Received: 19-05-2023 / Accepted: 29-06-2023
A pot experiment was carried out in net house to evaluate the effect of nitrogen fertilization levels (0.5; 1.0 and 1.5g N per 0.03m2pot) on photosynthesis, grain yield and bran oil of the promising line with thick aleurone layer (Ja12) and the check variety (the original Mizuhochikara) in both autumn and spring season. The photosynthetic rate was measured in 5 plants of each treatment at flowering, milkand dough stages while whole plant dry matter accumulation was measured in five plants at effective tillering, booting, dough and mature stages. At the harvesting stage, the grain yield, ratio of bran/brown rice, and oil content were analysed in 20 plants of each treatment.The experiment results showed that photosynthesis rate and dry matter accumulation increased in both rice varieties with increasing N fertilizer level. The grain yield and characteristics related to oil quality including lipid content and γ-oryzanol content ofJa12 were higher than those ofthe check variety at all fertilizer levels in both cropping seasons. Increasing the amount of nitrogen fertilizer did not increase the ratio of bran/brown rice but increased the content of bran oil and the γ-oryzanol content in both rice varieties, especially the increase was much higher in Ja12 than that in Mizuchihokara variety in both cropping seasons.