PLANT REGENERATION FROM SHOOT TIPS IN TRIPLOID LOQUAT

Triploid loquat (Eriobotrya japonica Lindl.) was regenerated for the first time using shoot tips as explants. Several experiments were carried out to investigate the effects of time of sampling and size of the explants, growth regulators on shoot tip sprouting, elongation, rooting and transplantation. Results showed that sampling in spring and shoot-tip size of 0.7 cm were appropriate, resulting in a survival rate of 77.5%. Appropriate initial culture medium was MS + 6-BA 1.0 mg L-1 + NAA 0.5 mg L-1 + NAA 1.5 mg L-1, in which the sprouting rate reached 91%. Suitable medium for shoot elongation was MS + 6-BA 0.5 mg L-1 + NAA 0.3 mg L-1 + GA3 0.3 mg L-1, which resulted in an average shoot height of 4.9 cm. The most suitable medium for shoot proliferation was MS + 6-BA 1.0 mg L-1 + NAA 0.3 mg L-1 + Tryptone 750 mg L-1, in which a high multiplication coefficient of 7.7 was obtained. The most suitable medium for rooting was ½ MS + NAA 0.25 mg L-1 + IBA 2.0 mg L-1, in which the rooting rate was 73.3%. The rooted plantlets, after hardening, survived at a rate of 93.67% in a transplantation substrate composed by organic fertilizers, garden soil, and sawdust (1:2:1).