Gibberellic Acid Sprays Research Articles

Response of Phosphorus, Sulphur and Foliar Spray of GA3 on Nutrient Content and Uptake of Soybean [Glycine max (L.) Merrill]

Background: Soybean is an important oil seed crop grown in a varied range of climate and soils in India. Phosphorous and sulphur is an important macronutrient required for plants. Their deficiency in soil is a worldwide concern for production of oil seed crops. The gibberellic acid involved in plant growth and development. Therefore, investigation was carry out to study influenced of phosphorus, sulphur and gibberellic acid on nutrient content and uptake of soybean. Methods: An experiment conducted during kharif-2020 on soybean in sub-sub split plot design with three replications. The twenty four treatment combinations were comprised viz. four levels of phosphorus (Control, 20, 40 and 60 kg ha-1), three levels of sulphur (15, 30 and 45 kg ha-1) and two levels of gibberellic acid (Foliar spray of GA3 @ 75 ppm and no spray). Result: Results revealed that application of 40 kg phosphorus ha-1 and 30 kg sulphur ha-1 is optimum dose for obtaining higher available nitrogen, phosphorus, potassium and sulphur in the soil after crop harvest, nutrient content in seed and straw and uptake of soybean crop. The foliar spray of gibberellic acid @ 75 ppm is also beneficial for improving productivity and profitability of soybean crop.

Foliar Spray of NPK and Gibberellic Acid on Growth and Yield of Chickpea Based Intercropping System

A field experiment was carried out during rabi seasons of 2019-20 and 2020-21 at Birsa Agricultural University, Ranchi, Jharkhand. The experiment was laid out in split-plot design with 3 replications. The treatments were comprised of 9 main plots, viz., sole chickpea, sole wheat, sole linseed, sole safflower, sole mustard, chickpea + wheat (6:3), chickpea + linseed (6:2), chickpea + safflower (6:2), chickpea + mustard (6:2) and 3 sub-plots viz., water(control), foliar spray of 1% NPK (19:19:19) and GA3 (100 ppm). Results revealed that maximum values of growth parameter (like plant height, dry matter accumulation), yield attributes (like number of pods, capsules, capitula, siliqua/plant and spikes/m2, 100-seed weight in chickpea and 1000-seed weight), grain and straw yield as well as harvest index were recorded under chickpea+ mustard (6:2). With regards to different foliar spray treatments, the maximum values for the above-mentioned parameters were found to be higher under the foliar spray of GA3 (100 ppm) at 45 days after sowing during both the years of experimentation.

Response of Foliar Spray of Iron and Gibberellic Acid on Growth and Yield of Greengram

The Field experiment was conducted during Kharif season, 2022 at Crop Research Farm, Department of Agronomy, Sam Higginbottom University of Agricultural Sciences, Prayagraj, U.P, India. To evaluate the Response of Foliar spray of Iron and Gibberellic acid on the Growth and Yield of Greengram . The Soil of the experimented field was Sandy Loam in texture, slightly alkaline reaction (pH 7.0), low in organic carbon (0.40%), available N (161.48kg/ha), available 151.2kg/ha) and available K(232.5kg/ha).The Treatment consisted of FeSO4 (foliar spray at 15,30 DAS) 0.5%, 1.0% and 1.5% ,and GA3(foliar spray at 20,40 DAS) 50ppm, 100ppm, and 150ppm . The experiment was laid out in a randomized Block design and comprised of different levels of Iron and GA3 with ten treatments and replicated thrice. The growth attributes which was plant height (53.83cm), No. of Nodules/plant (51.00), Plant dry weight (11.67 g/plant) was significantly increased with increase in level of Iron and GA3.The Yield attributes was obtained Maximum, No. of Pods/Plant (24.5), No. of Seeds/Pod (12.00), Test weight (20.50g), Grain yield (1.95 t/ha), Stover Yield (3.15 t/ha) and Harvest Index (33.83%)at harvest. Maximum Gross Return (INR 1,29,112.50 INR/ha), Net Return (INR 92,803.50 INR/ha), highest B: C Ratio (2.56).

