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La migration électrophorétique, sur gel d'agarose, de fragments résultant d'une restriction par l'endonucléase Taql d'ADN génomique, a permie d'isoler un ADN satellite de 371 pb spécifique du genre #Erianthus#, EaCIRI. Cette séquence présente 77% d'homologie avec un ADN satellite de 365 pb spécifique de #Helictotrichon convolutum#, ainsi que 72% d'homologie avec une séquence répétée en tandem de 353 pb spécifique de #Oryza sativa#. Des amorces PCR définies dans les zones conservées de ces séquences répétées ont permis d'isoler d'autres ADN satellites chez différents représentants du complexe #Saccharum# : SoCIRI chez #Saccharum officinarum#. SrCIR1 chez #Sacharum robustum#, SsCIR1 et SsCIR2 chez #Saccharum spontaneum# ainsi que MsCIR1 chez #Miscanthus sinensis#. EaCIR1 et SoCIR1 ont été localisés dans les régions subtélométriques des chromosomes, par hybridation #in situ# en fluorescence. La réalisation d'hybridations de type Southern, en utilisant deux représentants de cette famille de séquences répétées comme sondes, a illustré l'existence de la spécificité d'espèce de ces satellites, et démontré l'existence d'éléments répétés similaires chez le sorgho et la maïs.

Segregations of rice isozymes made it possible to ascertain the genetic control of 13 enzymes by 30 loci. In addition to numerous cases of independence, several linkages were observed. Got-2 and Enp-1 were localized on chromosome 3 and a linkage group composed of Pox-3, Pox-4, and Est-1 was identified. Inconsistencies of recombination rates between linked loci among different crosses were noted. Several cases of distorted segregations and pseudolinkages were recorded. The relationships between these results and the study of genome organization in cultivated rice are discussed.Key words: Oryza, isozyme, genetic analysis, segregation distortion, linkage.

The geographic pattern of isozyme variation among rice varieties (Oryza sativa L.) in Asia is described based on an electrophoretic survey of 1688 accessions for 15 loci. The distribution patterns are strongly determined by the existence of several varietal groups that are characterized by contrasting multilocus types with dissimilar environmental and macrogeographic distributions. The two main groups correspond to the indica and japonica subspecies. Other types are frequently found in the Indian subcontinent, especially along the Himalayan foothills. These types are predominant in the Indus River basin. They are differentiated into four groups in the eastern part of the Himalayan foothills. There is variation within the groups. Non-random allele distributions are observed, such as regional clines and narrow localization of alleles. Diversity among indica rice is evenly distributed in whole tropical Asia. Variation among japonica rice shows the hilly part of continental Southeast Asia to be the region of highest genetic diversity and its probable area of origin. All this information provides a guide for further analysis aimed at elucidating the history of cultivated rice in Asia and, subsequently, in other continents.Key words: Asian rice, genetic diversity, isozymes, geographic distributions.