GA3 Doses Research Articles

Application of combined GA3 and NAA treatments to improve yield and quality of Okra (Abelmoschus esculentus L.)

In Bangladesh, okra is an important popular summer vegetable. However, traditional farming practices often lead to suboptimal yields. Thus, the study was designed to determine the ideal GA3 and NAA doses for accelerating okra growth, yield, and quality characteristics. A three-replication, randomized complete block design was adopted. Foliar sprays with three concentrations of GA3 (0 ppm, 150 ppm, and 250 ppm) and NAA (0 ppm, 150 ppm, and 250 ppm) were applied in 2022 and 2023. In comparison to the control, the combined application of GA3 @ 150 ppm and NAA @ 150 ppm improved plant height, leaf number, leaf area, branch number, internode length, bud number, pod number, pod length, pod diameter, and 1000 seed weight average over the two years. Furthermore, GA3 @ 150 ppm with NAA 150 ppm increased yield by 35.08% and 27.01% in 2022 and 2023 respectively, above the control. Combining NAA @ 150 ppm with GA3 resulted in higher levels of vitamin C, TSS, magnesium, and zinc by 19.31%, 81.2%, 22.73% and 21.43% in 2022 and 22.83%, 50.57%, 18.07%, 33.33% in 2023 respectively, compared to the control. In contrast, GA3 and NAA decreased potassium and calcium in both year when compared to the control. Overall, the results of this experiment indicated that using GA3 @ 150 ppm with NAA @ 150 ppm could enhance okra growth, yield, and quality. These findings provide insightful information for improving okra cultivation techniques and improving Bangladesh’s productivity in agriculture and food security.

The Effects of Different GA3 and Mycorrhiza Dosages on Mini Tuber Production in Potatoes

This study was conducted in 2017 under greenhouse conditions using selected four different potato clones to determine the effects of different doses of GA3 and arbuscular mycorrhizal fungus on mini tuber production. The research, carried out in a randomized complete block design with three replications, applied GA3 doses of 0, 5, 10, and 15 ppm, and mycorrhizal inoculat doses of 0, 500, 1250, and 2000 mg/100 tubers. Parameters including emergence time, plant height, main stem number, tuber number, average tuber weight, tuber size distribution (>45 mm, 28-45 mm, <28 mm), and maturity period were examined. The effect of GA3 application on all investigated parameters except the number of main stems was significant, statistically. The highest mini tuber number (9.1 tubers) and mini tuber yield (408.4 g/pot) were obtained from the application of 15 ppm GA3, while the highest average mini tuber weight (46.74 g) was obtained from the control group. In mycorrhizal applications, the highest tuber number was obtained at a dose of 500 mg/100 tubers, and the highest mini tuber weight and yield were obtained at a dose of 1250 mg/100 tubers. As a result of the study, it was determined that the application of 15 ppm GA3 is suitable due to its positive effect on mini tuber multiplication, and the mycorrhizal application at a dose of 500 mg/100 tubers is appropriate due to its positive effect on increase of tuber number.

EFFECT OF SPACING AND FOLIAR SPRAY OF GIBBERELLIC ACID (GA3) ON GROWTH AND YIELD OF OKRA

An experiment was conducted at the Horticultural Farm of Sher-e-Bangla Agricultural University, Dhaka during March-July, 2016 to find out the best combination of plant spacing and GA3 dose for successful production of okra. The experiment consisted of two factors, Factor A: three levels of spacing, viz. S1: 60 cm × 30 cm, S2: 60 cm × 40 cm and S3: 60 cm × 50 cm and Factor B: four doses of GA3, viz. H0 (control; no GA3); H1: 50 ppm GA3; H2: 100 ppm GA3 and H3: 150 ppm GA3. The experiment was laid out in a Randomized Complete Block Design following 12 treatment combinations and replicated thrice. Results revealed that interaction effect of spacing and foliar spray of GA3 had significant positive effect on growth (plant height, leaves plant-1, branches plant-1 and leaf area), yield contributing traits (number of fruits plant-1, fruit length, fruit diameter, fruit yield plant-1 and stover yield plant-1) and yield (tha-1) of okra. Among different treatment combinations, the highest yield (19.92 t ha-1) was obtained from S3H2 combination. Based on the results of the study, it is concluded that foliar application of 100 ppm GA3 with the spacing of 60 cm × 50 cm produced the highest yield of okra as compared to other treatment combinations tested. From our present findings we can suggest that, 60 cm × 50 cm spacing with 100 ppm GA3 as foliar application would be one of the effective agronomic practices for economic production of okra.

