| In order to obtain rice varieties with low accumulation of heavy metals for safety rice production, an in situ field experiment was conducted in Chongqing. The accumulation capacity for heavy metals including metal cadmium (Cd), arsenic (As), lead (Pb), chromium (Cr) by 13 main rice cultivars with different genotype were compared in the experiment, and the characteristics of heavy metal absorption, translocation and distribution in rice plants in relation to the heavy metal contents in rice grains were analyzed. The results showed that: (1) The extreme values of Cd, As, Pb and Cr contents in rice grains of different rice varieties varied by more than 3, 4, 20 and 3 times, respectively, and the accumulative capacity of the same variety to different heavy metals was also greatly different. Thus, multiple elements should be consider in screening of rice varieties with low accumulation of heavy metals. (2) The heavy metal comprehensive accumulation index (PZ) was adopted to evaluate the ability of rice variety for heavy metal accumulation. The 13 rice varieties were divided into three categories: low cumulative capacity (PZ<0.7), medium (0.7≤PZ<1) and high (PZ≥1). Among them, Y Liangyou No.1, Longliangyou 534 and Longliangyouhuazhan accounted for low cumulative varieties. (3) The genotype differences on heavy metal accumulation in rice plants of different variety was mainly reflected by rice grains, followed by stem-leaf and root. The transport coefficient TFSL-G was an important manifestation of rice genotype difference, which was positively correlated with the content of heavy metals in rice grains (P<0.01). (4) The yield of 13 rice varieties ranged from 5.85 to 10.65 t·hm-2, with a maximum variation of 44.8%. The yields of the top 6 rice varieties exceeded 9.00 t·hm-2; and the average grain number per panicle was found to be the main yield-determination factor. Longliangyou 534, Y Liangyou 1, Yuanliangyou 908 and Yuxiang 203 are recommended as suitable varieties in Chongqing in consideration of both rice yield and rice heavy metal accumulation ability, which can not only achieve high yield but also benefit for rice safety production. |
