Ethephon Sprays Research Articles

Increasing Productivity and Fruit Quality of ‘Mutsu’ Apple Orchard by Dwarfing Treatments

The aim of this 2022 study was to evaluate the effect of tree growth-limiting treatments on the tree yield and quality of ‘Mutsu’ apples. The experiment was established on 7-year-old trees on M.9 rootstock in a commercial orchard in Wilga near Warsaw. Growth-limiting treatments included unilateral root pruning, spraying the trees with Regalis Plus 10 WG at various times, and spraying with Flordimex 480 SL. Eight combinations were used, with four replicates of 20 trees per repetition. The measurements included fruit set, length of this year’s shoots, yield per tree, average fruit weight, and the size structure of the yield. The distinctive physiological status of the apples was assessed directly after harvest, directly after 8 months of storage under CA conditions (1.5% CO2, 1.5% O2, 1 °C, >92% RH) and after an additional 7 days of shelf-life. Spraying trees with Regalis Plus 10 WG from the balloon stage onwards, irrespective of the treatment with root pruning, was most effective in both inhibiting long-stem growth and increasing tree yield (by almost two times) by increasing the number of apples per tree. The growth response of long-stemmed apple trees to both unilateral root pruning and Ethephon spray was significantly lower than it was to Regalis Plus 10 WG spray and had relatively little effect on their yield. Regalis Plus 10 WG resulted in a clear reduction in average fruit weight (by about 100 g), which, in the case of the large-fruited cultivar ‘Mutsu’, should be seen as an advantage. Its application from the balloon stage onwards promoted higher apple firmness at harvest and after simulated handling preceded by long-term storage.

Preharvest application of ethephon improved growth, maturity and quality of banana

Poor yield, non-uniform ripening, and delay in maturity are some serious issues faced by commercial banana growers in the country. This research was conducted in a commercial banana orchard of Chitwan from December 2021 to April 2022 in order to study the effect of different doses of ethephon on growth, maturity, and quality of banana. Five different doses of ethephon (200, 400, 600, 800, 1000 ppm) were sprayed on a banana bunch at 15th days after shooting which were compared with the control (no ethephon treatment) in RCBD design. The maturity of the bunch was significantly hastened at a higher concentration of ethephon (above 600 ppm). Fruit length and fruit weight were also observed higher at 600 ppm (10.21 cm and 62.68 g) and 800 ppm (10.67 cm and 63.26 g) ethephon spray. The bunch treated with 600 ppm ethephon had the highest TSS (10.78oB and 23.27oB at 0 and 5 days of storage, respectively) and PPR (1.65). Considering quantitative and qualitative parameters, preharvest ethephon spray @600 ppm significantly improved growth, maturity, and quality of banana fruits.

Effects of Spraying with Ethephon and Early Topping on the Growth, Yield, and Earliness of Cotton under Late-Sowing and High-Density Cultivation Modes

Late-sowing and high-density cultivation are typical cotton planting models that are widely applied in the Yellow River Valley of China. The model can easily lead to late maturity and reduced yields. Plant topping and ethephon spraying have been shown to improve cotton earliness and yields. However, the optimal topping date and ethephon concentration are yet to be established. A two-year field experiment (2020–2021) was thus conducted to assess the effects of spraying high-concentration ethephon and early topping on the growth, yield, and earliness of cotton under late-sowing and high-density cultivation models. The experiment employed a split-plot design, in which the main plots were sprayed with varying ethephon concentrations (2000 mL/ha, E2000; 4000 mL/ha, E4000; 6000 mL/ha, E6000), while subplots were plant topping dates (T13, 13 July, early-topped; T20, 20 July, suitable-topped; T27, 27 July, late-topped). Higher ethephon concentrations (E4000) increased the earliness of early-topped (T13) plants. Boll-setting and boll-opening rates increased by 12.00% and 16.83% in T13 plants, respectively, relative to T27 plants. However, the shedding rate for T13 plants decreased by 12.00%. Earliness and harvest index (HI) for the T13 plants were higher than those of the T27 plants by 8.01% and 18.91%, respectively. Even though the T13 plant yield decreased slightly, their boll weight increased by 3.99% and 12.27%, respectively, relative to those of the T20 and T27 plants. Earliness increased with increasing ethephon concentration. In conclusion, early topping and higher ethephon concentrations can effectively improve cotton yield and earliness.

