Abstract

The development of new virulent biotypes continuously forces entomologists and breeders to search for new sources of resistance to protect common wheat (Triticum aestivum L.) from the Hessian fly, [Mayetiola destructor (Say)]. Two hundred and seventeen durum wheats (T. turgidum L. var. durum) from Tunisia were evaluated in a greenhouse for resistance to biotypes of GP, D, and. L of Hessian fly. Of these, 88, 86, and 59% were considered potential sources of resistance to biotypes GP, D, and L, respectively. Twenty-five durum wheats from Morocco also were tested for resistance to biotypes D and L, and 60% were resistant to one or both biotypes. Four resistant Moroccan durum wheats, land races Oued Zenati and BD 1026 and cuitivars Jori and Hajj Mouline, were intercrossed and crossed to either or both of the susceptible checks ‘Zeramek S’ and ‘ACSAD 65’. Results from testing F₂ populations, F_2:3 families, and testcross F_1:2 families to biotype D showed that Oued Zenati possesses two independent dominant genes for resistance. The other land race, BD 0126, has a single dominant gene apparently allelic or closely linked to one of the genes in Oued Zenati. Resistance in Jori and Hajj Mouline is controlled by the same single dominant gene, independent of the genes in Oued Zenati and BD 0126 and of the H9 and H10 genes in the durum wheat ‘Elva’. Thus, the three genes in the Morocco durum wheats appear to be different from the previously designated genes H1 through H13, based on species of origin and reactions to biotypes D and L and to populations of Hessian fly in Morocco. The identification of a large number of Hessian fly-resistant durum wheats from Tunisia and Morocco, along with the presence of three independent genes in a sample of only four durum wheats from Morocco, indicates that North African durum germplasm is a rich source of new genes for resistance to Hessian fly in the USA.

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