Gene flow amongst AA genome rice species Oryza sativa (cultivated rice) and 0. rufipogon and 0. nivara (wild relatives) is known to occur in rice agro-ecosystems in many Asian countries. Gene flow leads to the formation of hybrid plants that may coexist with parental species. These hybrids (especially 'weedy rice'- plants that are very similar to cultivars but possessing undesirable traits) are a threat to rice production as they may reduce cultivated rice yields, both qualitatively and quantitatively. The precise origins of 'weedy' rice (WR) genotypes are unknown but two main hypotheses have been proposed: endoferality (by segregation and selection of weedy traits from existing heterozygous cultivars in areas where no wild rice exists) and exoferality via gene flow between cultivated and wild rice species. With a continuous growing world population especially in Asia, food demand has to be satisfied with an increase in rice production, playing a key role.