Fruit Titratable Acidity Research Articles

Potential of sustained deficit irrigation to enhance biological and nutritional quality of pomegranate fruit during storage

BackgroundWhile water availability is important for quality at harvest, it also continues to influence the quality of pomegranates during storage. Reducing the amount of irrigation, in addition to water saving has different effects on bioactive compounds of pomegranate during storage time. This study was conducted to determine the influence of irrigation level on fruit quality changes during storage period of two commercial Iranian pomegranate cultivars (‘Shishecap’ and ‘Malas-Yazdi’). Sustained deficit irrigation (SDI) was applied to plants that received 75% (moderate stress) or 50% (severe stress) of their normal water requirement. A control group received 100% of their water requirement.ResultsAt harvest time and during storage period, fruit weight loss and some biochemical traits such as fruit total soluble solids (TSS), titratable acidity (TA), pH, total phenolic compounds (TPC), total anthocyanins content (TAC), antioxidant activity and vitamin C were measured in pomegranate fruits. Also, the quantity of the produced product was also measured at the time of harvesting. Results indicated that control fruits exhibited more weight loss than those produced under water deficit during the storage period in both years. According to results, fruit TSS, TAC, and antioxidant activity significantly increased during storage period but fruit TA and vitamin C significantly decreased throughout storage period. Also, reduction in irrigation level resulted in a decline in the yield.ConclusionsThis study revealed a crucial link between irrigation level and the quality of pomegranate fruits, despite a reduction in the yield. This included affecting weight loss and the content of bioactive compounds, both at harvest and during storage.

Xanthan gum coatings augmented with lemongrass oil preserve postharvest quality and antioxidant defence system of Kinnow fruit under low-temperature storage

Kinnow mandarin is an important citrus fruit that undergoes various postharvest qualitative losses. Therefore, the present study aimed to investigate the effect of polysaccharide-based xanthan gum (XG) coatings and lemongrass essential oil (LG) on the nutritive quality of Kinnow mandarins stored at 5–7 °C, 90–95 % RH for 75 days. The results revealed that in comparison to control the coatings maintained the fruit titratable acidity (TA), soluble solid content (SSC), ascorbic acid (AsA) content, total flavonoid content (TFC), and juice content, along with reduced weight loss and spoilage incidence. The coated fruits also exhibited higher sensory quality, total antioxidant activity (TAA), and activities of enzymes; catalase (CAT), peroxidase (POD), and phenylalanine ammonia-lyase (PAL). At the end of storage, the fruits coated with XG 1.0 % + LG 1.0 % exhibited maximum TA (0.69 %), AsA content (203.5 mg L−1), and TFC (0.21 mg g−1) with minimum weight loss (7.57 %) and spoilage (3.01 %) and SSC (11.87 %). The scanning electron microscopic (SEM) images of the coated fruits also exhibited smooth surfaces with closed stomata pores. Overall, XG 1.0 % + LG 1.0 % proved as a potential postharvest treatment for maintaining the nutritive quality of Kinnow under low-temperature storage.

Growth and Yield of Strawberry Cultivars under Low Nitrogen Supply in Italy

Nitrogen plays a vital role in plants’ biochemical and physiological functions, and it contributes significantly to increasing plant yield and fruit quality. Plants that efficiently absorb and utilize nitrogen enhance the efficiency of fertilizers, reducing their input costs and preventing ecosystem damage. Thus, an adequate nitrogen supply can significantly improve plant growth, fruit quality, and nutritional value. This research focused on evaluating the plant vegetative and productive performance and fruit quality of three short-day strawberry genotypes (“Cristina”, “Romina”, and “Sibilla”) that were fertilized with different amounts of nitrogen, in a crop that was protected under a plastic tunnel. The trial was conducted during two cultivation cycles. The nitrogen rates were 113, 90, and 68 kg/ha for the first year, and 118, 97, and 76 kg/ha for the second. Reduced nitrogen inputs did not significantly affect plant height, indicating that decreased nutritional intake does not harm plant development. The fruit sugar content value remained stable across all nitrogen supplies, as did the fruit titratable acidity. The cultivars maintained a medium fruit firmness at a 60% nitrogen supply, and the Chroma index was not affected. This study found that reducing nitrogen inputs did not have a significant negative impact on the three tested cultivars, making them suitable for cultivation with reduced nitrogen inputs to reduce the environmental impact and save growers’ inputs.

