1. Dept. of Agronomy and Horticulture; Univ. of Nebraska; P. O. Box 830915 Lincoln NE 68583-0915
2. Univ. of Hawaii-IRRI Collaboration; Soil, and Water Sciences Division; International Rice Research Institute (IRRI) DAPO; Box 7777 Metro Manila Philippines
3. Flurstr. 240 22549 Hamburg Germany