Characterization of a novel high-tillering dwarf 3 mutant in rice.

Tiller number and culm length are important components of plant architecture and determinate grain production in rice. A line SIL046, derived from an introgression lines population developed by an accession of common wild rice (Oryza rufipogon Griff.) and a high-yielding indica cultivar Guichao 2 (Oryza sativa L.), exhibits a higher tiller number and shorter culm length phenotype than the recipient parent Guichao 2 (GC2). Genetic analysis showed that the high-tillering dwarf phenotype was controlled by a novel single recessive gene, referred to as the high-tillering dwarf 3 (htd3), which located within the genetic distance of 13.4 cM between SSR makers RM7003 and RM277 on chromosome 12. By means of fine-mapping strategy, we mapped HTD3 gene within the genetic distance of 2.5 cM and the physical distance of 3100 kb in the centromere of chromosome 12. Further identification of HTD3 gene would provide a new opportunity to uncover the molecular mechanism of the development of culm and tiller, two important components of yields in rice.