Gibberellic acid in the ‘Cabernet Sauvignon’ grape: effects on grape cluster morphology and wine quality

‘Cabernet Sauvignon’ is a commonly produced and consumed variety of grapes in Brazil, although late sprouting and flowering negatively affect wine production, hindering the production of elegant and balanced wines, especially in high-altitude regions of Santa Catarina. Therefore, this study sought to evaluate the effects of gibberellic acid (GA3) on reducing and eliminating ‘Cabernet Sauvignon’ grape berry seeds and evaluate the physicochemical parameters of the wine produced in Serra Catarinense. The experiments were conducted in a commercial vineyard. The treatments were 0.0, 40.0, and 80.0 mg L-1 of GA3 in the 2019/20 season and 0.0, 20.0, and 40.0 mg L-1 of GA3 in the 2020/21 season. The applications were performed in full bloom. The characteristics evaluated were cluster weight, berry diameter, berry mass, number of seeds per berry, seed mass, peel:pulp ratio, cluster length, cluster compaction index, rachis mass, and berries per cluster. In both harvests, the zero dose of GA3 was related to greater cluster compaction, berry and cluster mass, and seeds per berry. In the 2019/20 harvest, 80 mg L-1 of GA3 was correlated to must total soluble sugar, wine acidity, must acidity, color parameter at 520 nm, and color intensity. In the last harvest, the color parameters were more correlated with the highest GA3 dose, showing that this growth regulator increased free anthocyanins and total polyphenols. Moreover, 20–80 mg L-1 of GA3 reduced the number and size of seeds but increased the tannin content in one harvest. Bunch compaction, cluster weight, diameter, and berry weight were reduced using GA3. Lastly, 20 and 40 mg L-1 of GA3 increased the total polyphenols and monomeric anthocyanins in the wine.

Datura stramonium L.’da Tohum Uygulamaları ile Dormansinin Kırılması

Purpose: The study aimed to overcome the seed dormancy of Datura stramonium L. by chemical scarification, pre-chilling, and different gibberellic acid (GA3) levels.
 Materials and Methods: The seeds were prechilled at 4°C and 10°C for 7 days and treated with sulfuric acid (97-98% H2SO4) for 15 minutes, and increasing doses of GA3 (250, 500, and 1000 ppm). Distilled water for hydration and untreated seeds served as a control.
 Results: The results showed that no germination was observed in the control and prechilled seeds of Datura stramonium L. The dormancy rate was 100% and the seed dormancy resulted from both hard seed coat and physical dormancy. Mean germination time and germination index of control seeds could not be calculated because no seed germination occurred. Although the chemical scarification showed a beneficial effect for breaking dormancy, the gibberellic acid applications were more effective seed treatments for increasing germination compared to sulfuric acid. The germination percentage increased from 0.0% to 44.5% in the seeds scarified and treated with 1000 ppm GA3, while the germination percentage of primed seeds with 1000 ppm GA3 was 68.5%. Mean germination time was lessened by GA3 doses and scarification. Furthermore, the germination index was promoted by the applications of GA3, especially in the seeds without scarification. The higher germination index was obtained from control seeds under all levels of GA3. The highest shoot length was measured at the highest level of GA3 with 14.6 cm.
 Conclusion: Seed dormancy can be effectively broken by the application of 1000 ppm GA3 without chemical scarification.

