Potential of tetraploid wheats in plant breeding: A review.

Domestication syndrome, selection pressure, and modern plant breeding programs have reduced the genetic diversity of the wheat germplasm. For the genetic gains of breeding programs to be sustainable, plant breeders require a diverse gene pool to select genes for resistance to biotic stress factors, tolerance to abiotic stress factors, and improved quality and yield components. Thus, old landraces, subspecies and wild ancestors are rich sources of genetic diversity that have not yet been fully exploited, and it is possible to utilize this diversity. Compared with durum wheat, tetraploid wheat subspecies have retained much greater genetic diversity despite genetic drift and various environmental influences, and the identification and utilization of this diversity can make a greater contribution to the genetic enrichment of wheat. In addition, using the pre-breeding method, the valuable left-behind alleles in the wheat gene pool can be re-introduced through hybridization and introgressive gene flow to create a sustainable opportunity for the genetic gain of wheat. This review provides some insights about the potential of tetraploid wheats in plant breeding and the genetic gains made by them in plant breeding across past decades, and gathers the known functional information on genes/QTLs, metabolites, traits and their direct involvement in wheat resistance/tolerance to biotic/abiotic stresses. • Genetic erosion during domestication and modern breeding programs has led to reduce the genetic diversity of wheat. • Genetic structure of wheat can be improved through genetic enrichment by diversifying allelic combinations. • Tetraploid wheat subspecies are an excellent gene pool for improving tolerance to biotic and abiotic stresses. • Utilizing genes from tetraploid wheat subspecies provide great potential for increasing grain yield and quality of durum wheat. • Synthetic hexaploid wheat is an effective genetic resource to transfer important genes from wild relatives to common wheat. [ABSTRACT FROM AUTHOR]