Foliar Application Of GA3 Research Articles

The effect of foliar application of plant growth regulators on functional and qualitative characteristics of wheat (Triticum aestivum L.) under salinity and drought stress conditions

This study aimed to investigate the effect of salinity and water stress on the physiological and functional characteristics of winter wheat (Triticum aestivum L.) under the foliar application of plant growth regulators (PGRs). The experiment was carried out as a split plot based on a randomized complete block design with three replications in two environments. In each environment, water stress at two irrigation levels (after 90 and 120 mm of pan evaporation) and with two EC of 1.5 and 10 dS/m in the main plots and spraying of PGRs including salicylic acid (SA), gibberellic acid (GA3), and cytokinins (CK) (purine) content with a concentration of 100 ppm and the control treatment (spraying solution with normal water) were placed in subplots. Results indicated that all treatments caused significant increases in functional and qualitative characteristics and yield of Triticum aestivum L. The saline environment and irrigation level after 120 mm of pan evaporation caused a reduction in grain yield in all traits except for seed proline, seed nitrogen content, and seed protein content. Also, the combined foliar application of GA3 + CK + SA increased yield in most traits. The highest RWC of flag leaves was observed in the foliar application of GA3 + SA (3.36 kg/ha) and then in the foliar application of GA3 + SA + CK (57.87 kg/ha). GA3 interacts with PGR spraying to balance another development under saline and non-saline conditions.

Impact of Micronutrients and Plant Growth Regulators on Brinjal (Solanum melongena L.) Growth, Yield and Quality

The present research work conducted to find out the effect of plant growth regulators and micronutrients on growth, yield, and quality of Brinjal (Solanum melongena L.) under open field condition. The experiment was designed in a Randomized Complete Block Design (RCBD) with three replicates. The experiment was conducted on Horticulture farm at Sher-e-Bangla Agricultural University; Dhaka, Bangladesh from July 2022 to June 2023. The experimental treatments included three levels of PGR i.e. No PGR, 200 ppm gibberellic acid (GA3) and 100 ppm Naphthaleneacetic acid (NAA) and three levels of micronutrients i.e.no micronutrients, 200 ppm Boron and 200 ppm Zn. The treatments had a substantial effect on growth, yield, and quality of Brinjal. GA3 treated plants performed better than NAA and no PGR treated plants and Zn produced higher yields and quality than Boron and no micronutrients treated plants in most of the parameters. Considering treatment combination of PGR and micronutrients, plant height, leaf area (471.33 cm2), SPAD value (52.95), number of flowers plant-1 (65.33), number of fruits plant-1 (58.38), yield plant-1 (3312.8g), lipid (0.35%) were observed highest from the treatment combination of 200 ppm GA3 with 200 ppm Zinc whereas dry weight of whole plant (158.80 g), individual fruit weight (67.33g) and fiber (12.28%) were observed from the treatment combination of 100 ppm NAA with 200 ppm zinc but in case of number of branch (14.00) and Ash (8.44%) were observed from the treatment of 100 ppm NAA application . Maximum parameter showed lowest value under no treatment combination. This study suggests that foliar application of GA3 with micronutrients such as Zinc during flowering stage of eggplant is the most effective strategy for improving the nutritional quality of Brinjal fruits and increasing crop yields, both of which will help to reduce micronutrient malnutrition and hunger worldwide.

Effect of foliar application of trace elements and growth regulators on plant biomass and symbiotic efficiency of Lens culinaris M.

The present study was conducted to assess the impact of foliar application of plant growth regulators (IAA and GA3) and trace elements (ZnSO4 and boric acid) on shoot and root length and nodulation efficiency in Lentil (Lens culinaris). Results indicated that significantly (p ≤ 0.05) higher shoot and root length, nodule numbers plant−1 (77.0 ± 1.93 cm, 25.0 ± 1.10 cm and 31.0 ± 1.82, respectively) were recorded with foliar application of IAA @50 ppm concentration followed by IAA @ 25 ppm as compared to IAA@100 ppm and control treatment at fruiting stage of lentil. Similar trends have been seen with the application of GA3. At fruiting stage of lentil, significant (p ≤ 0.05) enhanced shoot length (21.35%), root length (11.76%) and nodule number plant−1 (180%) was observed with the foliar application of GA3 @50 ppm over the control treatment of lentil. Present study demonstrated that shoot and root length, nodule numbers plant−1 was markedly reduced at higher concentration. In the case of zinc sulphate and boric acid, significantly (p ≤ 0.05) higher shoot and root length, nodulation efficiency was recorded with zinc sulphate (ZnSO4) @ 50 ppm and boric acid @ 50 ppm in contrast to ZnSO4 @100 ppm and control treatment. Current study reported first time, results indicate that impact of plant growth regulators, and trace elements on nodulation and growth in lentil are totally concentration-dependent. Further, research is needed to understand the underlying mechanisms and the optimum application concentrations for an improved crop performance under field conditions.

