Sarhad J. Agric. Vol.29, No.4, 2013 EFFECT OF VARIOUS SEED RATES AND NITROGEN LEVELS ON THE PRODUCTIVITY OF LATE SOWN BRASSICA *INAMULLAH 1 , BILAL KHAN 1 , MIFTAHUD DIN 2 , MUHAMMAD SIDDIQ 3 ASAD ALI KHAN 1 , ABDUL MUNIR 1 , KAMRAN AZEEM 1 andGHUFRAN-UL-HAQ 4 1 Department of Agronomy, The University of Agriculture Peshawar - Pakistan 2 KyhberPakhtunkhwa Agricultural Research System, Peshawar - Pakistan 3 National Agricultural Research System, Islamabad – Pakistan 4 Agriculture Research Institute (ARI), Tarnab Peshawar - Pakistan *Corresponding author: drinam@aup.edu.pk ABSTRACT A field experiment was conducted at New Developmental Farm (NDF) of The University of Agriculture, Peshawar during winter 2011 to study the effect of various seed rates and nitrogen levels on the productivity of late sown brassica. The experiment was conducted in Randomized Complete Block Design having three replications. Five seed rates (2, 4, 6, 8 and 10 kg ha -1 ) and six nitrogen levels (0, 50, 75, 100, 125 and 150 kg ha -1 ) were used. Rapeseed variety DURR-E-NIFA was sown on 25 th Nov. Statistical analysis of different parameters revealed that days to maturity, siliques m -2 , grains silique -1 , thousand grains weight, grain yield and oil percentage were significantly affected by both nitrogen as well as seed rates. Late maturity (163 days) and higher number of siliques m -2 (27048) were observed with seed rate of 10 kg ha -1 . Number of grains silique -1 (24), thousand grains weight (3.5 g) and grain yield (2246 kg ha -1 ) was higher with seed rate of 8 kg ha -1 while oil percentage was maximum (44.9 %) with seeding rate of 6 kg ha -1 . Among nitrogen levels, nitrogen applied at the rate of 150 kg ha -1 delayed the maturity (163 days). Siliques m -2 (26863), grains silique -1 (24), thousand grain weight (3.6 g), and grain yield (2255 kg ha -1 ) was maximum with the use of 100 kg N ha -1 . Grain oil content was higher (44.7 %) with 75 kg N ha -1 . It was concluded that higher grain yield were observed with application of 100 kg N ha -1 and 8 kg seed ha -1 while higher oil content was recorded at 50 kg ha -1 N and 6 kg ha -1 seed rate which are recommended for higher yield and oil content for late sown brassica. Keywords: Brassica, seed rate, nitrogen, late sowing Citation: Inamullah, B. Khan, M.U. Din, M. Siddiq, A.A. Khan, A. Munir K. Azeem and G.U. Haq. 2013. Effect of various seed rates and nitrogen levels on the productivity of late sown brassica. Sarhad J. Agric 29(4): 503-509 INTRODUCTION Rapeseed/mustard is world’s third largest source of vegetable oil after soybean and palm oil. Worldwide production of rapeseed has increased six-fold between 1975 and 2007 (FAO, 2004). Every ton of rapeseedroughly yields ca. 400 kg of oil. World rapeseed/mustard production was 58.4 million tons in the 2010- 2011 growing season. In Pakistan during 2010-11, rapeseed canola was grown on an area of 217 thousand ha with 192 thousand ton production, with an average yield of 886 kg ha -1 .In Khyber Pakhtunkhwa during 2010-11, rapeseed canola was grown on an area of 17.1 thousand ha, with 7.9 thousand ton production, and average yield of 450 kg ha -1 (MINFA, 2011). Brassica is an annual rabi crop and the normal time of seeding of most of the rapeseed cultivars in Pakistan is from mid-October to mid-November (Khalil and Jan, 2002). With delay in sowing, the seed germination is seriously affected due to low temperature resulting in low plant population and thus lower yield. Thus, to maintain proper plant population, higher seed rates must be used.Maintaining optimum plant density in rapeseed is very difficult in the cold regions where low temperature in autumn decreasing germination percentage.High rain in winter damage seedling and clay soil result in poor seedbed conditions and thus inadequate density. Therefore, optimum plant population of rapeseed is more critical in the similar regions of the world. Factors reported to reduce plant populations of canola include inadequate or excessive soil moisture, soil crusting, low temperature, seeding equipment, late spring frost and hail damage (Mendham et al., 1995). Angadiet al. (2003) showed that rapeseed adjusted seed yield across a wide range of plant populations, although it did not compensate completely for the decreasing populations. Nitrogen fertilizer plays a vital role in enhancing crop yield (Rathkeet al., 2005; Amanullahet al.,2013). Many studies have shown that both growth and yield of rapeseed are enhanced significantly by high doses of applied