USE OF RANDOM AMPLIFIED POLYMORPHIC DNAS (RAPDS) FOR IDENTIFICATION OF RICE ACCESSIONS

Random amplified polymorphic DNAs (RAPDs) were identified in rice by amplification using single 10-mer primers of arbitrary sequence. The number of amplification products increased with increasing GC content of the primer in the range between 40% and 60% GC. Single-base substitutions of a primer altered amplification, providing new polymorphisms. The size of amplified DNA was mostly between 0.5 kbp and 2.2 kbp with the most common bands at 1.5 kbp. Sixteen rice accessions were assayed with 28 primers which generated 116 polymorphic amplified DNAs or RAPDs. All accessions were uniquely distinguished by at least one RAPD and clustered into three distinct groups which corresponded to Japonica, Javanica and Indica. Japonica differed on average from Indica with 80.1 RAPDs and from Javanica with 30.8 RAPDs. It was, thus, demonstrated that RAPDs were useful polymorphisms in rice and superior to RFLPs for their technological simplicity. RAPDs would be good alternatives for the construction of a genetic map because of the higher frequencies of polymorphism detection.