EFFECT OF VARIOUS CONCENTRATIONS OF GIBBERELLIC ACID ON GROWTH PERFORMANCE AND YIELD OF TOMATO IN FIELD CONDITIONS IN DHADING DISTRICT, NEPAL

A field experiment was carried out to assess the growth performance and yield of tomato cv. Srijana as influenced by various concentrations of gibberellic acid (GA3), during the period from February 2022 to June 2022 in Nilkantha, Dhading, Nepal. The experiment was laid out in Randomized Complete Block Design (RCBD) with four replications and five treatments. The treatments consisted spray of gibberellic acid of various concentrations i.e., 0 ppm (control), 20 ppm, 30 ppm, 40 ppm and 50 ppm. A single spray was administered 15 days following the transplantation of tomato plants in the main field. The results revealed that the tomato growth and fruit yield were significantly influenced by the levels of GA3. The highest plant height, days spanned to the first flowering, number of flower clusters per plant, number of flowers per plant, number of fruits per plant and fruit yield were observed in the 50 ppm GA3 treatment, while the lowest values were seen in the control group (0 ppm GA3). It could be suggested that the production of tomato could be improved by the application of GA3 @ 50 ppm in the field conditions of Dhading, Nepal.

Influence of Foliar Application of Growth Regulators on Vegetative Growth and Flowering Of Chrysanthemum

The pot experiment was conducted at the Floriculture field of Horticulture Research Centre (HRC), Bangladesh Agricultural Research Institute (BARI), Gazipur during August 2020 to May 2021 to evaluate the foliar spray of gibberellic acid (GA3), benzyl adenine (BA) and naphthalene acetic acid (NAA) on growth and flowering traits of chrysanthemum (Chrysanthemum morifolium). The experiment was laid out in Randomized Complete Block Design (RCBD) with three replications. Four weeks old seedlings of chrysanthemum genotype CM-019 (flower class: Pompon and flower colour: Orange yellow) were transplanted in pot keeping under natural sunlight. The aqueous solution of GA3, BA and NAA @ 100 and 200 ppm of each were sprayed on the flower plants at monthly interval starting after one month of transplantation of seedlings along with control (water). The results revealed that vegetative growth and flowering parameters were significantly influenced by plant growth regulators. Maximum number of leaves per plant (50.0) and leaf area per plant (7.5 cm2) were recorded from the spraying of BA @ 100 ppm closely followed by BA @ 200 ppm (48.0 and 7.0 cm2/plant) and GA3 @ 100 ppm only for number of leaves (47.0/plant). Spraying of GA3 @ 100 ppm produced the tallest plant (70.0 cm) and the highest plant spread (23.0 cm). Number of flowers (26.0/plant), flower size (7.8 cm), average weight of stalk (37.0 g) and vase life (15.0 days) were also found maximum from the application of GA3 @ 100 ppm, closely followed by GA3 @ 200 ppm (23.5/plant, 7.2 cm, 36.0 g, 14.0 days) and NAA @ 100 ppm (18.5/plant, 7.0 cm, 36.0 g, 13.0 days) and irrespective of concentrations, BA failed to improve these characters. GA3 @ 100 ppm recorded maximum length of stalk (37.5 cm) and rachis (29.0 cm), which was identical with GA3 @ 200 ppm (34.6 cm and 25.0 cm), and BA @ 100 ppm gave the lowest length of stalk and rachis. GA3 also caused faster initiation of flowering, whereas NAA and BA delayed it. GA3 @ 100 ppm took the minimum days to flowering (50.0 days) was observed when plants were sprayed with GA3 @ 100 ppm whereas it was maximum (69 days) from BA @ 100 ppm treatment. It can be concluded that GA3 @ 100 ppm provided the best results for obtaining better vegetative growth of plants, maximum number of cut blooms with longer stalk as well as bigger flower size with prolonged vase life in chrysanthemum.
 Bangladesh J. Agril. Res. 47(1): 69-80, March 2022

Effect of Potassium and Gibberellic Acid on the Growth and Yield of Cowpea (Vigna unguiculata L.)

The field experiment was conducted at experimental field of the Crop Research Farm, Department of Agronomy, Naini Agricultural Institute, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj, Uttar Pradesh, India. The soil of experimental field is Sandy loam in texture, nearly neutral in soil reaction (pH 7.1), low in organic carbon (0.36%) available N (171.48 kg/ha), available P (27.0 kg/ha) and K (291.2 kg/ha). The Experiment was laid out in Randomized Block Design with nine treatments and one control plot replicated thrice on the basis of one year experimentation. To determine the Effect of Potassium and Gibberellic Acid on the growth and yield of Cowpea (Vigna unguiculata L.). The treatments consisted of three levels of Potassium – 20 kg/ha, 25 kg/ha and 30 kg/ha and three levels of Gibberellic acid spray – 100 ppm, 120 ppm and 150 ppm. The results showed that treatment with the application of Potassium – 30 kg/ha + GA3 - 100 ppm was recorded significantly higher Plant height (68.8 cm), no. of nodules/plant (40.9), dry weight (39.32 g). Whereas, maximum Number of pods per plant (16.94), seeds per pod (13.46), seed index (18.36 g), higher seed yield (1459.70 kg/ha) and Haulm yield (2952.30 kg/ha).

