Fruit Splitting Research Articles

Anatomical features of pericarp and pedicel influencing fruit splitting in Daisy mandarin

Anatomical features of pericarp and pedicel influencing fruit splitting in Daisy mandarin

Shell structure impacts Camellia oleifera fruit splitting during dehydration

This study aims to enhance the processing efficiency of Camellia oleifera fruit by exploring the potential relationship between the splitting characteristics during the dehydration process and the structure of the C. oleifera shell. The analysis focused on understanding the structural changes, moisture transfer, and shrinkage strain of the C. oleifera shell during the shelling processes. The results indicate that the essence of shelling C. oleifera fruit is the uneven shrinkage strain of the shell after dehydration, with the uneven shrinkage of the mesocarp being the primary driving force for the separation of seeds from the shell. Because the cuticle prevents moisture transfer and epidermal cells limit shell shrinkage, the exocarp can restrict the efficiency of the shell shrinkage strain. By damaging the exocarp structure, the shelling efficiency of C. oleifera fruit can be increased by more than 50 % under both natural drying and hot air drying. Moreover, under hot air drying, the shelling efficiency of C. oleifera fruit with a damaged exocarp at a low temperature (55 ℃) is 12.5 % higher than that of undamaged fruit at a high temperature (75 ℃). This study provides new insights into improving the shelling efficiency of C. oleifera fruit.

Physiological and biochemical characterisation of split and healthy Daisy mandarin (Citrus reticulata Burm.) fruits

ABSTRACT Fruit splitting is a prevalent physiological disorder that has a significant impact on Daisy mandarin fruit production, posing challenges to farmers in terms of productivity and economic viability. Despite its impact, no prior research on fruit splitting in Daisy mandarin has been conducted. This study aimed to assess the effect of fruit splitting on quality, morphological characteristics, biochemical composition and nutrient content in Daisy mandarin. In 2022, a comprehensive analysis was conducted on both split and healthy Daisy mandarin fruits, budded on Rough lemon rootstock, to investigate their morphological characteristics, biochemical characteristics, mineral content and cell wall components. Additionally, the study examined the activity of cell wall-degrading enzymes, such as peroxidase (POD), cellulase (Cx) and polygalacturonase (PG). The Results indicated that split fruits exhibited larger fruit size and weight and increased water content in both the fruits and peel compared to healthy fruits. However, split fruits had thinner peel thickness and lower peel content. The peels of split fruits also contained higher level of total soluble sugars, amino acids, and proline content. Furthermore, the peels of split fruits displayed much higher activity of cell wall-degrading enzymes than those of healthy fruits. The nutrient analysis of the split fruits revealed a decrease in boron, calcium and potassium content in the peel compared to healthy fruits. The study provides crucial insights into the mechanisms underlying fruit splitting, identifying biochemical and physiological differences between split and healthy fruits. These findings offer valuable information for developing strategies to mitigate fruit splitting, enhancing fruit quality and reducing economic losses for citrus growers. Future research should explore the genetic and environmental factors contributing to fruit splitting and investigate potential interventions to improve nutrient management and fruit integrity in Daisy mandarin cultivation.

Impact of foliar application of growth regulators on fruit splitting, yield and quality of daisy mandarin (Citrus reticulata)

The experiment was conducted during 2021 and 2022 at the Fruit Research Station, Jallowal-Lesriwal, Jalandhar (Punjab Agricultural University), Punjab to study the effect of foliar application of growth regulators on fruit splitting, yield and quality of Daisy mandarin (Citrus reticulata Blanco). The different concentrations of gibberellic acid (GA3) (10, 20 and 30 ppm), naphthalene acetic acid (NAA) (10, 20 and 30 ppm), ethephon (10, 20 and 30 ppm) and salicylic acid (SA) (100 and 200 ppm) along with control were applied at different developmental stages of Daisy mandarin. The results revealed that the application of salicylic acid at 100 ppm effectively mitigated the severity of fruit splitting in Daisy mandarin during both the seasons and highest fruit weight, number of fruits and maximum fruit yield were observed with foliar application of GA3 at 10 ppm. Regarding the fruit quality attributes including total soluble solids, ascorbic acid, juice and flavonoid content, exhibited superior results with the application of 10 ppm GA3 as compared to untreated plants. The results suggested that application of 10 ppm GA3 and 100 ppm salicylic was effective in enhancing fruit quality attributes and reducing the incidence of fruit splitting in Daisy mandarin.