Impact of Diverse Plant Growth Regulators on Quality Traits of Garlic (Allium sativum L.)

The present study was conducted at the instructional cum research farm of the Department of Plantation Crops and Processing of Uttar Banga Krishi Viswavidyalaya, Pundibari, Cooch Behar, India during rabi season for consecutive two years (October-2019 to March-2020 and October-2020 to march-2021) to investigate the “Effect of Different Plant Growth Regulators on Quality attributes of Garlic (Allium sativum L.)” with various growth regulators (GA3@ 50 ppm, GA3 @ 100 ppm, GA3 @ 150 ppm, NAA @ 50 ppm, NAA @ 100 ppm, NAA @ 200 ppm, Kinetin @ 10 ppm, Kinetin @ 20 ppm, Kinetin @ 40 ppm and Control (Distilled water). In view of, effect of different plant growth regulators on quality attributes has observed significant variation. Results pertaining to total soluble solids, significantly highest TSS recorded under GA3 @100 ppm treated plots (32.10 °Brix), however, dry matter content of bulb was highest at GA3 @ 50 ppm (33.63%). Interestingly, highest oleoresin content of the bulb was also reported from the GA3 @ 50 ppm treated plots (0.24 g) with lowest physiological loss of bulb weight (7.04%). The control plots treated with distilled water was produced qualitatively inferior bulbs. The aim of the study provided valuable results to determine the potential growth regulator for enhancing post-harvest quality attribute of garlic by employing methodology of Randomized Block Design comprising of three replications with ten treatments. Based on the current experimental results, it may be concluded that foliar application of GA3 @ 50 ppm proved the best over other plant growth regulators.

Effect of Gibberellic Acid (GA3) and Benzyl Adenine (BA) on Vegetative Growth and Flower Induction in Gladiolus (Gladiolus grandifloras)

The present study was carried out during 2021 -2022 at the experimental farm of Division of Floriculture and Landscaping, Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, Chatha, Jammu and Kashmir. The trial was laid out in factorial randomized block design with three replications and twenty-one treatment combinations. The treatment comprised of three gladiolus varieties viz., American Beauty, White Prosperity and Red Beauty and two growth regulators with their three levels of each viz., BA (50, 75 and 100 ppm) and GA3 (100, 150 and 200 ppm), and compared with control. The influence of foliar application of plant growth regulator on vegetative growth and flower induction of three gladiolus varieties namely American Beauty, White Prosperity and Red Beauty. Growth regulators, viz., gibberellic acid (100, 150 and 200 ppm) and benzyl adenine (50, 75 and 100 ppm) were sprayed at 3 leaves and 6 leaves stage after planting of corms. The results revealed that foliar application of GA3 @ 200ppm on cv. ‘White Prosperity’ recorded maximum plant height (134.27 cm), number of leaves per plant (8.53), leaf area (74.41 cm2), minimum days to 50% spike emergence (95.00) and 50% basal floret showing colour (107.00 days). It can be concluded from the present investigation that gladiolus variety ‘White Prosperity’ performed better than other varieties in respect of all the vegetative and flowering parameters. Among interactions, foliar application of GA3 @200 ppm concentration significantly increased vegetative parameters and induced early flowering in variety White Prosperity.

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.

