Fruit Set Stage Research Articles

Root distribution patterns of reticulatus and inodorus melon (Cucumis melo L.) under subsurface deficit irrigation

Information on root growth patterns is crucial to understand cultivar adaptations to deficit irrigation, particularly for subsurface drip-irrigated crops, where root systems are more confined than furrow or sprinkler systems. A 2-year field experiment evaluated the effect of deficit irrigation (50% vs. 100% crop evapotranspiration, ETc) on root growth of melon (Cucumis melo L.) cultivars (Mission, Da Vinci, and Super Nectar) on a mollisol soil in southwestern Texas, USA. Root length intensity (La; mm cm−2), and root length density (RLD; cm cm−3) were measured at different growth stages using the minirhizotron and soil core methods, respectively. A higher La was recorded in 2012 than in 2011 (3.71 mm cm−2 vs. 0.50 mm cm−2), due to differences in temporal distribution of rainfall between years. Overall, deficit irrigation increased La as compared to 100% ETc, but significant effects occurred at depth (> 40 cm below the soil surface and > 25 cm below the subsurface drip tape). In 2012, moderate water deficit promoted deep root growth at the fruit setting stage but not in 2011, while root growth responses to cumulative deficit varied with cultivar. In 2012, deficit irrigation enhanced root growth in cv. Mission (cantaloupe; reticulatus) throughout the season, it was maintained in cv. Da Vinci (Tuscan; reticulatus), while it decreased in cv. Super Nectar (honeydew; inodorus) at the final harvest stage. Thus, the reticulatus melon cvs. Mission and Da Vinci can better adjust to moderate water-deficit conditions as compared to the inodorus melon cv. Super Nectar. Minirhizotron data provided useful information on root growth dynamics in deeper soil layers in a non-destructive way, which makes it a valuable tool in screening cultivars for water deficit adaptation.

Melatonin Induces Parthenocarpy by Regulating Genes in Gibberellin Pathways of 'Starkrimson' Pear (Pyrus communis L.).

Parthenocarpy, the production of seedless fruit without fertilization, has a variety of valuable qualities, especially for self-incompatible species, such as pear. To explore whether melatonin (MT) induces parthenocarpy, we used ‘Starkrimson’ pear as a material for morphological observations. According to our results, exogenous MT promoted the expansion and division of the mesocarp cells in a manner similar to hand pollination. However, the seeds of exogenous MT-treated fruit were undeveloped and aborted later in the fruit-setting stage. To further investigate how MT induced parthenocarpy, we studied changes of related hormones in the ovaries and found that MT significantly increased the contents of the gibberellins (GAs) GA3 and GA4. Thus, paclobutrazol (PAC), a GA-biosynthesis inhibitor, was used to study the relationship between GAs and MT. In addition, spraying MT after treatment with PAC did not increase GA content nor lead to parthenocarpy. Through a transcriptome analysis, we discovered that MT can cause significant upregulation of PbGA20ox and downregulation of PbGA2ox. However, no significant difference was observed in PbGA2ox compared with the control after PAC and MT applications. Thus, MT induces parthenocarpy by promoting GA biosynthesis along with cell division and mesocarp expansion in pear.

The First Report on Alternate Bearing of Barberry (Berberis vulgaris L.): Change in Total Carbohydrate and Phenolic Contents

Abstract Barberry (Berberis vulgaris L.) fruit is an important source of anthocyanins and is used for consumption and in medicine. However, fruit production of barberry is not regular. Two experiments in four locations were conducted on this plant to explore if it is alternate bearer and also to investigate carbohydrates and phenolics contents in leaves and shoots during growth season. Evaluation of barberry shrubs in three different location showed strong alternate bearing. The value of leaf number to berry number ratio was small. A correlation was found between tree age and alternate bearing index (ABI), because elder shrubs exhibited more ABI. Total carbohydrates and phenolics contents in vegetative organs showed an increase during the fruit setting stage, except for the carbohydrates in shoots. The highest value of carbohydrates was observed 10 days after leaf appearance and then decrease. ON bearing shrubs showed the highest value of total carbohydrates content in leaves during fruit setting stage, after which it decreased. However, OFF bearing shrubs indicated a reducing trend in this variable. In both bearing statuses (ON and OFF trees), total carbohydrates decreased with season progression. It is concluded that this plant is strongly alternate bearer and this characteristic may be related to carbohydrates and phenolics changes in leaf and shoot organs.

