Taxonomy and molecular phylogeny of natural and artificial wheat species

Abstract

The effective use of wheat biodiversity in breeding programs is dependent on a sound conservation strategy for sources of biodiversity, and on appropriate techniques of incorporation into modern cultivars. Producing artificial wheat amphiploids using genomes of related species is an effective way to increase the available gene pool. However, artificial amphiploids should be given botanic names and positions within genus Triticum classification to ensure effective collection and preservation in gene banks. In this review, an attempt to integrate the results of molecular-genetic analyses of natural and artificial wheats with their taxonomy has been made. The correspondence of earlier evolutionary and taxonomic specifications to phylogenetic relationships within Triticum has been estimated using chloroplast and nuclear DNA sequence data. The results indicated close relationships between all artificial and natural species. Based on the data, all wild and cultivated diploid wheat species were united in a separate section, Monococcon. Different variants of nuclear Acc-1, Pgk-1, and Vrn-1 genes have been detected in diploid A genome species. Detailed analysis of the genes showed that one of these variants was a progenitor for all A genomes of polyploid wheats except for that in Triticum zhukovskyi and some of the artificial amphiploids.