Effect of Phosphorus, Sulphur and Gibberellic Acid on Growth, Root Nodules and Yield of Soybean [Glycine max (L.) Merrill]

An experiment was conducted during kharif season 2020 at Instructional Farm, College of Agriculture, Ummedganj, Kota. The experiment comprised twenty-four treatment combinations, having four levels of phosphorus viz., 0, 20, 40 and 60 kg ha-1, three levels of sulphur viz., 15, 30 and 45 kg ha-1 and foliar spray of gibberellic acid viz., no spray and spray of GA3 @ 75 ppm laid out in sub-sub split-plot design with three replications. Results showed that application of 60 kg P2O5 ha-1 had significant effect on plant height, dry matter accumulation plant-1, branches plant-1 at 30, 60 DAS and at harvest, root nodules plant-1 and their dry weight at 45 DAS while root nodules plant-1 and their dry weight at 45 DAS andseed yield (1956 kg ha-1) over application of 40, 20 kg P2O5 ha-1 and control. Significantly higher seed yield (1956 kg ha-1) was recorded under application of 60 kg P2O5 ha-1 over application of 20 kg P2O5 ha-1 and control. However, it was found at par with application of 40 kg P2O5 ha-1. Application of 45 kg sulphur ha-1 had significantly higher plant height (cm) at 60 DAS and at harvest, dry matter accumulation (g plant-1) at 30, 60 and at harvest stages, branches plant-1 at 30, 60 and at harvest stage, number of root nodules and their dry weight (g) and seed yield (1742 kg ha-1) which was found at par with application of 30 kg sulphur ha-1 over 15 kg sulphur ha-1. Application of gibberellic acid @ 75 ppm as foliar spray gave significantly higher plant height (cm) at 60 DAS and at harvest stage, dry matter accumulation (g plant-1) at 60 DAS and at harvest, branches plant-1 at 30, 60 DAS and harvestand seed yield (1770 kg/ha) over control.

Influence of Foliar Spray of Brassinosteroids (BR), Salicylic Acid (SA) and Gibberellic Acid (GA3) on Vegetative Growth and Flowering Parameters of Cucumber (Cucumis sativus L) cv. Arpit.

An investigation entitled “Influence of foliar spray of Brassinosteroids (BR), Salicylic acid (SA) and Gibberellic acid (GA3) on vegetative and flowering parameters of Cucumber (Cucumis sativus L) cv. Arpit” was carried out at the Vegetable Research Farm, Department of Horticulture, Sam Higginbottom University of Agriculture, Technology & Science, Prayagraj, (U.P.) - 211007 during the year 2018-19 and 2019-2020. The experiment was laid out in a Randomized Block Design with 15 treatments and 3 replications and each replicated thrice. Source of variables were Brassinosteroids (BR) 0.05 PPM, Brassinosteroids (BR) 0.10 PPM, Brassinosteroids (BR) 0.5 PPM, Brassinosteroids (BR) 1.0 PPM, Brassinosteroids (BR) 2.0 PPM, Salicylic acid (SA) 0.05 mM, Salicylic acid (SA) 0.10mM, Salicylic acid (SA) 0.2mM, Salicylic acid (SA) 0.5mM, Salicylic acid (SA) 1.0mM, Gibberellic acid (GA3) 25 PPM, Gibberellic acid(GA3) 50 PPM, Gibberellic acid(GA3) 100 PPM, Gibberellic acid (GA3) 150 PPM  and combination of them with control treatment taken as 15 treatments. As far as the vegetative growth and flowering is concerned, application of different treatment of plant growth regulators significantly enhanced the Length of main vine (cm), Number of branches per plant, Number of leaves per plant, Diameter of main stem (cm), Inter-nodal distance (cm), Leaf area (cm2), Days to first flower bud initiate (DAS), Days taken to 50% flowering, Number of male flower per plant, Number of female flower per plant at all successive stages. The maximum vine length (143.17 and 146.04cm), number of leaves per plant (93.74 and 94.74), number of branches per plant (19.49 and 19.82), diameter of main stem (14.70 and 16.02cm), leaf area (277.42 and 280.90 cm2), internodal distance (7.27 and 6.97cm) and as per flowering parameters lowest days taken to first flower bud initiation (36.66 and 35.73 days), days taken to 50% flowering (42.40 and 422.73 days), number of male flower per plant (91.71 and 92.05) and  number of female flower per plant (47.59 and 46.92) were recorded in both successive year with T5 (Brassinosteroids (BR) 2.0 PPM) and minimum growth and flowering were observed in T0 (control).