Effects of plant biostimulants on fruit set, growth, yield and fruit quality attributes of ‘Orange rubis®’ apricot (Prunus armeniaca L.) cultivar in two consecutive years

Abstract Apricot (Prunus armeniaca L.) is a species particularly prone to erratic production and this behavior has been related to the narrow adaptability of this species. Plant biostimulants are known as organic substances that could enhance growth, development, tolerance to abiotic stresses and crop quality. In this study the effect of three commercial biostimulant products (Hendophyt®, Ergostim®, and Radicon®), compared with control, on fruit set, yield and physical-chemical traits of Orange rubis® apricot cultivar were studied. The investigation was conducted during 2015 and 2016 seasons in a commercial orchard in Cerignola (Foggia district, Apulia region, Southern Italy – 41° 15′ 49″ N; 15° 53′ 59″ E; a.s.l 126 m). Foliar treatments with biostimulants were applied at three times (at red ball, fruit setting and fruit development stages) during each growth season. Other than vegeto-productive behavior, as well as blossoming, fruit set and yield, physical, chemical and phytochemicals parameters (total polyphenols content and antioxidant activity) were evaluated. Fruit set percentage, productivity and qualitative attributes were affected mainly by seasonal growths. Significantly interaction between years and biostimulant applications were noted. All biostimulant treatments gave higher values of antioxidant activity respect to the control.

Reduction of plant water consumption through anti-transpirants foliar application in tomato plants ( Solanum lycopersicum L )

Abstract Optimizing water use efficiency (WUE) is a crucial goal worldwide. However, water savings must not be made at the expense of yield and/or fruit quality to secure economical sustainability for producers. A field study was undertaken to investigate the impact of different anti-transpirants (ATS) on WUE, water requirements (WR), net carbon assimilation rate (P-net), yield and fruit quality of tomato plants (Solanum lycopersicum L.). The aim of this study was to select the most suitable anti-transpirant (AT) that produces a satisfactory yield with less water under field conditions. Three types of ATS were sprayed at first fruit set stage: kaolin (KA) 3% and 5% as a reflective AT, Emulsion of Linus seed Oil tri-ethanolamine (ELO) 1% and 2% as a film forming AT and Fulvic acid (FA) 0.15% and 0.2% as a metabolic AT. The results showed that ATS application increased the relative water content (RWC) especially in the case of FA. However, CO2 assimilation rate was reduced with the minimum reduction observed under FA application. KA application reduced the canopy temperature (Ct) meanwhile, FA and ELO had no effect. ATS significantly reduced tomato WR where irrigation water reduction ranged between 21% up to 28% of that applied to control plants, with or without significant yield reduction or effects on fruit quality parameters depending on the ATs type and concentration. The results indicated that FA at 0.2% gave the maximum reduction in plant WR (28%) and the minimum reduction of P-net (11.13%) and marketable yield (2.3%), consequently WUE was increased by about 33.45% as compared to the untreated plants. Thus, ATS materials can be used to maintain crop yield and increase WUE in the locations where water resources are limited.

IMPACT OF THE INTERACTION BETWEEN AMINO ACIDS (AA), NAPHTHALENE ACETIC ACID (NAA) AND NAPHTHALENE ACETAMIDE (NAD) ON SANTA ROSA PLUM FRUIT ABSCISSION, YIELD AND QUALITY.

To decrease fruit abscission, increase yield and improve fruit quality of Santa Rosa (Prunus salicina Lindl.) plum; amino acids (AA), naphthalene acetic acid (NAA) and naphthalene acetamide (NAD) and a combination of them were applied at different concentrations; at full bloom stage and one week after fruit setting stage during 2015 and 2016, in a private orchard at Ashmoun, Monofia governorate, Egypt. Results indicated that fruit set percentage significantly increased by all AA, NAA and NAD treatments compared to the control. AA 0.25 ml/L+NAA 10 ppm + NAD at 10 ppm recorded the highest significant fruit set percentage and the lowest significant fruit drop percentage and gave the maximum yield (62- 64 Kg/ tree). With regard to fruit quality, the same treatment increased fruit weight, length, diameter, firmness, pulp/stone ratio, and total soluble solids content, but decreased titratable acidity in Santa Rosa plum. In addition, total carbohydrates, total nitrogen, and C/N ratio in leaves were higher in treated trees than the control ones. Anatomical studies indicated that inactive embryo development after ovule fertilization may be the major cause of young fruit drop observed in ‘Santa Rosa’ plum trees. Furthermore, there was a relationship between physiological fruit drop which occurred from the middle of Growth Stage 2 to the beginning of Growth Stage 3, and seed development which contains inactive endosperm. From this study, it can be concluded that the combination of AA, NAA, and NAD increased fruit set, reduced fruit abscission, enhanced C/N ratio in leaves, and improved fruit yield and quality of Santa Rosa plum. Thus, it may be recommended to spray AA 0.25 ml/l +NAA 10 ppm + NAD 10 ppm under similar conditions

