Evaluation of clonal variability in shoot coppicing ability and in vitro responses of Dalbergia sissoo Roxb

Abstract

Clonal variations were observed amongst 12 clones of Dalbergia sissoo belonging to four states (U.P, Uttaranchal, Haryana and Rajasthan) of India, representing four different geographical zones in respect of ex vitro shoot coppicing ability and in vitro responses. Coppicing ability of shoot hedges of clones exhibited significant variation which ranged from average of 13.81 coppiced shoots (Clone 40, Uttar Pradesh) to 9.29 (Clone 64, Haryana). Comparative analysis of clones from different regions in respect to their coppicing ability revealed that clones from U.P had higher coppicing ability whereas those from Haryana proved to be least coppicers. Regional variations were also exhibited in the in vitro multiple bud induction ability on nodal explants excised from shoot hedges of clones (mean number of buds induced and percentage of cultures forming multiple buds). Regional as well as inter clonal variations were recorded in the shoot proliferation efficiency as well as rootability of microshoots of these clones as well as their optimal plant growth regulator requirements. BAP alone (2.5 μM) was sufficient for inducing multiple buds on cultured nodal explants of Uttaranchal and Uttar Pradesh region clones. On the contrary, clones from Rajasthan and Haryana had higher optimal requirement of BAP and in addition, they required media to be supplemented with auxin (NAA) for induction of multiple buds on explants. Correlation analysis between shoot coppicing ability of clones and in vitro performances of explants of these clones cultured on 2.5 μM BAP indicates a positive correlation. Observation lays credence to our view that these characters are genetically controlled and shoot coppicing can be used as a marker character in optimizing in vitro performance of clones. Using the information generated by this paper in vitro production of elite planting material can be maximized by ameliorating plant growth regulator requirement in the medium.