IN VITRO PROPAGATION OF GLADIOLUS (Gladiolus grandiflorus)

Abstract

Gladiolus (Gladiolus grandiflorus) being a potential ornamental cut flower is cultivated throughout the world for its attractive spikes. The present study was intended to establish a protocol for in vitro plant regeneration of two gladiolus varieties. This research was conducted in tissue culture laboratory of Genetics and Plant Breeding Department, Sher-e-Bangla Agricultural University, Dhaka. The cormels of each variety as explants and media supplemented with various plant growth regulators (BAP, BA, NAA and IBA) of different concentrations were explored in In vitro propagation techniques. The effect of different combination and concentration of plant growth regulators on in vitro callus induction and plant regeneration was studied. The maximum days (7.58 days) required to callus initiation was noticed in T7 (2.0 mg/L BAP+ 1.0 mg /L NAA) in yellow variety (V1) and the minimum days (4.06 days) to callus initiation was found in white variety(V2) with T9 (1.5 mg/L BAP+ 1.5 mg/L NAA). The highest size of callus (0.93, 1.67 and 2.80 cm at 14, 28 and 42 DAI, respectively) found in the white variety (V2)was observed in T9 (1.5 mg/L BAP + 1.5 mg /L NAA) and the minimum size of callus (0.50, 0.92 and 1.52 cm at 14, 28 and 42 DAI) was found in yellow variety (V1) in T7 (2.0 mg/L BAP+ 1.0 mg/L NAA). The highest fresh callus weight (0.95. 1.67 and 3.11 g at 14, 28 and 42 DAI, respectively) was recorded in white variety (V2) in response to T9 (1.5 mg/L BAP+1.5 mg/L NAA) and the lowest fresh callus weight i.e. 0.45 and 2.08 g at 14 and 28 DAI respectively in T7 (2.0 mg/L BAP+1.0 mg/L NAA) and 1.00g in T8(1.0 mg/L BAP+1.5 mg/L NAA) was recorded in yellow variety (V1). The minimum days (6.61 days) to shoot initiation was found in T4 (3 mg/L BA) in white variety (V2) and the maximum days (25.20 days) to shoot initiation was found in T7 (2.0 mg/L BA+ 0.5 mg/L NAA)in yellow variety (V1). T4 (3.0 mg/L BA) showed the highest number of shoots(7.47, 13.20 and 17.87 at 14, 28 and 42 DAI, respectively) in white variety (V2). White variety (V2) produced the longest shoot i.e. (3.86, 5.67 and 8.11 cm at 14, 28 and 42 DAI, respectively) in T4 (3 mg/L BA) and yellow variety (V1) produced the smallest shoots (0.00, 0.50 and 0.80 cm at 14, 28 and 42 DAI, respectively) in T8 (3.0 mg/L BA+ 0.5 mg/L NAA). The maximum days (23.20 days) to root initiation, was found in yellow variety with T7 (2.0 mg/L NAA) and the minimum days (6.12 days) to root initiation in white variety (V2) at T3 (1.5 mg/L IBA). The maximum no. of roots i.e. 2.56, 4.94 and 8.33 was found in white variety with T4 (2.0 mg/L IBA) at 14, 28 and 42 DAI, respectively. White variety produced the longest root (2.45, 4.38 and 6.15 cm at 14, 28 and 42 DAI, respectively) at T4 (2.0mg/L IBA). The survival rate of the plantlets of white variety (80%) was greater than yellow variety (66.67%) under ex vitro condition.