Doubled haploid (DH) populations were generated from crosses between fusarium head blight (FHB)-resistant Chinese hexaploid germplasm and susceptible adapted cultivars. Four families of second-round DH plants were produced from resistant 93FHB#37 (HY616 x NING8331) and susceptible RL4761. These families are being tested for their FHB reaction by spray and infection inoculation. It is hoped that a family will show a single gene segregation ratio and can then be used to establish genetic linkage to PCR-based markers. Using the University of British Colombia's simple sequence repeat (SSR) Primer Set #9, 75 PCR-based polymorphisms were found between the parents. The polymorphic primers will be screened for linkages to FHB genes when single gene families have been identified. Breeding programs have made extensive use of Brazilian cv. Frontana and Chinese cv. Sumai 3 and derived lines as FHB resistance sources. The search for useful genes in wild grass species continues, in an attempt to broaden the basis of resistance. Lines with resistance levels higher than those of the susceptible adapted parents have been identified in Brazilian rye landraces, and in wide crosses between common wheat and Hordeum, Triticum, Thinopyrum, and Dasypyrum species. No resistant tetraploid lines resulted from crosses between resistant Chinese hexaploid and susceptible durum cultivars. Tetraploid Triticum species were screened for reaction to FHB. Two T. dicoccoides lines were used in crosses with durum line DT484. In a preliminary test, 80 F3 lines from two crosses were screened in an irrigated nursery. There was a high percentage of resistant lines in one cross. Selections will be made for future screening and backcrossing.

English

9806|AGRIS 9802

Jose Juan Caballero

CIMMYT Publications Collection