Counting tillers

Rice is the staple food crop for the majority of the world's population, making it crucial to understand the mechanisms that govern its growth and productivity. At maturity the rice plant has a main stem and a number of grain-bearing tillers, and it is the number of these tillers that determines grain yield. However, the molecular processes that control rice tillering have been poorly understood. In the April 10 issue of Nature, Xueyong Li and colleagues at the Chinese Academy of Sciences, Beijing, China, report the isolation and characterization of a gene that regulates rice branching (Nature, 422:618-620, April 21, 2003).

Li et al. screened rice plant collections for mutants with altered tiller numbers. Genetic analysis with reciprocal crosses between tiller mutants and wild-type plants revealed that mutants possess a recessive mutation in a single locus, termed Monoculm 1 (MOC1). The MOC1 gene was...