Analysis of organic acid metabolism reveals citric acid and malic acid play major roles in determining acid quality during the development of kiwifruit (Actinidia eriantha).

Actinidia eriantha is one of the most important kiwifruit species in Actinidia. The relative high accumulation of organic acids in fruit of A. eriantha is an unfavorable factor for organoleptic quality. To identify key metabolic enzymes and genes involved in organic acids accumulation during fruit development, physiological, biochemical, and molecular experiments were conducted for the dynamic fruit samples of a new kiwifruit cultivar, A. eriantha 'Ganlv 1'. The contents of citric acid and malic acid increased greatly during fruit development, while quinic acid content decreased obviously. Significant positive correlations were observed between fruit titratable acidity and the contents of both citric acid and malic acid, and a significant negative correlation was found between fruit titratable acidity and the quinic acid content. The high accumulation of citric acid was found to be caused by the increased activity of citrate synthase (CS), and the decreased activities of two degradation-related enzymes, mitochondrial aconitase and nicotinamide adenine dinucleotide (NAD)-dependent isocitrate dehydrogenase. In addition, the accumulation of malic acid depended mainly on the increased synthesis catalyzed by NAD-dependent malate dehydrogenase (NAD-MDH) and phosphoenolpyruvate carboxylase. Further analysis suggested that AeCS2 and AeMDH2 played pivotal roles in controlling the activities of CS and NAD-MDH respectively. The high accumulation level of citric acid relied on both the strong synthesis ability and the weak degradation ability. The accumulation level of malic acid was mainly affected by the synthesis. The novel information would be helpful for our understanding of the formation of fruit acidity quality. © 2023 Society of Chemical Industry.

Effect of mineral fertilizers on the taste qualities of apple varieties

This article presents the results of a 3-year research study into the effect of soil and foliar application of nitrogen and potassium fertilizers on the taste qualities of the Veniaminovskoe (Rvi6) and Sinap Orlovskii (3×) apple varieties bred at the Russian Research Institute of Fruit Crop Breeding (VNIISPK). The assumption that varietal features are the most important factor that determines taste was confirmed. In addition, the influence of weather conditions of the growing season on the chemical composition of fruits was observed. Thus, the year of 2019 was characterized by the most favorable weather conditions of the growing season. In August, during fruit ripening, the optimum temperature and humidity regime had a positive effect on the accumulation of soluble solids, sugars, and titratable acids in both varieties under study. However, the varieties responded differently to the same doses of mineral fertilizers. The application of fertilizers had no significant impact on the content of the studied components and the sugar-acid ratio in Veniaminovskoe fruits. Conversely, Sinap Orlovsky was found to be responsive to this agricultural practice. In 2019, the joint application of triple foliar and soil fertilizing using N30K40, N60K80, and N90K120 in various doses had a positive effect on the reduction of titratable acidity in fruits of this variety. As a result, the sugar-acid ratio increased by 1.3–1.9 times. Over the entire study period (2017–2019), a significant decrease in the content of sugars in Sinap Orlovsky fruits was observed in the variant with additional foliar fertilizing compared to the control. During the study period, the high doses of N90K120 nitrogen and potassium fertilizers along with foliar application contributed to a significant increase in the sugar-acid ratio in Sinap Orlovsky fruits, which significantly exceeded the control.