Effect of foliar spray of gibberellic acid (GA3) and borax on growth, productivity, and quality of tomato (Lycopersicon esculentum Mill.) under protected structure at Kaski, Nepal

Tomato (Lycopersicon esculentum Mill.) is a highly demanded solanaceous vegetable crop in Nepal. Poor vegetative growth, low flowering and fruit set are the major problems in tomato. Thus, an experiment was conducted to improve vegetative growth, flowering, fruiting and productivity of tomato (Nepali Variety Type 2) at Pokhara-14, Kaski, Nepal during spring- summer of 2019 in Split plot arrangement with gibberellic acid (GA3) as main factor and Borax as sub factor, with three replications. The main factor consisted of four concentrations of GA3 (0, 25, 50 and 75 ppm) which was applied thrice as foliar spray at 15, 30 and 45 days after transplanting (DAT) and sub factor consisted three concentrations of borax (0%, 0.25% and 0.5%) which was applied four times as foliar spray at 15, 30, 45 and 60 DAT. Growth characters viz., plant height, leaf area, leaf number, flower number per cluster, fruit number were significantly enhanced with application of 50 ppm GA3 and gave higher productivity (31.65 t ha-1) compared to other concentrations and control. Likewise, foliar spray of borax resulted in higher stem girth, flower clusters, number of flowers per cluster, and TSS content of tomato. Furthermore, borax @ 0.25% gave the highest productivity (30.78 t ha-1). The better effect of 50 ppm GA3 on growth and yield of tomato and effect of 0.25% borax on flowering and yield, makes them promising solutions to the problems of tomato at Kaski, Nepal. Thus, further research should be conducted by using GA3 and borax in several other tomato cultivars in field and under protected structure at different soil type and climatic conditions.

Non-Structural Carbohydrates, Foliar Nutrients, Yield Components and Oxidative Metabolism in Pecan Trees in Response to Foliar Applications of Growth Regulators

Foliar sprays of growth regulators have commercial potential for improving the performance of some of the parameters associated with alternate bearing in pecan trees. The objective was to evaluate the behaviour of alternate bearing through analysis of seasonal variations in buds and leaflets of non-structural carbohydrates (glucose, fructose, sucrose, and starch), mineral nutrients (N-total, P, K+, Ca2+, Mg2+, Fe2+, Cu2+, Mn2+ and Zn2+), yield components (nut weight per kilogram and kernel percentage) and oxidative metabolism (superoxide dismutase, hydrogen peroxide, catalase, guaiacol peroxidase and antioxidant capacity) in cv. Wichita pecan trees in response to foliar applications of gibberellic acid (50 mg L−1), calcium prohexadione (500 mg L−1) or thidiazuron (10 mg L−1). The experiment was of a completely randomized experimental design with five replicates. Foliar growth regulator (GRs) sprays help maintain the concentration of non-structural carbohydrates in the leaflets and buds between the evaluation years. With the exception of K+ (12.9 and 10.9 g kg−1) and Zn2+ (45.1 and 30.5 mg kg−1), the GRs did not show any effects on the concentrations of the foliar mineral nutrients. The results suggest foliar sprays of gibberellic acid improve the performance of parameters associated with alternate bearing, including oxidative metabolism.

