Development of improved rice varieties through the use of induced mutations in Malaysia

Beginning in 1972, the use of induced mutations for rice improvement was initiated in Malaysia. The initiative became more significant when, in 1979, UKM and MARDI undertook a major and concerted effort to screen for blast resistance in Mahsuri, a popular variety at the time, which had succumbed to the disease. Mutation breeding has used both EMS and gamma irradiation, which comes from a 60Co source at UKM and MINT facilities, and this approach, has now become part and parcel of the overall national rice breeding and selection programmes. Mutation breeding was aimed at developing inter alia disease resistance, insect resistance, photoperiod insensitivity, short stature, reduced maturity, improved plant type and good grain and eating qualities, and involved many rice genetic resources, ranging from traditional varieties to advanced breeding lines as well as commercial improved varieties. Amongst released varieties e.g. Mahsuri, Muda, Manik, MR 211 and MR 219, mutation breeding had been attempted directly on them for single trait improvements. Generally, induced mutations have yielded mutants which are either used directly or have some interesting and desirable traits for use in further cross breeding. Such mutants include Mahsuri Mutant, Muda 2, PS 1297 and Manik 817, MA03, SPM 29 and SPM 39, Q 34, MRQ 50, SPM 129, SPM 130 and SPM 142. The objectives of this paper are to describe some of these rice mutants which have been developed through mutation breeding until the present time, and also to highlight some of the current activities involving induced mutations. (author)