The Stability of Important Fruit Traits in Strawberry in Queensland

Information was collected on yield and fruit quality in ‘Festival’, ‘Fortuna’, ‘Red Rhapsody’, ‘Fronteras’, ‘Grenada’ and ‘Petaluma’ strawberry (Fragaria × ananassa Duch.) in southern Queensland, Australia. Marketable yield was similar in the cultivars and ranged from 352 to 416 g/plant. Fruit were smaller in ‘Festival’ and ‘Grenada’ (21.3 or 23.7 g), intermediate in ‘Fortuna’ and ‘Red Rhapsody’ (25.0 or 24.7 g), and larger in ‘Fronteras’ and ‘Petaluma’ (27.6 or 27.8 g). Fruit soluble solids content (SSC) was lower in ‘Fronteras’, ‘Grenada’ and ‘Petaluma’ (6.9% to 7.2%) than in the other cultivars (7.4% to 8.3%). Fruit titratable acidity (TA) was lower in ‘Fortuna’ and ‘Fronteras’ (0.55% to 0.58%) than in the other cultivars (0.63% to 0.69%). The cultivars had similar estimates of stability for fruit weight (0.74 to 1.27) using the method of Finlay and Wilkinson (1963), where a cultivar with a value of one has average stability in a group. This suggests that the cultivars behaved similarly to changes in conditions over the season. The estimates of stability for SSC were lower than one or higher than one in some cultivars (0.45 to 1.75). The estimates of stability for TA were lower than one for some cultivars (0.33 to 1.33). None of the cultivars had high values of fruit quality and stable values of fruit quality for all the three traits. ‘Festival’ would be an acceptable parent in a breeding programme used to increase fruit SSC. In contrast, the other cultivars would be acceptable parents to increase fruit size. Efforts need to be made to develop cultivars with high and stable values of quality and that are suitable for production under global warming.

Quantitative responses of tomato yield, fruit quality and water use efficiency to soil salinity under different water regimes in Northwest China

Reduced irrigation and high soil salinity are widely recognized to decrease tomato yield, but they can improve fruit quality and water use efficiency (WUE) when imposed appropriately. However, the response of plant to their interaction is still unclear, and the quantitative relationship of WUE and fruit quality with salinity under different water regimes is also lacking. This study investigated the responses of tomatoes in terms of yield, fruit quality, and WUE based on yield (WUEy), biomass (WUEb), and leaf (iWUE) to twelve treatments, consisting of combinations of three water regimes relative to the field capacity (FC) (W0, W1, and W2 refer to 95 % FC, 75 % FC, and 60 % FC, respectively) and four soil salinity levels (0 g, 2 g, 4 g, and 6 g salt mixtures added to 1000 g air-dried soil, respectively). Results showed that WUEy and WUEb had a negative correlation with salinity under different water regimes. Salinity resulted in a greater reduction in yield and biomass than water consumption compared to the control treatment. Therefore, lower water consumption of plants under W2 treatment alleviated the decrease of WUEy induced by salinity to a certain extent. From the leaf scale, iWUE was positively and linearly related with salinity, indicating that stomatal regulation was more prone to reduced stomatal conductance than the net photosynthetic rate under W0 and W1. Whilst it showed a quadratic relationship under W2, the results supported that a highly salinity-induced iWUE was dependent on water supply. In addition, although salinity had a negative correlation with fruit fresh mass (FM), dry matter content, and water content (WC) under W0 and W1, fruit titratable acidity (TA) and total soluble solids (TSS) were proportional to salinity regardless of water regimes. The results also showed that W1 increased the sensitivity of TA and TSS to salinity, but W2 resulted in weak sensitivity of FM and WC to salinity. Thus, we deduced that mildly reduced irrigation was an appropriate strategy to regulate iWUE and fruit quality under high salinity conditions. This study provides a water regime management basis for comprehensive changes in yield, WUE, and fruit quality of tomatoes grown in saline soils.