Fermentasi Kakao di Kelompok Tani Plea Puli Desa Bloro Kabupaten Sikka

Bloro Village is one of the villages in Nita District, Sikka Regency, East Nusa Tenggara Province with the majority of the population working as farmers. The leading commodity in this village is Cocoa. The Plea Puli Farmers Group is one of the farmer groups involved in cocoa cultivation, including the seeding and processing of the results. The Plea Puli Farmers Group has a chocolate industrial house with production products in the form of cocoa powder and chocolate bars. To get a quality chocolate bar and cocoa powder products, you need to pay attention to post-harvest handling, namely cocoa fermentation. Because it is at this stage that determines the precursor to the distinctive taste of cocoa. However, the fact is that most farmers do not ferment properly. This program aims to provide education to farmers about post-harvest handling, especially cocoa fermentation. Through this activity, it is hoped that farmers can understand that to obtain good quality cocoa beans, the thing that must be considered is post-harvest handling, especially cocoa fermentation. This program begins with a discussion with several members of the Plea Puli Farmers Group and the preparation of an activity plan with the farmer group. Followed by the preparation stage, namely preparing tools and materials. At the implementation stage, activities began with socialisation about cocoa fermentation, then continued with harvesting, fruit sorting, ripening, fruit splitting, wet bean sorting, fermentation, and drying activities with the Plea Puli Farmers Group.

Grafted and Nongrafted ‘Cherokee Purple’ Tomato Performance in Aquaponic and Hydroponic Greenhouse Production in Oklahoma

‘Cherokee Purple’ tomato (Solanum lycopersicum L.) plants are a highly sought-after heirloom cultivar in the United States but are low yielding and highly susceptible to soil-borne pathogens, and may benefit from being grafted. Soilless systems such as aquaponics and hydroponics help increase yield, mitigate disease, and serve as an alternative to field production. The objective of this study was to evaluate a grafting combination of ‘Cherokee Purple’ × ‘Maxifort’ and nongrafted controls in 1.85-m2 media grow beds with hydroponic and aquaponic systems using copper nose bluegill in a greenhouse. Grafting increased stem diameter, leaf count, stem height, flower count, and bud count compared with nongrafted plants. In aquaponics, grafting increased the phosphorus uptake over nongrafted plants grown in the aquaponic system. Grafting resulted in greater fresh (49.2%) and dry (40.0%) shoot biomass, and fresh (33.3%) and dry (42.8%) root biomass. Grafting also increased the uptake of copper and sulfur in the aquaponic systems. The hydroponic systems resulted in greater leaf count, soil plant analysis development, stem height, shoot biomass, and greater boron, phosphorus, potassium, iron, and manganese levels than aquaponic systems. Total fruit number and weight were greater in hydroponic systems than in aquaponic systems by 35.4% and 30.4%, respectively, but fruit splitting was a problem in both. Aquaponics resulted in greater root fresh weight than hydroponics. The nutrients zinc and copper increased with the use of aquaponic systems over hydroponic systems. This research suggests that the type of system can affect growth and nutrient uptake, and ‘Cherokee Purple’ should not be used in a soilless system because of excessive fruit splitting, leading to unmarketable fruit and low yield, unless environmental conditions can be managed during the heat of the summer.

Managing Fruit Splitting in Florida Citrus

Sometimes, the fruit on citrus trees will split open, making the fruit unmarketable; splitting can aid fungal and insect pests that subsequently damage fruit. A physiological disorder, pre-harvest fruit splitting begins with nutrient imbalances at flowering. Nutrient deficiencies weaken the rind, causing it to crack if interior parts of the fruit expand too quickly. Symptoms are only visible after it is too late to avoid the problem, but mitigation is still possible. Our goal is to define the problem and suggest management tactics for growers and Extension personnel to avoid or mitigate pre-harvest fruit splitting.

Pomegranate Fruit Cracking during Maturation: From Waste to Valuable Fruits.

