Influences of plant density on the seed yield and oil content of winter oilseed rape (Brassica napus L.)

A field experiment was conducted to investigate the influences of plant densities on the seed yield and oil content of the winter oilseed rape (Brassica napus L.), which included two varieties, Zhongshuang No. 11 (ZS) and Ganyouza No. 1 (GY), and three densities (2.4 × 104, 3.6 × 104 and 4.8 × 104 plant hm−2) treatments in two consecutive growing seasons (2009–2010 and 2010–2011). Results showed that, compared with 2.4 × 104 plant hm−2, the seed yield per plot of 3.6 × 104 and 4.8 × 104 plant hm−2 treatments were significantly increased in both growing seasons, which might be due to the raceme and pod numbers per unit area were significantly increased with the increase in plant densities. And the seed oil content was significantly increased with the increase in plant densities, which might be due to the proportion of seed yield of main raceme significantly increased. Meanwhile, the seed oil content and 1000 seed weight of main raceme were significant higher than branch raceme about 1.0% and 10.0%, respectively. And the influences of plant densities on the seed yield of winter oilseed rape are mainly on the branch raceme and less on the main raceme. These results indicated that increasing the main raceme numbers per unit area and the production capacity of main raceme might be an effective means to increase the seed yield and oil production of winter oilseed rape.

► Seed oil content of main raceme higher than branch raceme about 1%.
► Seed oil content was increased with the plant densities.
► The 1000 seed weight of main raceme much higher than branch raceme.
► Plant density mainly affects on branch raceme and less on main raceme.