Gladiolus (Gladiolus hybridus Hort.) is an important bulbous cut-flower crop and is famous for keeping- quality and exhaustive range of spike colour. Gladiolus hybrids currently under cultivation seem to have developed genetically form 23 sps. (Arora et al. 2002). In the cut- flower industry, gladiolus occupies the fourth place in international cut-flower trade (Bhattacharyaji, 2003). The most common method of improving gladiolus is through hybridization. Since gladiolus is highly heterozygous (Misra and Saini, 1990), it is essential to evaluate the wide germplasm available before adopting hybridization programmes to exploit the diversity in growth and flowering traits. An investigation was carried out on seven gladiolus varieties representing diverse morphological characters. These varieties were crossed by the half diallel method and were also selfed. The seeds were sown in seed beds and the material was carried to four cycles to obtain the required size of corms. Twenty one hybrids, along with their parents, were planted in a polyhouse in January, 2007 at Kittur Rani Chennamma College of Horticulture (University of Agricultural Sciences, Dharwad), Arabhavi in Randomized Block Design with two replications in raised beds with spacing of 30 x 20 cm Short communication J. Hortl. Sci. Vol. 4 (2): 177-180, 2009 Genetic variability in gladiolus for growth and flowering characters (Gladiolus hybridus Hort.) P. Hemanth Kumar and B.S. Kulkarni Department of Floriculture and Landscaping K.R.C. College of Horticulture, Arabhavi -591 310, India Gokak, Belgaum Dist, Karnataka E-mail: balajikrcch@gmail.com ABSTRACT Gladiolus Sylvia x Melody exhibited early corm-sprouting (6.82 days). The hybrid Melody x Summer Sunshine (84.63 cm), followed by American Beauty x Pricella (84.12 cm) were tall. Maximum stem girth was observed in American Beauty x Summer Sunshine (35.31 mm), followed by Vedanapoli x Magic (33.71mm) and American Beauty x Melody (33.47 mm). Number of leaves per plant was higher in Melody x Magic (9.62), followed by Salvia x Magic (9.49) and Melody x Vedanapoli (9.42). The length was maximum (67.32 cm) in Melody x Summer Sunshine followed by Summer Sunshine x Pricella (67.57 cm), American Beauty x Vedanapoli (67.00 cm) and Vedanapoli x Pricella (66.06 cm). The hybrid Salvia x Melody was earliest to initiate flower bud (60.58 days) and first floret opening (69.04 days). The total duration of flowering was maximum in Vedanapoli x Magic. Key words: Half-diallel, genetic variability, flowering, gladiolus and the data were collected for five randomly selected plants from each parents and F 1 ’s. Observations on different growth and flowering parameters were recorded in five randomly selected plants from each parent and F 1 and statistically analyzed to find out the significance of differences (Cochran and Cox, 1964). Analysis of variance revealed that all the growth and flowering characters were highly significant except leaf width (Table 1). Among the parents cv. Sylvia exhibited and late sprouting (20.60 days) was observed in cv. Magic (Table 2). Among the hybrids, Sylvia x Melody exhibited early sprouting (6.82 days), Vedanapoli x Magic (22.92 days) and Summer Sunshine x Vedanapoli (20.67 days) were late to sprout. The cv. Priscilla produced tallest plants (79.40 cm) at 90 days after planting followed by Summer Sunshine (78.94 cm) while Sylvia (58.49 cm) was the shortest. Swaroop et al. (2005) reported that cv. Sylvia had shorter plants (74.33 cm) plant height, which closely confirms present investigation. Among the hybrids, highest plant height (84.63 cm) was observed in Melody x Summer Sunshine, followed by American Beauty x Priscilla (84.12 cm) and Summer Sunshine x Priscilla (82.54 cm), while, the lowest plant height (57.58 cm) was recorded in Sylvia x Melody. 