Field Crop 2025, Vol.8, No.3, 126-138 http://cropscipublisher.com/index.php/fc 128 output under drought conditions to that under normal conditions. The physiological and ecological category includes leaf water content, chlorophyll, photosynthetic rate, as well as proline and soluble sugar content, which are used to reflect the state of plants under drought conditions. A single indicator is often difficult to be comprehensive. Therefore, in recent years, comprehensive evaluation methods have been mostly adopted. For instance, principal component analysis is used to extract key traits, and then combined with the membership function method to calculate the comprehensive score and rank the drought resistance of varieties (Figure 1) (Bao et al., 2023). This type of method has been verified on crops such as rice, soybeans, mung beans and wheat. Research on peanuts shows that total biomass, relative moisture content, peroxidase activity and soluble sugar are important indicators for distinguishing drought-resistant varieties from sensitive ones. Research on soybeans has found that chlorophyll content, single plant grain weight and the number of root nodules contribute the most (Yan et al., 2020). Meanwhile, yield-based indicators such as the Drought Sensitivity Index (DSI), Drought Tolerance Index (TOL), Average Productivity (MP), and Geometric Mean Productivity (GMP) are also commonly used, but they are easily affected by yield levels and thus are more suitable for combination with multiple indicators (Chen et al., 2012). This study will adopt methods such as relative yield, drought resistance coefficient and the comprehensive value of membership function for cross-validation to more comprehensively characterize the drought resistance capacity of varieties. Figure 1 The geographic overview of the North China Plain and the experimental site (Adopted from Bao et al., 2023) 2.3 Genotype-environment interaction and adaptability theory In multi-environment experiments, it is often encountered that a variety has a high yield in one place, but it falls behind once the environment is changed. This is actually what is called the interaction between genotype and environment (G×E). This situation is even more pronounced in drought-tolerant breeding. Some varieties perform well in arid areas, but they do not have an advantage when placed in humid conditions. The methods for analyzing the adaptability and stability of varieties are also changing. In the past, linear regression and double-label plots
RkJQdWJsaXNoZXIy MjQ4ODYzNA==