Mining New Diversity for Wheat Through the Introgression of Related Wild and Cultivated Grass Species

The transfer of genetic diversity from related wild and cultivated species into wheat to aid the development of new high yielding wheat varieties is an important step toward tackling the imminent problem of national and international food security.

The transfer of genetic variation will be achieved in two ways: 1) Development of F₁ hybrids between wheat and its wild relatives to produce new amphidiploids that will be screened for a range of target traits. 2) Transfer of small overlapping chromosome segments, covering the entire genome of the ancestral species, into wheat carrying the ph1 mutation to facilitate the production of recombinants. The primary target ancestral species for this system are Triticum urartu (e.g. photosynthetic capacity and disease resistance), Thinopyrum bessarabicum (e.g. salt and drought tolerance), Secale cereale (e.g. resistance to rust diseases and acid soils), and Aegilops speltoides(e.g. disease and potentially insect resistance).

Wheat parents were emasculated and pollinated using a wide range of alien species, followed by embryo rescue if necessary. F₁ hybrids with normal wheat are treated with colchicine to double the chromosome number and produce fertile amphidiploids. F₁ hybrids derived from crossing alien species to ph1 mutant wheat are crossed back onto normal wheat with a wild type Ph1 allele and screened with SNP markers. Introgressed alien segments will be identified using these molecular markers and the plant material simultaneously screened for a range of traits with the aim of discovering genes to generate varieties with elite performance for release.