Effect of Plant Density and Spraying with Ethephon on Yield and its Components of Sorghum (Var. Bohooth .70)

A field experiment was carried out during the spring and autumn season 2021 in Al-Kut region - Wasit Governorate, to study the effect of plant densities and ethephon spraying on the yield and yield component of Sorghum (var. Bohooth 70). The experiment was applied according to a randomized complete block design (RCBD) in a split split plots design with three replications. The main plots included three plant densities (80000, 66666 and 50000 plants.ha-1), while the sub plots included three stages of ethephon spraying (4, 8 and 12 leaf per plant). Sub-sub plots included three concentrations of ethephon (0, 800, 1600 ppm). The results showed that the lower plant density (50,000 plants.ha-1) led to a significant decrease in plant height and the rate of lying, and a significant increase in yield per plant, weight of 1000 grains, and number of grains per head. Spraying ethephon increased the yield per plant, weight of 1000 grains, number of grains per head and yield of grain (t.ha-1). On the other hand, there was a significant relationship between the concentration of ethephon and the decrease by plant height and the rate of lying when sprayed at the stage of 4 and 8 leaves. It can be concluded from this study that plant height and lying ratio can be reduced when using low density with ethephon spray during early growth stages for economical grain production.

Using brassinolide and girdling combined application as an alternative to ethephon for improving color and quality of 'Crimson Seedless' grapevines

AbstractThe color of 'Crimson Seedless' berries is a major constraint in expanding marketing and export potential. The target of this investigation is to enhance the color and quality of 'Crimson Seedless' by using brassinolide (BL) and girdling treatments, individually and in combination, as an alternative to ethephon over two consecutive seasons. The obtained results revealed that the combined treatment BL at 2.0 mg/L and girdling recorded the highest significant yield values (17.78 ± 0.29 and 18.26 ± 0.23 kg/vine) in both seasons, respectively, in contrast to ethephon and girdling treatments which had no significant influence. Besides, BL 2.0 mg/L + girdling presented high levels of physicochemical characteristics of clusters and berries compared to the control. Concerning berry color assessment, ethepon followed by BL at 2.0 mg/L + girdling recorded the highest significant improvement in the red color, as indicated by Color Index of Red Grapes and visual assessment, and had similar and elevated levels of anthocyanin content. On the other hand, flavonoids (3.46 ± 0.03 and 3.66 ± 0.02 mg/100 g FW), and antioxidant capacity (2.37 ± 0.02 and 2.43 ± 0.06 IC50) were obviously increased with BL 2.0 mg/L + girdling, with a slight decrease than ethephon application. As for phenylalanine ammonia-lyase activity, the data show that it increased by ethephon (7.91 ± 0.02 and 8.01 ± 0.02 U mg−1protein) and BL 2.0 mg/L + girdling (7.77 ± 0.04 and 7.79 ± 0.07 U mg−1protein), compared to the control (3.69 ± 0.02 and 3.80 ± 0.01 U mg−1protein) in both seasons, respectively. In terms of polyphenol oxidase activity, the increase in PPO was closely associated with PAL. Moreover, BL 2.0 mg/L + girdling was the most effective treatment for increasing dormant season parameters in both seasons, while ethephon spraying had no influence. All these confirmed that the combined treatment BL 2.0 mg/L + girdling exhibited a synergistic effect in improving the color and quality of 'Crimson Seedless'.

