In vitro control of fasciation in proliferating nucellar embryos of Mangifera indica L. var totapari red small for cloning.

Nucellar tissue contained in ovular halves of young fruits of Mangifera indica L. totapari red small, a dwarfing rootstock, differentiated fasciated embryonal structures in presence of 6-benzylaminopurine [BAP(0.15 mg l(-1))], 6-(gamma-gamma-dimethylallylamino) purine [2iP(0.15 mg l(-1))] and indole-3-acetic acid [(IAA(0.5 mg l(-1))] incorporated in the semisolid medium during 50-60 days. Due to embryonal fasciation, hardly 2-3 well-formed embryos could be obtained per culture of proliferating embryos. Of the 3 ethylene inhibitors [L-alpha-(2-aminoethoxyvinyl)-glycine-HCl (AVG), AgNO3 and salicylic acid (SA)] used, embryonal fasciation and necrosis of intervening tissue was completely controlled by 3-4 subcultures of fasciated mass of embryos under the influence of AVG (0.05 mg l(-1)) in presence of adenine sulphate [AdS (50 mg l(-1))] incorporated in the same medium. Almost synchronized development of isolated embryos, measuring ca 2 cm in length, was observed in a different medium used in liquid stationary state and supplemented, particularly with stress-producing substances [abscisic acid (ABA, 0.01 mg l(-1)); and polyethylene glycol (PEG, 100 mg l(-1))] besides certain other modifications. About 34% convertibility of processed embryos was obtained during a period of 90 days. The plantlets had well-developed roots along with laterals which were longer than leafy shoots. In vitro raised plants survived ex vitro for about 2 months.