Evaluation of interaction of the planting density and nitrogen on the agronomic traits of rice mutants (Oryza sativa L.)

Changing planting density changes the nitrogen requirement in rice cultivars. To determine the effect of planting density and nitrogen fertilizer on the growth and yield of promising mutants, a field experiment was conducted in the deputy of the Rice Research Institute in Mazandaran (Amol) in the cropping years of 2020 and 2021. The experiment was performed as a factorial split plot in a randomized complete block design with three replications, that urea fertilizer levels (100, 200 and 300 kg/ha) as the main plot and two genotypes (1117 and 215) and planting density at three levels (25×25, 13×30, 18×30) as sub-plots Implemented in factorial format. The results variance homogeneity test showed the non-uniformity of the data in two crop years. The results of 2021 crop year showed that the three-way effect (nitrogen×planting density×line) was significant for six traits of plant height, panicle length, number of filled, empty and total grains total seeds per panicle, and yield. The panicle length increased with the increase of urea fertilizer consumption. The weight of 1000- grains of line 1117 was equal to 28.9 grams, but line 215 had a weight of 21.2 grams per thousand seeds. The highest number of panicles per hill was obtained in the treatment combination of line 1117 and planting density of 13x30 (17.67±0.72). The best treatment combination to achieve maximum yield was the consumption of 300 kg of urea fertilizer at a planting density of 13 × 30 for line 1117 and equivalent to 6148.83 ± 0.1 kg per hectare.