Metabolic and Transcriptomic Analyses Reveal the Effects of Ethephon on Taraxacum kok-saghyz Rodin

The roots of Taraxacum kok-saghyz Rodin (TKS) are well-known and valued for their rubber-producing ability. Therefore, research on the analysis and detection of metabolites from the roots of TKS have been reported in previous studies. However, all of these studies have the shortcoming of focusing on only the rubber of TKS, without profiling the other metabolites in a systematic and comprehensive way. Here, the primary and secondary metabolites from the leaves of TKS were investigated using UPLC–ESI–MS/MS, and a total of 229 metabolites were characterized. Carboxylic acid derivatives, fatty acyls, phenols, and organooxygen compounds were found to be the major metabolites of TKS. The transcriptome data indicated that ribosomal, glycolysis/gluconeogenesis, phenylpropanoid biosynthesis, and linoleic acid metabolism genes were significantly differentially expressed. This study is the first to report the differences in the metabolic and transcriptome profiles of TKS leaves under exogenous ethephon spray, which improves our understanding of the main metabolites and their molecular mechanisms in TKS leaves.

Differential Regulation of NAPDH Oxidases in Salt-Tolerant Eutrema salsugineum and Salt-Sensitive Arabidopsis thaliana.

Reactive oxygen species (ROS) signalling is crucial in modulating stress responses in plants, and NADPH oxidases (NOXs) are an important component of signal transduction under salt stress. The goal of this research was to investigate whether the regulation of NOX-dependent signalling during mild and severe salinity differs between the halophyte Eutrema salsugineum and the glycophyte Arabidopsis thaliana. Gene expression analyses showed that salt-induced expression patterns of two NOX genes, RBOHD and RBOHF, varied between the halophyte and the glycophyte. Five days of salinity stimulated the expression of both genes in E. salsugineum leaves, while their expression in A. thaliana decreased. This was not accompanied by changes in the total NOX activity in E. salsugineum, while the activity in A. thaliana was reduced. The expression of the RBOHD and RBOHF genes in E. salsugineum leaves was induced by abscisic acid (ABA) and ethephon spraying. The in silico analyses of promoter sequences of RBOHD and RBOHF revealed multiple cis-acting elements related to hormone responses, and their distribution varied between E. salsugineum and A. thaliana. Our results indicate that, in the halophyte E. salsugineum, the maintenance of the basal activity of NOXs in leaves plays a role during acclimation responses to salt stress. The different expression patterns of the RBOHD and RBOHF genes under salinity in E. salsugineum and A. thaliana point to a modified regulation of these genes in the halophyte, possibly through ABA- and/or ethylene-dependent pathways.

Ethephon-Induced Ethylene Enhances Starch Degradation and Sucrose Transport with an Interactive Abscisic Acid-Mediated Manner in Mature Leaves of Oilseed rape (Brassica napus L.).

The leaf senescence process is characterized by the degradation of macromolecules in mature leaves and the remobilization of degradation products via phloem transport. The phytohormone ethylene mediates leaf senescence. This study aimed to investigate the ethephon-induced ethylene effects on starch degradation and sucrose remobilization through their interactive regulation with other hormones. Ethephon (2-chloroethylphosphonic acid) was used as an ethylene-generating agent. Endogenous hormonal status, carbohydrate compounds, starch degradation-related gene expression, sucrose transporter gene expression, and phloem sucrose loading were compared between the ethephon-treated plants and controls. Foliar ethephon spray enhanced the endogenous ethylene concentration and accelerated leaf senescence, as evidenced by reduced chlorophyll content and enhanced expression of the senescence-related gene SAG12. Ethephon-enhanced ethylene prominently enhanced the endogenous abscisic acid (ABA) level. accompanied with upregulation of ABA synthesis gene 9-cis-epoxycarotenoid dioxygenase (NCED3), ABA receptor gene pyrabactin resistance 1 (PYR1), and ABA signaling genes sucrose non-fermenting 1 (Snf1)-related protein kinase 2 (SnRK2), ABA-responsive element binding 2 (AREB2), and basic-helix-loop-helix (bHLH) transcription factor (MYC2).) Ethephon treatment decreased starch content by enhancing expression of the starch degradation-related genes α-amylase 3 (AMY3) and β-amylase 1 (BAM1), resulting in an increase in sucrose content in phloem exudates with enhanced expression of sucrose transporters, SUT1, SUT4, and SWEET11. These results suggest that a synergistic interaction between ethylene and ABA might account for sucrose accumulation, mainly due to starch degradation in mature leaves and sucrose phloem loading in the ethephon-induced senescent leaves.

