Title: Determination of the most suitable planting space and nitrogen fertilizer rate for the rice promising line of Ghodci
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 MN12 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 (4196 kg/ha) was significantly higher than 15 ×20cm (4046 kg/ha) while straw yield at 15 ×20 (5813 kg/ha was greater than 20 × 20 cm planting distance (5569 kg/ha) but did not differ significantly. Harvest index, grain nitrogen uptake and agronomic and physiological efficiency of nitrogen application at 20 × 20 planting space (43.1%, 61.4 kg / ha, 7.42 kg grain/ kg nitrogen fertilizer application and 42.14 kg grain / kg fertilizer nitrogen absorbed, respectively) were significantly higher than 15 ×20 cm planting distance (41.2%, 60 kg / ha, 3.3 kg grain / kg nitrogen fertilizer application and 28.66 kg grain/ kg nitrogen fertilizer absorbed, 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 75 kg N ha-1 with 20 × 20 cm (4492 kg ha-1) planting distance. Considering that the yield of this treatment did not differ significantly with application levels of 90 and 105 kg N / ha, application of 75 kg N / ha with 20 × 20 cm planting distance can be recommended for the MN12 line.
Keywords: MN12 breeding line – Nitrogen levels – Planting distance – Yield – Yield components