Abstract: 【Objective】The purpose of this study was to investigate the quality of rice under different non-flooded cultivations and its relationship with the concentrations of hormones in grains during grain filling. 【Method】Two rice cultivars, Zhendao 88 (japonica) and Yangdao 6 (indica), were used as materials. Four treatments, traditional flooding (TF), bare and non-flooded cultivation (BN), non-flooded plastic film mulching (PM) and non-flooded wheat-straw mulching (SM), were conducted during the whole growth season. 【Result】Compared with TF, both BN and PM significantly reduced grain yield, whereas there was no significant difference in the yield between TF and SM. SM significantly reduced the percentage of chalky kernels, chalkiness and setback value, while markedly increased gel consistency, alkali spreading value and breakdown value. The effects of BN and PM on the above quality traits were opposite to those of SM. No significant differences were observed in amylose content and protein content among the four treatments. The two cultivars behaved the same. Concentrations of indole-3-acetic acid (IAA), gibberellins (GA1 + GA4) and zeatin (Z) + zeatin riboside (ZR) in grains differed little among the treatments at the early grain filing stage, and showed SM > TF > PM > BN at the mid and late filling stages. Ethylene evolution rate of grains exhibited BN > PM > TF > SM. There were no significant differences in abscisic acid (ABA) concentrations in grains among the TF, PM and SM during the grain filling period. BN had the lowest ABA concentration at the early filling stage, whereas had the highest concentration at the mid and late filling stages among the all treatments. Concentrations of IAA and GA1 + GA4 at the mid and late filling stages, ABA concentrations at the early and mid filling stage and Z + ZR concentrations during the whole grain filling period significantly or very significantly and positively correlated with grain weight, brown rice, milled rice and breakdown value (r = 0.71* ~ 0.96**), and negatively correlated with setback value (r = -0.76* ~ -0.91**). Concentrations of IAA and Z + ZR at the late filling stage significantly or very significantly and negatively correlated with the percentage of chalky kernels and chalkiness (r = -073* ~ -0.85**). The ethylene evolution rates at each filling stage significantly or very significantly and negatively correlated with grain weight, brown rice, milled rice, alkali spreading value and breakdown value (r = -0.71* ~ 0-.91**), and positively correlated with the percentage of chalky kernels, chalkiness and setback value (r = 0.73* ~ 0.93**). 【Conclusion】The results demonstrate that SM improve, whereas BN and PM degrade, rice quality, and the formation of good or poor quality is closely associated with the concentration of hormones in grains during grain filling.

Key words: Rice, Non-flooded plastic film mulching cultivation, Non-flooded wheat-straw mulching cultivation, Grain quality, Hormones