In vitro morphogenesis in leaf sheath explants of sugarcane hybrid var. CoS 99259

Abstract

Leaf sheath explants of sugarcane variety CoS 99259 were inoculated on agar gelled Murashige and Skoog’ (MS) medium containing different auxins (NAA, IBA and 2,4-D) for callus proliferation. Maximum 70.7±8.1% explants showed callus initiation on MS medium containing 3.0 mg/l of 2, 4-D followed by 68.3±5.3% in presence of 4.0 mg/l. At lower concentrations of 2, 4-D (1.0–2.0 mg/l), the frequency of callus induction was significantly low. The frequency of callus formation in presence of NAA and IBA was significantly lower than that obtained in presence of 2,4-D at a particular concentration. The growth of callus was also inferior in presence of NAA and IBA than 2,4-D. The growth of callus was also influenced by the type and concentration of auxin. A good growth of callus was obtained in presence of 3.0–4.0 mg/ l of 2,4-D. For shoot regeneration, callus cultures were transferred on MS medium containing BAP and Kinetin with or without NAA and GA₃. Maximum 68.5 ± 4.6% callus cultures showed shoot proliferation on medium containing BAP, Kinetin and NAA (0.5mg/l each) which was significantly higher than the responses obtained on other hormonal treatments tried. The rate of shoot multiplication in terms of number of shoots per culture was also influenced by the growth regulators. Maximum 22.5 ± 1.9 shoots per culture could be counted on medium containing BAP, Kn and NAA (0.5 mg/l each) followed by 16.3 ± 1.2 shoots/culture in presence of BAP, Kn, NAA and GA3 (0.5 mg/l). The frequency of root formation increased significantly with the increasing concentration of NAA from 2.0 to 7.0 mg/l at a particular sucrose concentration. Similarly, an increase in sucrose level from 30 g/l to 50 g/l further enhanced the rooting percentage irrespective of NAA concentration. Maximum (85.5 ± 7.6%) rooting was recorded in presence of 5.0 mg/l NAA in combination with 50 g/l sucrose.