PRODUCTION OF TERTIARY TRISOMICS IN RICE (ORYZA-SATIVA L)

Tertiary trisomics, cytogenetical variants with an interchanged chromo some in addition to the normal chromosome complement, were produced th rough systematic three-way crosses (primary trisomics/reciprocal trans locations//normal disomics) in rice (Oryza sativa L.). Twenty-five ter tiary trisomics were selected on the basis of their morphology and see d fertility in the F1 progenies of the three-way crosses. They were id entified by observations of the breeding behavior of their selfed prog enies and of chromosomal configurations at meiosis. As the tertiary tr isomics produced in this study are useful for chromosome mapping, addi tional production of tertiary trisomics is under way.