Morpho-Physiological Adaptation of Sunflower Hybrids to Varying Plant Densities

This study evaluated the responses of five sunflower (<i>Helianthus annuus</i> L.) hybrids (Surimi CL, Integral CL, Alexa SU, Neta SU, and Davero SU) to three planting densities (84,034, 68,027, and 57,143 plants/ha) in terms of agronomic performance and photosynthetic efficiency. Higher plant density reduced leaf area and seed weight but enhanced uniformity of head formation. Among the tested hybrids, Integral CL and Surimi CL demonstrated superior performance under high density, maintaining higher chlorophyll content, photosynthetic activity, and yield stability. In contrast, Davero SU performed best under low density, characterized by greater leaf expansion, seed filling, and overall productivity. These findings highlight the potential of integrating physiological and agronomic traits to inform hybrid-specific planting density optimization under diverse environmental conditions.