Comparasion Studies On Rice Yield, Quality And Nitrogen Utilization Under Different Enviorments

Field experiments were conducted using different rice genotypes including 9 Japanese cultivars and 2 local cultivars under two eco-environments of Nanjing and Lijiang to investigate the effects of genotype(G), environment(E) and their interaction(G E) on yield, quality and nitrogen use efficiency under different eco-environments. The relationships between yield and dry matter accumulation, source-sink characteristics, non-structural carbohydrate content (NSC) and C/N ratio in rice plant were analyzed. The effects of G E on rice quality traits using same 9 genotypes at five eco-sites of three countries were also evaluated. The main results were as follows.1. Rice yield at Lijiang was significantly higher due to significant increasing of panicles compared with at Nanjing, but the differences in spikelets, setting rate and grain weight between two eco-sites was similar. By path analysis, spikelets per panicles was a key component limited grain yield increasing at Lijiang, while panicles at Nanjing. Grain yield and components were significantly affected by genotype (G), environment (E) and their interaction (G E). Rice yield, panicles and grain setting mainly affected by environment, while spikelets per panicle by genotype. GXE had little roles on yield and yield component though its effects was significant..2. Total dry matter accumulation, LAI, total spikelets per unit area and post-heading crop growth rate (CGR) at Lijiang were higher than at Nanjing. The effects of eco-environment were more significant on grain yield, total dry matter accumulation, LAI, total spikelets per unit area compared with that of genotype and G E, while ratio of spikelets to leaf area was significantly affected by genotypes. Grain yield was highly significantly correlated to LAI, total spikelets per unit area, total dry matter accumulation and post-heading CGR, and significantly with ratio of spikelets to leaf area. Total dry matter accumulation was highly significantly correlated to LAI and total spikelets per unit area, but not with ratio of spikelets to leaf area. The results indicate that increasing dry matter accumulation is an important physiological basis for grain yield. Furthermore, enhancing total spikelets andpost-heading CGR based on increasing LAI are favor for increasing rice grain yield.3. Nitrogen dry matter production efficiency (NDMPE) and NHI at Lijiang were significantly higher, but nitrogen grain production efficiency (NGPE) lower than at Nanjing. Nitrogen appearance transfer amount (NATA) significantly increased at Lijiang, but nitrogen transfer efficiency (NTE) showed no significantly difference between two eco-sites. The NGPE was significantly correlated to NDMPE and NHI; NGPE, NDMPE and NHI were positively related to nitrogen accumulation at heading, but negatively to post-heading and maturity. Furthermore, NGPE, NDMPE and NHI were positively significantly correlated to nitrogen transfer amount and transfer efficiency. These results indicted that increasing nitrogen transfer after heading with decreasing nitrogen accumulation was major physiological basis for improving NUE in rice.4. Genotype were key component effected NSC and C/N, the differences inNSC and C/N were smaller at two eco-site at full heading, but that were significant higher in NSC at filling stage and maturity than at Nanjing. C/N was higher at filling stage (FS) at Nanjing than at Lijiang, while at Lijiang was significant higher at maturity. Relationships between NSC and grain set rate was parabola and the grain set rate was higher when NSC was 14% at full heading (FH); there were significant parabola correlation between C/N and grain set rate, grain yield, the grain set rate and yield both were higher when C/N was from 9 to14.5. Genotypic differences in head rice rate (HRR), chalkiness degree (CHD) amlylose content (AC) and alkali spreading value (ASV) were bigger, and the differences in protein content (PC) and brown rice rate (BRR) were smaller. The quality in japonica rice was better than in indica rice. The rice quality in high latitu...