Abstract:

To investigate the varietal differences in cadmium (Cd) absorption and accumulation among different rice varieties, a field experiment was conducted with 10 rice varieties in slightly Cd-contaminated farmland. The variations in Cd absorption and accumulation capacities were compared. The results demonstrated that grain yields of different rice varieties ranged from 7.60 to 10.77 t/hm², with the highest yield observed in the cultivar ‘Liangyou 5078’, which was significantly higher than other varieties (P<0.05). The Cd content in brown rice of different varieties ranged from 0.177 to 0.503 mg/kg, with the Cd concentration in ‘Zhennuo 29’ being lower than the national limit standard (0.20 mg/kg). The enrichment factors of brown rice for total soil cadmium (Cd) in different rice varieties ranged from 0.281 to 0.858, all below 1. The enrichment factor of ‘Zhennuo 29’ was significantly lower than other varieties (P<0.05). Rhizosphere Soil pH values at the maturity stage varied between 5.49 and 6.93 across varieties, with a mean value of 6.27. The total Cd and available Cd contents in soil ranged from 0.407 to 0.827 mg/kg and 0.180 to 0.293 mg/kg, respectively, with average values of 0.634 mg/kg and 0.252 mg/kg. Through input-output ratio analysis of different rice varieties, the ratio for ‘Zhennuo 29’ reached 1.81, which was significantly higher than other varieties (P<0.05). The study demonstrates that ‘Zhennuo 29’ can be cultivated as a low-Cd-accumulating rice variety in safe utilization farmland in the region with high economic value.

Key words: low-Cd-accumulating rice varieties, screening, Cd absorption and enrichment, input-output ratio analysis