STUDIES OF PROBLEMS IN PRODUCING HYBRID RICE .1. CHEMICAL INDUCTION OF MALE-STERILITY IN RICE

The usefulness of Ethrel as a selective gametocide in rice was examined in 3 high-yielding varieties under pot culture and field conditions. A spray of 6000-8000 ppm of Ethrel 1 wk earlier to boot leaf stage or 2 sprays with 4000-6000 ppm, 1 wk earlier to boot leaf stage and the other at boot leaf stage induced as much as 90% pollen sterility. The successful use of Ehtrel in a commercial hybrid seed program of self-pollinated crops and the development of efficient treatment techniques that would ensure total but selective pollen sterility is discussed.