Factors influencing in vivo and in vitro micrografting of sandalwood (Santalum album L.): an endangered tree species

Abstract

In vivo micrografting of Santalum album was achieved (50%) by grafting 4- to 5-cm-long scions, collected from a candidate plus tree (CPT) of 50–60 years of age, onto 90-day-old nursery-grown rootstock. Scion size, rootstock age, and scion collection season were found to influence graft success. Grafted plants were incubated under greenhouse conditions for 6–8 weeks during the graft union process. In vitro micrografts were achieved by placing 1- to 2-cm-long scions derived from nodal shoot segments (collected from CPT) onto the hypocotyl of 45-day-old in vitro rootstocks. Use of in vitro grown shoots as a source of scion gave better graft success (60%) than scions collected directly from field-grown trees. In vitro grafting was also influenced by scion size and rootstock age. Under favorable conditions, scions and hypocotyls unite to form complete plants that produced two to four leaves after 6–8 weeks. This is the first report on in vivo and in vitro micrografting of S. album having potential for production of disease-free clonal plants for conservation and improvement targets.