<i style="">In vitro</i> shoot regeneration from cormel derived callus of gladiolus and bio-hardening of plantlets

Abstract

Callus mediated <i style="">in vitro</i> propagation protocol for a novel genotype of gladiolus, <i style="">viz</i>., Pusa Urmil, has been developed. The MS medium containing 4.44 µ<i style="">M </i>BAP+2.32 µ<i style="">M</i> KIN+2.68 µ<i style="">M</i> NAA induced the maximum and earliest callogenesis, while medium devoid of NAA showed less extent of callusing. The maximum regeneration frequency (58.15%) as well as the maximum number of shoots per explant (29.63) were obtained on the medium containing 8.88 µ<i style="">M</i> BAP+9.29 µ<i style="">M</i> KIN+1.07 µ<i style="">M</i> NAA. Presence of GA₃ along with auxin and cytokinin promoted the elongation of shoots. The plantlets had the maximum length of shoot (4.25 cm) in the medium containing 8.88 µ<i style="">M</i> BAP+9.29 µ<i style="">M</i> KIN+1.07 µ<i style="">M</i> NAA+ 0.58 µ<i style="">M</i> GA₃. The regenerated shoots were separated and transferred to the medium containing ½ MS+4.92 µ<i style="">M</i> IBA for rooting. The plantlets, while shifted to glasshouse, were subjected to different arbuscular mycorrhizal fungi (AMF) inoculation to enhance the <i style="">ex vitro</i> survival. The maximum survival (61.32%) was recorded for the plantlets treated with <i style="">Glomus manihotis.</i> The treatment with other two strains of AMF, viz., <i style="">Gigaspora gigantean</i> and mixed strain, was also at par with <i style="">G. manihotis</i>. The maximum root length (3.99 cm) was recorded in the treatment with <i style="">G. manihotis</i>, while significantly lower root length was observed in untreated plants. However, the maximum (13.32 cm) shoot length was observed when the plantlets were treated with mixed strain of AMF and was significantly higher compared to all other treatments (p≤0.05).