Indica-japonica differentiation of chloroplast DNA of weedy rice in the Changjiang and Huaihe River Valley of China.

To detect the cytoplasmic origin of weedy rice in the Changjiang-Huaihe River Valley of China,an InDel marker cpDNA69 was developed based on the 69 bp deletion in indica chloroplast DNA ORF100(cpDNA Open Reading Frame 100).Three accessions of common wild rice(Oryza rufipogon Griff.) from Guangxi,China and 22 cultivars(O.sativa L.) and two F2 populations with indica and japonica rice as maternal parent respectively were investigated by the length polymorphism for ORF100 region.The non-deletion cpDNA ORF100 was found in japonica cultivars and the F2 plants with japonica rice as maternal parent,and the deletion cpDNA ORF100 was found in the indica cultivars and the F2 plants with indica rice as maternal parent.The three accessions of common wild rice carried the non-deletion cpDNA type and one indica-like cultivar developed from the hybrid of japonica and indica carried the same non-deletion cpDNA type.These results confirm that cpDNA69 was a perfect marker to distinguish the indica/japonica cpDNA ORF100.Then the indica-japonica differentiation of chloroplast DNA in 22 accessions of weedy rice from the Changjiang and Huaihe River Valley were investigated with cpDNA69.The cpDNA of Ludao from Lianyungang,Jiangsu Province,and Tangdao from Huaiyuan,Laian,Quanjiao,Feidong,Anhui Province carried non-deletion type ORF100.However the cpDNA of red weedy rice discovered in recent years in Jiangsu Province carried the 69 bp deletion type ORF100.It is suggested that the indica-japonica differentiation of cpDNA has occured in weedy rice in the Changjiang and Huaihe River Valley.