Modulating Effect of PGRs on Growth and Biochemical Traits in Rice (Oryza sativa L.) under Salt Stress

An investigation was conducted to study the effect of plant growth regulators on rice (variety Sarju-52) grown under sodic conditions, during the kharifseason 2018 at the students’ instructional farm of ANDUA&T, Kumarganj, Ayodhya. The experiment was laid out in randomized block design with nine treatments and three replications, with different concentrations and modes of application of plant growth regulators (PGRs). The PGRs were applied as follows- seed priming of GA3 @25 ppm & 50 ppm and SA @ 10 ppm & 25 ppm, and foliar application of GA3 and SA, each @ 100 ppm & 200 ppm at 30 (DAT), along with untreated control. Seed priming was done for 12 hours in different concentrations of PGRs. Thirty five days old seedlings were transplanted to the field from the nursery. Observations were recorded on various growth parameters such as plant height, number of tillers, dry biomass/hill, relative water content and biochemical parameters like chlorophyll, and TSS, at 30, 60 and 90 DAT and at maturity (harvesting stage). Both seed priming and foliar application of PGRs positively influenced the growth characters, chlorophyll content, and total soluble sugars. Moreover, foliar spray of GA3 @200 ppm was found to have a more pronounced effect in improving the yield of the variety studied, among all the treatments, under sodic conditions. It can be concluded that foliar spray of GA3 @ 200 ppm is effective in improving the growth and yield of rice grown under salt stress.

EFFECT OF PRE-HARVEST APPLICATION OF GA3 AND POTASSIUM NITRATE ON YIELD AND QUALITY OF PEACH FRUIT

The research study entitled “effect of pre harvest application of GA3 and potassium nitrate on yield and quality of peach fruit” was carried out at Horticulture Research Farm, The University of Agriculture Peshawar during 2019. The plots were arranged using Randomized Complete Block Design (RCBD) with two factors. Three replications were used in the experiment. The experiment was conducted on already established peach orchard of almost 14 years old trees of Early Grande cultivar. The uniform size trees were selected and tagged for the experiment. The plants were managed under uniform cultural practices. The selected plants of peach cv. Early Grande were sprayed with various concentrations of Gibberellic acid (GA3) (0, 20, 40, 60 and 80 ppm) and potassium nitrate (KNO3) (0, 1000, 2000 and 3000 ppm) at berry stage. Peach plants were sprayed with GA3 and KNO3 and compared with control. The analysis of data showed that the foliar application of GA3 and KNO3 significantly influenced the yield and quality attributes of peach. Maximum fruit weight (111.98 g), chlorophyll content (51.00 SPAD), TSS (14.60 oBrix), fruit juice content (85.80 %), Fruit firmness (2.16 kg.cm-2), yield plant-1 (54.56 kg) and yield ha-1 (15.548 tons) were recorded in plants treated with 80 ppm of GA3. In case of KNO3 Maximum fruit weight (101.20 g), chlorophyll content (49.46 SPAD), TSS (13.38 oBrix), fruit juice content (84.86 %), Fruit firmness (2.12 kg.cm-2), yield plant-1 (51.56 kg) and yield ha-1 (14.829 tons) were recorded in plants treated with 3000 ppm of KNO3. Minimum days to maturity (72.52) and minimum number of fruits kg-1 (9.65) were found in plants sprayed with 80 ppm of GA3 while in case of KNO3 minimum days to maturity (76.92) and minimum number of fruits kg-1 (10.62) were found in plants sprayed with 3000 ppm of KNO3. Interactive effect of levels of GA3 and KNO3 was also found significant for some of the parameters. It is therefore concluded that when peach Early Grande cultivar sprayed with 80 ppm of GA3 and 3000 ppm of KNO3 the quality as well as yield of the crop were improved.

Effects of different plant growth regulators as the foliar application on growth and flower quality of potted rose (Rosa chinensis Jacq. cv. Nhung)

This study was conducted to evaluate the different concentrations of Naphthalene acetic acid (NAA), Benzyladenine (BA) and Gibberellic acid (GA3­) as foliar applications on growth and flower quality of potted rose Nhung (Rosa chinensis Jacq. cv. Nhung). The experiment was constructed in a completely randomized design, that included seven treatments, such as control (sprayed water), NAA, BA and GA3 at two different concentrations of 25 and 50 ppm, in six replications, with one plant/pot for each replication. The chemical solutions were applied three times at an interval of fifteen days. The results revealed that some plant growth regulators increased the growth and flowering time of rose cv. Nhung. Using pre-harvest foliar sprays of NAA and BA at 25 and 50 ppm concentrations showed maximum bud diameter, flower diameter and flowering duration as compared with the control treatment. The concentration of GA3 foliar application at 25 ppm increased plant growth (the height of flowering branches and Spad values) without affecting flower quality values and the flowering duration in comparison with the control treatment.