Effect of ethephon application on the cellular maturity of Olea europaea L. and on the extractability of phenolic compounds in virgin olive oil

BackgroundThe effect of the ethephon application at fruit set and veraison on cell maturity of Olea europaea L. olives and on the extractability of phenolic compounds (PC) in virgin olive oil has been studied.MethodsThe ethephon was sprayed on olive trees of the Moroccan Picholine at the fruit set stage and on other olive trees at the veraison stage at a concentration of 100 mg/L. The effect of these treatments was evaluated by the fruit yield and the determination of the period of olives growth and ripening. The extractability of the olive oil and the diffusion of the PCs in the fat as well as the embrittlement of the parietal structures are also monitored.Results and conclusionsA chemical thinning is entrained out by ethephon when applied at fruit set (16%) or veraison (12%). It also results in precocious ripening of fruits treated at fruit set (about 2 weeks) and a precocity of the harvest similar to that induced in olives treated at veraison (estimated at 6 weeks). At this stage, a significant increase in the fat accumulation (more than 26 g/100 g in the olives treated compared to 7.7 g/100 g olive pulp in the control) and quantities of extracted oils (87 and 83%, respectively, in the olives treated at fruit set and those treated at veraison compared to 70% in the control) as well as a significant improvement in the extractability of the diffusible PCs in these oils at maturity (540 and 590 mg/kg, respectively, in the treated olives at fruit set and those treated at veraison compared to 216 mg/kg in the control oil).

Efecto de la aplicación foliar de boro en el desarrollo fenológico y cuajado de fruto de gulupa (<i>Passiflora edulis</i> f. <i>edulis</i> Sims)

La gulupa es un frutal nativo producido en Colombia y exportado a diferentes mercados internacionales. Los principales problemas que afectan la producción del cultivo están relacionados con la floración y fructificación, debido a limitaciones nutricionales, como la deficiencia de boro (B). La presente investigación tuvo como objetivo, evaluar el efecto de la aplicación foliar de B en el desarrollo fenológico y cuajado del fruto en plantas de gulupa bajo condiciones de campo. El estudio se llevó a cabo en una plantación experimental del municipio de Pasca (Cundinamarca, Colombia), ubicado a 2.006 msnm. Los tratamientos correspondieron a la aplicación foliar de tres dosis de ácido bórico (0; 0,3; 0,6 y 0,9 kg ha-1) aplicados en la etapa de botón floral y cuajado del fruto, durante dos ciclos productivos. Se evaluaron la longitud de las ramas productivas, el número de entrenudos, el porcentaje de cuajado del fruto, el diámetro del fruto y la emisión de botones florales y frutos. La aplicación foliar de B en las dosis evaluadas aumentó la longitud de ramas secundarias, la emisión de botones florales y frutos, y el porcentaje de cuajado del fruto. Los mejores resultados de crecimiento en el primer y segundo ciclo se lograron con 0,3 kg ha-1; aunque el porcentaje de cuajado del fruto del tratamiento 0,6 kg ha-1 fue óptimo para el primer ciclo de producción (85,19%) seguido por 0,3 kg ha-1 para el segundo ciclo de producción (90%). Los frutos del tratamiento 0,3 kg ha-1 desarrollaron un mayor diámetro ecuatorial desde los 21 días depués de transplante (ddt), alcanzando el máximo diámetro (55,68 mm) a los 136 ddt.

