Document Type : Research paper
Department of Agronomy and Young Research Club, Qaemshahr Branch, Islamic Azad University, Qaemshahr, Iran.
Department of Agronomy, Jouybar Branch, Islamic Azad University, Jouybar, Iran.
This study examined to compare high-yielding cultivars and respond to N fertilization especially yield component and the aim of this development of rice cultivars suitable for low input requirements. An experiment was arranged in a randomized complete block design with a split-plot arrangement of five rice cultivars, three N rates with four replications in 2011 in Iran. N rates including 0, 69, and 138 kg N/ha as (N0), (N69) and (N138) and rice cultivars including Nemat (C1), Khazar (C2), Neda (C3), Shirodi (C4), and Tarom (C5). The results indicated that all traits response to cultivar and N rates were detected for the parameters examined. The lowest applied N rate had a lower yield than the other two N rates. Grain yields were 5552 for 69 kg N/ha and 6124 for 134 kg N/ha averaged over all cultivars. The grain yield of Khazar and Tarom was independent of the N rate, but the grain yield of Nemat, Neda and Shirodi increased when the N rate was increased from 67 to 138 kg/ha. Panicle density responded to an N rate similar to grain yield. Khazar produced more total spikelet number while Neda had a higher Panicle density. Grain yield and yield components of Nemat, Neda, and Shirodi respond to N rates dependently when planted into high nitrogen. Finally, modern rice cultivars were more efficient at recovering N than older cultivars.
- Increasing the amount of soil nitrogen does not always guarantee an increase in rice yield.
- Some rice cultivars do not need to use or increase soil nitrogen to increase grain yield.
- Agromorphological traits in rice are affected by soil nitrogen content.