Individual and synergistic effects of different fertilizers and gibberellin on growth and morphology of chili seedlings

Gibberellins (GA3), as well as the basic elements phosphorus (P), nitrogen (N), and potassium (K), are crucial to the growth of chili. This study investigates the effect of different fertilizers and plant growth regulator on the growth and morphology of chili seedlings. Soil application of NPK, urea, SOP, and DAP (2.5 g/L) was applied during sowing, and N in two splits at sowing and after twenty days of sowing while foliar application of GA3 (50 mg/L) was applied after fifteen days of germination. The result of five seedlings' traits plant height (PH), plant girth (PG), plant spread (PS), number of leaves (NOF), and root length (RL) demonstrated a significant difference among growth-related traits in chili seedlings owing to the use of fertilizers, GA3, and their combinations. An optimum level of K and P alone or in combination with GA3 had a significant effect on all traits. PH was particularly influenced by the combination of GA3 with K and P whereas other traits like PG, NOF, PS, and RL are greatly influenced by the application of NPK, urea, SOP, DAP, and their combination with GA3. The study results showed an increase in chili seedlings' growth and morphology in response to various fertilizers and GA3.

Effect of Plant Growth Regulator and Micronutrient on Growth, Flowering, and Physical Quality Parameters of Litchi (Litchi chinensis Sonn.) cv. Dehradun

The experiment was carried out at Horticulture Garden, Department of Fruit Science, Chandra Shekhar Azad University of Agriculture & Technology, Kanpur (U.P.) during two subsequent years i.e., 2020 and 2021. Sixteen treatments viz., four levels of GA (0, 20, 40 and 60 ppm) and Zn (0, 0.3, 0.5 and 0.7%) were studied in a Factorial Completely Randomized Design with three replications. Spraying was done twice i.e., before flowering (07 Feb.) and at pea stage (05 April) during both the years. Application of GA 60 ppm and Zinc 0.7% increases length of new shoot (24.41 and 24.44 cm), number of leaves per shoot (23.55 and 24.06), length of panicle (34.89 and 35.96 cm), number of fruit per panicle (21.11 and 22.19), length of fruit (4.21 and 4.30 cm), diameter of fruit (4.22 and 4.29 cm), fruit weight (20.22 and 21.16 g), weight of pulp (13.69 and 13.70 g), and pulp stone ratio (4.65 and 4.62) in both respective years and reduced days required to flowering after first spray (22.13 and 21.30) days, length of seed (2.16 and 2.14 cm), diameter of seed (1.32 and 1.30 cm), weight of seed (3.20 and 3.17 g) and rind weight (2.54 and 2.52 g). We suggest that the foliar application of GA (60ppm) and Zn (0.7%) may be included in strawberry farming for profitable yields and high GA and Zn concentration in strawberry fruit in the plains of Northern India.

Effect of Foliar Spraying of Gibberellins and Brassinolide on Cadmium Accumulation in Rice.

Cadmium (Cd) is one of the heavy metals that contaminate rice cultivation, and reducing Cd contamination in rice through agronomic measures is a hot research topic. In this study, foliar sprays of gibberellins (GA) and brassinolide (BR) were applied to rice under Cd stress in hydroponic and pot experiments. After foliar spraying of GR and BR, the biomass of rice plants grown in either hydroponics or soil culture was significantly higher or even exceeded that in the absence of Cd stress. In addition, photosynthetic parameters (maximum fluorescence values), root length and root surface area, and CAT, SOD and POD activities were significantly improved. The MDA content decreased in the shoots, suggesting that the application of GR and BA may have enhanced photosynthesis and antioxidant function to alleviate Cd stress. Furthermore, the BR and GA treatments decreased the Cd content of rice roots, shoots and grains as well as the Cd transfer coefficient. Cd chemical morphology analysis of rice roots and shoots showed that the proportion of soluble Cd (Ethanol-Cd and Water-Cd) decreased, whereas the proportion of NaCl-Cd increased. Analysis of the subcellular distribution of Cd in rice roots and above ground showed that the proportion of Cd in the cell wall increased after foliar spraying of GA and BR. The results indicate that after foliar application of GA and BR, more of the Cd in rice was transformed into immobile forms and was fixed in the cell wall, thus reducing the amount in the seeds. In summary, foliar sprays of GA and BR can reduce the toxic effects of Cd on rice plants and reduce the Cd content in rice grains, with GA being more effective.

