title: Resistance to the cereal cyst nematode (Heterodera avenae Woll.) transferred from the wild grassAegilops ventricosa to hexaploid wheat by a "stepping-stone" procedure.
abstract: Transfer of resistance toHeterodera avenae, the cereal cyst nematode (CCN), by a "stepping-stone" procedure from the wild grassAegilops ventricosa to hexaploid wheat has been demonstrated. The number of nematodes per plant was lower, and reached a plateau much earlier, in the resistant introgression line H93-8 (1-2 nematodes per plant) than in the recipient H10-15 wheat (14-16 nematodes per plant). Necrosis (hypersensitive reaction) near the nematode, little cell fusion, and few, often degraded syncytia were observed in infested H93-8 roots, while abundant, well-formed syncytia were present in the susceptible H10-15 wheat. Line H93-8 was highly resistant to the two Spanish populations tested, as well as the four French races (Fr1-Fr4), and the British pathotype Hall, but was susceptible to the Swedish pathotypes HgI and HgIII. Resistance was inherited as though determined by a single quasi-dominant factor in the F2 generations resulting from crosses of H93-8 with H10-15 and with Loros, a resistant wheat carrying the geneCre1 (syn.Ccn1). The resistance gene in H93-8 (Cre2 orCcn2) is not allelic with respect to that in Loros. RFLPs and other markers, together with the cytogenetical evidence, indicate that theCre2 gene has been integrated into a wheat chromosome without affecting its meiotic pairing ability. Introduction ofCre2 by backcrossing into a commercial wheat backgroud increases grain yield when under challenge by the nematode and is not detrimental in the absence of infestation.
authors.affiliation: Laboratorio de Bioquímica y Biología Molecular, ETS Ingenieros Agrónomos-UPM, E-28040, Madrid, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Delibes
authors.forename: D
authors.initials: D
authors.lastname: Romero
authors.forename: S
authors.initials: S
authors.lastname: Aguaded
authors.forename: A
authors.initials: A
authors.lastname: Duce
authors.forename: M
authors.initials: M
authors.lastname: Mena
authors.forename: I
authors.initials: I
authors.lastname: Lopez-Braña
authors.forename: M F
authors.initials: MF
authors.lastname: Andrés
authors.forename: J A
authors.initials: JA
authors.lastname: Martin-Sanchez
authors.forename: F
authors.initials: F
authors.lastname: García-Olmedo