Nitrogen effects on growth and development of sunflower hybrids under agro-climatic conditions of multan

The effect of nitrogen (n) on growth,development,yield and yield components of different sunflower (helianthus annuus l.) hybrids was evaluated under agro-climatic conditions of multan during spring 2008 and 2009. the experiment was laid out in a randomized complete block design with split plot arrangement having three replications,keeping cultivars in the main plots and n levels in the subplots. the net plot size was 4.2 m × 5 m. the results showed that,with increasing n rates,there was increment in the biomass,yield and yield components while the oil contents were adversely affected. however,there was high seed yield in 2008 as compared to 2009. among sunflower hybrids,hysun-38 gave more yield as compared to other sunflower hybrids (hysun-33,pioneer 64a93),while in case of n levels,180 kg ha -1 provided higher yield than other n rates (0,60,120,240 kg ha -1) in both years of study especially during 2008.