Etude d'un polymorphisme hétérochromatique chez cinq variétés de blé (Triticum durum desf et tretium aestivum L.)

Abstract

In the setting of one survey carrying polymorphism heterohromatic at some varieties of cultivated wheat in Algeria ; a particular attention was carried to the differential staining with Giemsa (or C-banding) putting the constitutive heterochromatin correspondent in evidence to some repeated sequences of ADN. The obtained results allowed us to identify the'genomes A and B of three varieties of durum wheat (T durum DESF.), and the genomes A, B and D of two varieties of common wheat (T aestivum L.). the genomes A and D were less heterochromatic ; however the genomes B were highly heterochromatic. Since it exist a heterochromatic variability among varieties in species T. durum DESF. The cytogenetic analysis of three varieties (Bidi 17, Waha, OuedZenati) reveals a numerous variations : The variety Oeud-Zenati showed overloading in heterochromatin (intensity and number of C bands) compared to' ' reference variety of Langdon. This results were on the contrary of that of Bidi 17 and Waha varieties ; where Waha variety was moderathly heterochromatic ; whereas Bidi 17 variety reveals less heterochromatin. This study allowed to establish a translocation occurrence in 1BL / IRS in Waha variety. Moreover : the cytogenetic study performed on two varieties of T aestivum L. Showed a heterochromatic variability ; That is Tessalah variety was poor in heterochrometin compared to Chinese Spring reference variety ; however, Ziad variety was rich in heterochromatin. The variations put in evidence in the two varieties indicated the presence of polymorphism heterohromatic. All the chromosomes wich carry the additional C bands are chromosomes rr ‘s markers. Therefore ; the obtained results allow us to advance the relation hypothesis existing between the heterochromatin abundance of Oued-Zenati and its adaptation to the difficult climate conditions.