Clonal maturation of Corymbia torelliana × C. citriodora is delayed by minimal-growth storage

Abstract

SummaryMinimal-growth storage may be a simple method to preserve germ plasm while tree varieties undergo clonal selection, but there has previously been little evidence to demonstrate that minimal-growth storage delays maturation. This study assessed the maturation of 10 Corymbia torelliana × C. citriodora clones whose shoots had been stored for 12 months using three different methods: (1) as ex-vitro stock plants in the nursery; (2) in-vitro at 25°C; and (3) in-vitro under minimal-growth conditions at 14°C. Minimal-growth storage increased the subsequent frequency of adventitious rooting in cuttings of 6 of the 10 clones, providing increases in rooted cutting production of between 53% and 163% over ex-vitro nursery storage. Minimal-growth storage also increased adventitious root number in two clones and root mass in four clones. C. torelliana × C. citriodora clones underwent maturation during ex vitro stock plant archiving in the nursery, but in-vitro storage under minimal-growth conditions was highly effective in delaying clonal maturation.