The pomegranate is an emerging functional food which is nowadays becoming more and more commercially attractive. Each part of this fruit (peels, arils and seeds) has a specific phytocomplex, rich in anti-oxidant and anti-radical compounds. Among these, punicalagin and ellagic acid continue to be widely studied for their numerous beneficial effects on human health (anti-inflammatory effects, anti-diabetes activity, cardio-protection, cancer prevention). Despite their exceptionally valuable composition and high adaptability to different climatic conditions, pomegranate fruits are highly susceptible to splitting during different stages of ripening, so much so that an estimated 65% of the production may be lost. A "zero-kilometer" approach should therefore be adopted to utilize such a valuable product otherwise destined to be downgraded or even incinerated, with a very high environmental impact. The aim of this work is to highlight and compare the compositional differences between whole and split pomegranates belonging to the cultivar Dente di Cavallo, grown in Apulia (Italy), to assess a valuable role for this split fruit usually considered as waste. The arils and peels are subjected to extraction procedures and the extracts analyzed by CIEL*a*b*, HPLC-DAD and HS-SPME/GC-MS. Moreover, an assessment of the inhibitory activity against α-glucosidase, acetylcholinesterase and tyrosinase enzymes has also been applied. The data show a better chemical profile in split fruits (namely 60% more anthocyanin content than intact fruit) with very interesting results in terms of α-glucosidase inhibition. The juices obtained by squeezing are also compared to commercial juices ("Salus Melagrana" and "La Marianna") processed from the same cultivar and subjected to the same protocol analysis.

Logistic regression analysis of relationship between severity of fruit splitting and mineral element content of Prunus salicina Lindl.

To investigate the relationship between mineral elements and the severity of fruit splitting of Prunus salicina Lindl., 15 orchards with different degrees of fruit splitting were selected and divided into mild, moderate and severe splitting wards. The correlations of the severity of fruit splitting with soil physical and chemical properties and mineral element content in leaves were analyzed by logistic regression analysis. The results revealed that when the content of soil organic matters was high, the bulk density was low and the total porosity was high, or when the calcium (Ca) content in soil and leaves was high, the fruit splitting of Prunus salicina Lindl. was milder. It is worthy of noting that the higher the manganese (Mn) content in soil and leaves, the severer the fruit splitting of Prunus salicina Lindl. Whether its pathogenic mechanism works by inhibiting Ca absorption or triggering Mn toxicity requires further research.

Controlled atmosphere storage impacts fruit quality and flavor chemistry of five cultivars of highbush blueberry (Vaccinium corymbosum)

Changes in highbush blueberry fruit quality and flavor chemistry following air or controlled atmosphere storage was determined for five blueberry cultivars. ‘Duke’, Aurora’, ‘Brigitta’, ‘Jersey’ and ‘Liberty’ fruit were stored for six weeks at 1 °C in chambers containing air or 0, 10.0, 12.5, 15.0, 17.5, or 20.0 kPa CO2 with 10.0 kPa O2. Elevated concentrations of CO2 reduced decay but did not affect fruit splitting, which differed among cultivars. Fruit firmness increased 36% in air-stored fruit, but decreased as CO2 concentration increased being 110% and 83% of initial values in fruit stored in 10 and 20 kPA CO2, respectively. Flesh discoloration increased following storage and in response to CO2 concentration. Sugar and acid content tended to increase in fruit stored in elevated CO2 concentrations but sugar/acid ratio declined. Volatile compounds were monitored using headspace solid phase microextraction-2 dimension gas chromatography-time of flight-mass spectroscopy. Concentrations of aldehydes did not change following storage regardless of atmosphere. Monoterpenoids and ketones declined after storage, but were not effected by storage atmosphere. Alcohols and esters increased after storage and in response to CO2 concentration. Ethanol, acetaldehyde and ethyl acetate increased in response to elevated concentrations of CO2 and were 1,100-, 90- and 150-fold greater in fruit stored in 20 kPa CO2 than in fruit prior to storage. Other ethyl and acetate esters also increased in response to elevated CO2 atmospheres. Differences in CO2 tolerance were observed among cultivars with ‘Liberty’ showing the least expression of fermentation-induced volatiles and ‘Aurora’ the least flesh discoloration. While storage of blueberries in elevated concentrations of CO2 is effective to reduce decay, its effects on fruit flavor must be considered in optimizing storage atmospheres.