Studies on the Effect of Preharvest Sprays of Gibberellic Acid and Benzyl Adenine on Postharvest Vase Life of Gypsophila (Gypsophila paniculata L.) CV. Star World

The impact of gibberellic acid (GA3) and benzyl adenine (BA) dose and application timing on vase life of gypsophila was examined. Freshly cut gypsophila flower stalks with pre harvest sprays of  growth regulators G1- GA3 at 150 ppm, G2- GA3 at 300 ppm, G3- GA3 at 450 ppm, G4- BA at 150 ppm, G5- BA at 300 ppm, G6- BA at 450 ppm, distilled water spray - G7 and were applied twice at S1- 30 and S2-at 30 and 45 days after pruning are harvested from the experimental plot early in the morning when 30 to 40% of flowers in the stalk open and held in vases containing 3 % sucrose solution flower stalks are harvested from the experimental plot early in the morning when 30 to 40% of flowers in the stalk open and held in vases Water absorption, fresh weight change, water loss by transpiration, physiological weight loss, 50 % discolouration and vase life. Among all the treatments, the flowers sprayed with GA3 at 450 ppm and single spray recorded maximum water uptake (13.19 g), transpirational loss of water (6.19), fresh weight change (62.51 %), dry weight of flowers (2.09), 50 per cent discolouration (13.41 days), Vase life (14 days) and minimum physiological loss in weight (1.78 g).

Parthenocarpy induction and reduction of seeds in fruits of 'Nadorcott' mandarin

Mandarins commercialization at international market requires seedless fruit production in addition to its ideal organoleptic and visual quality. The objective of the work was to evaluate the efficiency of applications of gibberellic acid and of copper sulfate during anthesis in reducing the number of seeds and in the productive behavior of the 'Nadorcott' mandarin in the conditions of the southern Brazil. The experiment was performed in an orchard of 'Nadorcott' mandarin trees grafted on Poncirus trifoliata. Two applications were conducted at anthesis with different levels and combinations of gibberellic acid and copper sulfate. Also, net was used as one of the treatments to prevent pollination. Net treatment provided a high frequency of seedless fruits, with greater skin color, however with less production. Gibberellic acid applications increased linearly the frequency of seedless fruits and with a maximum of two seeds. Copper sulphate applications did not affect any evaluated characteristics. Sprays of gibberellic acid of 100 mg L-1 concentration reduce the number of seeds per fruit and increase parthenocarpy, without effect on fruit size and peel color.

Postharvest quality maintenance of 'Crimson Seedless' grapes by preharvest applications

The present study was carried out during both 2018 and 2019 growing seasons on ‘Crimson Seedless’ grape vine grown on sandy soil. Vines received water, salicylic acid 200 mg/L, chitosan 10 g/L, putrescine 5 mM, phenylalanine 400 mg/L, ascorbic acid 500 mg/L, citric acid 700 mg/L, gibberellic acid 20 mg/L, active dry yeast 15 g/L at véraison (change of color) stages and at 10 days before harvesting time. Fruit clusters were harvested when total soluble solids (TSS) reached 16%, stored at 0°C and 85–90 relative humidity for 35 days then kept 2 days at shelf life (25 ±2°C and air humidity 70 ±2). Results at harvest time showed that, salicylic acid, putrescine, gibberellic acid and yeast increased average berry weight and juice volume. Salicylic acid, chitosan, putrescine, citric acid and gibberellic acid maintained the berry adherence strength and firmness. Salicylic acid, chitosan, putrescine and phenylalanine increased berry red color, as well as berry anthocyanin, TSS and sugars content. Highest acidity content was obtained by salicylic acid, chitosan, citric acid and gibberellic acid spraying. Results after cold storage and shelf life showed that, berry weight loss decreased significantly by all chemical sprays, except phenylalanine. High maintenance of berry adherence strength and firmness occurred by gibberellic acid followed by putrescine. All chemicals reduced the unmarketable grapes except the phenylalanine. 

Efficacy of various doses of salicylic acid, naphthalene acetic acid and gibberellic acid on vegetative growth and pod yield of broad bean (Vicia faba L.)

To investigate the efficacy of various doses of plant growth regulators on vegetative growth and pod yield of broad bean (Vicia faba L.), a field experiment was accomplished at Vegetable Research Farm, B.H.U., Varanasi during the winter season of 2019-20. Ten treatments were evaluated in randomized block design with three replications. Results indicated that the growth parameters like plant height, number of branches/plant significantly increased with foliar spray of gibberellic acid followed by NAA and salicylic acid. The yield attributes like pod width, fresh pod weight, number of pods/plant as well as fresh pod yield significantly enhanced by NAA followed by gibberellic acid and salicylic acid with various concentrations, respectively. The foliar spraying of 120 ppm GA3 tended to produce plant with maximum height (116.4 cm), number of branches/plant (6.3), pod length (7.5 cm), number of seeds/pod (4.6) as well as early 50 % flowering (57.3 days) whereas, spraying of 40 ppm NAA exhibited the maximum pod width (1.3 cm), fresh pod weight (4.6 g), number of pods/plant (87.5) as well as fresh pod yield (105.0 q ha-1) as compared to other treatments. The maximum net return (Rs. 337326.5 ha-1) was recorded with 40 ppm NAA with B: C ratio of 3.65 followed by 30 ppm NAA and 20 ppm NAA. The lowest net income (Rs. 162382.5 ha-1) and B: C ratio (1.76) was obtained from control. The spraying of NAA was found superior in terms of yield and yield attributes as well as benefit cost ratio followed by GA3 and salicylic acid.

