Dry matter and yield of lowland rice genotypes as influence by nitrogen fertilization

Rice is a staple food for more than 50% of the world's population and nitrogen (N) is one of the most yield limiting nutrients in lowland rice ecosystems. A field experiment was conducted for two consecutive years to evaluate dry matter production and grain yield of 12 lowland rice genotypes (BRS Jacana, CNAi 8860, BRS Fronteira, CNAi 8879, CNAi 8880, CNAi 8886, CNAi 8885, CNAi 8569, BRSGO Guara, BRS Alvorada, BRS Jaburu, and BRS Bigua) at five N rates (0, 50, 100, 150, and 200 kg ha(-1)). Genotypes showed significant variation in grain yield and shoot dry weight. Genotype BRSGO Guar a was highest yielding, whereas genotype BRS Jaburu was lowest yielding and the remaining genotypes were intermediate in grain yielding potential. Grain yield and shoot dry weight were having significant quadratic increase with increasing N rates in the range of 0 to 200 kg ha(-1). However, 90% of the maximum yield is often considered as an economical rate, which was 120 kg for shoot dry weight and 136 kg N ha(-1) for grain yield. Shoot dry matter was having significant positive quadratic association with grain yield across 12 genotypes.