Screening of seed germination requirements of some native plants of the Mediterranean region

In the present study, we aim to investigate the seed germination conditions of three Lamiaceae widespread in the Mediterranean region and growing spontaneously in Algeria: Marrubium vulgare L., Rosmarinus officinalis L. and Thymus algeriensis Boiss. et Reut. Two experiments were carried out: (i) Ex vitro germination test: without pre-treatment. Species seeds were sowed directly in the soil under continuous darkness at 4 °C, room temperature (23±2 °C), photoperiod (16 h/light/25±1 °C, 8 h/dark/15±1 °C) and in open green house conditions. (ii) In vitro germination test was achieved by incubating sterile and soaking seeds in various doses of gibberellic acid (GA3) (0, 125, 250, 500 mg/L) under photoperiod (16 h/light/25±1 °C, 8 h/dark/15 ± 1 °C) and continuous darkness (16 h/dark/25±1 °C, 8 h/dark/15±1 °C).In ex vitro experiment, results showed that the combination of darkness and cold, ambient temperature and photoperiod did not present any significant effect (P > 0.05) on germination success rate (GSR) in the three tested species. However, low GSR (23.3%) was observed in both Thymus algeriensis and Marrubium vulgare when seed samples were placed in a greenhouse. An effective sterilization protocol was developed to successfully germinate seeds under in vitro conditions where mercuric chloride (HgCl2) was used as the most powerful sterilizing agent. In in vitro experiment, Thymus algeriensis seeds presented high GSR (66.7% to 83.3%). Furthermore, the application of GA3 at 125, 250, 500 mg/L and continuous darkness resulted in significantly high GSR (P < 0.001) in Marrubium vulgare with 68.3%, 71.6%, 73.3% and 71.7%, respectively. The interaction of GA3 at 125 mg/L and darkness significantly increased the GSR to 93.3%. In addition, GA3 doses, photoperiod-dark and the interaction GA3 × phoroperiod-dark significantly influenced the germination speed (P < 0.001) in Marrubium vulgare. While, all the treatments: GA3 doses, photoperiod-dark and their interactions did not significantly affect the seed germination (P > 0.10) in Rosmarinus officinalis, which showed a very low GSR (6.7%).

The Effect of Different Gibberellic Acid (GA3) Doses on Seed Germination Properties of Some Soybean [Glycine max (L.) Merr.] Cultivars

In this study, the effect of different doses (0 (control), 50, 100, 200 ppm) gibberellic acid (GA3) treatment on the germination properties of Arısoy (C1), Crawford (C2) and Samsoy (C3) soybean cultivars were investigated. The experiments were factorial arranged in a completely randomized design with four replications. As a result of this study, final germination percentage (FGP), mean germination time (MGT), germination index (GI) value, germination energy (GE) value, seedling vigor index (SVI) value, seedling fresh weight (SFW), seedling dry weight (SDW) and seedling length (SL) were determined between 82-93%, 3-4.43 days, 27.8-37.3, 72-93%, 533-988, 0.57-0.71 g, 0.13-0.21 g, 6.5-10.6 cm, respectively. In terms of FGP, MGT, GI, GE, SVI, SL, SDW properties, a significant difference (P<0.01) was determined between cultivars, GA3 doses and cultivar x GA3 doses. Among the GA3 dose treatmens, FGP, GE, SVI, SL values with 100 ppm GA3 treatment and GI values with 150 ppm GA3 treatment reached the highest levels. MGT value was determined at the lowest 150 ppm GA3 treatment dose. Germination parameters were negatively affected with 200 ppm GA3 treatment dose. Responses of cultivars to GA3 doses were variable. In conclusion, seed priming with gibberellic acid (GA3) can be used to enhance germination properties of soybean cultivars.

Endogenous Hormone Profile and Sugars Display Differential Distribution in Leaves and Pseudobulbs of Laelia anceps Plants Induced and Non-Induced to Flowering by Exogenous Gibberellic Acid.

A profile of endogenous hormones and sugars in leaves and pseudobulbs of Laelia anceps subsp. anceps (Orchidaceae) plants induced and non-induced to flowering by the effect of different doses of exogenous gibberellic acid (GA3), considering the current and back growth structures (CGS and BGS), were investigated. A factorial experiment with five doses of GA3 and two growth structures was designed. Adult plants with undifferentiated vegetative buds were selected and sprayed with doses of 0, 400, 600, 800, and 1000 mg GA3 L−1. The main results showed a strong interaction between GA3 dose and growth structures, which promoted the highest kinetin (KIN) concentration in CGS. Exogenous GA3 increased endogenous GA3 in leaves and pseudobulbs induced (I-Leaf and I-PSB) and non-induced (NI-Leaf and NI-PSB) to flowering. For sugar concentration, the 400 mg L−1 GA3 dose promotes significant interaction with the CGS in NI-PSB. In general, the hormone profile revealed opposite balances of endogenous hormone concentrations for KIN, zeatin (ZEA), trans-zeatin (T-ZEA), indoleacetic acid (IAA), indole-3-butyric acid (IBA) and GA3, not only for growth structures but also for vegetative organs analyzed, depending on whether the plants were induced or not induced to flowering, with the highest concentration of endogenous hormones in pseudobulbs. Likewise, different sugar concentration balances were observed. These balances of both endogenous hormones and sugars are likely to be involved in the flowering of L. anceps.