Efficacy of various doses of salicylic acid, naphthalene acetic acid and gibberellic acid on vegetative growth and pod yield of broad bean (Vicia faba L.)

To investigate the efficacy of various doses of plant growth regulators on vegetative growth and pod yield of broad bean (Vicia faba L.), a field experiment was accomplished at Vegetable Research Farm, B.H.U., Varanasi during the winter season of 2019-20. Ten treatments were evaluated in randomized block design with three replications. Results indicated that the growth parameters like plant height, number of branches/plant significantly increased with foliar spray of gibberellic acid followed by NAA and salicylic acid. The yield attributes like pod width, fresh pod weight, number of pods/plant as well as fresh pod yield significantly enhanced by NAA followed by gibberellic acid and salicylic acid with various concentrations, respectively. The foliar spraying of 120 ppm GA3 tended to produce plant with maximum height (116.4 cm), number of branches/plant (6.3), pod length (7.5 cm), number of seeds/pod (4.6) as well as early 50 % flowering (57.3 days) whereas, spraying of 40 ppm NAA exhibited the maximum pod width (1.3 cm), fresh pod weight (4.6 g), number of pods/plant (87.5) as well as fresh pod yield (105.0 q ha-1) as compared to other treatments. The maximum net return (Rs. 337326.5 ha-1) was recorded with 40 ppm NAA with B: C ratio of 3.65 followed by 30 ppm NAA and 20 ppm NAA. The lowest net income (Rs. 162382.5 ha-1) and B: C ratio (1.76) was obtained from control. The spraying of NAA was found superior in terms of yield and yield attributes as well as benefit cost ratio followed by GA3 and salicylic acid.

Ameliorative effects of foliar spray of glycine betaine and gibberellic acid on cowpea (Vigna unguiculata L. Walp.) yield affected by drought stress

Ameliorative effects of foliar spray of glycine betaine and gibberellic acid on cowpea (Vigna unguiculata L. Walp.) yield affected by drought stress

Influence of pre-harvest sprays on flower quality and vase life of Alstroemeria

Alstroemeria, commonly known as Peruvian Lily, has high demand in the global market. The flowers are popularly known for their wide range of colours. Short postharvest life is a significant problem in Alstroemeria flowers. The objective of the study is to extend the vase life of flowers by application of pre-harvest foliar sprays. Foliar spray of Salicylic acid (50, 100 & 150 µM), Benzyl Adenine (50, 100 & 150 µM) and Gibberellic acid (200, 250 & 300 ppm) were applied twice during 2 weeks and 1 week before flower harvest with distilled water as control. The harvested flowers were placed in conical flasks containing distilled water as vase solution, and parameters like relative fresh weight, vase solution uptake, floret diameter, total chlorophyll content, ethylene evolution and vase life were recorded. The results showed that pre-harvest treatment of flowers with Gibberellic acid @ 300 ppm showed a significant increase in floret diameter (7.6 cm), total chlorophyll content (0.72 mg g-1 of fresh leaf), high relative fresh weight (88.50%) and high uptake of vase solution (2 g stem-1 day-1). Treatment with Benzyl adenine @ 150 µM has given favourable result by increasing the vase life of the flower up to 8 days followed by Gibberellic acid @ 300 ppm (7 days). Treatment with Salicylic acid did not show any favourable result. There was no significant difference in ethylene evolution pattern among treatments. From this experiment, it is concluded that pre-harvest treatment of flowers with Gibberellic acid @ 300 ppm and treatment of flowers with Benzyl adenine @ 150 µM showed positive results with treatment using Gibberellic acid @ 300 ppm as the best treatment.