Gibberellins, brassinolide, and ethylene signaling were involved in flower differentiation and development in Nelumbo nucifera

Hormones play important roles in vegetative and reproductive processes; however, the regulatory roles of hormones in Nelumbo nucifera (Lotus) growth and development are unclear. In this study, nine types of endogenous hormones, including gibberellins (GA1, GA3, and GA4), indole-3-acetic acid (IAA), brassinolide (BR), ethylene (ETH), jasmonic acid (JA), abscisic acid (ABA), and zeatin (ZT) were detected in dormant shoot tips, vegetative shoot tips, developing leaf buds, and developing flower buds of lotus. The results indicated that GA, ETH, and BR signaling can promote vegetative and reproductive development of lotus. GA signaling regulates plant height and stimulates flower bud differentiation. GA levels were the highest in the flower buds; exogenous GA3+4 increased plant height by approximately 90%, increased flower quantity by nearly 40%, and advanced flowering by 4 d. Suppressing GA biosynthesis using paclobutrazol decreased plant height and flower quantity by 38% and 87.1%, respectively, and delayed flowering by 15.6 d. ETH signaling has positive regulatory effects on vegetative growth and flower development. The ETH concentration in the developing leaf buds was at least 50% higher than that in other samples. Ethephon spraying led to remarkable increases in plant height and leaf thickness and extended the flowering duration. BR signaling acts as a growth promoter during vegetative and reproductive development in lotus. The highest BR levels were detected in the vegetative shoot tips. External application of 28-epihomobrassinolide resulted in growth-promoting phenotypes including longer scapes, thicker leaves, and prolonged flowering.

The Effect of Daily Light Integral, Ethephon, and Node Position of Impatiens ×hybrida Stock Plants on Flowering of the Harvested Unrooted Cuttings

Herbaceous stock plant production and cutting harvest methods affect the performance of cuttings harvested from those stock plants. Specifically, the effect of daily light integral (DLI), ethephon spray applications, and the stock plant node position (NPSP) of hybrid impatiens (Impatiens ×hybrida) ‘Compact Electric Orange’ stock plants on the flowering of the harvested cuttings was examined. The DLI treatments were grouped in ranges of low (5.1–5.5 mol·m–2·d–1), medium (7.6–8.8 mol·m–2·d–1), and high (10.3–12.0 mol·m–2·d–1) levels. The stock plants were treated weekly with 0, 50, 100, 200, or 300 mg·L–1 ethephon. Cuttings were harvested from six NPSP, which refers to the location on the stock plants from which the cuttings were harvested. Time to flower of the harvested cuttings decreased as DLI increased from 5.1 to 12.0 mol·m–2·d–1, as ethephon concentrations decreased from 300 to 0 mg·L–1, and as NPSP moved from lower to upper positions within the stock plant canopy. Time to flower was highly correlated with the node position on the cutting (NPC) where the first flower appeared. For example, when flowers appeared in the lowest NPC on the shoot (NPC 1), the first flower opened 2.5 weeks after sticking the unrooted cuttings in propagation, while flowers that appeared in NPC 7, the seventh-oldest node from the base of the cutting, opened at 9.0 weeks. The results demonstrate how stock plant management practices can be manipulated to produce cuttings that allow growers to produce flowering plants on different schedules, i.e., production time can be shortened from conventional production schedules, which may allow hybrid impatiens to be marketed like bedding plant species such as impatiens (Impatiens walleriana).