Gibberellic Acid (GA3) Applied to Flowering Heracleum sosnowskyi Decreases Seed Viability Even If Seed Development Is Not Inhibited.

Sosnowsky’s hogweed (Heracleum sosnowskyi Manden.), an important invasive species in Eastern Europe, is a monocarpic perennial plant that propagates exclusively by seeds. Hence, interfering with seed viability could help control its spread. In the present study, we investigated the effect of exogenous GA3 (25, 100 and 150 mg/L) sprayed twice onto flowering H. sosnowskyi plants on the development of fruits (mericarps) and their ability to germinate under field conditions over the growing seasons of 2018 and 2019. Mericarps from plants sprayed with GA3 failed to develop normally. The width/length ratio of mericarps decreased by 23% to 25% after 150 mg/L GA3 application and their average weight decreased between 7% and 39% under all GA3 treatments. X-ray radiographs revealed that the internal structure was malformed, with many of the mericarps lacking well-developed seeds. Proportionally fewer well-developed mericarps were produced by GA3-treated plants than water-sprayed control plants in 2018. Seed germination assessed outdoors in seeds buried in the ground was also severely reduced (from 58% to 99% after 150 mg/L GA3 application). This indicates that exogenous GA3 sprays result in incomplete seed development and a consequent decrease in viability and germination. As the highest GA3 dose used resulted in significantly reduced propagation of Sosnowsky’s hogweed through seeds in the field, GA3 provides a promising approach to the control of the spread of this invasive weed species.

The efficiency of prechilling and gibberellic acid (GA3) for breaking thermodormancy in lettuce

Abstract: The study focused on increasing the germination of lettuce cultivars under high-temperature conditions by seed treatments. The seeds of lettuce cultivars Yedikule, Iceberg, Iri Kıvırcık, and BT Iri Kıvırcık with different leaf morphology were primed by different doses of gibberellic acid (GA3) (0, 250, 500, and 1000 ppm) and preconditioned by chilling and heating. The seeds were germinated at optimal (20 °C) and high (35 °C) temperatures. The results showed that high temperature adversely influenced the germination percentage of lettuce cultivars. The mean germination percentage was 16.8% at 35 °C and 93.4% at 20 °C. Also, there was a significant difference among lettuce cultivars for germination at 35 °C. Iri Kıvırcık and BT Iri Kıvırcık showed a severe thermodormancy and hardly ever germinated at 35 °C. Prechilling and preheating promoted germination at 35 °C compared to unprimed seeds, but prechilling resulted in higher germination than preheating. GA3 was found to be the most useful treatment for improving germination compared to the others. The germination percentage of Iceberg, Yedikule, and Iri Kıvırcık primed with GA3 doses reached over 80%. The results suggested that the germination performance of lettuce cultivars suffering from thermodormancy or wherever climatic conditions with high temperatures should be promoted by the application of 500 ppm de GA3.

EFFECT OF GIBBERELLIC ACID ON GROWTH, TUBER YIELD AND QUALITY IN POTATOES (Solanum tuberosum L.)

