REGENERATION OF PLANTS FROM IMMATURE LEAF-DERIVED CALLUS OF STRAWBERRY (FRAGARIAXANANASSA)

Plant regeneration was studied using immature leaf explants taken from in vitro shoots and greenhouse grown plants of the strawberry cv. Redcoat. Both types of explants formed callus and multiple shoots at various frequencies in the presence of benzyladenine (BA) and 2,4-dichlorophenoxyacetic acid (2,4-D) at different concentrations. Highest shoot regeneration (31%) occurred with the calli of greenhouse leaf explants at 5 μM each of BA and 2,4-D in 24 weeks. Improved regeneration (50%) with vigorous shoot proliferation was achieved in 10 weeks by transferring the 5-week-old green compact calli derived from greenhouse leaf explants to MS basal medium supplemented with 10 μM BA and 1 μM 1-naphthaleneacetic acid (NAA) and incubating the cultures at 16 h light (62.5 μE·m-2 s-1). The calli from in vitro leaf explants had very poor shoot regeneration capacity. Seven other cultivars of strawberry also responded to this regeneration protocol albeit at different frequencies. The protocol may be useful for improvement of strawberry through somaclonal variation and selection of desirable traits. © 1990.