Ethephon Reduces Lodging and Enhances Seed Yield and Quality in Onion

Onion is an important vegetable crop grown in almost all parts of the World as a flavouring agent in food preparation. It is propagated by seeds and the seed crop is affected by several fungal, viral and bacterial diseases which cause lodging and reduces the seed yield and quality. Onion seed crop was sprayed with different concentration of ethephon (0, 100, 200, 400, 600, 800 and 1000 ppm) for two duration at 45 or 45+60 days after planting during (DAP) during 2018-19 and 2019-20 rabi seasons. The effect of ethephon on seed yield and seed quality was studied. In comparison to control ethephon application significantly reduced scape length and % lodging by 38.73% and 42.52% respectively. There was 31.90% and 89% enhancement in scape diameter and yield respectively. Ethephon spray also enhanced seed quality, highest germination and seed vigour was recorded in plants sprayed with 600 ppm ethephon at 45 and 60 DAP which was 19% and 51.65% higher than control. Highest seedling dry weight was observed in plants sprayed with 100 ppm ethephon at 45 DAP. Among the treatments, 100 and 200 ppm ethephon applied at 45 DAP had lower lodging and higher seed yield and seed quality. Hence spraying of onion seed crop with 100 ppm ethephon at 45 DAP is beneficial for getting higher seed yield and quality.

PENGARUH PENGGUNAAN PACLOBUTRAZOL, KNO3 DAN ETEFON PADA PEMACUAN PEMBUNGAAN TANAMAN MANGGIS (Garcinia mangostana L.)

Mangosteen (Garcinia mangostana L.) is a tropical plant that bears seasonal fruit and is one of Indonesia's leading export commodity. Mangosteen production in Indonesia is still low and not continuous, because there are several factors that influence it. One of them is the character of biennial bearing in mangosteen one year produce high fruit load followed by a next year of very low production. Therefore it is necessary to induce off season mangosteen flowering. This study aims to determine: (1) the effect of Paklobutrazol on the flowering of mangosteen plants, (2) the effect of adding KNO3 and Etefon on the acceleration of mangosteen flowering. This research was conducted in Mulangmaya Village, Kota Agung Timur District, Tanggamus, Lampung. Regency at an altitude of 250 m above sea level from September 2018 to April 2019. This research used a Randomized Block Design (RBD) with a single factor consisting of 3 treatments, namely P1 ( manure 10 kg/plant + NPK Nitrophonska 1 kg/plant, P2 (Paclobutrazol 2 ml/l + KNO3 20 g/l + manure 10 kg/plant + NPK Nitrophonska 1 kg/plant), and P3 (Paclobutrazol 2 ml/l + Etefon 40 ml/l + manure 10 kg/plant + NPK Nitrophonska 1 kg/plant). The data obtained were analyzed by analysis of variance and the mean separation was carried out by orthogonal contrast test at the 5% significance level. The results showed that the treatment of P2 (Paclobutrazol 2 ml/l + KNO3 20 g/l + manure 10 kg/plant + NPK Nitrophonska 1 kg/plant) on mangosteen plants was able to spur flowering faster with a difference of 12 days (8.70% ), and increased the total number of fruits per plant by a difference of 41 fruit (38.80%). The P3 treatment (Paclobutrazol 2 ml/l + Etefon 40 ml/l + manure 10 kg/plant + NPK Nitrophonska 1 kg/plant), unexpectedly causing significant leaf drop 3 days after Ethephon spray, and new leaves were formed a month later. Keywords : Ethephon, KNO3, Paclobutrazol, and mangosteen flowering

Differences in immunity between pathogen-resistant and -susceptible yam cultivars reveal insights into disease prevention underlying ethylene supplementation

Leaf necrosis induced by fungal pathogens is one of the most devastating diseases of yam. The objectives of this study were to examine the production of defensive phytohormones and perform a comparative transcriptome analysis between two yam cultivars with different resistance levels against Botrytis cinerea inoculation. After inoculation with B. cinerea, the endogenous ethylene level was found to have accumulated to a higher level in the MH1 resistant cultivar. Meanwhile, expression profiles identified differential defense regulation of ethylene pathway in MH1 (versus susceptible cv. MH3) in response to B. cinerea. A number of ethylene-synthesis and -responsive genes were expressed at higher levels in MH1 than in MH3 after inoculation. Furthermore, ethylene supplementation in MH3 plants by ethephon spraying indeed enhanced the resistance against B. cinerea and Colletotrichum alatae, and elevated the expression of DaEIN2 and DaERF96. Our work improves understanding of defense mechanism and highlights the function of ethylene potentially utilized for yam protection against diseases.

Effects of ethephon treatment at pre-harvest stage on leave color, growth time, and sesame seed yield and quality (Sesamum indicum L.)

