The eui gene of rice and the diversity of tall recessive germplasm of rice were newly identified. Male sterile lines with elongated uppermost internode, and their corresponding hybrids (-hybrids) possessing eui gene were developed and released. The goals and the target of -hybrid rice research and development are： to cut short dosage of GA3 used in hybrid rice seed production by 50%～90% with increasing seed yield and improving seed quality; to increase hybrid rice yield with decreasing N-fertilizer applied to rice.

The EUI1， EUI2 were isolated, and the diversity showing nucleotide deletion of euil and eui2 were also identified This will provide the materials to enhance the studies on following area： plant growth and development, GA melabolism, growth hormones and heterosis, molecular mechanism of mutation, as well as gene engineering.