Of the various seasonal flowers, Gaillardia (Gaillardia pulchella Foug.) is an important flower crop of the Asteraceae family. It is commonly known as “Blanket Flower” and is a native of America. Gaillardia is fast gaining prominence as a commercial crop, owing to its wide adaptability to varying soil and climatic conditions, better resistance to pest and diseases, hardy nature, long duration of flowering and attractive flower colour. In the Saurashtra region of Gujarat, flowers of Gaillardia are extensively used in preparation of garlands and for decoration purpose during weddings, religious ceremonies, festivals and social gatherings. It is widely marketed as a loose flower and often as a substitute for marigold and chrysanthemum, whenever these flowers are in short supply or out of season. In recent years, idea of regulating plant growth, flower yield and quality by application of plant growth regulators has assumed significant importance. Therefore an attempt was made to study the response of Gaillardia to gibberellic acid at three different concentrations and frequencies. The present experiment was conducted at the Horticultural Instructional Farm, Department of Horticulture, J.A.U., Junagadh during winter season of the year 2004- 05. The experiment was laid out in a Randomized Block Design (RBD) with three replications and ten treatments including control. The treatments comprised of three Short communication Effect of different GA 3 concentration and frequency on growth, flowering and yield in Gaillardia (Gaillardia pulchella Foug.) cv. Lorenziana D.V. Delvadia, T.R. Ahlawat and B.J. Meena Department of Horticulture Junagadh Agricultural University Junagadh-362 001, India E-mail: tahlawat@jau.in ABSTRACT The present experiment was conducted at the Horticultural Instructional Farm, Department of Horticulture, J.A.U., Junagadh during the winter 2004-05. The experiment comprised of ten treatments, viz., three concentrations of GA 3 (50, 150, 250 ppm) at three frequencies (single, double and triple spray at 30, 45 and 60 days from transplanting) and control. Each treatment was replicated thrice in randomized block design. Of the different treatments, GA 3 250 ppm single spray recorded maximum plant height and plant spread. Number of branches per plant was highest under double spray of GA 3 at 50 ppm. Longest flowering duration, maximum flower diameter and maximum shelf-life were observed with single spray of 250 ppm GA 3 . It also registered maximum number and weight of flowers per plant besides highest flower yield. Keywords: Gaillardia, GA 3 , growth, flowering, yield concentrations of GA 3 (50, 150 and 250 ppm) and three frequencies single, double and triple sprays. GA 3 was sprayed thrice, starting from 30 days of transplantation and at 15 days intervals for second and third sprays. The seedlings of Gaillardia were transplanted at a spacing of 45 x 45 cm. Uniform cultural practices were followed to raise a good crop. Five plants were selected randomly from the net plot in each treatment and tagged for the purpose of recording different observations. Characters such as plant height, plant spread, number of branches per plant and shelf- life were recorded at full bloom stage. The duration from first flower opening to final harvesting was recorded as flowering span. Flower diameter was measured using Vernier caliper. Number and weight of flowers per plant was computed by summing up number and weight of flowers obtained during each plucking from randomly selected five plants. The data were expressed per plant. While flower yield was calculated by multiplying average weight of flower with total number of flowers per plant. The data thus generated were statistically analyzed. Effect on growth parameters Plant height was significantly influenced by GA 3 at all levels (Table 1). The maximum height was recorded with J. Hortl. Sci. Vol. 4 (1): 81-84, 2009 82 a single spray and triple spray of GA 3 at 250 ppm (45.20 cm and 43.24 cm respectively). GA 3 was known to increase the plant height by influencing the internodal length, attributable to both cell division and cell elongation (Reddy and Sulladmath, 1983). Increased auxin content was reported due to the application of GA 3 and resulting in apical dominance, which may also have contributed to the increased plant height (Scott et al, 1967). Promotion in plant height as a consequence of GA 3 application was earlier reported by Makwana (1999) in