(281) Micropropagation of Trifoliate Orange Rootstock (Poncirus trifoliate Raf.)

Abstract

In vitro propagation of trifoliate orange rootstock (Poncirus trifoliate Raf.) was achieved using axillary buds taken from new flushes of mature trees and then cultured on Murashige and Skoog medium (MS). The addition of growth regulators [0.5 mg·L-1 gibberellic acid (GA3) or 0.1 mg·L-1 6-benzyladenine (BA) and 0.1 mg·L-1 indol-3-butyric acid (IBA)] were necessary to promote bud breakage and shoot elongation. Shoot proliferation was induced on MS medium supplemented with various levels of BA (0.0, 0.5, 1.0, 1.5, and 2.0 mg·L-1) and α-naphthalene acetic acid (NAA) (0.0, 0.1, and 0.5 mg·L-1). Maximal shoot multiplication (9.3 shoots/explant) and elongation (2.3 cm) occurred on media containing either 1.0 mg·L-1 BA alone or with 0.1 mg·L-1 NAA. Shoots rooted better and gave high root number (7.6 roots/shoot) and long roots (5.4 cm) when cultured on a liquid MS medium provided by 0.1 mg·L-1 NAA. Rooted shoots were successfully established in soil (≥90%).