The Study Of Vernalization Response And Gene Mapping In Rape

Brassica napus L is widely planted because of its high adaptability,high yield and high quality.It is one of the important oil crops in China.Vernalization is a necessary condition for flowering of winter rape,and the differences between winter rape and spring rape in the planting area and time form a distant relationship.Therefore,the use of winter rapeseed and spring rapeseed to construct a mapping populations,to further analyze of the mechanism of winter rapeseed vernalization,and to excavate important genes or QTL sites of winter rapeseed vernalization characteristics,can provide theoretical support for the winter rapeseed vernalization.1.Through vernalization treatment of sprouts of B.rapa and B.napus winter rapeseed,study whether winter rapeseed germinated seeds can experience low temperature through vernalization and the effect of different vernalization time on their phenotype,physiological and biochemical,and hormone indexes.The low temperature vernalization time required for winter rapeseed germination seeds to pass vernalization.The results showed that the sprouts of B.rapa winter rapeseed could feel the low temperature to complete the vernalization,while the sprouts of winter rapeseed B.napus treated for 60 days had a lower vernalization rate and could not meet the needs of rapid vernalization.The change of physiological status of germinated seed of winter rapeseed B.rapa is closely related to its vernalization.During the low-temperature vernalization,the seed germination of Longyou No.7 to complete vernalization(vernalization rate? 95%)required vernalization treatment for 76.90 d,and Longyou No.9 and Tianyou No.4 were 54.00 and 39.40 d respectively.Therefore,the low-temperature vernalization treatment of germinating seeds can be used for breeding practice of winter B.rapa..2.Using B.napus winter rapeseed and spring rapeseed seedlings(4~5 leaf stage)for chloroplast vernalization to study whether B.napus winter rapeseed seedlings can experience low temperature through vernalization,and the influence of their vernalization rate,physiological and biochemical indexes at different vernalization times.To determine the low-temperature vernalization time required for B.napus rapeseed seedlings to pass vernalization.The results showed that B.napus winter rapeseed at the 4~5 leaf stage could experience low temperature and pass vernalization,and the time required for 17NTS57 seedlings to complete vernalization(Vernalization rate ?95%)was 68.27 days.The B.napus spring rapeseed could bud and flower in all treatments.Therefore,seedlings of B.napus winter rapeseed can be used for breeding after low temperature vernalization.3.Constructed a genetic map of B.napus with 16 linkage groups using F2 population,which included 95 pairs of SSR molecular markers,with a total length of 4055.69 cM.Using the ICIM method in QTL Icimapping 4.0 software,a total of 1 QTL locus associated with vernalization of rapeseed was detected in the F2 population,located on chromosome A02,with a LOD value of 3.703 and a contribution rate of 11.52%.20 QTLs related to relative conductivity were detected,with a LOD range of 3.053%-21.05% and a contribution rate of 32.13%-63.08%.4.Using 17NTS57 B.napus as material,and using homologous cloning method to clone BnFLC and BnVRN2 gene sequences,and conduct bioinformatics analysis and relative gene expression under different vernalization time determination.The results show that BnFLC is gradually down-regulated.BnVRN2 is down-regulated in the early vernalization,and it is up-regulated in the late vernalization compared to the initial,indicating that BnFLC and BnVRN2 were play important role in low-temperature vernalization.