Effect of Plant Growth Regulators on Seed Yield of Mustard

An experiment was conducted at the research field of Regional Agricultural Research Station (RARS), Bangladesh Agricultural Research Institute (BARI), Cumilla during November 2019 to March 2021 to find out the effect of two plant growth regulators (PGR) of IAA and GA3 on yield attributes and yield of mustard (Var. BARI Sarisha-17). There were seven treatments viz. T1= IAA 50 ppm, T2= IAA 75 ppm, T3= IAA 100 ppm, T4= GA3 50 ppm, T5= GA3 75 ppm, T6= GA3 100 ppm, and T7= Control. The PGRs was sprayed twice on mustard plant at 22 and 33 days after sowing. Plant height, branches plant-1, siliqua plant- 1, 1000 -seed weight and seed yield ha-1 were influenced significantly by different levels of application of plant growth regulators. The highest plant height (115.9 cm), branches plant-1 (6.2), siliqua plant-1 (79.8), 1000- seed weight (4.1) and seed yield (1788.3 kg ha-1) was obtained from T5 (GA3 - 75 ppm) treatment. The lowest seed yield was obtained from the control plants (T7). Application of GA3-50 ppm, GA3-100 ppm, IAA-100 ppm, IAA-75 ppm, IAA- 50 ppm gave statistical identical yield. The highest gross return (Tk. 89145 ha-1), gross margin (Tk. 53215 ha-1) and benefit cost ratio (2.47) were also obtained from GA3 at 75 ppm followed by GA3 at 50 ppm (2.43). Foliar application of GA3 and IAA at the rate of 75 ppm could be used at early growth stage for obtaining higher seed yield and economic return.
 Bangladesh J. Agril. Res. 47(1): 99-104, March 2022

Effect of Plant Growth Regulators on Growth of Wallapatta (<em>Gyrinops walla</em> Gaertn.) Seedlings

Gyrinops walla Gaertn belongs to family Thymelaeaceae is the only agarwood producing plant species naturally found in Sri Lanka. With the recognition of its ability to produce highly valuable agarwood, the species is under threat due to illegal harvesting from the natural habitats. Commercial cultivation of the species is yet to be started due to lack of information on relevant cultural practices. The present study was therefore aimed at evaluating the effect of Plant Growth Regulators (PGRs) on growth of G. walla seedlings. The experiment was conducted at the Faculty of Agriculture, University of Ruhuna from August 2019 to May 2020. Different combinations of Gibberellic acid (GA3) and 6-Benzylaminopurine (6-BAP) were tested as foliar applications in an experiment arranged in Randomized Complete Block Design with 3 replicates. Stem height, stem diameter, fresh and dry weight of shoot and root were measured as growth parameters. The combination treatment of GA3 and 6-BAP at 50 ppm and 100 ppm respectively resulted in significantly (p<0.05) higher stem height, stem diameter, leaf area, fresh and dry weight of shoots and roots compared to those of the control which did not receive any growth regulator. Furthermore the treatment significantly (p<0.05) increased the shoot: root ratio also compared to the control. Based on the results, foliar application of GA3 (50 ppm) along with 6-BAP (100 ppm) can be recommended to enhance the seedling growth of G. walla.

Foliar Application of Gibberellin Alleviates Adverse Impacts of Drought Stress and Improves Growth, Physiological and Biochemical Attributes of Canola (Brassica napus L.)

