Molecular mapping of a novel QTL for resistance to cereal cyst nematode in F4 wheat population

Abstract

A wheat line selected from an off-type plant (Lnm136) was found to be resistant to Heterodera avenae (cereal cyst nematode, CCN). A F4 population developed by crossing this line with a CCN susceptible genotype, Ksu118, was used to study the map location of the CCN resistance. The results showed that the most significant QTLs for the cereal cyst nematode (CCN) score were identified on five chromosomes. One of the QTLs was located on chromosome 1B and linked closely to Xwmc85 based on composite interval mapping. A novel locus accounting for up to 70% of the resistance to CCN was mapped to chromosome 1B of Lnm136, by association with the microsatellite marker Xwmc85-1B. The selected CCN resistant F4 lines showed introgression for molecular markers identified to be linked with the CCN resistance locus Xwmc85-1B. This QTL on chromosome 1BS in the interval of Xwmc85–Xgpw4331 appears to be a major novel resistance locus. Multiple regression analysis showed the importance of the 1B region and marker-assisted selection for the favorable allele at this region should improve the resistance against CCN. The introgression lines can be used for marker-assisted transfer of Xwmc85-1B to elite wheat cultivars.