Gaillardia. A somewhat similar trend was observed in plant spread where all treatments registered a significant increase in plant spread over control. A single spray of GA 3 at 250 ppm registered the maximum plant spread (39.10 cm). According to Verma (1991) it was due to the formation of new cells in meristematic region and an increase in size and mass of cells produced. Similar findings were also reported by Singh et al (1991) in marigold. A significant increase in number of branches per plant was observed with the application of a single spray of GA 3 at 250 ppm, double spray of GA 3 at 50, 150 and 250 ppm and a triple spray of GA 3 at 150 and 250 ppm. Of the above treatments, GA 3 50 ppm double spray yielded the highest number of branches per plant (24.33). Increase in the number of branches with GA 3 treatment may be due to the hyper elongation of internodal length and a resultant increase in nodal count on the main axis. Consequently these nodes increased number of dormant buds from where the primary branches may have originated (Krishna Kumar and Ughreja, 1998). This confirms the report on an increase in number of branches with GA 3 application in Gaillardia by Patel (1998). Effect on flowering traits The influence of varying GA 3 levels on flowering traits and shelf-life of Gaillardia indicated significant differences in the flowering span, flower diameter and shelf life as affected by various treatments (Table 2). GA 3 250 ppm single spray, GA 3 50 ppm double spray and GA 3 250 ppm triple spray recorded a significant increase in flowering span. Advanced bud formation and onset of flowering in GA 3 treated plants was attributed to enhanced flowering duration (Dutta et al, 1993). Prolonged flowering duration owing to GA 3 was also documented by Dahiya and Rana (2001) in chrysanthemum. A 250 ppm single spray, 250 ppm triple spray, 150 and 50 ppm single spray of GA 3 showed a significant increase in flower diameter over control. They were all at par with each other. The enlargement in flower size is caused by drawing of photosynthates to the flower as a consequence of increased sink activity (Zieslin et al, 1974). According to Dutta et al (1993) the enhancement in flower size might be due to an increase in the length of the petals and pedicels accompanied by increased number of petals. It is in conformity with the observations of Meher et al (1999) in chrysanthemum. A single spray of GA 3 at 150 and 250 ppm significantly enhanced the shelf-life of flowers. These treatments were at par with each other. The maximum shelf life (72.80 h) was observed when the plants were subjected to a single spray of GA 3 at 250 ppm. GA 3 reduces water loss and has anti-senescence properties leading to enhanced shelf-life of flowers (Singh et al, 1994). Similar results were Table 1. Effect of various GA 3 concentrations and frequencies on vegetative growth in Gaillardia Treatment Plant height Plant spread No. of at full at full branches/ bloom (cm) bloom (cm) plant T 1 GA 3 50 ppm single 25.40 35.60 15.00 T 2 GA 3 150 ppm single 34.25 37.96 13.68 T 3 GA 3 250 ppm single 45.20 39.10 16.68 T 4 GA 3 50 ppm double 39.80 27.96 24.33 T 5 GA 3 150 ppm double 39.89 22.13 19.68 T 6 GA 3 250 ppm double 41.54 29.06 17.00 T 7 GA 3 50 ppm triple 39.60 26.83 11.33 T 8 GA 3 150 ppm triple 42.42 24.87 15.68 T 9 GA 3 250 ppm triple 43.24 29.90 19.67 T 10 Control 22.96 20.10 12.00 S. Em + 0.82 0.68 1.04 C. D. (P = 0.05) 2.44 2.02 3.10 C. V. % 3.61 4.14 10.64 Table 2. Effect of varying GA 3 levels and frequencies on flowering traits and shelf life in Gaillardia Treatment Flowering Flower Shelf-life span diameter of loose (days) (cm) flowers (hours) T 1 GA 3 50 ppm single 80.33 5.85 68.20 T 2 GA 3 150 ppm single 75.00 5.86 71.10 T 3 GA 3 250 ppm single 91.33 6.30 72.80 T 4 GA 3 50 ppm double 86.00 5.75 63.33 T 5 GA 3 150 ppm double 71.66 5.55 65.80 T 6 GA 3 250 ppm double 63.33 5.49 60.73 T 7 GA 3 50 ppm triple 58.33 5.67 69.43 T 8 GA 3 150 ppm triple 74.66 5.71 70.40 T 9 GA 3 250 ppm triple 85.33 5.95 67.87 T 1 0 Control 73.33 5.32 68.10 S. Em + 3.38 0.12 0.90 C. D. (P = 0.05) 7.06 0.50 2.72 C. V. % 5.42 5.20 4.05 J. Hortl. Sci. Vol. 4 (1): 81-84, 2009 Delvadia et al 83 also reported by Dutta and Seemanthini (1998) in chrysanthemum. Effect on yield characters Significant differences in flower yield and its associated traits were observed with application of GA 3 (Table 3). With the sole exception of GA 3 250 ppm double