RAPD POLYMORPHISMS AMONG VARIANT AND PHENOTYPICALLY NORMAL RICE (ORYZA-SATIVA VAR INDICA) SOMACLONAL PROGENIES

RAPD analysis was performed among eight rice somaclonal families known to vary for specific characters and four somaclonal families which we re phenotypically normal. The parental cultivar, indica rice cv. FR13A , was found to be homogeneous and homozygous at all but one of the 45 RAPD loci. Polymorphisms were found at 28 of the 45 bands among the so maclonal families, including both loss of parental bands, and the appe arance of novel non-parental bands. Segregation data revealed both het erozygous and homozygous mutation events, with recessive mutations mor e prevalent than dominant. All somaclonal families differed significan tly from the parental material, indicating that genomic alterations oc curred in all families regardless of phenotype. None of the variant fa milies could be regarded as isogenic lines of FR13A at the DNA level. However, some of the DNA level variation may be in highly repeated seq uences with no phenotypic effects. The implications for somaclonal bre eding and genetic engineering programs are discussed.