Yield and nitrogen-use efficiency of aromatic rice cultivars in response to nitrogen fertilizer

Aromatic cultivars of rice respond differently to nitrogen application as compared to nonaromatic rice. Most of the aromatic rice cultivars are susceptible to disease and insect pest attack, and are more prone to lodging. Therefore, nitrogen is the key input for increasing the productivity of aromatic rice. Research analyzing the effects of N level on yield and nitrogen-use efficiency (NUE) of modern aromatic cultivars is not well documented. Therefore, the present study was conducted to optimize N levels for higher yield and NUE of modern aromatic rice cultivars. Across all genotypes, the mean nitrogen-fertilizer response was highest at 40 kg N/ha as compared to other N levels (0, 20, and 60 kg N/ha), indicating that further increase in N level had no effect on crop response to fertilizer. The mean grain yield increased by 64.2% when plots were supplemented with 40 kg N/ha as compared to control (unfertilized). Among cultivars, 'Punjab Mehak 1' registered highest yield (4.3 t/ha), followed by 'Pusa 1121' (4.0 t/ha) and 'Punjab Basmati 2' (3.9 t/ha). Interactive effect between N levels and cultivars revealed that 'Punjab Mehak 1' responded significantly up to 60 kg N/ha due to more NUE and higher N uptake as compared to 'Pusa 1121' and 'Punjab Basmati 2'. Results from this study indicate that genotype differences in NUE existed in aromatic rice cultivars; therefore, NUE of different cultivars could be a useful tool to adopt the appropriate cultural practices for achieving high yield and N response exploration