‘Kordia’ sweet cherry fruit quality as function of the rootstock and storage conditions

Sweet cherry fruit of the cultivar ‘Kordia’ derived from trees growing on the GiSelA 5®, Colt and Mazzard F12/1 rootstocks were harvested at the stage of consumption maturity and stored for three weeks in control atmosphere – CA (20% CO2 and 3% O2, RH 90%, 2 ±0.5°C), modified atmosphere packaging – MAP (2–4% CO2, 13–18% O2, 2°C ± 0.5°C) and air atmosphere – AA (RH 80%, 2 ±0.5°C). The rootstocks had a significant effect on all tested fruit quality parameters directly after harvest, except for respiration rate in the first year and fruit titratable acidity in the second year of the study. After sweet cherry storage, the influence of the rootstock on most of fruit quality parameters was proven. The GiSelA 5® rootstock contributed to the preservation of high firmness, high soluble solids content and high soluble solids content/titratable acidity (SSC/TA) ratio. MAP retained good fruit quality, although more favorable quality parameters were recorded after sweet cherry storage in CA, especially with regard to such features as fruit firmness, low respiration rate, small mass loss, low percentage of fungal diseases and good preservation of green color of the stem.

Phenotypic and genotypic characterization to authenticate and trace a high-quality yellow tomato ecotype through the processing chain

In the last few years considerable interest is growing for high food quality, both for organoleptic and nutritional aspects. As for tomatoes, the yellow fruit varieties are conquering the consumer markets in many Mediterranean countries. Among the great variability of yellow tomatoes, one landrace of “Pomodorino giallo del Vesuvio”, named GiaGiù (E40), differs from the traditional “Pomodorino del Piennolo” for the fruit color and stands out for its quality traits, such as high glutamic acid, pectin content and titratable acidity of fruit, thus increasing its demand for both fresh consumption and cooking purposes. The aim of this work was to phenotypically and genotypically distinguish the GiaGiù landrace through morphological descriptors and molecular markers, in order to provide an effective tool to authenticate this product as fresh and processed tomatoes. Morphological characterization evidenced that the distinctive traits of GiaGiù landrace were the potato leaf morphology and the pyriform shape with a pointed apex of the yellow fruits. The genotypic distinction of E40 was performed by using two Cleaved Amplified Polymorphic Sequence (CAPS) markers designed on a Single Nucleotide Polymorphism (SNP) of the Phytoene synthase 1 (psy1) gene that confers the yellow color to tomato fruit and already known as specific of GiaGiù genotype. Additional CAPS markers were designed on two private mutations of E40 genes derived from data retrieved from a Genotyping-By-Sequencing (GBS) dataset, already available. These findings were confirmed by comparing E40 private mutations with the 360 accessions of the BGI tomato 360 genomes resequencing project. The designed markers allowed to distinguish GiaGiù genotype in all fresh and processed fruit tomato matrices, thus representing a molecular tool able to prevent food fraud and authenticate GiaGiù products.

Physicochemical, Morphological, and Functional Characterization of Edible Anthocyanin-Enriched Aloevera Coatings on Fresh Figs (Ficus carica L.).

In the present investigation, Aloe vera gel (AVG)-based edible coatings enriched with anthocyanin were prepared. We investigated the effect of different formulations of aloe-vera-based edible coatings, such as neat AVG (T1), AVG with glycerol (T2), Aloe vera with 0.2% anthocyanin + glycerol (T3), and AVG with 0.5% anthocyanin + glycerol (T4), on the postharvest quality of fig (Ficus carica L.) fruits under refrigerated conditions (4 °C) for up to 12 days of storage with 2-day examination intervals. The results of the present study revealed that the T4 treatment was the most effective for reducing the weight loss in fig fruits throughout the storage period (~4%), followed by T3, T2, and T1. The minimum weight loss after 12 days of storage (3.76%) was recorded for the T4 treatment, followed by T3 (4.34%), which was significantly higher than that of uncoated fruit (~11%). The best quality attributes, such as the total soluble solids (TSS), titratable acidity (TA), and pH, were also demonstrated by the T3 and T4 treatments. The T4 coating caused a marginal change of 0.16 in the fruit titratable acidity, compared to the change of 0.33 in the untreated fruit control after 12 days of storage at 4 °C. Similarly, the total soluble solids in the T4-coated fruits increased marginally (0.43 °Brix) compared to the uncoated control fruits (>2 °Brix) after 12 days of storage at 4 °C. The results revealed that the incorporation of anthocyanin content into AVG is a promising technology for the development of active edible coatings to extend the shelf life of fig fruits.

