Title: Determination of the most suitable planting space and nitrogen fertilizer rate for the rice promising line of MN5
Author: Masoud Kavoosi
Abstract: After wheat, rice is the world’s largest source of food. Introducing new varieties and suitable fertilizers is one way to increase rice production. In order to determine the planting space and to recommend appropriate N fertilizer for the MN5 line, this study was conducted as a factorial experiment in a completely randomized complete block design with three replications using five levels of nitrogen fertilizer including 0, 60, 75, 90, and 105 kg ha-1. The level of planting distance (15× 20 and 20× 20 cm) was carried out at Rice Research Institute of Iran (Rasht) for one year (1998). The results showed that the average grain yield at 20 × 20 (4293 kg/ha) was significantly higher than 15 ×20cm (4170 kg/ha) while straw yield at 15 ×20 (4310 kg/ha) was significantly greater than 20 × 20 cm planting distance (4066 kg/ha). Harvest index, total nitrogen recovery, and agronomic efficiency of nitrogen application at 20 × 20 planting space (51.6%, 40.7 % and, 20 kg grain/ kg nitrogen fertilizer application, respectively) were significantly higher than 15 ×20 cm planting distance (49.0%, 25.9%, and 12.9 kg grain/kg nitrogen fertilizer application, respectively). However, the amount of nitrogen uptake in the straw at 15 ×20 (30.8 kg/ha) was significantly higher than 20 × 20 cm (28.5kg/ha). Other traits were not significantly different in the two planting spaces. The results also showed that the highest yield was obtained from 90 kg N ha-1 with 20 × 20 cm (5050 kg ha-1) planting distance. Considering that the yield of this treatment differed significantly compared to other application nitrogen levels, application of 90 kg N / ha with 20 × 20 cm planting distance can be recommended for the MN5 line.
Keywords: MN5 breeding line – Nitrogen levels – Planting distance – Yield – Yield components