Prediction of wheat grain yield by measuring root electrical capacitance at anthesis

This methodological study evaluated the efficiency of predicting aboveground biomass and grain yield in fieldgrown winter wheat by measuring the saturation root electrical capacitance at anthesis. Three cultivars were grown over a threeyear period as sole crops and intercropped with winter pea at halved wheat density. The root capacitance readings were converted into saturation root electrical capacitance using the relevant soil water content, according to an empirical function. At plant scale, saturation root electrical capacitance at anthesis showed a significant (p < 0.001) linear regression with the total aboveground biomass (R2: 0.653-0.765) and grain yield (R2: 0.585-0.686) at maturity for each cultivar. At stand scale, both the mean saturation root electrical capacitance and shoot dry mass at anthesis and grain yield varied over the years, and were consistently higher for the intercrops compared to the sole crops. The relative increase in saturation root electrical capacitance due to intercropping corresponded with the changes in shoot dry mass and grain yield, especially in dry years. Saturation root electrical capacitance was significantly correlated with shoot dry mass (R2: 0.714-0.899) and grain yield (R2: 0.742-0.877) for each cultivar across all cropping systems and years. In conclusion, by mitigating the soil water content effect, the measurement of saturation root electrical capacitance at anthesis is adequate to forecast grain yield and cultivar response to a changing environment.