The identification of cultivar-specific responses to sowing density is important for simultaneously optimizing wheat productivity and grain quality. This study applied hierarchical cluster analysis to classify nine winter wheat (Triticum aestivum L.) cultivar × sowing density combinations on the basis of two-year mean values obtained on chernozem soil. Three cultivars, Glosa, Anapurna and Biharia, were evaluated at 780, 650 and 530 viable grains m−2. Separate dendrograms were constructed for grain yield, protein content, wet gluten content, Zeleny sedimentation value, thousand-kernel weight (TKW) and sowing density, using single linkage and Euclidean distances. The cluster structures demonstrated that the similarity among treatments was trait-dependent. For grain yield, Biharia at 780 and 650 viable grains m−2 formed a close pair, whereas the remaining treatments showed a different aggregation pattern and Biharia at 530 viable grains m−2 was positioned distinctly in the hierarchy. For protein, the three Biharia treatments formed a coherent group that was clearly separated from the Glosa and Anapurna combinations. Wet gluten produced three principal cultivar-related branches, with the closest similarities occurring within specific density combinations. Zeleny sedimentation and TKW also displayed cultivar- and density-dependent clustering, confirming that technological quality cannot be inferred from yield behavior alone. The dendrogram based on density produced three expected groups corresponding to 780, 650 and 530 viable grains m−2, independently of cultivar, validating the treatment coding and emphasizing the contrast among plant populations. Overall, hierarchical clustering revealed both cultivar identity and sowing density as important sources of phenotypic differentiation. The results support the use of cluster analysis as a complementary multivariate tool for identifying treatment similarities and for developing cultivar-specific sowing-density recommendations when yield and grain quality are considered together.

winter wheat; hierarchical cluster analysis; sowing density; grain yield; protein; wet gluten; Zeleny; thousand-kernel weight

agronomy

Presentation: poster