关键词: 产量, 长江中下游地区, 氮效率, 综合评价, 粳稻

Abstract:

【Objective】The main purpose of this study was to screen out the inbred japonica rice varieties with high grain yield and high nitrogen efficiency in the middle and lower reaches of Yangtze River, so as to provide a reference for the breeding and production application of high grain yield and high nitrogen efficiency varieties in this area.【Method】105 inbred japonica rice varieties (90 in 2017, 105 in 2018) from the middle and lower reaches of Yangtze River were used as experimental materials, and grain yield, dry matter accumulation, nitrogen uptake and utilization efficiency were determined at maturity stage under the treatment of nitrogen and no nitrogen. Nitrogen recovery efficiency, nitrogen agronomic efficiency, nitrogen physiological efficiency, nitrogen grain yield production efficiency and nitrogen dry matter production efficiency were used as the evaluation indexes of nitrogen absorption and utilization efficiency, and the comprehensive evaluation value of nitrogen efficiency (CEV) of each variety (line) was obtained by using the entropy weight fuzzy synthetic evaluation method. Then, the grain yield-nitrogen efficiency index (GYNEI) was calculated by using CEV and grain yield. According to the GYNEI, the varieties (lines) were classified by the method of cluster analysis.【Result】The tested varieties (lines) were divided into three types, and the average values of grain yield, nitrogen recovery efficiency, nitrogen agronomic efficiency, nitrogen physiological efficiency, nitrogen grain yield production efficiency, nitrogen dry matter production efficiency in Type Ⅰ were highest, while those in Type Ⅲ were lowest. Therefore, Type Ⅰ varieties (lines) were characterized by high grain yield and high nitrogen efficiency, and Type Ⅲ varieties (lines) were characterized by low grain yield and low nitrogen efficiency. According to the screening results, 23 and 27 varieties (lines) were divided into high grain yield and high nitrogen efficiency type in 2017 and 2018, respectively, and 19 varieties (lines), such as Nanjing9108, Nanjing5718, Ningjing7, Sidao15, Yangjing239 and so on, were classified into high grain yield and high nitrogen efficiency type in two years. In addition, stem dry matter weight, leaf dry matter weight, panicle dry matter weight, total dry matter weight, spikelet per panicle, grain yield, panicle nitrogen uptake, total nitrogen uptake of high grain yield and high nitrogen efficiency type (TypeⅠ) were significantly higher than those of Type Ⅱ and Type Ⅲ.【Conclusion】 19 varieties (lines) were preliminarily identified as high grain yield and high nitrogen efficiency varieties (lines), such as Nanjing 9108, Nanjing 5718, Ningjing7, Sidao15, and so on. Compared with the low grain yield and low nitrogen efficiency varieties (lines), the high grain yield and high nitrogen efficiency varieties (lines) showed the characteristics of larger biomass, more spikelet per panicle, higher nitrogen uptake, especially higher panicle nitrogen uptake. These results could provide a reference for the selection of inbred middle-ripe japonica rice varieties in the middle and lower reaches of Yangtze River, and also provided materials for the study of the synergistic mechanism of grain yield and nitrogen efficiency.

Key words: grain yield, the Middle and Lower Reaches of Yangtze River, nitrogen efficiency, comprehensive evaluation, japonica