1. Agronomy Dep.; International Rice Research Institute (IRRI); P.O. Box 933 Manila Philippines
2. Dep. of Forestry; Australian National Univ.; G.P.O. Box 4 Canberra A.C.T. 2601 Australia
3. CSIRO, Div. of Plant Industry; G.P.O. Box 1600 Canberra A.C.T. 2601 Australia