Effect of branch position on seed weight and oil content in canola (<i>Brassica napus</i> L.)

Increasing seed weight and oil content are the main pathways to increase canola seed oil yield. The effect of branch position on seed weight and oil content has not been previously reported in canola. Field experiments were conducted to explore the impact of branch position on seed weight and oil content. Four canola genotypes, Zheyou 50, Zhongshuang 11, Zheyou 18, and Zheshuang 8, were used to evaluate seed weight, oil content, carbohydrate profile, and nitrogen content in the main inflorescence and branches from the top to the bottom of the main stem. Seed weight and oil content decreased from the main inflorescence to the lower branches in the four genotypes. Lower carbohydrate and nitrogen content in the seed and low transport efficiency of the two chemical compounds in the silique and branches were responsible for the lower seed weight and oil content in Zheshuang 8 and Zheyou 18, respectively. However, the decreasing seed weight and oil content in the branches did not correspond with decreasing carbohydrate and nitrogen content in the branches from the top to the bottom. The result suggested complex carbohydrate and nitrogen metabolism in the canola seed in the different branches