Grain Yield and Nitrogen Use Efficiency in Rice under Different Ecological Locations

To study the difference of grain yield, dry matter accumulation and distribution and nitrogen use efficiency for rice cultivars under two different ecological locations(Changsha, Hunan Province and Xingyi, Guizhou Province), experiments were conducted with Wuyou 308, Luoyou 9348, Yuxiangyouzhan and Huanghuazhan under three nitrogen rates(0 kg/hm2, 161.25 kg/hm2 and 225 kg/hm2). The results showed that:(1)the grain yield was 11.98 t/ hm2 in Xingyi, which significantly produced 23.82% more grain yield than that in Changsha. There was a consistent trend in grain yield for all cultivars under two ecological locations, which the grain yield of Wuyou 308(9.41~12.80 t/hm2) was highest, then Luoyou 9348, Yuxiangyouzhan and Huanghuazhan, and there was a significant difference in grain yield attained by Wuyou 308 comparing with Yuxiangyouzhan and Huanghuazhan.(2)Panicles per m2, grain filling rate and 1 000-grain weight were significantly higher by 22.95%, 27.59% and 5.07%, respectively, in Xingyi than those in Changsha. Furthermore, panicles per m2 had the highest contribution to grain yield at two locations, then 1 000-grain yield in Xingyi and spikelets per panicle in Changsha.(3)There was significant difference in dry matter at heading stage and maturity stage between two locations, and respectively higher by 22.95%, 27.59% and 5.07% in Xingyi than those in Changsha.(4)Nitrogen uptake and partial fertilizer efficiency were 21.97 g/m2 and 64.86 kg/kg in Xingyi, respectively, which significantly higher by 29.40% and 26.15%comparing with Changsha. RE, AE, PE and PFP decreased with increasing nitrogen rate. Therefore, Xingyi produced more grain yield due to higher dry matter transportation rate and dry matter accumulation after heading stage, panicles per m2, grain filling rate and1 000-grain weight.