Alien introgression in rice

Cultivated rice, Oryza sativa has 22 wild species. They are a rich source of useful genes for rice improvement. Six wild species are closely related to cultivated rice and have the same genome. It is easy to transfer genes from these species to rice through standard hybridization procedures. However, various tissue culture and cytogenetic techniques are needed to transfer genes from distantly related species. Many important genes/QTLs for resistance to diseases and insects as well as tolerance to abiotic stresses have been transferred into rice from wild species. These genes provide yield stability of varieties. Thus usefulness of wild species germplasm in food security can hardly be over emphasized. Wild species germplasm must be collected, evaluated, preserved and utilized.