Selection And QTL Analysis Of Heavy Metal Accumulation And Rejection Related Traits In Brassica

Cadmium is one of the most biological toxicity metal, and it is also one of the main heavy metal pollutants in China. Cadmium pollution events emerged accompanied with food security problem in our country. In recent years, "Cadmium rice" events happened occasionally. The phytoremediation technologies which use the characteristics that plants can absorb different heavy metals has been widely concerned. It has features of low cost, wide adaptability, no secondary pollution, etc. Therefore, seeking for high biomass, rapid growth, wide adaptability, high repair efficiency of super accumulated plant resources, is the premise of phytoremediation technology industrialization. Meanwhile, the molecular mechanism of plant absorption of heavy metals is a hot spot of current research.Through hydroponic screening system, two significant different inbred lines of cadmium content were screened from varieties of Brassica napus under cadmium stresses. DH population were construct through the microspore culture, Under cadmium stresses of hydroponic conditions and combine with chip technology, QTL mapping were used to analysis cadmium absorption related traits. And the main results were as follows:1. A hydroponic screening system with cadmium stresses were set up in napus. Compared with the traditional soil culture system, the system is more stable, easy to manage, while reducing the soil borne disease and heavy metals pollution on soil environment. The hydroponic system can also be used for screening of salt resistant materials and speed up the growth of transgenic plants.2. Using the hydroponic system, two inbred lines 009 and 046 of significant different cadmium content of roots were screened from 114 Brassica napus under cadmium stresses. A DH population contain 192 plants were construct through the microspore culture.3. With chip analysis of the DH population under cadmium stresses, genetic linkage map of Brassica napus contain 5398 SNP markers were constructed.4. Using the composite interval mapping(MCIM), a genome-wide scan for QTLs was conducted. In three experiments, we detected tree traits, including the absorption of above-ground portion(AA), absorption of root(AR) and the ration of absorption of above-ground to root(RA). For the absorption of above-ground, nine QTLs were detected on LGs A1, A2, A3, A6, C4, C5 and C9, the additive effect of seven QTLs are negative, the individual QTL explains 6.43%-15.76% of the phenotypic variation. For the absorption of root, seven QTLs were detected on LGs A2,A7,C1,C8, the additive effect of 3 QTLs are positive, the individual QTL explains 7.86%-10.83% of the phenotypic variation. For the ratio of absorption of above-ground portion to root, seven QTLs were detected on LGs A2, A6, A8, A9, C8, the additive effect of four QTLs are positive, the individual QTL explains 6.43%-18.48% of the phenotypic variation.