The correlation between wheat black point and agronomic traits in the North China Plain

Abstract

Black point is an economically serious disease in cereals that affects crop yield and value, the incidence of which is known to vary with environmental conditions and fungal load. However, little is known about the genotypic differences in susceptibility towards the disease. We studied the correlations between 35 agronomic traits and the incidence of black point, using 48 representative wheat genotypes selected from a total of 403 genotypes. These 48 genotypes were inoculated with fungi and cultivated under field conditions during 2016–2018 in the North China Plain. The results showed that the incidence of black point varied across genotypes, fungal isolates, and years. First, we screened 28, 23, 19, and 23 genotypes susceptible or resistant to black point caused by Bipolaris sorokiniana, Alternaria alternata, Fusarium equiseti, and under natural field conditions, respectively. The correlations between black point incidence and agronomic traits were analyzed using the screened wheat genotypes. We found a positive correlation between incidence and filling stage (r = 0.652) and a negative correlation between incidence and freezing resistance (r = −0.613) during the three years. In addition, black point incidence was correlated with thousand grain weight, heading date, seedling habits, awn length, and glume opening; however, these associations varied across years and different fungal isolates. Black point incidence was not strongly associated with most of the agronomic traits studied, thus indicating that this disease was greatly affected by environmental factors. However, black point incidence was likely to be lower in genotypes with adequate freezing resistance and short filling stage. These results provide some markers of agronomic traits for breeders to improve the selection efficiency of high-yielding wheat varieties that are resistant to black point.