The invention discloses rice spikelet development regulation 
protein.The 
amino acid sequence of the 
protein is as shown in (A) Seq ID No: 2; or the 
protein is formed as shown in (B) formed in the mode that one or more amino acids are added to and / or substituted for in and / or deleted from the 
amino acid sequence defined by (A), has a function of regulating rice spikelet development and is derived by the (A).The invention further discloses genes for encoding the protein, such as the 
gene as shown in SEQ ID No:1 and the 
gene as shown in SEQ ID No:3.; the invention further discloses a recombinant vector and a transformant which contain the genes, a method for regulating gramineous 
plant spikelet development through 
gene transformed cells and application of the protein, the genes, the recombinant vector and the transformant to improvement of the yield and quality of gramineous plants.According to the rice spikelet development regulation protein, the encoding genes MSi thereof and application, a map-based 
cloning technology is utilized to separate the MS1 genes influencing rice spikelet development, the functions of the genes are identified through a genetically modified complementary experiment, and the genes can be utilized to research the 
molecular mechanism of rice glumes and seed size so that the yield of gramineous plants can be raised, and quality of gramineous 
plant can be improved.