Coix ( Coix lachryma-jobi L.) is an important medicinal and food crop, which is affected by the interaction of varieties and environmental factors. This study aimed to clarify the elevation adaptation of different Coix varieties, and analyze the relationships between agronomic traits and yield. From 2022 to 2023, three elevation gradients of 1100, 1300, and 1500 m were selected in Xingren City, Guizhou Province, China and four varieties of Coix , Xingren Xiaobaike (A), Wenyi 2 (B), Anguo Coix (C), and Shizong Heike (D), were used in field experiments to determine the main growth parameters and yield. The growth period of Coix increased significantly with increasing elevation, the number of tillers decreased significantly, and the plant height, stem diameter, leaf area index, and root morphology indices first increased and then decreased. In 2022-2023, grain yield was highest at 1300 m (3968.60 kg·hm -2 and 5905.50 kg·hm -2 , respectively), and Xingren Xiaobaike performed best (3857.64 and 5832.48 kg·hm -2 , respectively). PLS-SEM results showed that the 1000-grain weight had the most significant direct effects on grain yields, while agronomic traits exerted strong indirect effects through the effective spike (0.59), 1000-grain weight (0.61), and number of grains per spike (0.32) at three elevations. In summary, planting Xingren Xiaobaike at 1300 m elevation optimized growth and ensures high, stable yield.. These findings provide a scientific basis for the cultivation planning and elevation-based variety selection of Coix . Future research should explore the interaction between yield improvement and medicinal quality under optimized growing conditions. • Effects of elevation and agronomic conditions on growth and yield of Coix. • The 1000-grain weight and agronomic traits most significantly affected grain yields. • Xingren Xiaobaike varieties at a 1300 m elevation provides ideal Coix conditions.
An et al. (Fri,) studied this question.