178 Maximum stem girth (32.17 mm) was observed in the cv. American Beauty, followed by Vedanapoli (31.61 mm) and Summer Sunshine (30.95 mm), while, the hybrids American Beauty x Summer Sunshine exhibited maximum stem girth (35.31 mm), followed by Vedanapoli x Magic (33.71 mm), American Beauty x Melody (33.47 mm). The minimum stem girth (22.18 mm) was recorded in Sylvia x Magic (Table 2). Table 1. Mean sum of squares for vegetative parameters in a 7 X 7 diallele cross of gladiolus (Gladiolus hybridus Hort.) Sl. No. Trait Sources CD at CD at Treatment Error 5% 1% 1 Days to sprouting 47.29** 2.67 4.90 5.90 2 Plant height 142.55** 13.84 10.50 13.77 3 Stem girth 31.86* 4.58 5.91 7.75 4 No. of leaves 0.5946** 0.21 1.26 1.66 5 Leaf length 105.62** 10.19 0.88 1.15 6 Leaf width 0.42 0.16 1.13 1.46 7 Days required for bud initiation 84.59** 5.17 6.27 8.22 8 Days required for first floret opening 87.44** 7.49 7.46 9.81 9 Days required for first to last floret opening 4.34** 1.13 2.92 3.84 10 Duration of flowering 10.89** 1.20 3.01 3.94 d. f. 27 27 *Significant at 5% level, **Significant at 1% level Table 2. Mean performance of parents and hybrids (F 1 ’s) with respect to vegetative parameters in gladiolus (Gladiolus hybridus Hort.) Sl.No. Parent Days to Plant Stem girth No. of Leaf length Leaf width sprouting height (cm) (mm) leaves (cm) (cm) 1 A. Beauty 8.03 73.04 32.17 8.57 59.00 3.66 2 Sylvia 6.90 58.49 20.69 8.06 47.80 3.82 3 Melody 11.07 71.56 22.97 8.56 50.87 4.07 4 S. Sunshine 15.59 78.94 30.95 8.54 63.25 4.89 5 Vedanapoli 18.47 76.38 31.61 9.20 57.81 7.03 6 Magic 20.60 65.49 28.28 8.09 53.35 3.85 7 Priscilla 13.26 79.40 29.51 8.44 69.07 3.21 Hybrid 1 A. Beauty x Sylvia 20.20 66.96 26.56 8.14 54.11 3.45 2 A. Beauty x Melody 18.89 62.53 33.47 8.02 57.49 3.91 3 A. Beauty x S. Sunshine 15.26 73.49 35.31 7.99 60.83 4.28 4 A. Beauty x Vedanapoli 15.74 81.07 30.94 7.96 67.0 3.70 5 A. Beauty x Magic 19.69 68.75 26.61 8.62 52.26 4.11 6 A. Beauty x Priscilla 11.01 84.12 30.87 8.18 62.29 4.55 7 Sylvia x Melody 6.82 57.58 25.97 8.86 52.00 3.83 8 Sylvia x S. Sunshine 16.44 62.73 22.28 8.45 52.49 3.03 9 Sylvia x Vedanapoli 11.12 68.36 27.44 7.93 54.24 4.22 10 Sylvia x Magic 13.12 59.63 22.18 9.49 44.52 3.77 11 Sylvia x Priscilla 7.29 66.07 31.10 9.14 51.63 3.97 12 Melody x S. Sunshine 10.60 84.63 27.25 8.20 67.62 3.90 13 Melody x Vedanpoli 8.40 66.07 22.42 9.42 53.68 4.20 14 Melody x Magic 17.24 66.25 31.15 9.62 52.82 4.18 15 Melody x Priscilla 12.52 70.24 26.24 8.44 57.07 3.86 16 S. Sunshine x Vedanpoli 20.67 79.53 33.12 8.56 64.71 4.75 17 S. Sunshine x Magic 22.28 68.96 25.24 9.10 52.30 3.74 18 S. Sunshine x Priscilla 13.56 82.54 29.43 7.64 67.57 4.05 19 Vedanpoli x Magic 22.92 57.49 33.71 9.34 48.22 4.72 20 Vedanpoli x Priscilla 15.27 81.26 24.04 8.16 66.06 3.65 21 Magic x Priscilla 18.56 71.07 29.73 9.01 58.40 3.62 S. Em± 1.63 3.69 2.14 0.45 3.19 0.40 J. Hortl. Sci. Vol. 4 (2): 177-180, 2009 Hemanth Kumar and Kulkarni 179 Vedanapoli produced maximum number of leaves per plant (9.20), followed by American