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

Jinhai Liu1, 2, Longxin He1, 2, Haowen Luo1, 2, Tiaoyan Wu1, 2, Tantan Zhang1, 2, Runhao Wen1, Hua Tian1, 2, and Xiangru Tang1, 2*
 
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.
Keywords: 2-Acetyl-1-pyrroline, fertilizer, fragrant rice, grain yield, Oryza sativa subsp. japonica, seedling.
1South China Agricultural University, College of Agriculture, State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangzhou, 510642, PR China.
2Scientific Observing and Experimental Station of Crop Cultivation in South China, Ministry of Agriculture, Guangzhou, 510642, PR China.
*Corresponding author (tangxr@scau.edu.cn).