Induction of embryogenic mango cultures as affected by genotype, explanting, 2,4-D and embryogenic nurse culture

The nucellus was removed from immature seeds of 4 mango genotypes, and cultured under different induction conditions. The mango genotypes included polyembryonic 'Hindi' and 'Nam Doc Mai' and monoembryonic 'Lippens' and 'Tommy Atkins'. Nucellar explants were cultured on modified B5 basal medium under the following inductive conditions: i) 4.52 mu M 2,4-D; 2) no growth regulator (control); 3) 4.52 mu M 2,4-D + embryogenic 'Parris' nurse culture; 4) no growth regulator + embryogenic 'Parris' nurse culture. Induction of embryogenic competence was mediated by 4 factors: genotype, explanting, 2,4-D and the presence of a highly embryogenic nurse culture, although there was considerable difference in genotype response. 'Hindi' had the greatest embryogenic potential, followed by 'Lippens', 'Tommy Atkins' and 'Nam Doc Mai', respectively. Induction of embryogenic cultures of all genotypes at low frequency occurred as a result of explanting excised nucellus onto control medium. The most effective treatment for inducing embryogenic cultures was 2,4-D + embryogenic 'Parris' nurse culture with 'Hindi', 'Lippens' and 'Nam doc Mai', with the exception of 'Tommy Atkins', in which the treatment with 2,4-D alone was most effective.