Genetic methods for mitigating invasiveness of woody ornamental plants: Research needs and opportunities

Abstract

Because cultivation of exotic woody ornamental plants has led to establishment of a number of invasive species, there is considerable interest in breeding methods to reduce the propensity for spread. We review progress in conventional breeding and transgenic biotechnology approaches to producing sterile forms of ornamental woody plants. Conventional forms of inducing sterility, including induction of polyploidy, interspecific hybridization, and mutagenesis, are generally inexpensive and can be applied to a diversity of species at low to moderate cost. They have also been shown to be capable of producing commercially successful cultivars. In contrast, despite a variety of highly promising and rapidly developing approaches using transgenic methods, the inability to efficiently regenerate and genetically transform most ornamental species makes application of these innovations highly problematic. Moreover, because of the fragmented pattern of ornamental nursery ownership, the numerous species and varieties used, and the high regulatory cost for permits to sell most types of transgenic varieties (even when their environmental risk of spread has been reduced by sterility), application of transgenic methods is largely infeasible. A combination of fundamental regulatory reform and expanded biological research on generalized transformation and sterility methods is needed to overcome these barriers.