The Effect Of Hardiness And DNA Methylation Of Environmental Selection For Winter Rapeseed(Brassica Rapa L.)

This experiment is mainly to study over-wintering rates, physiological and biochemical characteristics and agronomicraits, DNA methylation about winter rape after different environm-ent sselected, which explore the environment effects on breeding for cold resistance in winter rapeseed. The main results are as follows:1. Research results indicate that low temperature stress can obviously improve cold resista n-ce of different materials and weak cold resistance materials are increase more significantly than strong cold resistance materials. Environments and interactions between environment and genotype are importantly caused change of planting cold-resistance and physiological and bioche-mical characters after different conditions, which shows that the key of promote wint e-r rapeseed cold resistance in north of China is select optimum environments and cultivars for breeding.2. This study show that the environmental selection has great influence in cold resistance in winter rape in the North and agronomictraits. With the enhancement of environmental selection pressure, the offspring over-wintering was significantly increased, and agronomic got improvem-ents. By selecting the appropriate environment to choose strong materials of cold resistance, you can reduce the time of breeding for cold resistance in winter rapeseed.3.This study was statistic different varieties(lines) of vernalization rate, measure individual hei-ght with winter rape sowed in Spring to identify their capability, by method of subordinate function and correlation analysis, which found that induced by high temperatures can identify winter rape cold resistance and further for winter rapeseed cold resistance breeding provide theory basis.4. After environments selection, winter rape(Brassica rapa L.) full gene group DNA main occurred get rid of methyl to adapted environment pressure. Compared with first gene-ration, the greater environment pressure was endured, the higher over-wintering rate and level of off methylation next generation was; changes of DNA methylation in different cold resistance winter rape were different. For example, methylation degree of super strong cold varieties longyou 7 was less than cold varieties Tianyou 4 after environment selection.5. After low temperature stress, winter rapeseed genomic DNA in different cold resistance occurred methylation off and surplus methylation at the same time, and former was do-minant, and showed varieties’ speciality: varieties with strong cold resistance genomic doubl-e chain full methyl of(CmCGG) degree lower, CCGG bit points occurred half methylation of degree high; in the mode of DNA methylation changes, main occurred to methylation off, methylation degree of longyou series varieties was more greatly than Tianyou series;MS AP different sequencing results showed that winter rape DNA methylation associated with cold re sistance-related gene expression and regulation.