<em>In vitro</em> clonal propagation of PPR-1, a superior temperate mulberry variety

Abstract

A protocol was developed and standardized for the <em>in vitro</em> clonal propagation of PPR-1, a superior temperate mulberry variety using nodal explants. When the nodal explants of PPR-1 mulberry variety were inoculated onto various concentrations and combinations of cytokinins supplemented media, maximum axillary bud proliferation was obtained on combinational rather than individually supplemented hormonal media. Over all, maximum axillary shoot length (7.2 ± 0.61 cm) and maximum number of leaves per explant (8.1 ± 0.85) was obtained on combinational media of 6 benzylaminopurine (BAP) (1.5 mg/L) and kinetin (2.0 mg/L) after 20 days of culture. On individually supplemented cytokinins hormonal media maximum axillary shoot length (4.7 ± 0.61 and 3.2 ± 0.22 cm) with more number of leaves (7.4 ± 0.16 and 6.0 ± 0.35) per explant was obtained at 1.5 mg/L and 2.0 mg/L concentration of BAP , respectively after 20 days of culture. The proliferated axillary shoots when transferred on to different concentrations of auxins containing rooting media, good response of rooting (100%) was observed on Murashige & Skoog (MS) media supplemented with 2.0 mg/L concentration of indole butyric acid (IBA). The raised plantlets were then hardened using 1 : 1 ratio of vermicompost and soil, then gradually they were acclimatized to field conditions. The survival rate of <em>in vitro</em> raised PPR-1 plantlets in field conditions is about 70%.