Grant C A, Clarke J M, Duguid S, Chaney R L
AAFC Brandon Research Centre, Box 1000A, R.R.#3, Brandon, MB Canada, R7A 5Y3.
Sci Total Environ. 2008 Feb 15;390(2-3):301-10. doi: 10.1016/j.scitotenv.2007.10.038. Epub 2007 Nov 26.
Natural variation occurs in the uptake and distribution of essential and nonessential trace elements among crop species and among cultivars within species. Such variation can be responsible for trace element deficiencies and toxicities, which in turn can affect the quality of food. Plant breeding can be an important tool to both increase the concentration of desirable trace elements and reduce that of potentially harmful trace elements such as cadmium (Cd). Selection programs for a low-Cd content of various crops, including durum wheat, sunflower, rice and soybean have been established and low-Cd durum wheat cultivars and sunflower hybrids have been developed. In durum wheat (Triticum turgidum L. var durum), low-Cd concentration is controlled by a single dominant gene. The trait is highly heritable, and incorporation of the low-Cd allele can help to reduce the average grain Cd to levels below proposed international limits. The allele for low-Cd concentration does not appear to affect major economic traits and should not cause problems when incorporated into durum cultivars. The cost of Cd selection in a breeding program is initially large both in terms of Cd determination and reduced progress towards development of other economic traits, but declines as more breeding lines in the program carry the low-Cd trait and are utilized in new crosses. Production of low-Cd crop cultivars can be used as a tool to reduce the risk of movement of Cd into the human diet.
必需和非必需微量元素在作物物种之间以及物种内的品种之间的吸收和分布存在自然变异。这种变异可能导致微量元素缺乏和毒性，进而影响食物质量。植物育种可以成为增加所需微量元素浓度和降低潜在有害微量元素（如镉（Cd））浓度的重要工具。已经建立了包括硬粒小麦、向日葵、水稻和大豆在内的各种作物低镉含量的选择计划，并培育出了低镉硬粒小麦品种和向日葵杂交种。在硬粒小麦（Triticum turgidum L. var durum）中，低镉浓度由一个显性单基因控制。该性状具有高度遗传性，引入低镉等位基因有助于将平均籽粒镉含量降低到国际建议限值以下。低镉浓度等位基因似乎不影响主要经济性状，将其引入硬粒小麦品种时不应产生问题。在育种计划中，镉选择的成本最初在镉测定和其他经济性状发育进展降低方面都很高，但随着该计划中更多育种系携带低镉性状并用于新杂交，成本会下降。生产低镉作物品种可作为一种工具，降低镉进入人类饮食的风险。
