Effect of Shading on Saffron (Crocus sativus L.) Performance under Intense Solar Radiation: Interactions with Planting Depth and Corm Weight

Background Agronomic practices that mitigate temperature stress and optimize light conditions are vital for enhancing saffron ( Crocus sativus L.) yield under intense solar radiation and minimal rainfall. This study evaluated the interactive effects of four shading levels (0%, 15%, 30%, 45%), three planting depths (10, 15, and 20 cm), and two corm weight classes (4–6 g and 9–11 g) in a splitfactorial design with three replications in an arid–semiarid context. Results Shading emerged as the dominant factor limiting yield, with high shade (45%) significantly decreasing pigment content, daughter corm weight, and stigma yield. Deeper planting under shaded conditions accelerated chlorophyll degradation—particularly in larger corms—while moderate shading (15–30%) promoted carotenoid accumulation. Heavier corms (9–11 g) partially mitigated the negative effects of shading and depth. Peroxidase activity increased over time across treatments and was consistently higher in larger corms. Optimal yield was achieved under moderate shading and shallow planting (10 cm) using heavier corms. Conclusions These findings highlight that moderate shading combined with shallow planting and heavier corms optimizes saffron performance in environments characterized by intense solar radiation, temperature fluctuations, and minimal precipitation. Tailored management of light exposure, planting depth, and corm size may significantly improve yield under such challenging environmental conditions.