Integrated Physiological and Metabolomic Analyses of the Effect of Potassium Fertilizer on Citrus Fruit Splitting.

Potassium (K) nutrition plays a key role in alleviating a variety of peel disorders in tree fruit, but the effect of this nutrient on the physiological and metabolic profiles involved in the fruit splitting of citrus remains unclear. Three levels of K were used to treat citrus ‘Ehime Kashi 34’ (Citrus Nishinoka × C. Shiranui), a hybrid cultivar with fruit that easily split. The results showed that the roots of the treatment with K fertilizer increased the contents of calcium (Ca2+), nitrogen (N), and K in the skin and flesh, the fruit firmness ratio of the peel to the flesh, photosynthetic rate, stomatal conductance, and concentration of intercellular CO2. In contrast, it decreases the relative chlorophyll index and content of Ca2+ in the leaves. Simultaneously, 59 and 13 differentially expressed metabolites (DEMs) were detected in the peel and flesh, respectively, after treatment with K. Of them, five compounds were upregulated, including the synthesis of various amino acids in the peel and the accumulation of various glycoside metabolites in the flesh which were upregulated. The accumulation of levels of gibberellin and glycoside were downregulated. That could be the main reason why potassium alleviates fruit splitting.

CONTROLLING OF FRUIT SPLITTING IN POMEGRANATE (PUNICA GRANATUM L.) BY FOLIAR APPLICATION OF GROWTH REGULATOR AND NUTRIENTS

Various growth regulators have been used to improve the quality of different fruit crops. Foliar spray of macro and micronutrients play an important role in vegetative growth, yield and fruit quality. In the present study, the influence of foliar application of growth regulators and nutrients on fruit splitting and fruit quality was evaluated. For that purpose, Naphthaleneacetic acid (NAA), Potassium nitrate (KNO3) and Boric acid (H3BO3) at the rate of 40 ppm, 1% and 0.3% were used respectively. Spray of chemicals were applied in 2nd and 8th week from full bloom to yield in pomegranate cultivar ‘Golden pearl’. The experiment was designed under Randomized Complete Block Design (RCBD) comprised with seven treatments and replicated thrice. Fruit splitting was reduced (48.68%) significantly with application of KNO3 + Boric acid, while maximum fruit size (60.26 cm2), fruit weight (84gm), fruit grain weight (136.38gm), total soluble solid (TSS) 12.52% and yield (21.9kg/plant) were observed in KNO3 + Boric acid. Moreover, peel weight was increased in control (60.66 gm) and minimum was observed in 48.62 gm in KNO3 + Boric acid. Finally, it is concluded KNO3 %+ Boric acid reveled best results against fruit splitting % and other fruit quality parameters. These findings show that application of KNO3+ Boric acid significantly influences fruit quality of pomegranate when fruit are in the beginning stages of growth and development.

Physiological disorders of selected Citrus fruit species in Sri Lanka and their effect on fruit quality

PurposeThis study was conducted to identify the physiological disorders and their symptoms of selected Citrus fruit species (C. sinensis, C. limon and C. crenatifolia). Furthermore, it was aimed to determine whether physicochemical and sensory properties were affected by physiological disorders.Research methodCitrus fruits with physiological disorderswere observed separately for visible changes and characters were recorded and photographed. Moreover, Citrus fruits with physiological disorders were analyzed for physicochemical and sensory properties.FindingsMany physiological disorders were recorded from three Citrus fruit species including chilling injury, sun burn, stem-end rind breakdown, oleocellosis, rind disorder, puff and crease, granulation, wind injury, peteca, fruit splitting and fruit cracking. Based on the overall result of sensory analysis, it can be concluded that most of the physiological disorders in studied Citrus species appear on the peel but not adversely affect the edible internal portion of the fruits. Physicochemical properties of C. limon are not adversely affected by physiological disorders whereas C. sinensis and C. crenatifolia are affected by physiological disorders.Limitations: Availability of selected Citrus fruit species throughout the year is limited due to their seasonality.Originality/Value: This study provides novel information about the physiological disorders of some Citrus species in Sri Lanka and other parts of Asia and a future potential exists in controlling these disorders to provide healthy and quality fruits to the market.

