| Chemical fertilizers are essential to maintain current production levels of the global crop, and even more important to the continued high production in the future, but excessive application of nitrogen, phosphorus not only reduces the nitrogen and phosphorus use efficiency, and the result decline of economic benefits, rice quality, but also caused great environmental threat. It is an ideal approach for enhancing nitrogen/ phosphorus use efficiency and reducing environmental pollution to explore and utilize crop"s natural potential to screen efficient rice genotype. A field experiment was carried out to study the variations of N/P use efficiency in different rice genotypic by use 186 mini core collection, which from different ecological environment, as materials under the low N treatment (no N fertilizer), normal nitrogen (90 kg N/hm") and the low P treatment (no P fertilizer), normal phosphorus (45 kg P/hm2) level. Genotypic variations of N/P efficiency of difference rice genotypic were analyzed. System clustering of grain yield, plant height, germplasm types under normal and stress level, respectively. Based on these results, evaluation and classification nitrogen and phosphorus absorption and utilization efficiency were done. The main results were as follows:1. There were all significant differences in grain yield, plant height and germplasm of rice genotypes under different N levels. Clustering analysis was conducted based on the grain yield and plant height of different genotypic rice by using the method of Euclidean distance and the deviation square. Analysis the variations in nitrogen uptake and use efficiency of different production types, plant height, germplasm rice under different N levels.Correlation analysis showed that:There were significantly positively correlated to straw and panicle nitrogen accumulation in rice heading and mature period, nitrogen harvest index (NHI), N Grain production efficiency (NUEg) under the normal and no nitrogen application. Rice grain yield and nitrogen content in straw and panicle of heading period and straw of mature are significant or very significant negative correlation.Whether nitrogen or not, there are highly significant differences in plant height under different genotypic of rice. The plant height and nitrogen content of heading and mature straw, panicle showed a highly significant negative correlation, indicating that the higher of plant height, the lower of nitrogen content in plant organs. The plant height and nitrogen accumulation (NA) of straw and panicle in heading period, straw of mature, dry matter production efficiency (NUEp) at maturity period were highly significant positive correlation.The nitrogen content of indica rice varieties was significantly greater than the japonica rice varieties under application nitrogen, indica was more sensitive to nitrogen; Application nitrogen increased dry matter accumulation of rice varieties japonica rice varieties was more obvious than indica rice; Whether application nitrogen or not, to the nitrogen accumulation, indica rice varieties was always higher than the japonica rice varieties, but normal nitrogen application was more efficiency to the nitrogen accumulation in japonica rice varieties; To the NUEp and NUEg, application nitrogen were more efficiency to indica rice varieties than japonica rice varieties; but, to the nitrogen transport ratio, japonica varieties were more sensitively than indica varieties.Clustering analysis of dry matter productivity (NUEp) in mature, nitrogen accumulation (NA) in mature panicle, nitrogen grain production efficiency (NUEg), nitrogen harvest index (NHI) and grain yield under Normal and do not nitrogen application treatments, respectively,186 different genotypic were divided into 5 categories:the use of high absorption of high yield, high absorption of low-yielding type of uncoordinated low yield, the use of low absorption of low yield, low absorption and utilization incompatible low-yielding, low absorption of the high use of high-yielding type. Get a group of nitrogen high efficient and low efficient materials, the choice of materials for further breeding and nitrogen uptake and utilization efficiency related gene mapping, cloning provides the basic materials.2. Whether or not application phosphorus, rice grain yield, plant height and germplasm type were highly significant differences under the different genotypes. Clustering analysis was conducted based on the grain yield and plant height of different genotypic rice varieties by using the method of Euclidean distance and the deviation square.Correlation analysis showed that:whether application phosphorus or not, grain yield and straw weight of heading and mature period, phosphorus accumulation in straw of heading period, straw and panicle of mature period and phosphorus grain production efficiency (PUEg) and phosphorus grain harvest index (PHI) showed highly significant positive correlation. The plant height and phosphorus content of straw was significant or very significant negative correlation. Application phosphorus can significantly improve plant phosphorus content of various organs, and had significant impact to the phosphorus content of mature straw; The plant height and phosphorus accumulation of mature period was significantly negatively correlated, but with phosphorus accumulation of heading period straw and panicle, mature straw were highly significant positive correlation; Under the normal P application, the plant’s phosphorus grain production efficiency (PUEg) decline with the rise in height; but without P application, it decline with the height of the drop down. P treatment has the same effect on P harvest index and P grain production efficiency.With the extension of growth period, indica rice were less than japonica varieties at the rise range of phosphorus content, whether or not application phosphorus. But for the phosphorus treatment, the phosphorus content of indica rice varieties were higher than japonica rice at the heading of straw, mature straw and panicle; Whether application phosphorus or not, to the phosphorus accumulation the heading of straw were higher than in the mature period of straw, and indica rice varieties were less than the rise in japonica rice varieties; Accumulation of phosphorus of panicle in the mature period were higher than heading period, but for different P treatments, indica and japonica varieties are different; whether or not application phosphorus, dry matter production efficiency of mature than heading dry matter production efficiency, while the indica and japonica varieties had different increased range with different phosphorus treatments; Grain weight in mature period were higher than those heading panicle weight, and indica are greater than the japonica rice rise; indica rice phosphorus grain production efficiency were higher than japonica rice, and this difference were more obviously in the no P treatment. Whole height in the normal P higher than low P treatment application, the whole japonica rice plant height were higher than indica varieties, then the japonica rice varieties rise than indica rice varieties.Comprehensive analysis shows that:P accumulation (PA), dry matter production efficiency of phosphorus (PUEp), phosphorus grain production efficiency (PUEg), phosphorus harvest index (PHI) and grain yield were closely related to phosphorus absorption and utilization efficiency. Therefore, based on the normal and no phosphorus treatment, respectively, use these five indicators, the 186 different genotypic were divided into 4 categories:the use of high absorption of high yield, low absorption and utilization and low yield, low absorption and utilization incompatible low-yielding, low absorption of high-yielding type of use. Get a group of phosphorus high efficient and low efficient materials, choice of materials for further breeding and efficient absorption and utilization of phosphorus-related gene mapping, cloning provides the basic materials. |
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