Genotypic variation in Rice (Oryza sativa L.) for Nitrogen Use Efficiency Under
Optimal and Sub Optimal Nitrogen Levels
Surekha K*, Nagendra V, Sailaja N, Neeraja C N N, Subrahmanyam D and Voleti SR
ICAR–Indian Institute of Rice Research, Hyderabad 500 030, India
*Corresponding author (email: email@example.com)
Received: 2nd Nov. 2018 Accepted: 12th Dec. 2018
A field experiment was conducted for two years (2011-12 and 2012-13) at the ICAR-Indian Institute of Rice Research (ICAR-IIRR) Rajendrangar, Hyderabad, to assess the differences in grain yield and nitrogen (N) utilization efficiency of rice genotypes. Fifteen popular high yielding genotypes with varying acquisition and utilization of soil and fertilizer N were tested at N-0 (no external application of N) and N-100 (100 kg N/ha) levels in each year covering four seasons (two wet and two dry seasons) in total. Significant differences among the genotypes were observed in grain yield and nitrogen use efficiency parameters such as: agronomic efficiency (AE), physiological efficiency (PE), recovery efficiency (RE), partial factor productivity of applied N (PFP), per day productivity (PDP), harvest index (HI), N requirement (NR), N uptake rate (NUR) and N harvest index (NHI). Based on the grain yield data, the genotypes were grouped into efficient, responsive and efficient as well as responsive genotypes. The N-efficient genotypes that produced high grain yield utilizing soil available N alone were: Swarna, Jaya, Sampada, DRRH2, Tulasi; the responsive genotypes to the applied N were: Rasi, Annada, Tulasi, IR 64; the efficient as well as responsive genotypes those gave higher yield both at N0 and N100 levels were: Varadhan, PHB 71, DRRH2, RPBio 4918-248, RPBio4919-458, KRH2, DRRH3, Akshayadhan. Based on the N use efficiency indices, the genotypes were ranked. Rasi, Tulasi, Annada, MTU 1010 and Anjali from early duration group; Varadhan, PHB 71, RP bio 4918-248, RPBio4919-458, KRH2 from medium duration group and Swarna from late maturing group were found most promising. Thus, genotypic variation for N use efficiency in rice was evident and in the present study, the performance of genotypes over a range of soil and fertilizer N supply was consistent over two seasons in some genotypes and with seasonal variation in some genotypes.