Dissipation of Trifloxystrobin + Tebuconazole WG (Nativo 75% WG) in Pomegranate and Soil in Western Maharashtra

Results of a field experiment conducted during the year 2015 at the Seed Farm, MPKV, Rahuri, Distt. Ahmednagar to determine the residues and dissipation of Nativo 75 per cent WG (trifloxystrobin 25% + tebuconazole 50%) in/on pomegranate and soil are reported. Three sprays of Nativo 75 WG were given @ 300 and 600 g ha−1 at an interval of 10 d initiating first spray at fruit setting stage. Pomegranate samples were collected at 0, 1, 3, 5, 7, 10, 15 and 20th d after the last spray and the soil samples at harvest. The pesticide residues were analysed by using validated QuEChERS method on gas chromatography mass spectrometry. The average initial residues of trifloxystrobin in immature fruits were 0.63 and 1.45 mg kg−1 and that of tebuconazole 1.11 and 2.71 mg kg−1 at the single and double doses. These reached below quantification limit on 15th and 20th d, respectively. The half life values of trifloxystrobin were observed to be 4.17 and 4.55 d and tebuconazole, 4.11 and 4.74 d, respectively. Soil samples collected at harvest did not show any residues of trifloxystrobin, its metabolite CGA-321113 and tebuconazole at their quantification limit.

Growth, yield and fruit quality of Kinnow mandarin as affected through foliar application of zinc and boron

The investigation was undertaken with a view to determine the growth, yield and fruit quality of Kinnowmandarin as affected through foliar application of zinc and boron. The results revealed that combined applicationof 0.2 per cent boric acid + 0.5 per cent zinc sulphate at fruit set and peach size stage of fruit through foliarspray exerted significant influence on plant height, tree spread and shoot length. The maximum fruit retention (71.77%), number of fruits plant−1(486.24), fruit weight (163.23 g), fruit volume (194.79 cc), fruit diameter (7.16 cm), yield plant−1 (79.32 kg) and yield ha−1 (31.73 t) were recorded in treatment T9 (0.2 per cent boric acid + 0.5per cent zinc). The same treatment had markedly influenced the quality of Kinnow fruit and the maximum TSS (12.18 oBrix), TSS/acid ratio (16.66), reducing sugars (3.87%), total sugar (7.22%), ascorbic acid (25.16mg/100 g)and juice content (41.43%) were recoreded in this traetement (T9). The lowest acidity (0.73%) and rind thickness (2.79 mm) were also recorded in treatment T9 (0.2 per cent boric acid + 0.5 per cent zinc). This treatment alsoincreased the zinc (100.08 ppm) and boron (80.81 ppm) level of kinnow mandarin leaves.

Population Dynamics Study of T. absoluta in Western Shewa of Central Ethiopia

Tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is an important pest infesting Solanaceous plants all over the world. It became a problem on tomato crop since 2012 in Ethiopia. For enhancing the IPM control of this pest, very few studies have been conducted for assessing seasonal abundance and spatial distribution in Ethiopia. This study aims to monitor the population fluctuation and infestation rate of T. absoluta on tomato crop under glasshouse and open field conditions. Different stages of T. absoluta were investigated in glasshouse during three plantation periods in 2015-2016 and four plantation periods for open-field study in 2015-2017. Different stages of T. absoluta were investigated in glasshouse and open fields during 2015 to 2017 for six and four plantation periods, respectively. At August 2016 the highest populations of T. absoluta per plant were recorded under glasshouse whereas under open fields the highest populations of T. absoluta per plant were recorded at December and March during 2015-2016. Low number of T. absoluta was recorded in the first cropping cycle at December 2015 and 2016. The field study showed that T. absoluta population progress is increasing during tomato phenologic cycle, the period of peak activities of T. absoluta compromise at vegetative time with flowering and early fruit setting stages of the crop.

Effect of Phenological Stages on Essential Oil Content, Composition and Rosmarinic Acid in Rosmarinus officinalis L.

Rosemary (Rosmarinus officinalis L.) is an important medicinal plant that contained a wide range of secondary metabolites such as rosmarinic acid. In this study, essential oil content and composition and rosmarinc acid were determined at three phenological stages (before flowering, full flowering and fruit set stages). Hydro distillation method was used for essential oil extraction and GC and GC/MS was used for essential oil composition. On the basis of the obtained results rosemary plants in full flowering stage had higher amount of essential oil (1.99 ml/100 g dry weight) than in before flowering and fruit set stages (1.2 and 1.01 ml/100 per g dry weight, respectively). The extracted essential oil was contained 1,8-cineole, α-pinene, verbenone, camphor, geraniol, borneol acetae, camphene and linalool as major constituents. These constituents were affected by phenological stages. Before flowering, 1,8-cineole, α-pinene and verbenone (13.68%), in full flowering, 1,8-cineole (17.90%) and in fruit set α-pinene (21.77%) were the main constituents of the reosemary essential oil. Using HPLC analysis on leaf extract showed that the highest amount of rosmarinic acid (25.92mg/g DW) was observed in the fruit set stage. In conclusion, for essential oil content full flowering stage can be recommended for harvesting of Rosmarinus officinalis L. and for rosmarinic acid, fruit set stage can be the best time for harvesting of this medicinal plant.

