Trait phenotyping and identification of trait-specific donor genotypes for agronomic improvement and ideotype breeding in browntop millet (Urochloa ramosa L.)

Introduction: L.) is a climate-resilient crop valued for its tolerance to harsh environments and high nutritional quality. However, limited genetic improvement has restricted its wider utilization. This study aimed to assess genetic diversity and identify trait-specific donors for enhanced agronomic performance. Material and methods: was evaluated for key agronomic traits. Genetic parameters including variability, heritability, and genetic advance were estimated. Correlation and path coefficient analyses were performed to determine trait associations. Principal component analysis (PCA), cluster analysis, and multi-trait genotype-ideotype distance index (MGIDI) were employed to identify superior genotypes. Results: Significant genotypic variation was observed across all traits. Grain yield and fodder yield exhibited high heritability and genetic advance, indicating additive gene action. Correlation and path analysis revealed strong positive associations between yield and contributing traits. PCA showed that the first five components explained 68.66% of total variation. Cluster analysis grouped genotypes into four clusters, with Cluster IV containing superior accessions. MGIDI analysis identified 11 promising genotypes, including GPUBT 6, VBT 004, TNAU 164, IC 613548, IC 613553, TNAU 129, TNAU 110, TNAU 134, TNAU 140, HBr 2, and TNAU 150. Conclusion: The study highlights substantial genetic variability in browntop millet and identifies promising genotypes for dual-purpose improvement. These findings provide a foundation for developing high-yielding, early-maturing, and climate-resilient cultivars.