Characterization and screening of high nitrogen efficient rice genotype to curtail environmental pollution

An experiment with aim to screen more nitrogen efficient genotype to curtail nitrogen pollution caused due to applied N fertilizer in rice crops was performed during rainy season of 2009 at GBPUAT Pantnagar, India. The response of rice genotypes namely Pant Shankar Dhan-3 (PSD-3), Vasumati, Kasturi, Tulsi and Krishna Hamsa to N fertilization (urea) were conducted as N₀ (without N applied), N₅₀, (50 kg N ha⁻¹), N₁₀₀ (100 kg N ha⁻¹) and N₂₀₀ (375 kg N ha⁻¹) in pot experiments. The genotypes screened on the basis of growth dynamic, physiological and agronomical responses to nitrogen rates. Results showed, traits associated with growth (plant height, leaves number, tillers number), physiological (leaf area index, photosynthetic rate (P_N), SPAD value (Chlorophyll content), leaf N content and NR activity) and agronomical (grain number, grain weight) enhanced significantly (P<0.05) with rising N rates. The PSD-3 (hybrid) screened most nitrogen efficient genotype among all genotypes. Experiment concluded that hybrid genotype has more capacity to uptake and extract applied nitrogen from the soil and proficient to assimilate in their tissues. Therefore, most N efficient genotypes can be strongly suggested to rice growers. Using most N efficient genotypes, yield could be enhanced, environmental pollution and global warming occurred due to contributions of N and its derivatives, and cost toward fertilizers would be reduced.