Callus Induction and Somatic Embryogenesis from Anther Cultures of Hevea brasiliensis Muell Arg.

Abstract

Hevea brasiliensis is an economically important perennial tree in southeast Asia. However, few studies have been conducted to evaluate the effects of sucrose and genotype on callus induction and plantlet regeneration from anther culture. Male flowers at the uninucleate stage were collected from clones numbered 2-nr, 6-nr, 1-tF and 1-em. An excised cluster of anthers was cultured on callus induction medium (CIM) consisting of Murashige and Skoog (MS) medium supplemented with 1 mg.L-1 2,4-diclorophenoxyacetic acid, 1 mg.L-1 kinetin (KN), 1 mg.L-1 α-naphthalene acetic acid (NAA) and sucrose at various concentrations ranging from 3 to 10%. The results revealed that the highest callus induction frequency (87.5%) was obtained from clone 1-em on CIM with 8% sucrose. Callus derived from clone 2-nr culturing on CIM supplemented with 5% sucrose gave the highest frequency and number of somatic embryo (SEm) formations. CIM supplemented with 5% sucrose and 5% coconut water caused a decrease in the percentage of callus induction (30.88%). The highest SEm formation at 20% was obtained when callus of clone 2-nr aged 8 wk was cultured on MS supplemented with 3% sucrose, 0.2 mg.L-1 NAA, 1 mg.L-1 6-benzyladenine, 3 mg.L-1 KN and 0.05 mg.L-1 gibberellic acid (GA3). When calluses were cultured on CIM supplemented with 5% sucrose and maintained in darkness, 16% SEm formation was obtained. Calluses and SEms from the culture medium showed the same ploidy level as the mother plant after evaluation by flow cytometry.