Study on yield stability and dry matter characteristics of super hybrid rice

Chinese. 探明超级杂交稻在不同种植地点和不同施肥量条件下的产量表现及干物质生产特点。于2004～2005年在湖南省桂东、长沙、衡阳、南县和永州5个地点进行大田试验，按照NsP2O5sK2O为1s0.5s1的比例，设置3种施肥量处理（135、180、225 kg N•ha-1），田间采用随机区组排列，4次重复，以超级杂交稻组合准两优527和两优293为试验材料。超级杂交稻收获产量以桂东点产量最高，地点间差异显著，其中准两优527平均为7 492.3～12 209.2 kg•ha-1，两优293为6 984.0～11 679.5 kg•ha-1。产量构成因子和干物质生产量的地点间变化与收获产量一致，但在同一地点的不同施肥量处理间收获产量和干物质生产量差异均不显著。收获产量与单位面积穗数、结实率和千粒重表现为正相关，而与每穗粒数表现为负相关。超级杂交稻存在适宜的种植区域，且在施肥量为135～225 kg N•ha-1的范围内，施肥量不是超高产栽培的限制因子。超级杂交稻的库容量大，提高结实率和粒重是获得超高产的可能途径。

English. The yield stability and dry matter characteristics of super hybrid rice were analyzed under different fertilizer rate conditions at different growing locations. Field experiments with two super hybrid rice cultivars (Zhunliangyou527 and Liangyou293) were conducted in Changsha, Guidong, Hengyang, Nanxian and Yongzhou of Hunan province in 2004 and 2005. According to the ratio of NsP2O5sK2O as 1s0.5s1, three fertilizer rate treatments (135, 180, 225 kg N•ha-1) were designed by using random block with four replications. The results showed that the harvest yield of super hybrid rice was highest in Guidong and existed significant differences among five sites, of which the averaged yield of two years and three fertilizer rate treatments ranged from 7 492.3-12 209.2 kg•ha-1 for Zhunliangyou527 and from 6 984.0-11 679.5 kg•ha-1 for Liangyou293. The regional variation of the dry matter accumulation and grain yield components showed the same tendency with the harvest yield. And no significant differences in harvest yield and dry matter production existed among three fertilizer rate treatments at same site. The harvest yield showed significantly positive correlations with productive panicles, seed setting rate and grain weight, and negative correlation with spikelet number per panicle. Super hybrid rice prefers suitable or optimum growing area. The fertilizer rate in the range from 135 kg N•ha-1 to 225 kg N•ha-1 was not the limiting factor for harvest yield performance. Since super hybrid rice has larger sink capability, it is feasible to achieve high yield through increase of grain setting rate and grain weight.