Botanical Society of China and Institute of Botany, the Chinese Academy of Sciences
Abstract
Plant height is one of the important agronomic traits of rice. Over
higher plant would easily result in plant lodging and output reducing.
On the other hand, the dwarf varieties with proper plant height had
higher lodging resistance and a greater harvest index, allowing for the
increased use of nitrogen fertilizer. Dwarf breeding had made a great
breakthrough in the rice breeding. The breeding and extension of
excellent dwarf varieties remarkably improved the yield potential of
rice. Therefore, the plant height is still one of the focuses in rice
genetic research. So far a great deal of study has been made on the
dwarf trait of rice, and about 60 dwarf and semidwarf genes have been
reported (Kinoshita, 1984; Nagato and Yoshimura, 1998). More than 20
dwarf and semidwarf genes have been located on the rice chromosomes by
using methods of classical genetics, and three semidwarf genes (Liang
et al, 1994; Maeda et al, 1995; Jiang et al, 2002) and nine dwarf genes
(Kishimoto et al, 1992; Yoshimura et al, 1992; Yu et al, 1992; Abenes
et al, 1994; Ideta et al, 1994a; 1994b; Ashikari et al, 1996) have been
mapped by using molecular markers. Recently, two rice dwarf genes, d1
(Ashikari et al, 1999 ) and d61 (Yamamuro et al, 2000 ), have been
cloned, which resulted in dwarf by acting on the signaling pathway of
the endohormone. In the present study, a small grain dwarf mutant,
designated as "162d", was identified from a semidwarf variety Shuhui
162, and the mutant gene was mapped with microsatellite markers.
Meanwhile, the phenotype effects of the mutant gene were analyzed by
using the near isogenic lines