Crop production under changing environment

TBA 

 

All crop species were domesticated from wild plants, and in most cases, their wild progenitors are known. The discovery of our crops’ wild ancestors happened surprisingly late in the history of science.  Spontaneous primary crosses between wild and domesticated plants give rise to hybrid swarms, in which interbreeding between hybrid or backcrosses to parental genotypes has resulted in an admixed genomic make-up. Backcrosses “dilute” introgressed segments, purging deleterious alleles and ensuring that only regions with fitness benefits would be retained. Several instances of adaptive introgression of wild alleles into crops have been reported.

We aim to study the causes and consequences of spontaneous hybridization between wild and domesticated barley and its potential for adaptive gene flow from the crop into its wild relative. Barley (Hordeum vulgare) is an important crop species that is grown globally in temperate regions. Its conspecific wild progenitor is Hordeum vulgare subsp. Spontaneum.  The two most important characters distinguishing H. vulgare from H. spontaneum are non-shattering and six-rowed spikes. In wild barley, the central axis of the spikes (the rachis) disintegrates at maturity into individual dispersal units, the spikelet triplet. These triplets are composed of one central and two lateral spikelets. In wild barley, only the central spikelets bear grains, while the lateral ones are thin, infertile rudiments. In six-rowed barleys, the lateral spikelets are completely fertile. They are now the predominant type of barley grown worldwide. H. spontaneum is two-rowed, but there are reports about six-rowed barleys that grow “wild”, meaning that they thrive without human support. For the past 80 years, it has been a matter of debate in how far these can be considered “wild” in the sense of being descended not from domesticated barley, but from H. spontaneum populations, or even of being the wild progenitors of current six-rowed domesticated barley.

Brittle six-rowed barleys have also been observed in Israel and interpreted as hybrid swarms occurring in distributed habitats such as fallow fields, edge of fields, and roadsides. So far, no genetic studies have been carried to understand the genomic ancestry of Israeli six-rowed wild barleys.