Crop Regulation in Pomegranate (Punica granatum L.) through Induced Water Stress and Ethrel Application

The present investigation was carried out at ICAR-CIAH, Bikaner, Rajasthan, India during 2017 to 2019 to regulate crop production in pomegranate at the desired period with higher number of bisexual flower for higher quality fruit yield and to minimize fruit splitting through water stress, pruning and ethrel application. Pooled data analysis revealed that horticultural interventions, chemical treatments and their interactions significantly improved plant volume, bisexual flower number, maturity index, fruit yield with significant reduction in fruit splitting, mite and fungal spot incidence. Among different treatment combinations, maximum canopy volume, number of bisexual flowers, maturity index, fruit yield and lower fruit splitting were recorded (8.56 m3, 85.11 plant-1, 47.81, 124.01 q ha-1 and 1.87 kg plant-1) in withholding irrigation during June+pruning+thinning+ethrel 2 ml l-1 as compared to absolute control (3.41 m3, 75.62 plant-1, 33.35, 85.66 q ha-1 and 2.41 kg plant-1), respectively. The mite and fungal spot incidence were recorded minimum (4.72 and 8.50%) in withholding irrigation during June+pruning+thinning+ethrel 3 ml l-1 application in comparison to maximum recorded in absolute control (29.73 and 33.68%), respectively. Therefore, it can be concluded that withholding irrigation during June+pruning+thinning with ethrel 2 ml l-1 treatment significantly improved quality fruit yield with higher number of bisexual flowers and reduced fruit splitting through induction of flowering and fruit growth during optimal climatic conditions.

Cuticle and skin cell walls have common and unique roles in grape berry splitting

The skin protects a fruit from environmental stresses and supports the fruit’s structure. Failure of the skin leads to fruit splitting and may compromise commercial production for fruit growers. The mechanical properties of the cuticle and skin cell walls might influence the splitting susceptibility of fleshy fruits. Thin shell theory and fracture mechanics were utilized in this study to target the potential factors contributing to splitting susceptibility. The study analyzed the structure of the cuticle and epidermis in ripening grape berries and examined the temporal dynamics of berry splitting. Cuticular waxes were partially removed, and skin cell walls were manipulated using wall stiffening and loosening solutions that altered reactions involving hydrogen peroxide. A more than twofold difference in cuticle thickness among grape cultivars did not account for their differences in splitting resistance. However, while removing predominantly epicuticular wax did not alter the berries’ splitting resistance, their surface appearance and increasing yield strength following partial wax removal support the notion that cuticular waxes contribute to berry mechanical properties. Immersing berries in H2O2-based cell wall loosening solutions increased the splitting probability and accelerated berry splitting, whereas cell wall stiffening solutions decreased the splitting probability and delayed berry splitting. These results showed that both cuticle and skin cell walls contribute to the mechanical properties of grape berries and to their splitting resistance. The results also suggest that the two current explanations for fruit splitting, the critical turgor model and the zipper model, should be viewed as complementary rather than incompatible.

EFFECT OF PLANT GROWTH REGULATORS ON FRUIT SPLINTING IN THOMPSON NAVEL ORANGE

Fruit splitting is one of main problems extensively observed in citrus-growing area located in the northern parts of Iran. In order to investigate the effect of 2,4-D and GA3 on incidence of fruit splitting in Thompson ‘navel’ orange, an experiment, as a factorial arrangement in a randomized complete block design (RCBD) with three replications, was carried out in two consecutive years of 2016 and 2017. The main factors of this experiment included timing of spray at different growth stages (full bloom, petal fall, and June drop), 2, 4-D (0, 10, 20 mg L–1), and GA3 (0, 50, and 100 mg L–1). In the end of experiment, the characteristics including fruit length, fruit diameter, rind thickness, cellulase and polygalacturonase activities, total soluble solid, percentage of split fruit, and fruit yield were measured. Results showed that using 2, 4-D and GA3 not only decreased the rate of fruit splitting but also increased fruit yield as compared to controls. The highest fruit length, fruit diameter, rind thickness, total soluble solid and the lowest activities of cellulase and polygalacturonase were obtained using 100 mg L–1 GA3 and 20 mg L–1 2, 4 D during the full bloom. In general, the results revealed that using 2, 4-D and GA3 during the full bloom increased fruit yield while reduced fruit splitting and maintained the qualitative characteristics of Thompson ‘navel’ orange.

