Seed characters in oilseed rape (Brassica napus) in relation to nitrogen nutrition

Abstract

A greenhouse experiment was conducted to study the influence of N supply on seed weight and number of seeds per pod in oilseed rape (Brassica napus L.) in relation to position of raceme on the plant. Three levels of N supply (2, 7 and 12 mM N as NH4NO3 ) were applied as treatments. Weight of 1000 seeds and number of seeds per pod were estimated from the terminal raceme and five axillary racemes at 27, 44 and 61 days after bloom (DAB). Seed weight was increased significantly by N supply up to 7 mM N irrespective of raceme position on the plant. Number of seeds per pod was increased by N only on the lower racemes at 27 and 61 DAB but was increased on every raceme at 44 DAB. Seed numbers for the lower portions of racemes were generally fewer than those for the upper portions. Nitrogen influence on seed weight was greater than it was on seed number, and the lower the raceme position was on the plant, the fewer the number of seeds per pod was likely to be.