spray, all other treatments recorded a significant increase in number of flowers over control. Maximum numbers of flowers (150.48) were observed with a single spray of GA 3 at 250 ppm. This is attributed to the production of large number of laterals at an early stage of growth, which then had sufficient time to accumulate reserve carbohydrates for proper flower bud differentiation (Dutta et al, 1993). Increasing number of flowers per plant was observed because of the production of large number of branches and more plant spread due to GA 3 application. This result finds support from the findings of Poshiya et al (1995) in Gaillardia. All treatments proved significantly superior over control in increasing weight of flowers per plant. Single spray of GA 3 at 250 ppm registered the highest flower weight (341.60 g). This treatment was at par with a single spray of GA 3 at 50 and 150 ppm, a double spray of GA 3 50 ppm and a triple spray of GA 3 at 150 ppm. Increase in weight of flowers per plant with GA 3 may be attributed to the production of more number of flowers with larger size and more florets. Dehale et al (1993) also observed similar results in chrysanthemum with GA 3 application. A significant increase in flower yield was observed by the application of GA 3 at all levels. A single spray of GA 3 at 250 ppm recorded the highest flower yield (18.06 t/ ha). The increase in flower yield was due to the production of more number of flowers per plant and improvement in weight of flowers per plant. Similar results were reported by Pandya (2000) in marigold. It can thus be inferred that a single spray of GA 3 at 250 ppm was found best for optimum growth and production of Gaillardia flowers under South Saurashtra conditions of Gujarat. REFERENCES Dahiya, D.S. and Rana, G.S. 2001. Regulation of flowering in chrysanthemum as influenced by GA 3 and shade- houses of different intensities. South Ind. Hort., 49:313-314 Dehale, M.H., Deshmukh, P.P. and Moharkar, V.K. 1993. Influence of foliar application of GA 3 on quality of chrysanthemum. J. Soils and Crops, 3:135-137 Dutta, J.P. and Seemanthini, R. 1998. Growth and flowering response of chrysanthemum (Dendranthema grandiflora cv. Tzvelev.) to growth regulator treatments. Orissa J. Hort., 26:70-75 Dutta, J.P., Seemanthini, Ramdas and Khader. A.M.D. 1993. Regulation of flowering by growth regulators in chrysanthemum (Chrysanthemum indicum L.) cv. CO-1. South Ind. Hort., 41:293-299 Krishna Kumar and Ughreja, P.P. 1998. Effect of foliar application of GA 3 , NAA, MH and Ethrel on growth, flowering and yield of chrysanthemum (Chrysanthemum morifolium Ram.) cv. IIHR-6. J. Applied Hort., 4:20-26 Makwana, M.K. 1999. The effect of plant growth regulators on growth, yield and quality of gaillardia (Gaillardia pulchella) cv. Lorenziana. M.Sc. (Agri.) thesis, GAU, Sardar Krushinagar Meher, S. P., Jitode, D.J., Turkhede, A.B., Darange, S.O., Ghatol, P.U. and Dhawad, C.S. 1999. Effect of planting time and growth regulator treatments on flowering and yield of chrysanthemum (Chrysanthemum morifolium Ramat). Crop Res., 18:345-348 Pandya, P.N. 2000. Effect of plant growth regulators on growth, yield and vase life of African marigold (Tagetes erecta L.) cv. Lemon Yellow. M. Sc. thesis GAU, Sardar Krushinagar Patel, S.L. 1998. Effect of plant growth regulators on growth, flowering and flower yield of annual (Gaillardia pulchella) var. Lorenziana. M.Sc. (Agri). thesis, GAU, Sardar Krushinagar Table 3. Effect of different GA 3 levels and frequencies on yield characters in Gaillardia Treatment No. of Total Flower flowersper weight of yield plant flowersper (t/ha) plant(g) T 1 GA 3 50 ppm single 120.20 320.20 15.68 T 2 GA 3 150 ppm single 131.80 323.90 16.08 T 3 GA 3 250 ppm single 150.48 341.60 18.06 T 4 GA 3 50 ppm double 104.53 319.80 15.09 T 5 GA 3 150 ppm double 97.25 290.10 14.21 T 6 GA 3 250 ppm double 91.30 288.03 14.06 T 7 GA 3 50 ppm triple 110.67 312.93 15.35 T 8 GA 3 150 ppm triple 122.10 323.10 15.85 T 9 GA 3 250 ppm triple 102.93 312.43 15.52 T 1 0 Control 82.20 259.50 12.51 S. Em + 3.14 9.53 0.41 C. D. (P = 0.05) 10.14 28.10 1.33 C. V. % 5.32 5.18 5.10 Effect of gibberellic acid on Gaillardia J. Hortl. Sci. Vol. 4 (1): 81-84, 2009 84 Poshiya, V.K., Katariya, G.K. and Chovatia V.P. 1995. Effect of growth substances on growth and yield in gaillardia. J. Applied Hort., 1:99-100 Reddy, Y.T.N. and Sulladmath, U.V. 1983. 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