عنوان مقاله [English]
The food legumes are given high priority in world agriculture because they constitute 2.3 or more of protein in the diet of the inhabitants of the tropics and they are the potential source to fill the protein-gap. Mung bean belongs to plant family Fabaceae, and is the most important pulse crops of the world. It has great value as a food, fodder and green manure. Potential yield of Mung bean can be achieved through optimum use of inputs and agronomic practices. Plant density and suitable sowing time are the most important factors affecting the yield. Plant density is considered as one of the important determinative factors of yield of this plant. The purpose of proper density is more efficient use of the plant from different environmental potential such as water, nutrients, light, etc. to achieve higher yield. Too early sowing may not successfully germinate, while yield from too late sown crop may be low due to unfavorable condition for growth and development of Mung bean. The aim of this study was to determine the optimum sowing date and plant density to achieve maximum performance of the Mung bean in both irrigated and rainfed conditions.
Material & Methods
In order to evaluate the effects of planting date, plant density and irrigation on yield and yield components of Mung bean (VC-1973A genotype) an experiment was performed in Research Station of Islamic Azad University, Gorgan Branch at 2012. In this study, a factorial experiment in a randomized complete block design with three replications was used. Three planting dates (6 July, 21 July and 6 August) and two densities (12.5 and 25 plant per square meter) were the treatments. The experiments were conducted in two separate conditions of irrigation (at the beginning to flower and pod stages) and rainfed. Dry weight of the seeds in physiological maturity was determined. Also in full maturity, after removing the effect marginal, yield and yield components were calculated. Analysis of variance was carried out using the SAS software. Comparison of means also was performed using LSD test at 5% level and corresponding graphs were plotted with Excel software.
Results & Discussion
The results of analysis variance showed that both in irrigation and rainfed conditions, there was a significant difference between planting dates in terms of number of pods per plant, seeds per pod, seed weight, biological yield and harvest index. But there was no statistically significant difference for these factors between densities (12.5 and 25 plant/m2). The highest and lowest number of pods per plant, number of seeds per pod and seed weight observed in 6 July and 6 August planting dates, respectively. In irrigation condition, planting dates of 6 July and 6 August had the highest (6400 kg per hectare) and lowest (3614 kg per hectare) biological yield. Also, in rainfed condition, maximum and minimum of biological yield were obtained for planting date of 6 July (4276 kg) and 6 August (2673 kg per hectare), respectively. Planting date July 6th had the highest harvest index under both irrigated (45.3%) and rainfed (38.2%) conditions. Planting date July 6th also had the highest seed yield under both irrigated (2900 kg/ha) and rainfed (1636 kg/ha) conditions. Irrigation in beginning of flowering and pod stages increased seed yield and aboveground dry mater, significantly. Late planting date decreased vegetative stage, caused reducing in pod number per plant and seed number per pod, resulted in reduction of seed yield. The results showed that Mung bean crop has a high production potential under climate condition of the Gorgan.
The results of analysis variance showed that under both irrigation and rainfed conditions, there was significantly differences between planting dates in terms of number of pods per plant, seeds per pod, seed weight, biological yield and harvest index. But there was no statistically significant difference for these factors between densities (12.5 and 25 plant/m2). In both irrigated and rainfed conditions, date of planting 6 July, was the best planting date. The grain yield under irrigated and rainfed conditions were 2900 and1636 kg per hectare, respectively. Irrigation at early flowering and early pod stages, led to an increase in grain yield and dry matter compared to the rainfed conditions. The results showed that this plant has a high production potential in weather conditions of Gorgan. Thus, cultivation of Mung bean in Gorgan is recommended. Moreover, planting date July 6th and density of 25 plants /m2 can be a good choice for Mung bean cultivation in this region.