The effect of ethephon spray on leaves at pre-harvest stage to accelerate the ripening process of capsules and sesame defoliation was studied. Sesame plant was treated with ethephon at concentrations of 0, 50, 100, 200, 300, 400 and 500 ppm when the capsules on plant began to mature, the seeds turned black. The results showed that ethephon treatment caused yellowing of leaves, accelerated defoliation and the growth time of sesame plants was shortened from 5 to 6 days compared to the control sample. In addition, the ethephon concentration of 50 and 100 ppm caused yellowing of leaves with chlorophyll index measured at 3 days after treatment was 13.5 and 12.7, respectively. At ethephone concentration of 200-500 ppm caused complete yellowing and defoliation of leaves in 3 days after treatment. The leaves of control sample were still green and had chlorophyll index of 22.2. Treatment of ethephon with concentrations of 50-300 ppm did not reduce the yield and lipid content in the seeds compared to the control sample, but from 400 ppm or more caused cracking of capsules, reducing yield and lipid content in the seeds. Ethephon treatment did not affect the number of capsules/plant, number of seeds/capsule, weight of 1000 seeds, protein content and seed color.

Effect Of Ethephon Doses On Vegetative Characters, Sex Expression and Yield Of Cucumber (Cucumis sativus cv. Bhaktapur Local) In Resunga Municipality, Gulmi, Nepal

A study on the effect of ethephon doses on vegetative characters, sex expression and yield of cucumber (Cucumis sativus cv. Bhaktapur Local) was conducted in Gulmi, Nepal during 21st April to 24th August 2017. The experiment was laid in single factor Randomized complete Block Design (RCBD) with 4 replication and 5 treatments. Four different doses of ethephon 100, 200, 300 & 400 ppm with control were applied. Two sprays of ethephon was made one at two true leaf stage and other at four true leaf stage. Ethephon was found to reduce the plant height compared to control, minimum (238.8 cm) with 400 ppm and maximum (310.4 cm) with the control. The number of nodes and branches per plant were found to be highest with 300 ppm. Ethephon was found to shift first male flowers and female flowers towards upper and lower nodes respectively. The plot treated with 300 ppm ethephon, bearing 20.31 female flowers per plant was found superior to other doses for increasing total female flowers. Maximum and minimum number of male flowers per plant was recorded with control(107 per plant) and 400 ppm (46.90 per plant) respectively. Similarly, 300 ppm of ethephon was found superior for reducing (male: female) sex ratio. Maximum yield 27.51 t/ha was recorded with 300 ppm and minimum yield of 17.48 t/ha with the control. 57% increment in the yield was observed with 300 ppm ethephon as compared to the control. Thus, proper use of ethephon is found to be beneficial to farmers.
 Int. J. Appl. Sci. Biotechnol. Vol 7(3): 370-377

Multiple season-long sprays of ethephon or NAA combined with calcium chloride on ‘Honeycrisp’ apples: I. Effect on bloom and fruit quality attributes

‘Honeycrisp’ apple trees are highly prone to biennial bearing and predisposed to bitter pit. The hypothesis that tank mix sprays of ethephon (ETH), naphthaleneacetic acid (NAA), and 1-aminocyclopropane carboxylic acid (ACC) combined with calcium chloride (CaCl2) can mitigate these production problems was tested in a 3-yr study. Mature ‘Honeycrisp’ trees were treated with either three or six summer applications of 150 mg L−1ETH or 5 mg L−1NAA, all tank-mixed with and without CaCl2, or two or five applications of 150 mg L−1ACC (without CaCl2). Treatments were applied at 10-d intervals and initiated between 21 and 26 June. All treatments had little effect on enhancing return bloom of ‘Honeycrisp’. NAA, ETH, and CaCl2all influenced fruit maturity and quality at harvest to varying degrees and across years. Fruit treated with NAA were firmer compared with untreated fruit in 2 out of 3 yr, whereas overall, fruit treated with six sprays of ETH had lower fruit firmness and were more mature. NAA had less influence on fruit quality attributes at harvest than did ETH, and decreased pre-harvest fruit drop (PFD). PFD increased with ETH in 1 out of 2 yr, whereas ACC and NAA both decreased PFD in 1 out of 2 yr. Overall, ETH and NAA, with or without CaCl2, had significant but inconsistent effects on fruit quality and maturity, all dependent on the year and number of applications. Adding CaCl2decreased fruit firmness in 2 out of 3 yr.

