Weedy rice, a hidden gold mine in the paddy field

Weedy rice(Oryza spp.)is an increasingly invasive paddy weed,which mimics cultivated rice at the seedling stage but is distinguished from cultivated rice with strong seed shattering and seed dormancy,which are typical phenotypic characteristics of wild rice.On the origins of this conspecific form of cultivated rice(Oryza sativa),four hypotheses have been proposed and debated for decades:(1)origination from wild rice(Oryza rufipogon or possibly other wild Oryza species);(2)origination following hybridization between wild and cultivated rice;(3)direct descent from escaped cultivated rice;and(4)intervarietal hybridization between different domesticated rice varieties(Ellstrand et al.,2010).Recent population genomic investigations based on whole-genome variation provide powerful phylogenetic and demographic evidence for the de-domestication origination of weedy rice(Li et al.,2017;Qiu et al.,2017,Qiu et al.,2020;Sun et al.,2019).