Under the current climate change scenario, water stress is one of the key factors that reduce the production of crops. Gibberellic acid (GA3) is an efficient endogenous plant hormone that shows a vital role in plant growth and development. Production of canola (Brassica napus L.) and its oil contents are severely affected under drought stress. The present study was conducted to investigate the potential of GA3 in alleviating drought stress in canola. Three levels of GA3 (G0 = 0 mg L−1, G1 = 100 mg L−1, and G2 = 150 mg L−1) as foliar applications were applied under two drought-stress conditions (D1 for three days of drought stress and D2 for six days of drought stress) on two canola varieties (Punjab canola and Faisal canola). Irrigation was applied after 3 weeks of germination, while foliar application of GA3 was done at intervals of 4 and 5 weeks after germination. When comparing the output of all the GA3 treatments, it was noticed that in G0 = 0 mg L−1 (control plants), water-stress conditions markedly reduced plant production and seed oil contents but increased protein and linoleic acid. With the application of G2 = 150 mg L−1, the maximum values of plant height (90.83 cm), no. of siliqua plant−1 (15.50), seed siliqua−1 (15.55), siliqua length (5.08 cm), relative water contents (77.60%), yield plant−1 (0.46 g), chlorophyll a (0.62), carotenoid contents (39.52), and oleic acid contents (60.20) were recorded under drought stress. Based on these results, it is concluded that the adverse effect of drought stress on different yield parameters of canola could be ameliorated by the exogenous application of GA3 through foliar application at a dose of 150 mg L–1. Moreover, the same treatment improves the quality parameters, i.e., the oleic acid contents of the oil, obtained from the canola.

Effect of Plant Growth Regulators on Growth and Yield of Tomato (Lycopersicon esculentum L.)

This investigation was undertaken to study “the effect of plant growth regulators on growth and yield of tomato (Lycopersicon esculentum L.) during Kharif season of 2021 at the Crop Research Farm, Department of Horticulture, Naini Agricultural Institute, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj (U.P), India. The experiment was laid out in a randomized block design with 10 treatments and each replicated thrice. The treatments consisted of plant growth regulators GA3 at 10, 20 and 30 ppm, NAA at 10, 20 and 30 ppm and 2,4-D at 2,3, and 4ppm and a control plot. The results showed that among all the treatments, foliar application of GA3 (30 ppm) had positive impact on growth, yield and quality parameters i.e., plant height (81.68 cm), number of clusters per plant (36.66), days to 50% flowering (63.11 days), flowers per plant (72.22), fruits per plant (55.33), fruit yield per plant (3.90 kg), fruit yield per hectare (58.5 t), total soluble solids (4.20 Brix) and acidity (0.41%) were obtained. Foliar application of GA3 (30 ppm) was found to be productive as it recorded major growth and yield attributes as compared to other treatments.

Response of various plant growth regulators on growth, yield and yield attributing traits of tomato (Solanum lycopersicum L) cv. Heemsohna under protected structure

Tomato is universally treated as “Protective food” because of powerful antioxidant associate with lower risk of cancers, heart and related disease. Plant growth regulators play an important role in increasing the growth, yield as well as quality of the produce if applied in suitable forms and at appropriate concentrations. Therefore, an experiment was carried out during 2020–21 in polyhouse of School of Agriculture Science and Technology, RIMT University, Mandi Gobindgarh, Punjab, India to evaluate the response of various plant growth regulators on growth, yield and yield attributing traits of tomato cv. Heemsohna under protected structure. The experiment was laid out in Randomized Complete Block Design with ten treatments and three replications. The treatment combinations are of GA3 (25, 50 and 75 ppm), IAA (25, 50 and 75 ppm) and NAA (25, 50 and 75 ppm). The results highlighted that, the growth, flowering and fruiting parameters like plant height (181.14 cm), number of branches per plant (22.56), inter-nodal distance (11.06), stem diameter (3.07 cm), leaf length (15.40 cm), leaf width (11.99 cm), days of first flowering (46.78 days), number of cluster per plant (11.11), number of flowers per plant (30.11), number of fruits per plant (3.48), weight of three fruit (194.82 g), yield (3.48 kg/plant and 31.35 kg/plot), polar diameter (4.80 cm) and equatorial diameter (5.23 cm) were significantly increased by the foliar application of GA3 @ 50 ppm. Thus, on the basis of present study it may be concluded that the foliar application of GA3 @ 50 ppm has been proved best for growth, flowering, fruiting and yield of tomato under protected structure.