Multiple season-long sprays of ethephon or NAA combined with calcium chloride on Honeycrisp: II. Effect on fruit mineral concentrations and incidence of bitter pit

Honeycrisp apple trees are highly prone to biennial bearing and bitter pit (BP). This 3-y study tested the hypothesis that tank mix sprays of ethephon (ETH), naphthaleneacetic acid (NAA), and 1-aminocyclopropane carboxylic acid (ACC) combined with calcium chloride (CaCl2) can mitigate these production problems. Mature ‘Honeycrisp’ were treated with either three of six applications of 150 mg.L-1 ETH, 5 mg.L-1 NAA or two of five applications of 150 mg.L-1 ACC, all tank-mixed with and without CaCl2 and applied at 10-d intervals starting 21–26 June over three growing seasons. Fruit cortical tissue nutrient concentrations were influenced by applications of CaCl2, ETH, NAA, and ACC. In one year, Ca concentrations were significantly higher in fruit from trees treated with six sprays of ETH or NAA with CaCl2 compared with the untreated control. Compared with untreated trees, fruit Ca concentrations were 115% and 148% higher with three and six applications, respectively. Applications of CaCl2 significantly reduced the incidence and severity of BP post-harvest in two of three years when fruit tissue Ca levels were low. ETH alone also increased the incidence and severity of BP two-fold compared with the control, while early season sprays of NAA reduced BP incidence and severity compared with the untreated control. High and similar levels of BP incidence and severity were observed when six sprays of NAA were applied with or without Ca. Fruit tissue K levels were generally reduced with the addition of CaCl2, and within 1 year, K levels were higher in fruit treated with ACC. Fruit Mg concentrations generally decreased with the addition of Ca or NAA. Six applications of ACC resulted in a 30-fold increase in fruit Mg concentrations compared to the untreated control. Tank mixing CaCl2 with the flower-promoting bio-regulators ETH and NAA proved to effectively reduce BP and increase fruit tissue Ca levels. This approach would offer cost savings when repeat sprays of each are required on a bi-weekly basis.

Ethephon Foliar Sprays Are Influenced by Carrier Water Alkalinity and Ambient Air Temperature at Application

The plant growth regulator (PGR) ethephon [(2-chloroethyl) phosphonic acid; ETH] can be sprayed on floriculture crops to inhibit internode elongation, hinder apical dominance, increase lateral branching, and abort flower buds and flowers. However, the efficacy of ETH can be reduced as the pH of the carrier water used to mix the spray solution or temperature increase. Therefore, our objective was to quantify how the efficacy of ethephon sprays is influenced by carrier water alkalinity (CaCO3; ALK) and the air temperature at application (TEMP). Young plants of verbena (Verbena peruviana) ‘Aztec Blue Velvet’, ivy geranium (Pelargonium ×peltatum) ‘Precision Pink’, and petunia (Petunia ×hybrida) ‘Easy Wave Neon Rose’ were transplanted into 11-cm-diameter containers and grown in a greenhouse with an average daily air temperature (ADT) set point of 21 °C. Before the ETH spray application(s), the ADT in each greenhouse compartment was changed from a set point of 21 °C to 14, 17, 20, 23, or 26 °C for ≈24 hours. Plants were sprayed with 0, 250, 500, or 750 mg·L−1 ETH mixed with carrier water containing ≈50, 150, or 300 mg·L−1 CaCO3 2 and 3 weeks (Expt. 1) or 1 or 2 weeks (Expt. 2) after transplant. Generally, high ALK had a negative effect on spray efficacy. For example, an increase in ALK from 50 to 300 mg·L−1 CaCO3 resulted in one and five fewer ivy geranium and verbena branches, respectively. In addition, as application TEMP increased above 23 °C, chemical efficacy generally decreased in all species. For instance, as ETH increased from 0 to 750 mg·L−1 across ALKs, inflorescence number of ivy geraniums increased from 7 to 18 at a TEMP of 23 °C, but was unaffected at 26 °C. Based on our results, we can conclude that both ALK and TEMP influence ETH efficacy and are additional factors for greenhouse growers to consider when making applications.

