Potentiality of Wild Rice in Quality Improvement of Cultivated Rice Varieties

Abstract

Rice serves as a major food crop to the majority of the world’s population. O. rufipogan and O. nivara are the two common wild varieties of rice found in Asia. O. sativa and O. glaberrina are two of the cultivated varieties of rice found in Asia. O. rufipogan has disease resistance and drought tolerance. Domestication of rice started when people thought to cultivate rice in different geographical regions to where they migrated. The cultivated rice varieties started to adapt to new climatic and environmental conditions in which they are cultivated, resulting in domesticated varieties of rice. Genetic diversity of rice is exploited to breed new varieties of rice. Rice blast, a disease caused by Xanthomonas oryzae in rice, can be controlled by breeding disease-resistant varieties through the exploitation of genetic diversity. Techniques like molecular markers and other next-generation sequencing technologies have been used to identify the genetic variation among different varieties of rice. For broadening the gene pool of the rice varieties, a technique known as wild hybridization has been widely used. It involves the hybridization of rice with related species of wild varieties. Marker-assisted selection method of breeding increases the efficiency of breeding rather than conventional methods. Marker-assisted pyramiding involves combining many genes together to form one genotype. This method is useful in providing pest resistance and tolerance to abiotic stress. Gene introgression involves the movement of alleles of a species to the gene pool of other species. Gene introgression can result in plant evolution because it introduces variations among genes for the plant to adapt changes in the environment. Nevertheless, gene introgression provides short-term genetic diversity; the original genetic diversity of rice species is usually lost.