Ia Mouche de Hesse presents chez quatre Aegilops par Oum Keltoum El Khlifi( 1 ), Mohamed Malki( 1 ) et Bent habib Ouafae( 2 ) (/) Faculte des sciences A in Chock, km 8. Route El Jadida, B.P. 5366, Maar(/: Casablanca, Maroc (2) IAV Hassan II, B.P. 6202, 10101. Rahat. Maroc arrive le 2fevrier 2001. accepte le 10 mai 2001 Resume.-Des croisements interspeciliques de deux Bles cultives, le Ble tendre (Triticum aestivum) et le Ble dur (T. durum), avec quatre especes d'Aegilops (Ae. ovata, Ae. triaristata, Ae. squarrosa et Ae. ventricosa) ont ete realises. Une etude comparative de I' aptitude au croisement de ces especes d'Aegilops avec les Bles a montre qu'elles n'ont pas toutes Ia meme aptitude a se croiser avec les cultivars de Bles testes. Une variabilite a ete observee au niveau des pourcentages de nouaison et de plantes hybrides, en lonction de l'espece utilisee et du sens de croisement, direct ou reciproque. Le pourcentage de nouaison et celui de plantes hybrides F 1 (hybrides de Ia premiere generation) sent peu corrales au rendement en descendants interspeciliques. La viabilite et Ia lertilite des F 1 et de leurs descendants seraient des criteres plus determinants de Ia production de lignees d'introgression. Mots-des : croisements interspeciliques -Aegilops sp. -Triticum aestivum-T. durum.Abstract.-Interspecific crosses between the two cultivated wheat (Triticum durum, T. aestivum) and lour species of Aegi/ops (Ae. triaristata, Ae. ovata, Ae. ventricosa and Ae. squarrosa) have been made. Comparative study of the crossing capability of the lour species of Aegilops with cultivated wheat showed that both seed set and plant hybrids produced are variable and not related to the yield interspecific progeny. The crosses giving the best seed set were not those who produced a viable interspecific progeny. The viability and fertility of F 1 hybrids and their progeny are better criteria to evaluate the success of the introgressed lines.

Mots-des : Aegilops squarrosa -analyse meiotique -croisements interspecifiques -Mayetiola destructor (Say) -Triticum durum.Abstract.-Hessian fly (Mayetiola destructor (Say) is probably the most serious pest on wheat crops (Triticum sp.) in many countries. Interspecific crosses were carried out between durum wheat cultivars and different Ae. squarrosa accessions that are resistant to the Hessian fly. The low viability and the sterility of the interspecific hybrids F 1 and its progenies 1st, 2nd and 3rd generations have a determinant impact on seed set and percentages of the interspecific hybrid produced. The rate of univalent percentages decreased clearly in the second generation, in connection with spontaneous chromosomal doubling. Most interspecific offspring were resistant to the Hessian fly. At F 4 and F 5 they still showed a segregation of resistance. Few interspecific progenies showed higher resistance, especially at the 5th generation.