effect of different types and concentrations of growth regulators on callus induction in different strawberry (fragaria ananassa duch.) cultivars

the present investigation was conducted to study the effects of type and concentration of auxin and cytokinin on callus induction of three strawberry (kurdistan, parose and camarosa) cultivars. for this purpose, leaf blade, nodal, petiole, receptacle, stamen and flower bud explants were cultured on murashige and skoog (ms) medium at three separate experiments included 2, 4 dichlorophenoxyacetic acid (2,4-d) at 2, 3, 4, 5 and 6 mg/l, naphthalene acetic acid (naa) at 2, 3, 4, 5 and 6 mg/l and different concentrations (0, 0.5, 1.0, and 2.0 mg/l) of benzyl adenine (ba) combination with 4 mg/l naa. the concentration and type of growth regulators, cultivar and explant type were found critical to the callus induction and callus physical appearance. all explants exception of receptacle incubated on medium formed callus. the leaf and nodal were the most responsive explant to produce callus. ms medium supplemented with combination of auxin and cytokinin were evidently higher than those in the single auxin treatments. 4.0 mg/l naa + 1 mg/l ba yielded the highest percentage of callus in all types of explants. in this medium, the highest callus induction (98.50%) was recorded in nodal explants of kurdistan cultivar.