Beauty (8.5) and Melody (8.56). Among the hybrids, Melody x Magic recorded maximum number of leaves per plant (9.62), followed by Sylvia x Magic (9.49) and Melody x Vedanapoli (9.42). Minimum number of leaves (7.64) was observed in hybrid Summer Sunshine x Priscilla. Number of leaves may be related to stored food reserve in the corms (Sharma and Gupta, 2003). The length of leaves was maximum (69.07 cm) in cv. Priscilla, followed by Summer Sunshine (63.25 cm). Among the hybrids Melody x Summer Sunshine (67.62 cm) recorded maximum leaf length, followed by Summer Sunshine x Priscilla (67.0 cm) and Vedanapoli x Priscilla (66.06 cm), while, minimum length (44.52 cm) was observed in Sylvia x Magic. Maximum width of leaves at mid-point was recorded in Summer Sunshine x Vedanapoli (4.75 cm), Table 3. Mean performance of parents and F 1 hybrids with respect to flowering in gladiolus (Gladiolus hybridus Hort.) Sl.No. Parent Days for bud Days for first floret Days for first to Duration of initiation opening last floret opening flowering 1 A. Beauty 62.81 70.67 14.38 15.11 2 Sylvia 66.14 72.97 12.12 10.66 3 Melody 63.25 72.80 13.68 15.77 4 S. Sunshine 66.86 75.12 14.57 12.40 5 Vedanapoli 77.71 85.18 14.57 15.86 6 Magic 80.93 88.72 13.34 17.92 7 Priscilla 71.88 80.40 13.69 17.28 Hybrid 1 A. Beauty x Sylvia 68.93 77.34 13.23 14.69 2 A. Beauty x Melody 61.76 69.71 10.57 12.69 3 A. Beauty x S. Sunshine 68.10 76.90 15.30 15.69 4 A. Beauty x Vedanapoli 70.16 77.57 15.22 15.33 5 A. Beauty x Magic 82.11 89.11 13.42 14.06 6 A. Beauty x Priscilla 61.24 71.68 13.07 16.28 7 Sylvia x Melody 60.58 69.04 11.51 12.95 8 Sylvia x S. Sunshine 68.07 76.46 15.24 9.33 9 Sylvia x Vedanapoli 63.94 71.87 13.72 16.69 10 Sylvia x Magic 65.74 71.43 10.15 15.68 11 Sylvia x Priscilla 69.19 79.29 11.16 14.24 12 Melody x S. Sunshine 68.73 76.40 14.16 16.33 13 Melody x Vedanpoli 62.18 70.43 15.16 13.75 14 Melody x Magic 69.93 78.47 11.89 15.88 15 Melody x Priscilla 67.34 75.24 12.40 15.89 16 S. Sunshine x Vedanpoli 74.69 82.37 15.25 16.75 17 S. Sunshine x Magic 78.62 89.93 13.78 16.56 18 S. Sunshinex Priscilla 66.23 73.86 13.34 11.57 19 Vedanpoli x Magic 82.21 90.52 15.40 19.35 20 Vedanpoli x Priscilla 73.90 84.62 13.18 13.91 21 Magic x Priscilla 77.22 84.62 14.40 18.92 S. Em± 2.27 2.73 1.06 1.09 followed by Vedanapoli x Magic (4.72 cm) and American Beauty x Priscilla (4.55 cm), and, minimum (3.03 cm) was recorded in Sylvia x Summer Sunshine. Data (Table 3) on number of days for flower bud initiation revealed that cv. American Beauty was the earliest to exhibit flower bud initiation (62.81 days), followed by Melody (63.25 days) while the hybrid Sylvia x Melody was the earliest (60.58 days) followed by American Beauty x Priscilla (61.24 days) and American Beauty x Melody (61.76 days). The hybrid Vedanapoli x Magic (82.21 days) was the last to initiate flower bud. Arora and Khanna (1985) reported that time taken for spike emergence varied significantly among various cultivars. These findings are closely confirmed with the present results. Further, Neeraj et al. (2000) suggested that gladiolus can be grouped as early, mid, late and may be cultivated for longer duration of flowering and garden display. The cv. American Beauty took Genetic variability in gladiolus J. Hortl. Sci. Vol. 4 (2): 177-180, 2009 180 less days (70.67 days) for first floret opening followed by Melody (72.80 days) and Sylvia (72.97 days) while the