Secoisolariciresinol diglycoside (SDG) lignan content of oil flax: Genotypic and environmental variations and association with other traits

The secoisolariciresinol diglycoside (SDG) lignan of oil flax (Linum usitatissimum L.) is influenced by genotype, environment and the interaction of genotype ​× ​environment. This field study was conducted to investigate the effects of genotype and environment on the SDG lignan content, six genotypes (Longya 8, Zhangya 2, Linxiabai, Shandanbai, Gaolanbai, and DYMS) were sown under eight locations (Hohhot, Datong, Minle, Yili, Shuangta, Jingtai, Guyuan, and Zhangjiakou) in 2014 and 2015 in China. The experimental design was a randomized complete block with three replications. Results showed that Longya 8 had the highest SDG lignan content (7.27 ​mg/g) and Shandanbai had the lowest (4.71 ​mg/g) across 16 environments. The SDG lignan content ranged from 4.70 ​mg/g at Datong to 7.74 ​mg/g at Minle Research Station. In the present study, the results indicated that differences among genotypes in SDG lignan content accounted for 51.38% variation of the total variation and environments accounted for 44.40% variation of the total variation. Moreover, we found that the altitude had a positive effect on SDG lignan content of flaxseed, presumably owing to differences in temperature, humidity, sunshine time, etc. These results indicated that the SDG lignan content was genetically controlled, and was also to be influenced by environmental conditions, especially altitude.