Influences of alternate partial root-zone irrigation and urea rate on water- and nitrogen-use efficiencies in tomato

Traditional water and fertilizer inputs are often much higher than the actual demands of tomato, which causes a reduction in water- and fertilizer-use efficiencies. To investigate the advantage of alternate partial root-zone irrigation (AI) on water- and nitrogen (N)-use efficiencies of tomato modified by water and N management, taking conventional irrigation (CI) as the control, the effects of AI on root morphology and activity, fruit yield and water and N use efficiency were studied using pot experiments. There were four combinations of irrigation levels and growing stages of tomato for AI, i.e. AI1 (high water (WH) from blooming to harvest stage (BHS)), AI2 (WH from blooming to fruit setting stage (BFS) and low water (WL) at the harvest stage (HS)), AI3 (WL at BFS and WH at HS) and AI4 (WL at BHS) at three urea rates, i.e. low urea rate (NL), middle urea rate (NM) and high urea rate (NH) in the form of urea. Irrigation quotas for WH and WL in AI at BFS or HS were 80% and 60% of that in CI, respectively. Compared to CI, AI decreased water consumption by 16.0%-33.1% and increased water use efficiency of yield (WUEy) and dry mass (WUEd) by 6.7%-11.9% and 10.2%-15.9%, respectively. AI1 did not decline yield, total N uptake (TNU) and N use efficiency (NUE) significantly. Compared to NL, NM enhanced tomato yield, TNU, WUEy and WUEd by 28.5%, 35.3%, 22.6% and 16.3%, respectively. Compared to CINL, AI1NM reduced water consumption by 12.5%, but increased tomato yield, TNU, WUEy and WUEd by 35.5%, 58.4%, 54.4% and 53.7%, respectively. Therefore, AI1 can improve water use efficiency and total N uptake of tomato simultaneously at medium urea rate. Keywords: alternate partial root-zone irrigation, nitrogen level, nitrogen uptake, tomato, water use efficiency, yield DOI: 10.25165/j.ijabe.20171006.2541 Citation: Liu X G, Li F S, Zhang F C, Cai H J, Yang Q L. Influences of alternate partial root-zone irrigation and urea rates on water- and nitrogen-use efficiencies in tomato. Int J Agric & Biol Eng, 2017; 10(6): 94–102.

Irrigation Management of HLB-Affected Trees

Water is a limiting factor in Florida citrus production during the majority of the year because of the low water holding capacity of sandy soils resulting from low clay and the non-uniform distribution of the rainfall. In Florida, the major portion of rainfall comes in June through September. However, rainfall is scarce during the dry period from February through May, which coincides with the critical stages of bloom, leaf expansion, fruit set, and fruit enlargement. Irrigation is practiced to provide water when rainfall is not sufficient or timely to meet water needs. Proper irrigation scheduling is the application of water to crops only when needed and only in the amounts needed; that is, determining when to irrigate and how much water to apply. With proper irrigation scheduling, yield will not be limited by water stress. With citrus greening (HLB), irrigation scheduling is becoming more important and critical and growers cannot afford water stress or water excess. Any degree of water stress or imbalance can produce a deleterious change in physiological activity of growth and production of citrus trees. The number of fruit, fruit size, and tree canopy are reduced and premature fruit drop is increased with water stress. Extension growth in shoots and roots and leaf expansion are all negatively impacted by water stress. Other benefits of proper irrigation scheduling include reduced loss of nutrients from leaching as a result of excess water applications and reduced pollution of groundwater or surface waters from the leaching of nutrients. Recent studies have shown that for HLB-affected trees, irrigation frequency should increase and irrigation amounts should decrease to minimize water stress from drought stress or water excess, while ensuring optimal water availability in the rootzone at all times.

