Spontaneous Hybridization between Bread Wheat (Triticum aestivum L.) and Its Wild Relatives in Europe

Abstract

In Europe, wild wheat relatives of the Triticum–Aegilops complex grow in sympatry with cultivated bread wheat (Triticum aestivum L.) and spontaneous hybridization is known to occur. With the development of transgenic wheat, an understanding of the likelihood and occurrence of hybridization and introgression between wheat and its relatives is needed for use in risk assessment. To assess the probability of wheat to wild relative gene introgression, the distribution and biology of wheat wild relatives and their genome affinity and crossability with bread wheat were reviewed. Twelve of the 22 known Aegilops species, as well as one wild Triticum species, T. monococcum L. subsp. aegilopoides (Link) Thell., are known to occur in Europe near or within wheat cultivation. Five tetraploid species, Ae. cylindrica Host., Ae. triuncialis L., Ae. geniculata Roth., Ae. neglecta Req. ex Berthol., and Ae. biuncialis Vis., have wide distribution in most European countries. Bread wheat, wild Aegilops species, and Triticum species are predominantly autogamous (except Ae. speltoides Tausch, typically allogamous), but outcrossing among species is possible depending on species sympatry, concurrent flowering, and sexual compatibility. Spontaneous hybridization with wheat was reported for most of the tetraploid Aegilops species. The probability of gene transfer and gene retention in hybrid progenies is, however, higher when a gene is located on a shared genome, particularly on the D genome shared with Ae. cylindrica and Ae. ventricosa Tausch. Case‐by‐case and region‐by‐region assessments are needed to evaluate the risk associated with production and competitiveness of hybrids and their progeny.

A Comparative Analysis of Chromosome Pairing at Metaphase I in Interspecific Hybrids between Durum Wheat <i>(Triticum turgidum </i>L<i>.)</i> and the Most Widespread <i>Aegilops</i> Species

“…Cultivated wheats can spontaneously hybridize with some of their wild Triticum and Aegilops relatives when they grow in sympatry and their flowering periods overlap [Jacot et al, 2004;Zaharieva and Monneveux, 2006]. Diploid relatives show a limited geographical distribution and cannot be found far from their origin center.…”

Genetic diversity of Tunisian accessions ofAegilops geniculataRoth and durum wheats (Triticum durumDesf.) using RAPD markers

“…dicoccoides, 2n = 28) has been identified as the donor of the A and B genomes of durum and bread wheats. Furthermore, Zaharieva and Monneveux (2006) added that bread wheat, wild Aegilops species and Triticum species are predominantly autogamous, but outcrossing among species is possible depending on species sympatry, concurrent flowering and sexual compatibility. Spontaneous hybridization with wheat was reported for most of the tetraploid Aegilops species.…”

How to track genetically modified (GM) plants in the field? The VDI standard method of floristic mapping of GM plants as an efficient tool

“…Crop-weed-complexes are described e.g. for sugar beet (Desplanque et al 1999, Soukup and Holec 2004, oilseed rape (Hall et al 2000, Salisbury 2002, FitzJohn et al 2007) and bread wheat (OECD 1999, Zaharieva andMonneveux 2006).…”