Identification and Genetic Characterization of a Novel Tillering Dwarf Semi-Sterile Mutant &i&tdr&/i&1 in Rice

摘要

Tillering and plant height are important components of plant architecture and grain production in rice. We identified a novel high tillering, dwarf and semi-sterile mutant, as named tdr 1 in a rice maintainer line E20 derived from the cross between between IR68888B and Luxiang 90. The investigation of tiller dynamic in the tdr 1 line displayed 3 different phases: rapid increasing of tillers in the vegetative growth stage, producing no new tillers in the transition stage from the vegetative growth to reproductive growth, and regeneration of new tillers after heading. The assay of hormones showed the significant reduction of brassinolide level and no change of the levels of gibberellic acid, cytokinin and strigolactone in the tdr 1 line. Genetic analysis indicated the phenotype of high tillering, dwarfism and semi-sterility is controlled by a recessive gene in several different segregation populations. The TDR 1 gene was mapped in the 105 kb interval between RM3288 and RM6590 on chromosome 4. Cloning of TDR 1 gene would provide a new opportunity to uncover the molecular mechanism of the development of plant height and tiller in rice.