In vitro adventitious shoot regeneration from leaf explants of some apricot cultivars

ABSTRACT Apricot is one of the most valuable commercial fruits. In vitro propagation of apricot is very important for rapid multiplication of cultivars with desirable traits and production of cleaning up and virus-free plants. Low frequency of multiplication is the main limiting factor for traditional propagation methods. In this regard, the objective of our investigation was to study the morphogenetic capacity of apricot leaf explants of the promising cultivars ‘Iskorka Tavridy’, ‘Magister’ and ‘Bergeron’ for regeneration system development and solving some breeding questions. The source of explants was in vitro plants regenerated and cultured on QL medium. Leaves were maintained in the dark at 24±1 °C in thermostat for three-four weeks. Morphogenic callus and structures were mainly formed at the central and proximal parts of leaves on MS, QL and WPM media with 1.5 or 2.0 mg L-1 BAP and 1.5 or 2.0 mg L-1 IAA in different combinations, or TDZ (0.6 and 1.3 mg L-1). Callus with adventive buds was transferred to regeneration medium and placed into a growth chamber at 24±1 °C and 16-hour photoperiod with a light intensity of 37.5 μmol m-2 s-1. The best results were obtained when adaxial leaf surface was in contact with the culture medium. Frequency of leaf callus formation on MS medium with 1.5 mg L-1 BAP and 1.5 mg L-1 IAA was higher in the explants of ‘Iskorka Tavridy’ (80.0%) than in - ‘Bergeron’ (50.0%) and ‘Magister’ (36.7%). The best results of callogenesis for ‘Magister’ was obtained on MS medium with 1.3 mg L-1 TDZ (53.3%). Active microshoot regeneration in ‘Iskorka Tavridy’ cultivar was shown on MS medium with BAP and IAA and in ‘Magister’ cultivar - on MS medium with TDZ. Rhizogenesis was obtained on half strength MS medium with 2.0 mg L-1 IBA. RESUMO O damasco é considerado uma das frutas mais valiosas comercialmente. A propagação in vitro de damasco é muito importante para a multiplicação de cultivares com características desejáveis, saudáveis e livres de vírus. O fator limitante para a propagação por métodos convencionais é a baixa frequência na multiplicação. Nesse contexto, o objetivo desse estudo foi investigar a capacidade morfogenética de explantes foliares das cultivares ‘Iskorka Tavridy’, ‘Magister’ e ‘Bergeron’ visando o desenvolvimento de sistema de regeneração e solucionar algumas questões relacionadas ao melhoramento genético. Plantas regeneradas in vitro e cultivadas em meio QL foram usadas como fonte de explantes. Folhas foram mantida