ABSTRACT The experiment about the effect of seed storage duration and KNO concentration for the growth seedlings of rubber, had been carried out since March 19, 1990 until June 19, 1990 at Potrobangsan, Magelang, Central Java. The soil type is regosol with pH 6.5 on the altitude 375 m above sea level. Experiment design used factorial with arranged by Completely Randomized Desi…