The purpose of this study was to determine the effects of different doses of gibberellic acid (GA3) on growth, tuber yield and some tuber quality traits of potato. The experiment was arranged in a split-plot design with three replicates, cultivars Marabel, Alegria and Agria were arranged in the main plots, and GA3 doses (0, 25, 50 and 100 mg GA3 L-1) in the sub-plots. Gibberellic acid was applied to leaves by spraying on the 50th day after planting (during flowering). The effects of GA3 applications on tuber yield of potato cultivars were varied. GA3 applications resulted in significant decrease on chlorophyll content (SPAD), tuber dry matter and chips quality of potato. But it caused significant increase on number of tubers and tuber yield plant-1. In 2019 and 2020 years, the highest tuber yield was obtained from Alegria cultivar (62.78 and 50.55 t ha-1 respectively). Total tuber yield values increased from 52.08 t/ha to 65.14 t ha-1 in 2019 and from 42.12 t ha-1 to 53.94 t ha-1 in 2020 with increasing to 100 mg GA3 L-1 from 0 mgL-1. Overall, increasing doses of GA3 resulted in a reduction in tuber dry matter and starch ratio. The GA3 applications caused deformations in tuber shape, the deformations increased with increasing GA3 doses.

Effects of Moist-Cold Stratification and Gibberellic Acid Applications on Breaking Seed Dormancy in Foxtail Lily (Eremurus spectabilis M.Bieb.)

Eremurus spectabilis is a wild edible perennial herbaceous geophyte species with medicinal and popularornamental uses. In this study, gibberellic acid (GA3) with moist-cold stratification treatments were applied to break thedormancy of E. spectabilis seeds. For this purpose, seeds were soaked in gibberellic acid solutions (GA3: 500 and 750 ppmfor 24 and 48 hours). Pretreated seeds were then subjected to moist-cold stratification treatments for different durations (30,50, 80 and 100 days) at 4 ºC. In 24-hour GA3 treatments, the germination and emergence ratios (21.04%) were obtainedfrom the 500 ppm GA3 dose and 100 days of stratification treatments. In 48-hour GA3 treatments, the GA3 doses did nothave any significant effect on germination and emergence ratios; the greatest germination ratios were obtained from the 500ppm (20.36%) and 750 ppm (20.00%) doses and 100 days of stratification treatments, and the best emergence ratios wereobtained from the 500 ppm GA3 dose and 100 days of stratification treatments (18.51%). It is considered that it is beneficialto try the combinations of moist-cold applications with different treatments in future studies.

SEEDLING EMERGENCY AND BIOMETRY OF FRUITS AND SEEDS OF Cariniana pyriformis FROM THE MIDDLE MAGDALENA VALLEY, COLOMBIA

ABSTRACT Aiming at contributing to the knowledge of the biology and propagation of Cariniana pyriformis Miers, a native species with high timber and ecological attributes, ripe fruits were harvested. Initially, in 400 seeds and 320 fruits, the size, fresh mass, seed water content, number of seeds per fruit, number of seeds per kilogram and fruit color were assessed. Then, a homogenous seed sample was immersed for 24 hours in five doses (0, 250, 500, 750 and 1000 mg.L-1) of gibberellins (GA3) and cultivated in a greenhouse. For this, a completely randomized design was adopted with six replications of 25 seeds each. Fruits and seeds showed values, on average ± standard deviation, of 76.1 ± 11 mm and 48.1 ± 8.2 mm in length, and 49.6 ± 5 mm and 7.2 ± 0.7 mm of width, respectively, with 62.3 ± 22.3 g of fresh mass per fruit and 13 ± 3.1 seeds per fruit. One kilogram corresponded on average to 6715 seeds with 11% water content. In the greenhouse, emergence speed index and emergency percentage of seedlings increased as the GA3 dose increased, allowing a more concentrated emergency process in a shorter period. Highest variation was found for fresh mass per fruit (CV= 35%) and number of seeds per fruit (CV= 24%). Immersion in 1000 mg.L-1 in GA3 for 24 hours triggers seedling emergency in C. pyriformis (approx. 71%), and then it is recommended for plant propagation, since the treatment accelerated and synchronized seedling emergency.

Gibberellic acid reduces clusters rot of ‘Sauvignon blanc’ grapes

Abstract The ripening of grapes is impaired by climatic conditions due to the prolonged rainy season and thus facilitates the proliferation of diseases such as grape clusters rotting, caused by the fungus Botrytis cinerea, even before the ideal harvesting point. The aim of the study was to evaluate the effect of gibberellic acid (GA3) on rot and on physical-chemical quality of ‘Sauvignon Blanc’ grapevine. The experiment was carried out in the production season of 2016 and 2017 in Campanha region in Rio Grande do Sul, Brazil. The GA3 treatments were at the doses of 0 (control); 2; 4; 6 and 8 mg L-1 of GA3. The percentage of clusters rotting and maturation index decreased, however, the titratable acidity increased with GA3 doses. The cluster and rachis length increased with application of GA3. The cluster width; cluster, rachis and berry mass and the soluble solids were not influenced by application of GA3. In ‘Sauvignon Blanc’ grapevine, GA3 reduced the percentage of clusters rotting and improved the cluster and rachis length characteristics and titrable acidity.

