HOST RESPONSES OF DIFFERENT TRITICEAE TO SPECIES OF THE CEREAL CYST-NEMATODE COMPLEX IN RELATION TO BREEDING RESISTANT DURUM-WHEAT

Twenty eight lines or cultivars of diploid (genomes A, D, S-I, U), tet raploid (genomes AB, (DMv)-M-v, UM, USv), and hexaploid (genome ABD) w heat were studied for their capacity to sustain the development of nin e populations of Heterodera avenae originating from six countries (Alg eria, France, Spain, Australia, India, and Israel), two populations of Heterodera filipjevi from Russia and Bulgaria, and one population of Heterodera latipons from Israel. Screenings were performed in artifici al conditions using miniaturized tests. High resistance against Popula tions of H. avenae sensu stricto occurred in the three levels of ploid y and in several genomes: S-I (T. longissimum), (DMv)-M-v (T. ventrico sum), UM (T. ovatum), USv (T. variabile), and ABD (T. aestivum AUS 493 0). Total or intermediate resistance was found in genome D (T. tauschi i CPI 110813 or AUS 18913) but their expression in synthetic hexaploid wheat was incomplete resistance. It was confirmed that the Cre1 gene from wheat cv. Lores is ineffective against H. avenae populations from Australia, India, and Israel but also against H. filipjevi. Inter- an d intraspecific differentiation within the cereal cyst nematode comple x, based on (a)virulence to Triticeae and fitness, and the use of tota l and intermediate resistance in breeding programmes are discussed. (C ) Orstom/Elsevier, Paris.