Wild Oryza grain physico-chemical properties

Of the 22 species within the Oryza genus, only two, O. sativa and O. glaberrima, have been domesticated. Although food security is supported by accessing wild Oryza resources for new genes and alleles which enhance plant performance, wild Oryza grain properties have not been extensively studied. Evaluation of the grain physico-chemical properties of eight wild Oryza species found amylose content, amylopectin structure and cooking properties fell within a narrow range relative to cultivated rice. The amylopectin of the wild species had a lower proportion of short branch chains (DP 6-14) relative to cultivated rice and were all of high apparent amylose content and gelatinization temperature. The grain of the wild species did not elongate to the same extent as the cultivated rice and had lower viscosity parameters. These results highlight how significant physio-chemical changes have been made by human selection in the domestication of rice, especially japonica rice. The wild species may be useful for improving the nutritional value of rice and other cereal crops.