hybrid Sylvia x Melody took less (69.04 days) days for first floret opening followed by American Beauty x Melody (69.71 days) and Sylvia x Magic (71.43 days). Where as the hybrid Vedanapoli x Magic took maximum (90.52 days) number of days for first floret opening. The range for days for first floret opening was between 69.71 to 90.52 days. Similar range for first flowering was observed by Swaroop et al. (2005). The variety Summer Sunshine and Vedanapoli (14.5 days) took more number of days for first to last floret opening followed by American Beauty (14.38 days) while the hybrids Vedanapoli x Magic took more number of days (15.40 days) followed by Summer Sunshine x Vedanapoli (15.25 days) and Sylvia x Summer Sunshine (15.24 days). The parents Sylvia exhibited shorter flowering duration (10.66 days) followed by Summer Sunshine (12.40 days) and American Beauty (15.11 days). While the hybrid Sylvia x Summer Sunshine reported shorter flowering duration (9.33 days) followed by Summer Sunshine x Priscilla (11.57 days) and American Beauty x Melody (12.69 days). Where as the hybrid Vedanapoli x Magic exhibited wider flowering duration (19.35 days). The range for flowering duration was observed between 11.33 to 19.35 days, while Saini et al. (1991) reported a range of 17 to 25.9 days in the field experiment. Considerable morphological variation was observed for all the characters except for the leaf width among the various parents and F 1 ’s. Hence these characters could be considered as useful selection criteria for further improvement in gladiolus. Among 21 hybrids, American Beauty x Vedanapoli, American Beauty x Priscilla, Melody x Summer Sunshine, Summer Sunshine x Vedanapoli, Summer Sunshine x Priscilla, Vedanapoli x Magic, and Vedanapoli x Priscilla were found to be promising for various growth characters and American Beauty x Melody, Sylvia x Melody, Melody x Vedanapoli, Summer Sunshine x Priscilla and American Beauty x Priscilla were found to be promising for various flowering characters. REFERENCES Arora., J. S. and Khanna, K. 1985, Evaluation of gladiolus cultivars. J. of Res. Punjab Agril. Univ., 22:635-662 Arora J.S., Misra R.L., Singh K., Singh, P. and Bhattacharjee S.K., 2002. Gladiolus. Technical Bulletin No.14. Publlished by All India Coordinated Research Project on Floriculture, Division of Floriculture and Landscaping, Indian Agriculture Research Institute, New Delhi- 110 012, India, pp 110 Bose, T. K. and Yadav, L, P., 1989. Commercial Flowers. Naya Prokash Publications, Culcutta, pp 267-350 Cochran, W.G. and Cox, J.M, 1964. Experimental Designs. John Wiley & Sons, London Misra, R.L. and Saini, H.C. 1990.Correlation and path- coefficient studies in gladiolus. Ind. J. Hort., 47:127- 132 Neeraj, Mishra, H.P. and Jha, P.B. 2000. Evaluation of gladiolus germplasm under North Bihar conditions. Ind. J. Hort., 57:178-181 Saini, R.S., Gupta, A.K. and Yamdagni, R. 1991. Performance of different cultivars of gladiolus (Gladiolus floribundus L.) under Hissar conditions. South Ind. Hort. 39:99-101 Sharma, T.R. and Gupta, R.B. 2003. Effect of corm size and spacing on growth, flowering and corm production in gladiolus. J. Orn. Hort., 6:352-356 Swaroop, K., Singh, K.P and Singh, K.P. 2005. Performance of gladiolus under Delhi conditions. J. Orn. Hort., 8:31-35 (MS Received 7 August 2007, Revised 24 August 2009) J. Hortl. Sci. Vol. 4 (2): 177-180, 2009 Hemanth Kumar and Kulkarni