Morphological Characterization, Genetic Variability, and Multivariate Diversity Analysis of Finger Millet (Eleusine coracana) Germplasm Collected from Tigray, Northern Ethiopia

Finger millet (Eleusine coracana (L.) Gaertn.) is a climate-resilient, nutritionally essential cereal that remains under-characterized across much of its Ethiopian range. This study evaluated 38 finger millet landraces collected from farmers in the Tigray region of northern Ethiopia for five agronomic traits across three locations over two cropping seasons (2024–2025), using a row–column randomized complete block design with three replications. Combined analysis of variance revealed highly significant (p < 0.001) effects of genotype, location, and year for most traits, with genotype × location × environment interactions that were generally small relative to the main effects. Additive Main Effects and Multiplicative Interaction (AMMI) analysis revealed a statistically significant genotype × environment interaction only for days to flowering (p = 0.025), while grain yield, days to maturity, plant height, and panicle length indicated non-significant interaction terms indicating that environment rather than genotype-specific response was the dominant source of variation for those traits. Broad-sense heritability ranged from very low for days to maturity (4.1%) to moderately high for days to flowering (70.2%), and genetic advance as a percentage of the mean was greatest for panicle length. Grain yield correlated most strongly with days to flowering (r = 0.54), while plant height and panicle length were positively associated with each other (r = 0.62). Principal component analysis extracted two components with eigenvalues above 1, jointly explaining 69.2% of total phenotypic variation, with flowering time, plant height, and panicle length as the leading contributors. Path coefficient analysis identified plant height and head weight as the traits exerting the largest positive direct effects on grain yield, while Mahalanobis distance analysis revealed considerable genetic divergence among accessions (D² range: 0.38–35.59). Collectively, these results provide baseline diversity information for Tigray finger millet landraces and highlight plant height, panicle length, and days to flowering as priority traits for selection in future breeding and conservation programs.