Mapping of FHB resistance QTLs in the Mini Mano/Frontana and Frontana/Remus DH populations

Abstract

Fusarium head blight (FHB) is a devastating disease of wheat (Triticum aestivum L.) world-wide. The objective of this study was to identify FHB resistance QTLs of the Brazilian spring wheat cultivar Frontana through molecular mapping. Frontana has small and medium effective QTLs. These types of QTLs are sensitive for the environmental factors and for the problems of heterogeneity. 206 DH lines from Frontana/Remus (IFA-Tulln)/2005–2006/ and 105 DH lines of Mini Mano/Frontana (CRC Szeged)/2006–2007/ were inoculated with isolates of F. graminearum and F. culmorum. The Frontana/Remus DH population had wide differences in flowering time and plant height. MM/Frontana was created by CRC, Szeged so that too early and late DH lines were discarded and the remaining lines flowered within five days. Lines with extra plant height were also discarded, so differences were kept within 20–30 cm. In the Frontana/Remus population QTLs were identified on the chromosomes 3B, 5A, 6B. In the MM/Frontana population chromosomes 3B and 5B gave positive signal. Although in both populations Frontana was the resistant parent no QTL markers were identical for them. It seems that the more homogeneous population increases the accuracy of the QTL analysis. An increased morphological homogeneity seems to be necessary to decrease „background noise” in QTL analyses and increase precision. Until now no QTL were found that gave positive signs for all epidemic situations. As QTLs are not validated, it is early to apply MAS in breeding.