Different seedling managements and fertilizer rates at tillering stage influences the yield formation and aroma content in fragrant rice

Abstract

In fragrant rice (Oryza sativa L. subsp. japonica Kato) production, seedling management and fertilization both are important parts. However, the effects of different seedling managements and fertilizer rates on grain yield and 2-acetyl-1-pyrroline (2-AP, main and key compound of fragrant rice aroma) content of fragrant rice are still unknown. In present study, four seedling managements (mechanized transplanting (MT), mechanized direct-seeding (MDS), seedling throwing (ST) and seeds broadcasting (BS)) combined with three fertilizer rates (450 (Fer1), 600 (Fer2) and 750 (Fer3) kg ha-1) at tillering stage were applied in a 2-yr field experiment. The results showed that the grain yield and 2-AP content differed in different seedling management and fertilizer rate treatments. The highest grain yield and 2-AP content were recorded in MTFer3 treatment which were 4.81-4.86 t ha-1 and 307.68-390.99 μg kg-1 FW, respectively, while the lowest were recorded in BSFer1 treatment which were 3.96-4.09 t ha-1 and 62.92-165.09 μg kg-1 FW, respectively. Furthermore, the lowest expression of gene BADH2 related to 2-AP biosynthesis was recorded in MTFer3 treatment. Under the same fertilizer rate treatment, MT treatment produced the highest grain yield and 2-AP content which ranged between 4.49-4.86 t ha-1 and 222.16-390.99 μg kg-1 FW, respectively. Under the same seedling management treatment, the highest or equally highest grain yield and 2-AP content were recorded in Fer3 treatment.