Citrus Irrigation Management

Water is a limiting factor in Florida citrus production during the majority of the year because of the low water holding capacity of sandy soils resulting from low clay and the non-uniform distribution of the rainfall. In Florida, the major portion of rainfall comes in June through September. However, rainfall is scarce during the dry period from February through May, which coincides with the critical stages of bloom, leaf expansion, fruit set, and fruit enlargement. Irrigation is practiced to provide water when rainfall is not sufficient or timely to meet water needs. Proper irrigation scheduling is the application of water to crops only when needed and only in the amounts needed; that is, determining when to irrigate and how much water to apply. With proper irrigation scheduling, yield will not be limited by water stress. With citrus greening (HLB), irrigation scheduling is becoming more important and critical and growers cannot afford water stress or water excess. Any degree of water stress or imbalance can produce a deleterious change in physiological activity of growth and production of citrus trees. The number of fruit, fruit size, and tree canopy are reduced and premature fruit drop is increased with water stress. Extension growth in shoots and roots and leaf expansion are all negatively impacted by water stress. Other benefits of proper irrigation scheduling include reduced loss of nutrients from leaching as a result of excess water applications and reduced pollution of groundwater or surface waters from the leaching of nutrients. Recent studies have shown that for HLB-affected trees, irrigation frequency should increase and irrigation amounts should decrease to minimize water stress from drought stress or water excess, while ensuring optimal water availability in the rootzone at all times.

A Study on the Effect of Nitrogen Spray at Different Times on Color and Yield Parameters of Grape cv. Pykany

In order to study the effect of nitrogen spray at different times on color and yield parameters of grape cv. Pykany, an experiment was carried out in factorial based on randomized complete block design with four replications in Khalil Abad County in 2015. The treatments included three concentrations of nitrogen (0, 5 and 10 ppm) and three spray times (Late April, before bloom stage, and after pollination and fruit set stage). Color parameters such as brightness rate (L), redness (a) and yellowness (b), chroma, hue angle and browning index were evaluated in this experiment. The results of variance analysis and means comparison showed that the effect of treatment containing spray at concentration of 10 ppm on yield was significant at 1%. There were not significant differences among treatments of urea concentrations and spray times on L and b but different concentrations of urea had significant effect on a* at the level of 1%, so that the highest amount of significant difference was due to the treatment of urea spray at the concentration of 10 ppm and the lowest amount was due to the control treatment. Furthermore, the interaction effect of concentration and different times of nitrogen application on color intensity index was significant at the level of 5%. Based on the results, the effect of different concentrations of urea spray on hue angle was significant at 1% so that the highest level of significant difference was due to the concentration of 10 ppm and the lowest was related to control treatment.

Response of sap flux and evapotranspiration to deficit irrigation of greenhouse pear-jujube trees in semi-arid northwest China

The objective of this study was to investigate the response of sap flux (SF) and evapotranspiration (ET) to deficit irrigation (DI) at different growth stages of greenhouse pear-jujube trees (Zizyphus jujube Mill.). Taking full irrigation (FI) as the control treatment (CK), moderate water deficit (50% of FI) at bud burst to leafing stage (stage I) (T2), flowering to fruit set stage (stage II) (T3), fruit growth stage (stage III) (T4), and fruit maturation stage (stage IV) (T5) were treated on greenhouse 8-year old pear-jujube trees in two growing seasons. Water deficit at different growth stages reduced SF, after the re-watering, SF had significant compensatory effects. Therefore, compared with CK, water deficit treatments (T2–T5) didn’t decrease SF significantly for the whole growing seasons, with maximum decrease of 10.5%. Simultaneously, SF under T2–T5 showed typical diurnal patterns on sunny and cloudy days, and nighttime SF accounted for 23.7%–52.3% of total SF for all the weather conditions. There was significantly positive relationship between SF and reference evapotranspiration, with R2 of 0.349–0.594. Principal component analysis (PCA) indicated that 97% of SF of pear-jujube can be characterized by relative humidity (RH), solar radiation (Rs), air temperature (Ta), and vapor pressure deficit (VPD), and VPD was the main variable affecting SF for all the treatments (P<0.001). Averaging the two years, ET of pear-jujube were 258–288mm for all the treatments, compared with CK, T2–T5 could decrease ET by 2.3%–10.3%.