Performance and Phytochemical Content of 22 Pomegranate (Punica granatum) Varieties

Pomegranate is a drought-tolerant and salt-tolerant crop. Its fruits contain high levels of phytochemicals that have many health benefits. Pomegranate has the potential to be an alternative crop in areas where water availability is limited, such as west Texas. However, more than 500 pomegranate varieties are estimated to exist worldwide, and little is known about which varieties are suitable for growing in the west Texas region. Therefore, the objective of this study was to evaluate the field performance of 22 pomegranate varieties, specifically based on phenology, resistance to sunburn, fruit split, fruit rot (resistance was calculated by subtracting the percent incidence by 100), yield, fruit phytochemicals, and Brix over the course of 3 years from 2016 to 2018. Cold damage, caused by below-freezing temperatures encountered from Nov. 2018 to Feb. 2019, was also evaluated in Apr. 2019. Our results showed significant varietal differences in nearly all response variables measured, indicating that varietal selection is important for pomegranate production for specific regions, such as west Texas. Leaf budding ranged from 47 to 62 days in 2016, 41 to 54 days in 2017, and 49 to 60 days in 2018. Anthesis ranged from 87 to 119 days in 2016, 80 to 94 days in 2017, and 92 to 114 days in 2018. Fruit resistance to split was broad and ranged from 7.3% to 79.1% in 2017 and from 14.2% to 99.7% in 2018. Fruit sunburn resistance ranged from 14.0% to 64.6% in 2017 and from 28.3% to 90.0% in 2018. Fruit heart rot incidence was nominal for all varieties. Total phenolic compound contents of the pomegranate fruit juice ranged from 0.81 to 1.52 mg GAE/mL, and the total antioxidant capacity ranged from 3.44 to 6.81 mg TE/mL. The yield per tree ranged from 1.00 to 7.96 kg in 2017 and from 0.81 to 10.26 kg in 2018. Brix ranged from 12.5% to 17.4% in 2017 and from 13.9% to 18.4% in 2018. Early winter below-freezing temperatures caused different degrees of cold damage; however, 5 of 22 varieties that originated from Russia did not show any cold damage. Results of a hierarchical cluster analysis based on the means of the key response variables of yield and Brix indicated that four varieties (Al-Sirin-Nar, Russian 8, Ben Ivey, and Salavatski) were notable for having both high yield and high Brix.

DETERMINING OF THE FRUIT CHARACTERISTICS OF PISTACHIO GRAFTED ON WILD Pistacia terebinthus L. UNDER THE CENTRAL KELKIT BASIN/TURKEY ECOLOGICAL CONDITIONS

The study was carried out to determine fruit quality characteristics in „Uzun” pistachio cultivar grafted on terebinth rootstock (P. terebinthus L.) in Suşehri under Central Kelkit Basin/Turkey ecological conditions in 2017. In the study, it was determined that the ratio of the split fruit was 80%; the blank fruit ratio was 8%; nut weight was 0.93 g; kernel weight was 0.50 g and kernel ratio was 53.8%. As a result of analyses, it was assessed that the fruit consists of 19.39% protein, 3.74% moisture, 2.38% ash, 53.30% fat, 7182.45 mg/kg potassium, 4046.79 mg/kg phosphorus, 1592.96 mg/kg calcium, 974.35 mg/kg magnesium, 16.14 mg/kg iron, 4.42 mg/kg manganese, 11.38 mg/kg copper and 27.05 mg/kg zinc. It was determined that the total phenolic content was 1989.8 mg GAE kg–1 dw, the total flavonoid content was 363.0 mg QE kg–1 dw; DPPH was 30.9 mmol TE kg–1 dw; FRAP was 36.2 mmol TE kg–1 dw.