EFFECT OF ETHEPHON CONCENTRATION AT DIFFERENT GROWTH STAGES ON YIELD AND ITS COMPONENTS OF WHEAT

An experiments were carried out at the field of Crops Dept., Coll. of Agric., Univ. of Baghdad, Abu Ghraib during 2010-2011 and 2011-2012 seasons to study effect of foliar stages and concentrations of ethephon on some growth traits and the yield of wheat (Triticumaestivum L.) Abu Ghraib-3 var. A split plot arrangement according to RCBD was used with four replications. The main plots were spray ethephon with four stages according to Zadok's scale which is: one leaf throught the sheath (ZGS10), three leaves unfolded stage (ZGS13), elongation stage (ZGS30) and flag leaf ligue visible (ZGS39), and the sub-plots was ethephon spray with three concentrations (0.400, 0.600 and 0.800) Kg.ha-1 in addition to control treatment. The results showed that ZGS13 gave lowest mean for height plant (90.47 and 92.80) cm, while ZGS30 was superior in number of tillers (493.61 and 535.35) tiller.m-2, percentage of tillers carried of spike (78.83 and 81.21, number of spikes (389.64 and 636.80) spike.m-2, grain yield (4.07 and 4.32) ton.ha-1, biological yield (11.29 and 11.59)ton.ha-1 and harvest index (36.03 and 37.26)% for both seasons, respectively. Also, the results showed that 0.800 Kg.ha-1 produced lowest means for height plant (77.91 and 86.25) cm and lodging index (3.65 and 2.75), and this treatment (0.800 mg.L-1) gave highest means for number of tillers (499.22 and 540.99) tiller.m-2, percentage of tillers carried of spike (78.88 and 78.15)%, number of spikes (393.84 and 423.91) spike.m-2, grain yield (4.14 and 4.12) ton.ha-1, biological yield (11.47 and 11.70)ton.ha-1 and harvest index (36.11 and 37.62)% for both seasons, respectively. The interaction between ZGS30 and 0.400 Kg.ha-1ethephon gave highest percentage of tillers carried of spike (80.96%) in the first season only.

Response of Two Wheat Varieties to Irrigation Blocking and Ethephon Foliar Application

A filed experiment was carried-out during the winter season of 2010-2011 and 2011-2012 at the experimental farmof Baghdad University. The main objectives were to asses the role of irrigation blocking and ethephon spraying on growthof wheat cultivars. Two bread wheat cultivars were included. These were IPA-99 and Abu-ghraib-3. Ethephon foliarapplication and irrigation blocking was applied at elongation and booting developmental stages. A split-plot design withfour replicates was used. Main plots were assigned to irrigation blocking-ethephon spraying treatment, whereas, cultivarsassigned to sub-plots. Data presented as an average of the two seasons since the interaction of season treatments was notsignificant. over irrigation blocking-ethephon spr aying treatment the wheat cultivar IPA-99 was significantly superior toAbu-Ghraib-3 in plant height, flag leaf area, dry weight of flag leaf, specific weight of flag leaf, chlorophyll content,tillers number and dry weight of above ground plant parts after 95 and 155 days of sowing. Meanwhile, the differencebetween the two cultivars had not reached the level of significance in crop growth rate and relative growth rate. Irrigationblocking and ethephon spraying at elongation stage, although significantly increased plant height, flag leaf area, dryweight of flag leaf, specific weight of flag leaf, chlorophyll content, tillers number/plant and dry weight of plant after 95and 155 days, the difference in crop growth rate and relative growth rate between elongation and booting stages wasinsignificant. It might be concluded that ethephon foliar application might compensate the suppressing effect of irrigationblocking through modifying plant physiology and regulate the transmission of auxins that lead to reduction in water needand an increase in wheat plant growth.