Grain yield and yield attributes of newly developed low-cadmium rice varieties

Excessive grain cadmium (Cd) accumulation poses a major challenge for rice (Oryza sativa) production in Hunan Province, China, and in many other rice-growing regions worldwide. To address this issue, several low-Cd rice varieties have recently been developed in Hunan. These varieties have been validated to maintain grain Cd concentrations below China's national maximum residue limit when grown on Cd-contaminated soils considered potentially safe for use. However, information on their agronomic performance remains limited. Field experiments were conducted in 2024 and 2025 to compare grain yield and the yield attributes of four newly developed low-Cd rice varieties, namely Anliangyou 2 (ALY2), Qingliansimiao (QLSM), Qinglianxiangzhan (QLXZ), and Xizi 3 (XZ3), with a widely grown non-low-Cd variety, Nongxiang 42 (NX42), under five nitrogen (N) application rates. The results showed that compared with NX42 across the five N application rates (with no interaction between variety and N application rate), ALY2 and QLSM produced higher grain yields in both years, with increases of 10%–22%; QLXZ exhibited comparable grain yield across both years; and XZ3 showed similar grain yield in 2024 but 11% higher yield in 2025. Regarding the yield attributes associated with the superior yield performance of ALY2 and QLSM, the former had 5%–25% greater spikelets m–2, sink capacity, and harvest index, whereas the latter had 4%–12% higher spikelet filling percentage and harvest index. These results suggest that ALY2 and QLSM are promising alternative varieties for cultivation on Cd-contaminated soils considered potentially safe for use, offering the added benefit of higher grain yield through improvements in different yield attributes.