Abstract:

In the early stage of this study, a DH population containing 282 lines was constructed by microspore culture with Zhongshuang 11 （ZS11） as female parent and QU as male parent. Through the investigation of two environmental phenotypes and DH genotyping, the chlorophyll content （SPAD value） of Brassica napus leaves was analyzed and located, and a main QTL was obtained in the range of A2 chromosome 21.87-22.91 Mb. In order to further clarify the relationship between chlorophyll content and yield of Brassica napus, the near isogenic line population constructed by chlorophyll major QTL with ZS11 as recurrent parent were used to determine SPAD value of leaves at seedling stage, and then the correlation between SPAD value of chlorophyll and yield per plant was analyzed. The results showed that：（1） the SPAD values of DH population were normally distributed in Xining and Huzhu, the parents' SPAD values were significantly different （P<0.01）, and the higher SPAD values of F₁ showed that the trait was partially dominant, and the chlorophyll content of the same population was different under different environmental conditions. Under the condition of high altitude and low temperature, chlorophyll content increased. （2） In a certain range, the increase of chlorophyll content was helpful to improve the yield of single plant, chlorophyll SPAD value was positively correlated with plant yield, and the correlation coefficient increased with the decrease of sample size. （3） There was significant difference in yield per plant between two groups of near isogenic lines with different genotypes （P<0.01）. （4） According to the confidence interval of genetic linkage map, two co-dominant InDel markers with good polymorphism and six SNP markers with good typing based on KASP technology were developed as candidate markers for molecular mark assisted breeding.

Key words: Brassica napus L., SPAD value, near isogenic lines, yield, correlation, linkage marker