Integrating physiological and genetic characteristics to identify drought-resilient foxtail millet genotypes

Foxtail millet (Setaria italica L.) is a drought-resistant C4 crop that is known to exhibit excellent water-use efficiency and tolerance to dry and semi-dry areas. Twenty-two foxtail millet genotypes were accessioned and tested under field conditions throughout the 2023 and 2024 Kharif seasons to select physiological markers linked with drought tolerance. A randomized block design was utilized to examine the physiological characteristics of chlorophyll content, SPADcc, RWC, EL, SRM, and yield traits. There were significant genotypic variations for all traits except RWC, indicating that there was considerable genetic variation in the germplasm. Heritability was high and genetic advance was high for leaf area and SPADcc, which implied strong additive genetic control and hence these characters can be taken as good indicators for selection. PCA and hierarchical clustering segregated the genotypes based on their physiological efficiency and tolerance to drought and isolated FMC-3, FMR-2, and FMU-3 as high performers with better pigment stability, RWC, and photosynthetic efficiency. These findings prove that physiological characteristics can efficiently differentiate drought-tolerant genotypes and serve as a base for breeding programs to improve stress resilience and yield stability in foxtail millet.