Profiles of citrus orchard nutrition and fruit quality in Hunan Province, China

ABSTRACT Understanding of orchard nutrition status can facilitate the proper management of orchards for higher fruit yield and quality. From 2011 to 2019, the nutrition status of orchards in Hunan Province, a major citrus-producing area in china, were assessed. A total of 361 soil samples, 378 leaf samples and 285 fruit samples of sweet oranges including navel orange (citrus sinensis l. Osbeck ‘newhall’) and common sweet orange (citrus sinensis l. Osbeck ‘bingtangcheng’), and mandarins including satsuma mandarin (citrus unshiu marc. ‘miyagawa’) and ponkan (citrus reticulata blanco ‘xinnu’) were collected. These samples were from112 sweet orange orchards and 140 mandarin orchards. Parameters of soil, leaf and fruit nutrition and fruit quality were analyzed based on these samples. The results revealed that soil acidification occurred in 79.0% of sweet orange orchards (ph 3.56 to 8.12) and 74.7% of mandarin orchards (ph 2.75 to 8.15). Soil organic matter (om) was abundant in both sweet orange orchards (21.3 g/kg on average) and mandarin orchards (19.77 g/kg on average). Nutrient analysis demonstrated deficiencies of nitrogen (n), potassium (k) and boron (b) in soils and leaves of sweet orange and mandarin orchards. Zinc (zn) was abundant in soils but deficient in leaves, suggesting a low zn utilization efficiency in these orchards. Besides, excessive iron (fe), magnesium (mn) and copper (cu) were found in sweet orange and mandarin leaves, which may be associated with low soil ph and fungicides application in this area. The average contents of n, phosphorus (p) and k in the fruit were about 0.80%, 0.11% and 0.51%, respectively, with a ratio close to 1:0.14:0.6. Multiple linear regression (mlr) analysis revealed that leaf npk and molybdenum (mo) significantly affect fruit fresh fruit weight (ffw) and total soluble solids (tss), and leaf p is closely correlated with fruit titratable acid (ta).

Field inoculation responses of arbuscular mycorrhizal fungi versus endophytic fungi on sugar metabolism associated changes in fruit quality of Lane late navel orange

Arbuscular mycorrhizal (AM) fungi and plants require sugars, especially during fruit ripening stage, while the underlying mechanism influencing sugar accumulation in response to AM fungi is still unclear. The objective of this study was to analyze the field inoculation response of three AM fungi (Acaulospora scrobiculata, Diversispora spurca, and D. versiformis) and an endophytic fungus (Piriformospora indica) on internal as well as external quality parameters of Lane late navel orange (Citrus sinensis) fruits, with emphasis on monosaccharide and disaccharide components and expressions of sucrose-associated enzyme genes and sugar transporter genes. Root fungal colonization rate increased by 51.2−109.6% with the inoculation of D. spurca displaying the best response after two years of field inoculation. The fungal introduction also improved the external fruit quality attributes to some extent, especially longitudinal and transverse diameter, sarcocarp weight, and fruit coloration value in response to inoculation of A. scrobiculata and P. indica. Fruit number increased in response to inoculation with D. versiformis. Although none of the four symbiotic fungi influenced the soluble solids of fruits, however fruit titratable acids registered a significant reduction leading to an increase in soluble solids-titratable acids ratio in response to A. scroblculata and D. spurca. Inoculation with A. scrobiculata and D. spurca also reduced sucrose while increased glucose, fructose, and trehalose concentrations in fruit sarcocarps, along with up-regulated expressions of CsVINV1, CsA/NINV4, and CsSWEET in fruit sarcocarps, suggesting that AM fungi played a pivotal role in sucrose transport, synthesis, and cleavage in fruits. In contrast, inoculation with P. indica only increased the sucrose and up-regulated expressions of CsSPS1 and CsSPS4 in fruit sarcocarps, implying that Pi mainly triggered the sucrose synthesis in fruits. These symbiotic fungi increased concentration of one of the three sweeteners (arabinose, xylitol and fucose) in fruit sarcocarps, with an exception of A. scrobiculata responding to an increase in the three sweeteners. These results provided strong clues that symbiotic fungi have an important role in improving the fruit size and different sugar components in citrus fruits by regulating the expression of genes related to sucrose synthesis, cleavage, and transport, with A. scrobiculata outplaying the response of other three symbiotic fungi.