Effect of some Drip Irrigation and Nano-Silicon Treatments on Growth, Yield and Water Relations of ''Washington Navel'' Orange Trees Grown in New Reclaimed Soils

The deficiency of irrigation water is a main factor of limiting the growth and production of fruit trees, particularly in arid and semi-arid areas regions. So this study was conducted in order to assess the influence of applying silicon in the nano form to minimize the negative effects caused by water stress. A field trial was behaved in 2016 and 2017 seasons at Beheira Governorate to study the effect of three rates of drip irrigation viz.high irrigation rate (control=100%) and two deficit irrigation regimes (75 and 50% from the control), foliar application of nano- silicon (0, 100, 200 and 300ppm) and their interaction on growth, yield and water relations of ''Washington Navel'' orange trees grown in sandy soil and irrigated by drip irrigation method. The findings showed that, deficit irrigation treatment (I3) was related with reduced vegetative growth aspects (canopy volume, No. of shoots /branch, Shoot length) as well as stomatal resistance, however transpiration rate was increased in both seasons, in addition, nano-silicon spraying at 300 or 200ppm caused a significant increase in previous growth aspects over the control.The combination between high or moderate irrigation rate (I1 or I2) with nano-silicon spray at 300 ppm (S4) were more effective in enhancing growth parameters. In both seasons, deficit irrigation treatment (I1) decreased leaf mineral contents and increased leaf proline content. However, high concentration of nano-silicon markedly increased leaf mineral contents but reduced leaf proline contents. Both low and high irrigation rates (I2 and I3) or high concentration of nano-silicon (S4) and their interaction achieved the highest values of bound water and osmotic pressure and the lowest values of total and free water contents. Furthermore, the yield and components, water use efficiency and most of external and internal fruit properties were significantly increased under moderate irrigation (I2) or high concentration of nano-silicon and their interaction (I2 xS4), while, the percentage of fruit splitting was decreased. Finally, trees irrigated with moderate irrigation rate combined with nano-silicon at (300 ppm) enhancement the growth, yield and fruit properties. On the contrary decreased fruit splitting(%) and applied irrigation water by 25% , whereas, increased water use efficiency compared to high irrigation rate (control) without nano-silicon spray.

Irrigation Regime and Soil Conditioners Impact on Characteristics of Sandy Soil and Washington Navel Orange Trees

Due to limited water resources it has become needed to study the best ways to decrease irrigation water use, increasing the water use efficiency, improve tree growth and sustain citrus crop production under those circumstances. Afield experiment was conducted during 2015/2016 and 2016/2017 seasons at El-Nubaria city, Beheira Governorate to investigate the effect of irrigation regime (80% and 60% from full irrigation) and soil conditioners (hydrogel at rate of 50 and 100g/tree as synthetic water absorbing soil amendments or organic plant residues at rate of 3.5 and 6.5kg/tree as natural absorbing soil amendments) on some properties of sandy soil, growth, yield, quality and productivity of irrigation water (PIW) for Washington navel orange trees under drip irrigation system. The obtained results pointed out that: The application of soil conditioners led to enhancing the properties and microorganisms activities and macronutrients of sandy soil especially with the high rates. Whereas, the low values of soil field capacity (10.47%), wilting point (4.26%) and available water (6.21%) were recorded with full irrigation without conditioners while, the high values (11.31 to 12.28%), (4.35 to 4.68%), (6.78 to 7.62%) respectively under irrigation regime combined conditioners. Soil conditioners application combined with irrigation regime increased the available nitrogen (up to 22.76%, phosphours (up to 9.98%), potassium (up to 15.14%), organic matter (up to 41.79%, CEC (up to 16.53%) and salinity (up to 4.64%) while soil bulk density was decreased (up to 5.66%) compared to full irrigation without conditioners. Moderate irrigation plus organic plant residues at rate of 6.5 kg/tree (T5) or plus hydrogel at 100g/tree (T3) significantly increased the most growth parameters (canopy volume, number of shoots/branch and leaf area), fruit set and decrease the fruit drop. Lowest percentage of fruit splitting (6.58 and 5.87 %) coated with T3 and T5 compared to deficit irrigation treatments plus the lowest rate of hydrogel or organic plant residues (T8 and T9). The highest yield was obtained by T3 (78.6 kg/tree) and T5 (79. 6 kg/tree). Control treatment (T1) followed by T3 and T5 tended to improve the physical fruit quality meanwhile deficit irrigation treatments T8 and T9 increased the most of chemical fruit quality. PIW mean values of Washington navel orange with full irrigation without conditioners were low (2.75 kg m-3) while, irrigation regime at 80 % and 60% recorded high values (3.49 kg m-3 and 3.88 kg m-3, respectively). PIW was increased with the high rates of soil conditioners.