Abstract: Oryza officinalis Wall ex Watt (C genome) is an important reservoir of useful genes.However,low crossability and limited recombination rate between chromosomes of the cultivated rice (O.sativa L.A genome) and wild species limit the transfer of such genes.We analyzed an O.officinalis monosomic alien addition line (MAAL) of rice and its backcross progenies.The results of molecular marker analysis showed that the additional chromosome was a mosaic chromosome 7 including the long-arm of O.officinalis and the short-arm and centromere of cultivated rice.The MAAL was backcrossed to cultivated rice and a backcross population consisting of 109 plants was evaluated for 9 agronomically important traits.We found that the introgressed fragments affected some traits including plant height(PH),percent seed set(PSS),percent seed set per cm(PSSPC),leaf width(LW),1000-grain weight(TGW) and spikelets per panicle (SPP).Correlations among these traits were positive.