Influence of growth regulators and carbon sources on callus induction, growth and morphogenesis from leaf tissues of peach (Prunus persicaL. Batsch)

SummaryLeaf segments of Prunus persica (L.) Batsch ‘Elberta Queen’ were collected from in vitro-grown proliferating shoots and cultured onto a basal medium containing half-strength Murashige and Skoog (MS) salts, Staba vitamins, 30 g l−1 sucrose and 6.5 g l−1 Difco-bacto agar. The influences of six growth regulators supplemented at three levels (5, 10 and 15 µM) on callus induction were investigated under light conditions (16 h photoperiods). For all growth regulator treatments, caulogenesis was observed along cut margins of leaf explants. Among cytokinins tested, thidiazuron (TDZ) induced compact green calli, 6-benzyladenine (BA) and zeatin induced small calli, and kinetin failed to induce callus. For auxin treatments, both dicamba and 2,4-D induced friable white to yellowish calli. In another experiment, leaf explants collected from greenhouse-grown ‘Bellaire’ and in vitro-grown ‘Elberta Queen’ were cultured onto the basal medium supplemented with a wide range of TDZ concentrations (3 to 23 µM). Caulogenesis was optimum for both genotypes at TDZ concentrations of 8 to 13 µM, while higher TDZ levels resulted in necrosis of leaf explants. In a third experiment, the influence of glucose, fructose, and sucrose on caulogenesis was investigated. Leaf explants grown on media containing glucose developed a higher frequency of green and compact calli than those grown on either fructose or sucrose.