Maintaining the Quality of ‘Red Jonaprince’ Apples during Storage by 1-Methylcyclopropene Preharvest and Postharvest Treatment

‘Red Jonaprince’ cultivar production is rapidly increasing; therefore, the interest in harvesting in various regions, as well as in improving and maintaining the quality of the apple, is also increasing. The aim of this study was to analyze the possibility of applying 1-MCP treatment in pre- and postharvest treatment for ‘Red Jonaprince’ apples for maintaining the quality of the apple after Ultra-Low Oxygen (ULO) storage. The studied apples were assessed in four groups: 0—control group without any specific treatment applied; group 1—1-MCP applied preharvest; group 2—1-MCP applied postharvest; group 3—1-MCP applied preharvest and postharvest. Measurements were conducted directly after 3, 5 and 6 months of ULO storage and additionally after 7 days of simulated distribution for each period of storage. The 24 groups obtained (four treatments × three storage periods × two simulated distribution periods) were evaluated for firmness, soluble solids content (SSC) and titratable acidity (TA). No statistically significant impact on the SSC of ‘Red Jonaprince’ for all groups was stated (p > 0.05), while for the firmness and TA values, there was a statistically significant impact of applied treatment (ULO storage period and simulated distribution) (p < 0.05). Longer ULO storage as well as longer simulated distribution were associated with decreasing firmness and decreasing TA of apples (p < 0.05). For samples subjected to 1-MCP treatment postharvest and those subjected to 1-MCP treatment preharvest and postharvest combined, the apples in the majority of analyses were protected against decreasing firmness and decreasing TA. It may be concluded that postharvest 1-MCP treatment applied for ‘Red Jonaprince’ apples allows maintaining its quality parameters, including firmness and TA of fruits. Taking this into account, our recommendation is that the postharvest 1-MCP treatment should be sufficient, in order to avoid unreasonable management of 1-MCP, which is not justified to be applied preharvest, or preharvest and postharvest combined, for ‘Red Jonaprince’ apples.

Programas comerciais de resfriamento rápido para manga ‘Rosa’: Impactos na qualidade da fruta

ABSTRACT This study aimed to verify the impact of commercial fast-cooling programs on physicochemical quality of ‘Rosa’ mangoes. The study was carried out in a mango packing house in the São Francisco Valley region, Petrolina, PE, Brazil, between August and October 2018. The experiment followed a randomized block design, with three replicates and one pallet per replicate. The treatments were organized in a factorial scheme 2 × 2 × 3 (two fast-cooling times [120 and 240 min] × two storage times x three positions in the pallet). Sixty mangoes were proportionally distributed in three layers at different heights on each of the six pallets. Three pallets were subjected to fast cooling for 120 min and the other three for 240 min. All fruits were stored for 7 and 14 days at 6 °C plus three days of shelf-life at 20 °C. Regardless of cooling program and fruit position in the pallet, the seven-eighths cooling time (SECT) was not attained. The titratable acidity of fruits under 240-min fast cooling decreased significantly after 14 days of cold storage. Fruit weight loss, pulp firmness, dry matter, and soluble solids content were not affected by the fast-cooling programs, both after storage and during shelf-life period. Commercial fast-cooling program can be performed for 120 min.

