A Database for Triticeae and Avena
UNIVERSIDAD POLITÉCNICA DE MADRID
Departamento de Biotecnología, E.T.S. Ing. Agrónomos.- C. Universitaria, 28040, Madrid, Spain.
A. Delibes, I. López Braña, M.J. Montes, and M. Gómez Colmenarejo.
CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS
Serrano, 115, 28006, Madrid, Spain.
D. Romero and M.F. Andrés.
UNIVERSITY OF LLEIDA AND
INSTITUTE FOR FOOD AND AGRICULTURAL RESEARCH AND TECHNOLOGY (UdL-IRTA)Center of R&D, Rovira Roure 177, 25198 Lleida, Spain.
J.A. Martín-Sánchez, E. Sin, C. Martínez, and A. Michelena.
JUNTA DE EXTREMADURA
Servicio de Investigacion Agraria.
J. del Moral and A. Mejías.
Line TR-353, derived from the cross (T. turgidum/Ae. triuncialis//T. aestivum), was characterized by in situ hybridization and isozyme markers. A total of 27 isoenzyme systems from the seven homoeologous groups were fractionated by IEF and conventional electrophoresis. Line TR-353, with 42 chromosomes after successive selfing, has a B-genome chromosome pair substituted by one from the D genome. This result and those of the isozyme analyses, such as the patterns of acid phosphatase (Acph-1), b-amylase (b-Amy-2), alcohol dehydrogenase (Adh-1), and aconitase (Aco-2), suggest that the substituted pair in this line is for chromosome 4D.
Line TR-353 has the resistance gene Cre7 (previously denominated Cre Aet) to H. avenae and also had a high level of resistance to the biotype of Hessian fly prevalent in southwestern Spain. Two, single dominant genes (Cre7 and HAet) seem determine both resistances. We studied the genetic relationships with other resistance sources.
The gene Cre7 from TR-353 line confers resistance to two Spanish populations, four French races, and two Swedish of CCN tested. Studies of the segregation of resistance in F1 and F2 populations from crosses of TR 353 (Cre7) with Loros and Iskamish (Cre1), H-93-8 (Cre2), and two synthetic hexaploid wheats with Cre4, show that all plants of F1 generation had a similar level of resistance than their resistant parents. Most of the F2 plants were resistant with a few susceptible plants. The classification of the F2 population is consistent with an independent segregation of two dominant genes, fitting a 15:1 resistant:susceptible ratio in each cross. These results confirm the hypothesis of two different loci, with two alleles in each cross, both resistance genes being dominant. From these results, we concluded that the gene Cre7 is not allelic to Cre1, Cre2, and Cre4 and could be determined by one different locus with respect to these genes. Hexaploid wheats with the Cre3 gene were not effective against the Ha71 Spanish pathotype, and the cross of TR-353 with these cultivars gave a 3:1 resistant:susceptible segregation for resistance, as expected.
Lines from the backcross of TR-353, as donor parent, and T. aestivum cultivars Cartaya, Anza, and Betrés, as recurrent parents, show a high level of resistance to H. avenae. These lines, which were morphologically similar to the recurrent parents, have a major agronomic yield.
The segregation of resistance to the Hessian fly biotype prevalent in Azuaga of F1 and F2 populations from the crosses 'Ella (H9)/TR-353(HAet)' and 'Kay (H11)/TR-353(HAet)' was studied. All plants of F1 generation had a level of resistance similar to their resistant parents. Most of the F2 plants were resistant, but there were a few susceptible plants.
Classification of the F2 populations is consistent with the independent segregation for two dominant genes, fitting a 15:1 resistant:susceptible ratio. These results support the hypothesis of two different loci with two alleles in each cross, and the resistance genes are dominant. So, the resistance to Hessian fly in TR 353 is determined by one different locus with respect to the genes H9 and H11 from Ella and Kay, respectively.
We are coöperating with Drs. T. Bleve-Zacheo and M.T. Melillo (CNR-Bari, Italy) in the histochemical localization of enzymes related to H. avenae resistance in wheat. We have initiated a program to analyze changes in enzyme activity in the resistant wheat line TR-353 during cyst nematode infestation to identify biochemical markers for resistance. We are also coöperating with Dr. E. Lagudah (CSIRO Plant Industry, Camberra, Australia) in the characterization of resistance genes Cre2, Cre6, and Cre7.
This work was supported by grant AGF98-1057-Co4 from CICYT 'Comision Interministerial de Ciencia y Tecnologia' of Spain.