Enhancing cane and sugar productivity applying variable modes of plant growth regulators in sugarcane (Saccharum sp. complex) cultivation under coastal climatic conditions of India

A field experiment was carried out for three crop seasons at Sugarcane Research Station, Nayagarh (Odisha) during spring seasons of 2015-16, 2016-17 and 2017-18 to assess the effect of ethrel and gibberellic acid on growth, yield attributing characters, yield and quality of sugarcane (Saccharum sp. complex). Pooled data of three years study indicated that different treatments with plant growth regulators had significant effect on growth, yield and quality parameters of sugarcane. Germination percent of cane buds was the highest in the treatment involving planting of sugarcane setts after overnight soaking in 100 ppm ethrel solution followed by foliar application of gibberellic acid @35 ppm at 90,120 and 150 days after planting (DAP). Other sugarcane growth parameters, viz. number of tillers and plant heights were significantly higher with the application of growth regulators which produced higher number of millable canes (at harvest) than that of other treatments in the test. Overnight soaking of cane setts in 100 ppm ethrel solution followed by foliar application of gibberellic acid @35 ppm at 90,120 and 150 days after planting also produced significantly higher yield parameters, viz. number of millable cane (84.26’ 000 ha-1), cane length (313.6 cm), cane girth (2.94 cm) and single cane weight (1.64 kg) as compared to conventionally planted sugarcane crop. There was no significant influence on juice quality parameters due to various treatments in this study. However, overnight soaking of setts with 100 ppm ethrel solution followed by foliar application of gibberellic acid @ 35 ppm at 90, 120 and 150 days after planting showed comparatively higher values in all the juice quality parameters. Significantly higher cane and sugar yields of 116.14 t/ha and 12.82 t/ha, respectively were obtained with planting of sugarcane after overnight soaking in 100 ppm ethrel solution followed by gibberellic acid spray @ 35 ppm at 90, 120 and 150 days after planting. The above higher yields were attributed mainly to marked improvement in growth and yield attributes in response to application of plant growth regulators. Therefore, it can be concluded that combined application of ethrel and gibberellic acid had the positive effect to improve the growth parameters, yield and quality of sugarcane.

Effects of pre-harvest gibberellic acid spray on endogenous hormones and fruit quality of kumquat (Citrus japonica) fruits

ABSTRACT Gibberellic acid (GA3) is important in plant growth, development, ripening, and senescence. In the present study, we evaluated the effect of pre-harvest GA3 application on the maintenance of postharvest fruit quality in kumquat (Citrus japonica). On-tree fruits were sprayed with 20 mg/L GA3. Unsprayed harvested fruit stored at 6 °C were used as the control. The contents of indoleacetic acid, GA3, and zeatin ribosides in the GA3-sprayed fruits were significantly higher than those in the control, while the contents of both abscisic acid and titratable acid in sprayed fruits were lower than those in the control. Regarding peel colour, GA3 treatment resulted in a lower decrease in hue angle value, with a slow increase in citrus colour index and browning index. Additionally, GA3 treatment inhibited the accumulation of malondialdehyde. In conclusion, pre-harvest application of GA3 may represent a novel strategy for the preservation of fruits on trees, by maintaining nutritional quality and prolonging the postharvest life of kumquat fruits.

Techniques to modify cluster architecture and their effect on the viticultural performance of the Sauvignon Blanc cultivar

Abstract: The objective of this work was to evaluate the effect of different techniques to modify grape cluster architecture on the incidence and severity of botrytis bunch rot, as well as on the viticultural performance of the 'Sauvignon Blanc' grapevine (Vitis vinifera). Associated with fungicides, four treatments were tested: control, 30 ppm gibberellic acid sprayed at full bloom, 1,000 ppm prohexadione calcium sprayed at full bloom, and berry thinning at the stage of beginning of berry touch. The experiment was carried out in the 2015, 2016, and 2017 vintages. Clusters were treated with fungicides during the stages of full bloom, beginning of berry touch, veraison, and around 15 days before harvest. Berry thinning does not cause losses in the yield and quality of 'Sauvignon Blanc', and, despite having little effect on cluster architecture, is effective in reducing the incidence and severity of Botrytis cinerea. Prohexadione calcium improves grape phenolic maturation, is effective in reducing the incidence and severity of B. cinerea, and reduces cluster compactness by decreasing berry diameter. The application of gibberellic acid spray at full bloom is not recommended because it decreases yield and bud fertility and increases berry susceptibility to B. cinerea infection.