Field testing and molecular marker characterization of near-isogenic lines with Fusarium Head Blight resistance QTL from CJ9306 in Zebra and Berserk spring wheat backgrounds

Fusarium head blight (FHB or head scab) is a devastating disease of wheat (Triticum aestivum L.) and other small grain cereals induced by Fusarium spp. all around globe, causing higher yield loss and increased mycotoxin contamination like Deoxynivalenol (DON) which is a serious risk for human and livestock health. The sustainable way to reduce the problems of Fusarium infection is to increase resistance by stacking Quantitative Trait Loci (QTL) on our cultivars. Resistance breeding depends heavily on Chinese resistance cultivar Sumai 3 and its derivatives with focused on the Fhb1 QTL. The purpose of our study were to (i) confirm the allelic states of FHB resistance QTL Fhb1, QFs.nau-2DL and Qfhi.nau-5AS in the NILs derived from the cross between CJ9306 (derivative of Sumai 3) and Zebra, Berserk spring wheat cultivars of Norway by marker genotyping, (ii) investigate the effect of three QTL and their combination on FHB resistance traits (visual symptom, DON content and anther excretion (AE)), and (iii) to evaluate the potential side-effects of the QTL on the important agronomic traits like plant height (PH), days to heading (DH), grain yield, and grain quality parameters. To determine the association between FHB severity and passive resistance related traits like DON, DH, PH, and AE; grain spawn inoculation in one field trial out of three was performed in Norway, where FHB scoring was done. Strong significant correlation between these traits were confirmed except for DH. Highly significant correlation (0.483***) between FHB severity and DON was obtained. PH was associated most with DON content (-0.353*, - 0.464*, -0.413*) followed by FHB severity (-0.241, -0.357*, -0.341) in all three experimental fields. Similarly, AE had higher correlation with DON (-0.371*, -0.356*) than with FHB severity (-0.298*, -0.201). Genotyping of 57 BC1F5 NILs with Kompetitive allele specific PCR (KASP), Sequence tagged sites (STS) and Simple sequence repeat (SSR) markers confirmed the allelic states of the NILs. The resistant allele at QTL were found to be introgressed in NILs successfully. Fhb1 and 5AS were found introgressed in 26 lines and 2DL on 19 lines out of 57 NILs. QTL Fhb1 and 2DL were found significant with DON content reduction while 5AS did not have any measurable contribution. Besides, effects of these three QTL on FHB severity were not significant. Fhb1 was found delaying DH by one day in NILs. However, the QTL were not found significant with PH and AE. The stacking of QTL with resistance allele showed stronger effect on the traits than acting alone. Effect of all three QTL combination for grain quality parameters like test weight, protein content, starch content and yield in both the agronomic field trial were not in measurable amount. However, 2-3 gm reduced 1000 kernels weight was seen for QTL combination in both agronomic field trail. Therefore, promotion of Marker – assisted selection based on QTL introgression of Fhb1, 2DL and phenotypic selection method of high AE and optimal PH are recommended to the companies and research institution working on resistance breeding for wheat FHB in Norway