Defoliation and Pre-Harvest Drop of Camu-Camu Fruits in Floodable Area

The effect of defoliation and gibberellic acid (GA3) on the fall of the fruit in the induced period of harvest of Myrciaria dubia (camu-camu), in a flooded area on the banks of the Amazon River, Iquitos-Peru, was evaluated. The soil is clayey-silty with 2.15% organic matter, pH 6.29, 0.10% Nitrogen, 40.76 ppm Phosphorus and 228 ppm potassium. The average temperature is 27.45 ° C, relative humidity of 86% and 3111.4 mm of rain. The defoliation was carried out with NaCl solution in water (50 g.L-1). GA3, was applied every 15 days at doses of 0, 50, 100 and 150 mg.L.-1. The variables were evaluated: number of flowers per branch (FLR1-4), number of flowers per plant (FLP1-4),% of fruits retained in phase 3 (FR3),% of fruits retained in phase 5 (FR5), weight of fruits (PF), number of harvested fruits (FC), approximate yield of fruits (RAF), and the real fruit yield (RRF). The design was completely randomized (DCA), in 2x4 factorial arrangement. Defoliation significantly reduced FLP1-4 from 6938 to 3701, while GA3 did not influence that character. Defoliation significantly increased the FR3 retention, but reduced the PF and FC. GA3 significantly influenced FLR1-4, FR3 and PF. In FR5, no statistical difference was recorded for either D or GA3, nor was there significant interaction between the two defoliation and GA3 factors. For FC, RAF and RRF, highly significant differences were found for Defoliation, with superiority of non-defoliated plants but no differences were found for GA3 doses. It is concluded that in F3 the defoliation favored significantly, effect that was diluted in F5, while the application of GA3 negatively influenced this retention. Fruit yield was significantly higher in non-defoliated plants without showing significant difference between GA3 doses.

PERBANYAKAN VEGETATIF BIDARA UPAS (Merremia mammosa (Lour.) Hallier f) KEBUN RAYA BOGOR

Bidara upas (Merremia mammosa (Lour.) Hall.f.) is a medicinal plant, , that traditionaly use by Indonesian and Malaysian people. Regarding Indonesia Biodiversity Strategy and Action Plan released by The National Development Planning Agency, it is included in the extinct medicinal plant list (2003). As the center for plant conservation, Bogor botanical garden conducted vegetative propagation study on this plant by air layering, cutting, and tuber cutting. The aim to this study is to find effective for bidara upas which method is vegetative propagation. Air layering and cutting propagation modified by Rootone-F did not give any result, whereas tuber cutting propagation with GA3 gave positive result. Principally, propagation by tuber cutting modified by 50 ppm of GA3 dose gave the most rapid and highest uniformity on shoot emergence, the best on growing variables, namely average height of shoot growing, the number of secondary roots, the number and length of the primary roots. It cannot be concluded yet that propagation by tuber cutting modified by GA3 was the most effective. Hence, it is necessary to conduct another propagation studies of air layering and cuttings with more variants of treatments, especially Rootone-F dose.

Study of nitrogen and GA3 on growth, flowering and bulbs production of tuberose (Polianthes tuberosa L.) cv. Double

The present investigation was conducted at Horticultural Research Farm J. V. College, Baraut, Baghpat. The experiment carried out following Complete randomized design (CRD) with three replications of eight treatment combinations including three levels GA3 and single dose of nitrogen, In which Tuberose (Polianthes tuberosa L.) cv. Double is used to effect on growth, flowering and bulb production response of GA3 (100, 150 and 200 ppm) and single dose of nitrogen 7g along with having control, these doses were applied with check. Growth regulators results also indicated that, GA3 150 ppm and nitrogen @7g/pot decreases the days to sprouting and increases maximum number of sprout per bulb as compared to other treatment of gibberellic acid, while GA3 200 ppm and nitrogen @ 7 g observed the better effect on , number of leaves per plant, length of leaf, days taken to first flowering spike initiation, number of florets per spike, length of spike, number of spikes per plant, weight of spike and bulb production bulbs per plant of tuberose in western Uttar Pradesh condition.

