Nitrogen use efficiency (NUE) in rice crop is the need of the hour for reduction of nitrous oxide emission resulting from excess nitrogen (N) fertilizer application and also in reduction of cost of cultivation. Ten rice genotypes were grown under low and recommended dose of N application and characterized in terms of parameters related to yield, yield related components and NUE indicators. Wide genetic variability under low N conditions was observed with significant variation for 15 yield related parameters in interactions of genotypes and treatment. Limitation of N has led to the decrease of all yield and yield related parameters, but for grain filling % and 1000 grain weight. Two genotypes, Rasi and Varadhan have shown minimum differences between low and recommended N conditions. Correlation analysis of various yield components showed the importance of the secondary branches for the total grains under low N. Expression analysis of OsSPL14 (LOC_Os08g39890) gene reported to be associated with increased panicle branching and higher grain yield through real time PCR in leaf and three stages of panicle has shown differential temporal expression and its association with yield and yield related components across the genotypes. The expression of OsSPL14 at panicle stage 3, has shown correlation (P < 0.05) with N% in grain. Since OsSPL14 is a functional transcription activator, its association of expression in leaf and three panicle stages with yield components as observed in the present study suggests the role of nitrogen metabolism related genes in plant growth and development and its conversion into yield components in rice.
水稻氮素利用效率（NUE）是減少過量施氮肥產(chǎn)生的氧化亞氮排放的需要，也是降低種植成本的需要。10個水稻基因型在低劑量和推薦施氮量下生長，并在產(chǎn)量相關(guān)參數(shù)、產(chǎn)量相關(guān)成分和NUE指標方面進行了描述。