Abstract
Tertiary trisomics, cytogenetical variants with an interchang'ed chromosome in addition to the normal chromosome them complemcnt. were produced through systematic three-way crosses, (primary tris'omics reciprocal translocations normal disomics) in rice (Oryza sativa L.). Twenty-five tertiary trisomics were selected on the basis of their morphology and seed fertility in the Fl prog'enies of the three-way crosses. They were identified by obs'crvations.' of the breeding behavior of their selfed progenies and of chromosomal config'urations at meiosis. As the tertiary trisomics pro duced in this .study are useful for cht'omosome mapping, additional production of tertiary trisomics is under way.
