Growth and Yield Response of Mungbean (Vigna radiata L.) Cultivars to Varying Levels of Nitrogen

Response of two mungbean cultivars namely NM-54 and NM-92 to nitrogen levels of 0, 20, 40 and 60 kg haG was studied under field conditions. The cultivar NM-92 gave significantly higher seed yield than cultivar NM-54 due to higher number of pod bearing branches plantG, number of pods plantG and number of seeds podG. Yield and yield components were also influenced significantly by nitrogen levels. The application of nitrogen at the rate of 60 kg haG significantly depressed the seed yield and yield components except number of pods plant which were statistically similar with nitrogen application of 40 kg haG. Maximum increase in seed yield, recorded at 40 kg N haG, was about 31 percent higher of control. The increase in seed yield with nitrogen application was related to higher number of pods plantG, number of seeds podG and 1000-grain weight. Protein contents were also influenced significantly by nitrogen application, being maximum (26.18%) at nitrogen level of 40 kg haG. Nitrogen application at the rate of 40 kg ha seems to be the optimum level for harvesting higher yield of mungbean. Introduction Mungbean (Vigna radiata L.) is one of the roost important Pulses grown in Pakistan. Soils in Pakistan are mainly deficient in nitrogen due to mineralization, leaching and volatilization (Nisar et al., 1996). Patel et al. (1984) obtained the highest seed yield with NP application of 20 and 40 kg haG, respectively. Fertilizer applied above these levels had non significant effect on yield of mungbean. Raju and Verma (1985) reported that seed inoculation and application of 15 to 60 kg N haG significantly increased nodulation and seed yield of mungbean. They further found that 50 kg N haG was the most effective dose. Hamid (1991) reported that in both field and pot trials 10 mg N litreG increased seed yield more than higher or lower nitrogen rates. Yield increases were associated with the number of pods plantG and number of seeds pod rather than the increase in the seed weight. Mumtaz (1996) reported that yield and yield components of mungbean like number of branches plantG, number of pods plantG, number of seeds podG and 1000-seed weight were significantly affected by NP application. He obtained the maximum yield with NP application of 100 and 250 kg haG, respectively. Ahmed et al. (1992) reported significant differences among cultivars with regard to number of pods plantG, number of seeds podG, 100-grain weight, seed yield ha and seed protein contents. Rana (1998) reported that cultivar NM-54 gave significantly higher seed yield than NM-92 due to higher number of pods plantG and 1000-seed weight. The present study was, therefore, undertaken to compare the growth and yield performance of two mungbean cultivars and also to determine the most appropriate level of nitrogen for mungbean under agro-ecological conditions of Faisalabad. Materials and Methods The experiment was conducted under field conditions, during the year 1996, on a sandy clay loam soil having 0.085 percent nitrogen, 9.2 PPM available phosphorus and 134 PPM available potassium. The experiment was laid out in randomized complete block design with four replications having a net plot size of 2.4 m x 5 m. Two mungbean cultivars NM-92 and NM-54 were fertilized at rates of 0, 20, 40 and 60 kg N haG. Phosphorus was applied at a rate of 75 kg haG in the form of single superphosphate. The whole quantity of nitrogen and phosphorus was side drilled at sowing time. Crop was sown in the second week of March in 40 cm apart rows with a single row hand drill. The crop was harvested on 2nd of June when about 80% of pods had reached to maturity. Ten plants from each plot were selected at random to record average number of pod bearing branches plantG, average number of pods plantG and average number of seeds podG. From each plot 1000-seeds were counted and weighed to determine the 1000-seed weight. Seed yield obtained from each plot was converted to quintals ha The protein contents in seeds were determined by using Gunning and Hibbard's method of H2S04 digestion and using micro kjeldhal method for distillation (Jackson, 1962). Data collected were analyzed statistically using Fisher’s analysis of variance technique and the least significant difference test at 0.05 probability level was employed to compare the difference among the treatment means (Steel and Torrie, 1984). Results and Discussion The data regarding various parameters recorded are given in Table 1. Both cultivars produced statistically different number of pod bearing branches plantG. The cultivar NM-92 produced more number of branches plant than cultivar NM-54. These differences can be attributed to genetic traits of crop plants. Ahmed et al. (1992) had also reported significant differences among mungbean cultivars. The application of nitrogen fertilizer did not significantly affect the number of pod bearing branches plantG. However, the