Reduced Nitrogen Fertilizer Rates Maintained Raspberry Growth in an Established Field

Optimizing nitrogen (N) fertilizer rates maintains good red raspberry (Rubus idaeus L.) production while alleviating environmental risks. Although raspberry growers in Washington are using the caneberry nutrient management guides derived from western Oregon, these guides may not be appropriate for other production regions given the differences in climate, soil type, and crop productivity. However, limited research has been conducted to observe the impact of the N fertilizer rate on floricane red raspberry growth, yield, and fruit quality in Washington. The aim of this study is to evaluate the response of “Meeker” floricane red raspberries grown in northwest Washington, USA, to different N fertilizer rates in order to provide information for future local nutrient management guides. Treatments of urea (46% nitrogen (N)) were surface-applied to raised beds of established ‘Meeker’ raspberry plots at controls, low, medium, and high rates (0, 34, 67, and 101 kg N ha−1, respectively) in 2019 and 2020. The experiment was arranged in a randomized complete block with three replications. Fruit yield and quality, plant growth and leaf tissue nutrient concentrations, and soil characteristics were evaluated. There were no N fertilizer rate treatment effects for the yield, fruit quality, plant growth, leaf tissue nutrient concentrations, and soil characteristics, except for fruit titratable acidity and soil ammonium (NH4-N) concentrations. The lack of a plant response may be due to nutrients mineralized from soil organic matter (3.81–4.0%) and the utilization of plant nutrient reserves. Based on the results, the soil organic matter level and plant nutrient reserves should be considered when making nutrient management suggestions. Fertilizer costs as well as the potential for environmental pollution from excess fertilizers could be reduced through utilizing these two potential sources of nutrients. Furthermore, longer periods of research is warranted to understand how to adjust N fertilizer rates based on plant and soil characteristics while sustaining yields.

Fruit quality prediction based on soil mineral element content in peach orchard.

Mineral nutrition of orchard soil is critical for the growth of fruit trees and improvement of fruit quality. In the present study, the effects of soil mineral nutrients on peach fruit quality were studied by using artificial neural network model. The results showed that the four established ANN models had the highest prediction accuracy (R 2 = .9735, .9607, .9036, and .9440, respectively). The results of prediction model sensitivity analysis showed that available B, Ca, N, and K in the soil had the greatest influence on the single fruit weight, available Fe, K, B, and Ca in the soil had the greatest effect on fruit soluble solid content, available Ca, N, B, and K in the soil had the greatest influence on the fruit titratable acid content, and available Ca, Fe, N, and Mn in the soil had the greatest effect on fruit edible rate. The response surface methodology analysis determined the optimal range of these mineral elements, which is critical for guiding precision fertilization in peach orchards and improving peach fruit quality.

Pruning intensity on blackberry phenology and production

The study aimed to evaluate the effect of pruning intensity on the phenology and production of blackberry cv. Xavante. The experiment was carried out at the Federal University of Paraná – Palotina, PR, Brazil, during the 2018/2019 season. The completely randomized design was used as a statical model with four treatments and seven replications. The treatments consisted of different number of stems of 1 m height retained per bush after the pruning: 2, 4, 6, and 8, and each plot consisted of one bush. Data collection included: sprouting and flowering (%), number of fruits per bush, fresh weight, total soluble solids content and titratable acidity of fruits. The number of stems per bush significantly influenced the number of shoots, flowers and fruits per bush, titratable acidity, soluble solids and maturation index. Under the growth conditions, the treatments consisted of 2 and 4 stems per bush resulted in more uniform growth development and higher chemical quality of fruits. However, the highest number of fruits per bush was observed when 8 stems per bush were retained.

Tomato growth, yield, and quality response to mixed chemical–organic fertilizers and grafting treatments in a high tunnel environment

Tomato (Solanum lycopersicum L.) is a major vegetable crop world-wide and grown in high tunnels in many regions. This study investigates the use of two fertilizer sources, chemical and integrated (composted poultry manure plus urea) fertilizers, and grafting on growth, nitrate-N content, yield, and fruit quality of tomato grown in high tunnels in northwestern Washington. Grafting treatments consisted of ‘Panzer’ tomato grafted on one of three tomato rootstocks ‘Estamino’, Maxifort’, ‘DRO138TX’, or non-grafted (control). Application of chemical fertilizer increased number of leaves per plant, plant height, and cumulative fresh biomass of pruned suckers relative to tomato plants grown with the integrated fertilizer treatment. Grafted tomato plants had greater plant growth than non-grafted plants throughout the growing season. There was no significant difference between fertilizer treatments on nitrate-N concentration in plant tissue or fresh petiole sap; however, grafted plants contained higher levels of nitrate-N than non-grafted plants. Total and marketable fruit weight and number did not differ due to fertilizer source, but total and marketable fruit weight was higher for grafted plants than for non-grafted plants in 2016. There was no significant effect due to fertilizer source on fruit firmness, water content, pH, titratable acidity, and β-carotene; however, total soluble solids (TSS) and lycopene content were higher for fruit grown with integrated fertilizer in 2016. Grafting enhanced water content of tomato fruit in 2015, and TSS (°Brix) in 2016.

