop yield.

Preharvest applications of monopotassium phosphate to improve fruit quality and volatilome composition in cold-stored cherry tomatoes

The experiment addressed the effects of preharvest KH2PO4 foliar spraying (20 mmol · L−1) on fruit quality and composition (including volatile organic compounds, VOCs) of cherry tomatoes (‘Caravaggio’, ‘Sugarland’ and ‘Top Stellina’) after 0 (S0), 7 (S7) and 14 days (S14) of storage at 8.0 °C. On the average of the 3 genotypes, the KH2PO4 treatment improved fruit pressure firmness, total soluble solids (TSS), titratable acidity (TA), total phenols and carotenoids concentrations, along with the fruits' antioxidant capacity (by up to 17% for FRAP assay). Within the S7–S14 period, control fruits showed the highest reductions in TSS, TSS/TA ratio and total carotenoids (−17, −12 and −45, respectively), whereas treated fruits proved the strongest increase in DPPH (+12%). Sixteen out of 32 VOCs were promoted following KH2PO4 application, including the aldehydes hexanal, (E)-2-hexenal and (Z)-3-hexenal and the apocarotenoids (E)-citral, (E)-β-ionone, geranylacetone and 6-methyl-5-hepten-2-one. Proceeding from S0 to S14, several VOCs decreased more strongly in control fruits, as for hexanal (−48%∖) and total aldehydes (−42%∖, whereas at S14 treated fruits had higher concentrations of linalool, geranylacetone and 6-methyl-5-hepten-2-one (1.06, 52.50 and 79.27 μg · kg−1, respectively). ‘Caravaggio’ demonstrated the strongest apocarotenoid reduction at S14, whereas ‘Top Stellina’ was more responsive to KH2PO4 (mainly for β-cyclocitral, geranylacetone and total terpenes/terpenoids), thus highlighting the central role of the genotype in responding to other experimental factors. Nonetheless, these results suggest that proper preharvest KH2PO4 applications can preserve specific commercial, nutritional and quality traits of cold-stored cherry tomatoes.

Overexpression of SlALC Increases Drought and Salt Tolerance and Affects Fruit Dehiscence in Tomatoes.

The bHLH transcription factors are important plant regulators against abiotic stress and involved in plant growth and development. In this study, SlALC, a gene coding for a prototypical DNA-binding protein in the bHLH family, was isolated, and SlALC-overexpression tomato (SlALC-OE) plants were generated by Agrobacterium-mediated genetic transformation. SlALC transgenic lines manifested higher osmotic stress tolerance than the wild-type plants, estimated by higher relative water content and lower water loss rate, higher chlorophyll, reducing sugar, starch, proline, soluble protein contents, antioxidant enzyme activities, and lower MDA and reactive oxygen species contents in the leaves. In SlALC-OE lines, there were more significant alterations in the expression of genes associated with stress. Furthermore, SlALC-OE fruits were more vulnerable to dehiscence, with higher water content, reduced lignin content, SOD/POD/PAL enzyme activity, and lower phenolic compound concentrations, all of which corresponded to decreased expression of lignin biosynthetic genes. Moreover, the dual luciferase reporter test revealed that SlTAGL1 inhibits SlALC expression. This study revealed that SlALC may play a role in controlling plant tolerance to drought and salt stress, as well as fruit lignification, which influences fruit dehiscence. The findings of this study have established a foundation for tomato tolerance breeding and fruit quality improvement.

Effect of Organic Granules on the Productivity, Quality, and Nutrient Uptake Level of Tomato and the Fertility and Microbial Population of the Soil

Organic vegetable production is needed worldwide to minimize the use of inorganic fertilizers, protect the environment, and produce healthy food. Accordingly, in the present study, the effects of organic granules on the productivity, quality, and nutrient uptake level of tomatoes and the fertility and microbial population of the soil were determined. Briefly, organic NPK granules and organic N, P and K-rich sources were compared with synthetic NPK granules and synthetic fertilizers administered at 100 and 75% of the recommended fertilizer levels. Among the various treatments applied, treatment with 100% of the recommended NPK using the synthetic NPK granules (Urea, DAP and MOP) led to higher growth, yield attributes, and yield (fruit yield, – 24.21 t/ha and stover yield, -15.01 t/ha) of tomato. This treatment also enhanced the nutrient uptake by tomato. However, quality parameters, such as total soluble solids (6.64% ), titrable acidity (0.62% ), ascorbic acid content (14.31 mg/100 g), lycopene content (3.54 mg/100 g), reducing sugars (3.11%), non-reducing sugars (1.02%), total sugar (4.13% ), and shelf life (15.76 days ) of tomato were higher with 100% of the recommended NPK from organic NPK granules than from synthetic granules. This treatment also enhanced the available nutrients and microbial population in the soil. Notably, the same trend was observed for tomatoes fertilized with 75 % of the recommended NPK. The lowest values were obtained with the absolute control. Based on the results of this experiment, the application of 100% of the recommended NPK using organic NPK granules is the best approach to improve the quality of tomato fruits and to enhance the soil fertility.

Combining magnetized water with biodegradable film mulching reshapes soil water-salt distribution and affects processing tomatoes' yield in the arid drip-irrigated field of Northwest China

In arid areas, biodegradable film has recently had the potential to replace polyethylene (PE) film to address plastic pollution. However, the positive effect of biodegradable film on soil moisture and salt control is weaker than that of PE film. Magnetized irrigation water technology is expected to compensate for this limitation. This study comprised a field experiment in 20212023 to study how two types of biodegradable film (M1, black; M2, transparent) and six magnetization intensity on irrigation water (T0, 0 Gs; T1, 1000 Gs; T2, 2000 Gs; T3, 3000 Gs; T4, 4000 Gs; T5, 5000 Gs) affect the degradation rate of biodegradable film, soil watersalt distribution, growth, and quality of processing tomatoes. The traditional PE film mulching and non-magnetized irrigation were used as the control group (MPET0). The results demonstrated that magnetized water irrigation slowed down the degradation rate of biodegradable film. In addition, the magnetized irrigation water can redistributed the soil water-salt patterns under the biodegradable film, improving the soil water content and salt leaching efficiency, with better results in M1 than in M2. Moreover, magnetized water irrigation promoted the growth of tomato leaf area under the biodegradable film, enhancing photochemical efficiency and potential activity of PSII, thereby improving fruit yield, quality, and water use efficiency of tomato. Principal component analysis showed that the comprehensive score of M1T3 treatment was the highest throughout the three years. Furthermore, M1T3 treatment has the highest processing tomato economic benefits during 2021–2023 (24634986 CNY hm2 more than MPET0). Therefore, the use of 3000 Gs magnetized irrigation water combined with black biodegradable film is conducive to improving soil water and salt conditions, reducing residual film pollution, and improving the yield and quality of processing tomatoes, thus ensuring the sustainable development of oasis agriculture.