Water use characteristics and drought tolerant ability of different winter wheat cultivars assessed under whole growth circle and at seedling stage

Using drought-resistant cultivars is important to increase crop production in water limited regions. Cultivar performance is influenced by genetic, management and environmental factors, and selection good performance cultivars is often a challenge. Five seasons (2016–2021) of field experiments and three seedling growing durations in a greenhouse, both under three water supply levels (serious water deficit, moderate water deficit and normal water supply), were conducted to assess 10 winter wheat cultivars for their water use characteristics and drought tolerance ability based on seven drought resistance indices and agronomic traits. The performance of the cultivars varied seasonally under field growing conditions. Drought resistance screened by a single index or based on the results from a single season was inconsistent. To avoid seasonal changes in cultivar performance, principal component analyses (PCA) and hierarchical cluster analysis (HCA) were conducted based on the seven indices to classify the ten cultivars into four types of drought responses. The drought resistance classification under field growing conditions at the grain yield level was highly consistent with that obtained under greenhouse growing conditions for biomass at the seedling stage. The results showed that the biomass at the seedling growing stage of the winter wheat cultivars could be used to predict the yield performance and water use characteristics when grown in the field under different water supply conditions. Precisely controlled greenhouse pot experiments could amplify the water use characteristics of different wheat cultivars for assessment. The cultivars with strong stomatal control ability had higher drought resistance and biomass production. Under field growing conditions, lower canopy temperature, deep root growth, a high root/shoot ratio and the maintenance of stomatal conductance under water stress were associated with high drought resistance. These findings provide references for selection methods and indicators for assessing drought-resistant winter wheat cultivars under different growing conditions.