Influences of open-central canopy on photosynthetic parameters and fruit quality of apples (Malus × domestica) in the Loess Plateau of China

Although open-central canopy (OCC) is popular in apple (Malus × domestica) orchards in Loess Plateau of China, its relevant photosynthetic mechanisms have not been elucidated. In this study, changes in photosynthetically active radiation (PAR), gas exchange, chlorophyll fluorescence quenching and fruit quality in apple trees were measured in OCC and compared with those in the conventional condensed round and large canopy (RLC). Results showed that light intercepted at different orientations was 44% higher by OCC than that by RLC. The improved light environment within OCC remarkably increased leaf maximum net photosynthetic rate (Pnmax) and significantly decreased stomatal limitation. Under high light, the ratio of photorespiratory rate to gross photosynthetic rate (Pr/Pg) in OCC was higher than that in RLC. Moreover, reversible component in non-photochemical quenching (r(qE)) was increased, while irreversible component (r(qI)) was decreased in OCC than in RLC. As a result, the fruit quality in OCC was greatly boosted as evidenced by the significantly increased single fruit weight, fruit flesh firmness and fruit soluble solid contents and the sharply decreased fruit titratable acid contents. PAR intercepted by the canopy and the fruit soluble solid contents, leaf Pnmax or single fruit weight were positively correlated, while PAR or Pnmax was negatively correlated with the fruit titratable acid contents. Accordingly, the improved crown light environment and the enhanced leaf photosynthetic performance and photoprotective capacity in OCC led to the boosted fruit quality.

Bacillus subtilis biofertilizer application reduces chemical fertilization and improves fruit quality in fertigated Tarocco blood orange groves

Rhizobacteria have been used for plant growth promotion of horticultural crops. In this field study, we evaluated the effects of liquid Bacillus subtilis commercial microbial fertilizer (BCMF) on fruit quality and plant nutrient status of fertigated citrus groves of Tarocco blood orange (Citrus sinensis (L.) Osbeck). A total volume of 600 mL BCMF per plant (containing over 2.0 × 108 colony-forming units (CFU)mL−1) was applied by diluted to 15 L through an integrated water and fertilizer irrigation system after the schedule of conventional fertilization (CF) of 100 % (CF100 + BCMF) and 50 % (CF50 + BCMF), and 15 L of clean water were used for irrigation after 100 % CF as the control treatments (CK). Both BCMF applications had positive correlation with fruit internal quality parameters, such as fruit maturity index (FMI), juice yield, edible rate, and per fruit weight (PFW), along with improved fibrous root density. However, the application of CF100 + BCMF delayed fruit peel and pulp coloring, and the highest nutrition partition ratio from soil to leaf of N (NNPRsl) and K (KNPRsl) and leaf nutrients concentration of N and K during harvest stage were achieved. In contrast, the CF50 + BCMF treatment led to a simultaneous color change in the fruit peel and the pulp along with a lower NNPRsl during the early stage of fruit ripening and leaf K concentration during fruit ripening due to the reduction of chemical fertilizer application as compared with the CK treatment. Meanwhile, the BCMF applications increased soil available P content and caused fruit titratable acids (TA) reduction. Our results suggest that the influence of B. subtilis biofertilizer application on fruit quality depends on the amount of the chemical fertilizers used, the application of biofertilizers contributes to reducing fertilizer input and exerts positive effects on the fruit quality in fertigated Tarocco blood orange groves.