[en] Sugar cane is planted in large areas in Brazil. A rotation crop for sugarcane should be early maturing. With the objective of obtaining early mutants in soybean for rotation with sugar cane, seeds of two cultivars of soybean were treated with gamma rays or EMS. The tests in one location indicate that some precocious mutants which maintained the level of productivity of the original cultivar ''Parana'' were obtained with 22 krad. The mutants M₁-M₄ and M₆ especially show a significantly earlier maturation while maintaining the capacity of grain production of the original cultivar