[en] By developing and spreading the Ps41 variety, having a high resistence to mosaic disease which is a number one disease in Indonesia's sugarcane culture, the problem of the disease has more or less been solved. Mutation breeding by means of gamma irradiation was carried out in 1973. Irradiation amounting to 5000R/1 is a stable one. Artificial pokkahbung and top borer (Scirpphopaga nivella intacta Sn) infection was treated to see the tolerance of Ps41/5U00R/1 against these disease. It can be concluded that this variety has a higher tolerance and a more significant difference than the control. Trials of this mutant against the original Ps41 on large plot (furrows) with 3 replications will be conducted at Kebonagung sugar estate in planting year 1975/1976. At this estate (400m above sea level) with a wet climate, the pokkahbung infestation is very pronounced together with a high top borer infestation. The production level can also be determined. (author)