5Kang Y S,Morita S,Yamazaki K.Root growth and distribution in some japonica-indica hybrid and japonica type rice cultivars under field conditions.Japanese Journal of Crop Science,1992,63:118-124.
6Peng S,Gassman K G,Virmani S S,Sheehy J,Khush G S.Yield potential trends of tropical rice since release of IR8 and the challenge of increasing rice yield potential.Crop Science,1999,39:1552-1559.
7FAO.Statistical databases,Food and Agriculture Organization (FAO) of the United Nations.2004.
8Yuan L P.Hybrid rice breeding in China.In:Virmani S S,Siddiq A,Muralidharan K,eds.Advances in Hybrid Rice Technology.Philippines:International Rice Research Institute,1998:27-33.
10Yang J,Peng S,Zhang Z,Wang Z,Visperas R M,Zhu Q.Grain and dry matter yields and partitioning of assimilates in japonica/indica hybrid rice.Crop Science,2002,42:766-772.