Diversity assessment and characterization of safflower ( Carthamus tinctorius L.) accessions from Ethiopia using morpho-agronomic traits

Abstract To facilitate the utilization and improvement of safflower in Ethiopia, characterizing the diversity of core local germplasm through quantitative morpho-agronomic traits is paramount. To this effect, a total of 144 Ethiopian safflower germplasms, including 142 core accessions and two released varieties as checks, were characterized based on 12 quantitative morpho-agronomic traits. The experiment was conducted in the field using a 12 × 12 simple lattice design. Significant differences for all studied traits were observed, indicating substantial variability among the accessions. The phenotypic and genotypic variance coefficients were notably high for most agronomic traits, such as primary branches, capitulum, seed yield per plant, seeds per capitulum, and yield per plot. Broad-sense heritability was moderately to very high, alongside moderate to high genetic advance for all evaluated traits. Path coefficient and correlation analyses indicated that traits such as leaf length, leaf width, and primary branches per plant, along with 1000-seed weight and seed yield per plant, had a significant positive association and direct effect on yield per plot. To decompose the sources of variation, the analysis of the principal components conducted revealed the first three components explain 68.67% of the total variation. The primary contributors to the variation are traits such as days to maturity, days to 50% maturity, days to flower initiation, plant height, leaf length, leaf width, seed yield per plant, and yield per plot. Further, the accessions were categorized into three different groups based on the studied morpho-agronomic traits, demonstrating considerable genetic variation among accessions for different clusters. Taken together, these findings indicate the presence of sizable trait variation among the accessions that can be exploited as selection marker to design and facilitate breeding strategies for safflower improvement.