Effect of pre-harvest spray of calcium nitrate, boric acid and zinc sulphate on storability of Nagpur mandarin (Citrus reticulata Blanco)

An investigation was carried out at Fruit Research Farm, Department of Fruit Science at College of Horticulture and Forestry, Jhalawar during 16 September, 2014 to 1 March, 2015 to study the individual effect of Pre-harvest spray of Calcium nitrate, Zinc sulphate and Boric acid as well as their interaction on Storability of Nagpur mandarin (Citrus reticulata Blanco) after fruit set stage. Among different pre-harvest treatments, T27 treatment (Ca 3.0% + B 0.6% + Zn 0.6%) treated fruits had the longest shelf-life of 15 days at ambient conditions with lowest PLW (9.27 %), decay per cent (15.23 %) and better organoleptic ratting (8.41/10) and higher retention of juice percent (39.12 %) till end of storage period.

Effect of the exogenous application of abscisic acid (ABA) at fruit set and at veraison on cell ripeness of olives Olea europaea L. and the extractability of phenolic compounds in virgin olive oil

BackgroundThe effect of the exogenous application of abscisic acid (ABA) at the fruit set and veraison on the cell maturity of the olive Olea europaea L. and on the extractability of phenolic compounds (PC) in the virgin oil olive was studied.MethodsThe ABA was sprayed on olive trees of the Moroccan Picholine variety at a concentration of 10−3 mg/l, some olive trees are treated at fruit set stage and other olive trees are treated at veraison stage. The effects of these treatments were evaluated by fruit yield and determination of the date of veraison and ripening period of the olives. The extractability of olive oil and diffusion of PC in the latter as well as the weakening of the parietal structures are also estimated.Results and discussionThe application of ABA at fruit set causes a decrease in the production of fruit about 50% and precocity of ripening estimated 45 days. At this stage, comparing with the control in the same period, there was a significant accumulation of fat in olives, an increase in oil extractability and a significant improvement in the diffusion of PC in oils. The treatment of the olives by the ABA at veraison has no effect on yield. However, we observe physiological and biochemical changes to be identical during the treatment by ABA at veraison but smaller than that at fruit set.Graphical abstractEffect of exogenous application of ABA on the ripening of Moroccan Picholine olives and on the extractability of the fat and phenolic compounds in virgin olive oil. ↑, Increase; ∼, environ.

Effect of deficit irrigation on flowering and fruit properties of pomegranate (Punica granatum cv. Shahvar)

Pomegranate is one of the oldest and most valuable fruits and its consumption has been risen recently. Limited water resources in subtropical regions as well as long flowering period of pomegranate trees during the season are two major problems impede the fruit production management. In the present study, the effects of regulated deficit irrigation (RDI: no watering until fruit set stage, while and then watering was applied similar to control) and sustained deficit irrigation (SDI: 50% ETC throughout the growing season) on flowering and fruit characteristics of pomegranate were compared to the control trees (100% ETC throughout the growing season) during two consecutive years (2014/2015). The characteristics of flowers and fruits were studied at three different positions (solitary flowers, as well as terminal and lateral flowers in the cluster). Results showed that RDI trees were under mild water stress early in the growing season (midday stem water potential: −1.4MPa, 2014 and −1.8MPa, 2015) and they recovered immediately after the start of irrigation. However, SDI treatment caused severe (midday stem water potential: −2.1MPa, 2014 and −2.8MPa, 2015) water stress in plants. The RDI treatment reduced early season vegetative growth, postponed the first flowering wave on the one hand and accelerated next blooming wave on the other hand. Thus, the flowering period of RDI trees was shortened in both seasons. In all irrigation treatments under study, the number of lateral flowers was higher than solitary and terminal positions, but its hermaphrodite/male (H/M) sex ratio was lower. The solitary and terminal positions of RDI trees showed the highest value of flower (ovary) width, fruit set, average fruit weight and juice, especially in the second year of experiment. SDI fruits had higher values of total phenolic compounds (TPC) and greater antioxidant activity (AA), while the fruits of control and RDI exhibited the lowest TPC and AA. In the second year, values of fruit number, yield and water productivity (WP) was improved in the control (17.2%, 8.1% and 13.9% respectively) and RDI (15.5%, 19.1% and 5.9% respectively) trees compared with 2014year, but not in SDI treatment. The yield per tree dropped by 36.2% (2014) and 52.1% (2015) in SDI treatment compared to the control trees. In the first year of experiment, WP in deficit irrigation treatments was more than the control trees (58.6% in SDI and 49.7% in RDI), though this value in SDI dropped severely in the second year (22.2%). The results suggest that using RDI strategy has positive effects on pomegranate flowering and fruits, whereas, SDI treatment adversely affect pomegranate production in arid and semi-arid areas.