Characterization of agronomic traits in a population of wheat derived from Triticum timopheevii and their association with Fusarium head blight

Abstract

Fusarium head blight (FHB), caused mainly by Fusarium graminearum, is one of the most destructive diseases of wheat especially in humid and semi-humid wheat growing areas of the world. Agronomic traits such as plant height, flowering date, and presence/ absence of awns play important roles in wheat life cycle and grain yield. In the present study, characterization of agronomic traits and their association with Fusarium head blight were investigated in a population of recombinant inbred lines (RILs) derived from the cross of Canadian bread wheat cultivar ‘AC Brio’ to Triticum timopheevii-derived line ‘TC 67’. The population was grown under both greenhouse (Winnipeg, MB, Canada) and field (Carman and Glenlea, MB, Canada) conditions and measurements were made for agronomic traits including plant height, flowering date, presence/absence of awns, and glume threshability. The wheat genotypes were also assessed in the greenhouse for disease severity (type II resistance) and in field plots for disease incidence (type I resistance), disease severity (indicating a combination of type I and type II resistance), deoxynivalenol (DON) content (type III resistance), and Fusarium-damaged kernels (FDK) which is an indicator of type IV resistance. Results showed that there was significant variation in plant height, flowering date, and FHB resistance among the genotypes, and the frequency distributions of these traits were continuous, indicating the quantitative inheritance of the traits. While both plant height and flowering date showed negative correlations with disease incidence, severity, and DON content, they both were positively correlated with FDK under field conditions. In the greenhouse, both plant height and flowering date were positively correlated with disease severity. Awnedness and seed threshability were also significantly associated to all FHB-related traits. While the presence of awns was associated with a significant decrease in FHB, the genotypes that were easy to thresh were more susceptible to the disease. The line ‘TC 67’ with novel FHB resistance derived from T. timopheevii may be useful in wheat breeding, but the positive association of disease resistance with undesirable agronomic traits such as plant height may delay cultivar development efforts.