Assessment of RAPD markers to detect genetic change in protoplast-derived rice plants

Fourteen different primers were used to amplify DNA from selfed progenies of 117 diploid plants regenerated from haploid cell suspension protoplast of rice (cv. Miara). This survey, which permitted to generate 69 different major fragments in control Miara plants as well as in protoclone DNA, did not reveal genetic change among protoclones compared to the donor variety except independent amplification of an additional fragment in nearly half of the lines by two 10-mers. This polymorphism in the protoclonal population was attributed to natural intravarietal variation among the donor plants which have been collected to establish the microscope-callus suspension culture. However, polymorphism could not be detected in calluses grown from cell clumps collected in the 21-month old cell suspension. This apparent lack of tissue culture-induced polymorphism at the molecular level contrasts with the results of a previous field evaluation of the progenies which exhibited both wide range and high frequency morphological changes. These observations highlight the absence of apparent relationship between morphological variation and molecular changes. The interest of RAPDs as a convenient method to test genetic integrity of the regenerants, that would preclude the need for further field evaluation, is discussed. (Résumé d'auteur