Enhancing Host Resistance to Fusarium Head Blight: Pyramiding Genes in Spring Wheat.
William Berzonsky, Emma Gamotin, and Gene Leach. North Dakota State University, NDSU-Plant Sciences Dept., 370G Loftsgard Hall, Fargo, ND 58105-5051
Fusarium head blight (FHB) is a serious fungal disease of cereal crops in the Northern Great Plains. Alsen, a widely grown FHB resistant hard red spring wheat cultivar derives its resistance from Sumai 3 and a quantitative trait locus (QTL) on chromosome 3B. A related tetraploid wheat, Triticum turgidum L. var. dicoccoides, derives its resistance from a QTL located to chromosome 3A. This study was initiated to pyramid the two different sources of resistance and compare the resistance of a line with both sources to that of a similar line with only the Sumai 3 source. Alsen was hybridized to a synthetic hexaploid wheat expressing the T. dicoccoides resistance, and progeny were backcrossed twice to Alsen. After pollination with maize to produce doubled-haploid (DH) lines, molecular markers were used to select DH lines and confirm the presence of the resistance QTL from Sumai 3 and T. dicoccoides. Two DH lines, one with only the Sumai 3 source of resistance (Line 1) and another with both sources (Line 2) and control genotypes were evaluated for FHB resistance in two greenhouse and one field experiment. A single spikelet in the center of the spike was inoculated with a fungal spore concentration of 50,000 conidia ml-1. Disease severity for genotypes was recorded at 21 d after inoculation. Grain was harvested from inoculated spikes and evaluated for Fusarium damaged kernels. A sample of the ground grain was used to determine deoxynivalenol (DON) content. In the first greenhouse experiment, Line 1 exhibited a mean FHB severity of 14%, while Line 2 exhibited a mean of 7%. The DON content of Line 1 was 6.4 ppm, while the DON content for Line 2 was 1.6 ppm. Results from the first greenhouse experiment suggest that pyramiding enhanced the level of resistance to FHB.