Effect of different growth regulators on in vitro regeneration of cotyledon explants of rough lemon (Citrus jambhiri Lush.) via callus induction

Abstract

In order to establish in vitro protocols for raising aseptic cultures of cotyledon segments excised from five-week-old in vitro raised seedlings were used as explant material. Among surface sterilants, mercuric chloride 0.1% for three minutes provided least rate of contamination (24%) and the maximum explant survival (76%). The highest per cent culture establishment of 97.79% was obtained in cotyledon explants on Murashige and Skoog (MS) containing 2,4-D (3.0 mg/l) and maximum callus induction (95.41%) was observed on MS medium supplemented with 2,4-D (2.0 mg/l). Among different plant growth regulator treatments, maximum callus regeneration of 82.19% was observed on MS medium supplemented with BAP (3.0 mg/l) whereas, minimum callus regeneration (4.33%) was found in MS medium supplemented with BAP (3.0 mg/l) in combination with IAA (0.75 mg/l) and malt extract (500 mg/l). Maximum rooting response (96.00%) was recorded on MS (half strength) medium with NAA (2.0 mg/l) and was at par with rooting percentage of 92.00% on MS (half strength) medium supplemented with NAA (1.5 mg/l). The plantlets were successfully acclimatized in different potting mixtures and highest survival rate (91.35%) was achieved in potting mixture containing garden soil with sand and farmyard manure (1:1:1).