Abstract:
Two years field study was carried out with the objective to determine the effect of different levels of nitrogen (N) on
growth, development, yield and yield components of sunflower (Helianthus annuus L.) hybrids under agro-climatic
conditions of Faisalabad-Pakistan in spring 2008 and 2009. The experiments were laid out in randomized complete block
design with split plot arrangement keeping hybrids in the main plots and N levels in the subplots with three replications. The
net plot size was 4.2 m x 5.0 m. The results indicated that with increasing N rates, there was also increment in the total dry
matter (TDM), grain yield and yield components while the oil content was negatively affected. There was higher grain yield
during 2008 as compared to 2009, probably due to more rainfall in the formation of TDM than in the latter stages. Hysun-38
hybrid gave maximum TDM (13.51 t ha-1) and maximum grain yield (3.08 t ha-1). Minimum TDM (11.94 t ha-1) as well as
grain yield (2.92 t ha-1) was observed from Hysun-33. Among different N rates, 180 kg ha-1 gave maximum TDM at 14.02 t
ha-1 and achene yield at 3.57 t ha-1 than other N rates. Maximum oil content (41.9%) was resulted from Hysun-38 without
application of N fertilizer and minimum oil content (38.4%) was observed from N5 treatment where 240 kg N ha-1 was
applied. It was concluded that Hysun-38 with 180 kg N ha-1 proved to be better for good yield of sunflower crop under the
prevailing semiarid conditions
