PLANT SIZE CONTROL IN APPLE THROUGH GENETIC ENGINEERING

Abstract

Tree size control is essential for modern apple production. Chemical controls and different managements have been practically used in commercial production of apple rootstocks and cultivars in order to generate dwarf trees. However, these practices are either inefficient or unfriendly to human health and environment. In contrast, genetic engineering offers a better possibility to improve plant properties. By introducing well-characterised genes that control the growth vigour, it is possible to dwarf an existing genotype without disturbing its main genetic background. Up to now, some genes have been introduced into different plant species and proved to be effective in reducing plant size. Among the genes tested, the rolC, gai and GA oxidase have shown to be able to reduce plant size in most cases. In our previous studies, we have introduced the rolC and gai genes into apple rootstocks and cultivars. Both in vitro and grown analysis in greenhouse have shown that transgenic plants with one of these genes did display reduced plant height in most cases. Since plant height is mainly controlled by gibberellins, regulation of GA biosynthesis would be a better way to control plant size in the future.