Assessment of Appropriate Doses of GA3 and Row Ratio for Better Seed Yield of a Promising Hybrid Rice Variety

A field experiment was carried out at the Bangladesh Rice Research Institute (BRRI) farm, Gazipur during dry season 2013-14 to find out the appropriate GA3 dose and row ratio for hybrid seed production. GA3 doses were applied @ 0, 80, 160, 240 and 320 g ha-1 with different row ratio. Results revealed that GA3 application influenced the panicle exsertion rate only. The calculated optimum GA3 dose was 302.4 g ha-1 with the highest PER (84.62%). Seed yield and OCR were influenced by row ratio. The highest OCR was observed with 2:12 row ratio while the highest seed yield was found in 2:14 row ratio.Bangladesh Rice j. 2015, 19(1): 57-61

Determination of Gibberellic Acid (GA3)-Induced Oxidative Stress in a Model Organism Galleria mellonella L. (Lepidoptera: Pyralidae).

The plant growth regulator gibberellic acid (GA3) is known to negatively impact growth and development of insects. In this study, larvae of Galleria mellonella L. (Lepidoptera: Pyralidae) were fed a diet with varying dosages of GA3 to investigate how antioxidant enzymes are influenced. Activity levels in last instars reared in laboratory at 25 ± 2°C, 60 ± 5% relative humidity, and a photoperiod of 12:12 (L:D) h were measured for superoxide dismutase (SOD), glutathione S-transferase (GST), and catalase (CAT). Treatment with GA3 in diet resulted in a remarkable increase in the activities of both SOD and GST at lower GA3 doses (50-1,000 ppm) with respect to control and higher doses. The activity of CAT in the hemolymph of last instars significantly increased at all doses when compared with that in the hemolymph of untreated larvae. This trend in the increase of CAT was not dose-wise, except for the significant increases at 2,000 and 5,000 ppm when compared with that of untreated and all treated groups. Consequently, our results showed that GA3 is effective at activating the antioxidant defense system of insects as a source of free radical and can be toxic for larvae in a dose-dependent manner. Therefore, we suggest that the increase in the activity of GST, SOD, and CAT in larvae may indicate a physiological adaptability to compensate for GA3-induced stress.

Effects of Gibberellic Acid on Hemolymph-Free Amino Acids of Galleria mellonella (Lepidoptera: Pyralidae) and Endoparasitoid Pimpla turionellae (Hymenoptera: Ichneumonidae)

Abstract The impacts of the plant growth regulator, gibberellic acid (GA3) were investigated on hemolymph free amino acids (FAAs) of Galleria mellonella L. (Lepidoptera: Pyralidae) larvae and its endoparasitoid Pimpla turionellae L. (Hymenoptera: Ichneumonidae) reared on host treated with different doses (50–5,000 ppm) of GA3 in diet. High-performance liquid chromatographic analysis of the hemolymph revealed that out of the 20 amino acids detected, 18 FAAs were found in the hemolymph of treated and untreated host larvae, whereas 19 were present in that of parasitoid. The total pool of FAAs in host larvae after treatment by GA3 fluctuated among doses and the ratio of essential amino acids in the pool increased to reach 9.54% at 1,000 ppm. Parasitoid larval total FAA concentration exhibited an increase at all treatments. However, the ratio of essential amino acids in the pool decreased &amp;gt;50% at all doses except for 50 ppm. Dose-dependent variations in individual FAAs in larval hemolymph of both species were also detected. Tyrosine, methionine, isoleucine, lysine, and tryptophan generally occurred in lowest amount both in control and treated G. mellonella larvae. The amount of serine, asparagine, glycine, isoleucine, leucine, and phenylalanine displayed differences only among GA3 doses in treatments. Great variations in the amount of all amino acids occurred at most of the treatment doses in wasp larvae hemolymph. Our study indicated that application of GA3 resulted in different effects on the quantity of FAAs associated with energy metabolisms of the pest species and its natural enemy.