Cultivated Plant Taxonomy - Contemporary Issues

Contemporary Issues

Current challenges for cultivated plant taxonomists include: the use of large plant name databases; ways of dealing with the use of non-scientific names in commerce (known as trade designations), especially for plant labels in nurseries; intellectual property and plants; adapting modern technology, in particular molecular techniques, to the creation and identification of cultivars; maintaining germplasm collections of cultivars, including herbaria; the recording and registration of cultivars.

The ways in which the plant variation resulting from human activity is named and classified remains contentious. The replacement of the expression “cultivated plant” with the word “cultigen” is not universally accepted. The debate continues concerning the notions of ranks and taxa as applied to cultigens. Is it appropriate to call the highly modified transgenic products of human artificial selection “taxa” in the same way we do for the products of natural selection in the wild? To overcome this difficulty the term culton (pl. culta) has been suggested to replace the word taxon when speaking about cultigens.

Then, most “wild” plants fit neatly into the nested hierarchy of ranks used in Linnaean classification (species into genera, genera into families etc.) which aligns with Darwinian descent with modification. Choosing classification categories for cultigens is not clear-cut. Included among cultigens are: simple selections taken from plants in the wild or in cultivation; artificial hybrids produced both by accident and intention; plants produced by genetic engineering; clonal material reproduced by cuttings, grafting, budding, layering etc.; graft-chimaeras; selections from the wild; ancient selections of crops that date back thousands of years; selections of aberrant growth such as witches brooms; the results of deliberate repeatable single crosses between two pure lines to produce plants of a particular general appearance that is desirable for horticulture, but which are not genetically identical. The question remains as to whether the classification categories of cultivar, Group and grex are the most appropriate and efficient way to deal with this broad range of plant variation.