Multivariate trait profiling and genetic diversity in a global foxtail millet germplasm panel

Foxtail millet (Setaria italica L.), known for its climate resilience and dual-purpose utility, is underutilized in breeding programs despite its agricultural potential. To address this, a comprehensive evaluation of 260 accessions from 19 countries was undertaken to assess phenotypic diversity and identify elite germplasms for breeding. Field-based assessments were conducted using 22 traits (8 quantitative and 14 qualitative) measured at seedling and maturity stages. Data were analysed using genetic diversity indices, correlation analysis, principal component analysis (PCA) and hierarchical clustering. Seven traits showed high variability, with yield (CV: 25.92%), grain weight per panicle and single panicle weight being most diverse. Yield positively correlated with plant architecture, panicle structure and biomass traits. PCA revealed four principal components explaining 80.20% of the total variation. Cluster analysis grouped accessions into four phenotypically distinct clusters. The study identified four key groups of accessions: lodging-resistant, dual-purpose high-yielding, early-maturing and agronomically balanced types. This integrative phenotypic analysis enables efficient identification of superior accessions and supports targeted breeding and conservation strategies to improve foxtail millet adaptation and productivity across diverse agroecological zones.