Effects of amount and timing of nitrogen application on yield production and quantitative charcteristics of karela (Momordica charantia L.)

In order to study the effects of rate and time of nitrogen application on yield and yield components of karela (Momordica charantia L.)، a field experiment as split plot design with three replications was conducted in 2011 at Research Center for Agriculture and Natural Resources of Sistan. The treatments consisted of three levels of nitrogen fertilizer، obtained from urea source، at the rate of N1=75، N2=150 and N3=225 kg N. ha-1 as main plot، and three time application including: T1=1/2 at 3 and 4 leaves and 1/2 before flowering، T2= 1/2 at 3 and 4 leaves and 1/2 after fruit to start and T3=1/3 at 3 and 4 leaves، 1/3 before flowering and 1/3 after fruit to start were used as sub plot. Results showed that nitrogen application had significant effect on the yield and amount of biomass production (p < 0. 01) in karela. By increasing nitrogen level from 75 to 225 kg N. ha-1، yield and biomass values increased. The amount of yield increased about 63. 1%. Nitrogen treatment had positive and significant effect on yield components including plant height، number of lateral branches، number of fruits per plant، number of seeds per fruit، the length and diameter of fruit. Timing of nitrogen application had only significant effect on yield، the amount of biomass production، number of fruits per plant، length and diameter of fruit. The maximum yield of karela was obtained at T2 treatment.