Validation of micrografting to evaluate drought tolerance in micrografts of kiwifruits (Actinidia spp.)

Abstract

Drought-tolerant rootstocks have been used to improve production efficiency of graft-propagated crops. Kiwifruit is a high-valued fruit crop of the world. Drought stress widely occurs in many of kiwifruit-growing regions including China. The present study used micrografting for evaluation of drought tolerance in four kiwifruit cultivars micrografted on the drought-tolerant rootstock MX1. When stressed by PEG-induced drought, the micrografted kiwifruit cultivars showed significant differences in accumulation of ROS (O2·− and H2O2), physiological metabolism (total soluble sugar, total soluble protein and free proline), activities of antioxidants (SOD and CAT), endogenous ABA levels and expression levels of ABA biosynthetic genes (DREB1 and DREB2). Drought tolerance of the micrografts varied with the four kiwifruit cultivars, with the highest and lowest drought tolerance found in ‘Yuxiang’ and ‘Hayward’, respectively. Micrografting provides an alternative strategy for fast and efficient evaluation of drought tolerance of plant cultivars, thus assisting sustainable development of production of the graft-propagated plant species. In vitro micrografting provided a fast and efficient approach to evaluate drought tolerance of kiwifruit, and has potential applications to other graft-propagated plant species.