[1] UNIV OSNABRUCK, FACHBEREICH BIOL CHEM, D-4500 OSNABRUCK, FED REP GER
[2] PIONEER HI BRED INT INC, DEPT BIOTECHNOL RES, JOHNSTON, IA 50131 USA
[3] ROTHAMSTED EXPTL STN, DEPT BIOCHEM, HARPENDEN AL5 2JQ, HERTS, ENGLAND
[4] UNIV BRISTOL, LONG ASHTON RES STN, DEPT AGR SCI, BRISTOL BS18 9AF, AVON, ENGLAND