Effects of Foliar and Soil Application of Gibberellic Acid (GA3) at Different Growth Stages on Agronomic Traits and Yield of Rice (Oryza sativa L.)

Use of Gibberellic acid (GA3) application in rice cultivation for increasing the grain yield is well documented. However, improper and untimely use of GA3 could result in poor response to GA3 application. This study was aimed at to investigate the timing of application during different growth stages and mode of application of GA3 on the growth and yield of MR219, a popular Indica rice variety, released by Malaysian Agricultural Research and Development Institute (MARDI). Two commercial GA3 formulations, namely ProGibb SG containing 40% GA3 and ProGibb silica Granule containing 0.1% GA3 were used for foliar and soil application, respectively. GA3 was applied at late tillering stage and at 10-30% panicle heading stage. Interestingly, GA3 application as foliar spray during the early reproductive stage, ie at 10-30% panicle heading stage enhanced the grain yield significantly, recording over 27% grain yield increase over the untreated control. Moreover, two applications of GA3 at 7 days’ interval has consistently given higher grain yield than single application. However, there is no significant difference in flag leaf characteristics, one thousand grain weight and milling qualities among different treatments. Our study has clearly illustrated that foliar application of GA3 at weekly interval at 10-30% panicle heading stage, can increase rice grain yield significantly.

Foliar application of gibberellic acid improves yield and head phenolic compounds in globe artichoke

Applications of gibberellic acid (GA3) during the vegetative stage is used routinely in artichoke production systems in semi-arid regions to induce vernalization and improve yield. The objective of this two-year field study was to evaluate the effect of exogenous GA3 (20 mg l−1) application date (4th and 8th leaf stages) and frequency (two and three times) on morphological and physiological traits, yield and head quality of globe artichoke (Cynara cardunculus L. cv. Green Globe Improved) under a warm and semi-arid environment. Foliar application of GA3 at the 4-leaf stage increased plant height across growing seasons. However, no significant differences between application dates were noticed in plant width, gas exchange and leaf area index when measured at the harvesting period. GA3 application frequency (two or three) did not affect yield and head quality. Interestingly, foliar application of GA3 at 8-leaf stage increased yield by 13%, chlorogenic acid by 19%, cynarin by 30% and total N by 20% compared to the application at 4-leaf stage. In both years, GA3 applied at 8-leaf stage delayed the harvesting by 10 days when compared to plants that received GA3 application at 4-leaf stage. Considering the increase in yield and head quality without negative effects in canopy morphology or leaf physiology two applications of GA3 at the 8-leaf stage appears an effective crop management strategy for globe artichoke grown under warm climates.

Assessment of seed chilling, GA3 foliar application, girdling, and grafting as affecting transition to functional flowering in pumpkin

ABSTRACT Temperature is a factor governing the transition for pumpkin (Cucurbita spp. L) from vegetative to reproductive growth that is necessary for fruit and seed production. Under high-temperature plants may not flower at all. An experiment investigated functional flowering induction of a recalcitrant-to-flower cv. El-Zarka (C. maxima Duchesne) in response to foliar GA3 application, pre-sowing seed chilling, vine girdling, and grafting on rootstock of the ready-to-flower cultivar cv. Kafr El-Battikh (C. moschata Duchesne ex Poir.). The recalcitrant cv. flowered when subjected to all treatments. The best responses were GA3 at 10 mg∙L−1, seed imbibed for 36 h and subjected to chilling (4–5°C) for 12 d, vine girdling of 30-day-old plants, and grafting onto rootstock of 7–10-day-old plants of the ready-to-flower cultivar. Transition to flowering in the ready-to-flower and recalcitrant-to-flower cvs. was consistently accompanied by an elevation in leaf total sugar content. Female flower percent was positively associated with enhanced fruit yield and flesh quality. Isozyme analyses exhibited shared bands for seed chilling with application of GA3 and another between girdling and grafting. The common consistent elevation of leaf total sugar content indicates flowering may be mediated via sugar signaling plus carbohydrates availability (response limiting factor). The methods tested appear to control flowering recalcitrance in pumpkins.