Response of sunflower hybrids to various levels of nitrogen and growthregulator

Four sunflower hybrids (Aritar 93 Peshawar 93, Hysun 33 and Tarnab 96)and one open pollinated variety (Suraj Muhki Tarnab) were sown using fivenitrogen levels (0, 60, 120, 160, 200 kg/ha) and two levels of growth regulator(0, 30 ppm of IBA). Growth regulator was allocated to main plots while nitrogenand hybrid combinations were maintained in sub plots. Half of the nitrogenwas applied at the time of sowing while remaining half of nitrogen was appliedwhen plants reached knee height stage. Days to 50% flowering increased withincrease in nitrogen levels. Variety SMT took maximum days to flowering whilehybrid Peshawar 93 took fewer days. In the interaction of C x N hybrid Hysun33 took maximum days to flowering when applied 200 kg N/ha. Days tomaturity increased with increase in nitrogen levels. Nitrogen level of 200 kgN/ha delayed maturity. Variety SMT took more days to maturity while hybridPeshawar 93 matured earlier. Interaction between C x N showed that hybridHysun 33 took more days to maturity when applied 200 kg N/ha. Plant heightwas significantly affected by cultivars, nitrogen levels and interaction betweenCxN. Plant height increased with increase in nitrogen levels. Interaction of CxNshowed that variety SMT produced tallest plants when received 200 kg N/ha.Number of leaves per plant were significantly affected by nitrogen andcultivars. Leaf area increased with increase in nitrogen levels. Maximum leafarea was produced in plot receiving 200 kg N/ha. Variety SMT producedmaximum leaf area, whereas hybrid Peshawar 93 produced minimum leaf area.Leaf area index (LAI) was significantly affected by cultivars, nitrogen levelsand interaction of CxN. Significant increase in head diameter was observedwith increase in nitrogen levels. Maximum head diameter vas produced in plotsreceiving 160 kg N/ha. Hybrid Hysun 33 produced larger heads while hybridPeshawar 93 produced smaller heads. Head diameter increased in plotsreceiving 30 ppm IBA. In the interaction of CxN maximum head diameter wasobserved for Hysun 33 that received 200 kg N/ha. Stem diameter wassignificantly affected by cultivars, nitrogen and growth regulator. Stemthickness increased with increase in nitrogen levels. Thousand grain weightsignificantly increased with increase in nitrogen levels. Maximum thousandgrain weight was produced in plots receiving 160 kg N/ha. Maximum thousandgrain weight was produced by hybrid Hysun 33. Grain yield per plaitincreased with increase in nitrogen levels, however maximum grain yield perplant was found in plots receiving 160 kg N/ha. Hybrid Hysun 33 producedmaximum grains yield per plant. For the interaction of CxN maximum grainyield per plant was observed in plots of Hysun 33 that received 160 kg N/ha.Data shown that grain yield per hectare increased with increase in nitrogenlevels, however maximum grain yield per hectare was produced in plotsreceiving 160 kg N/ha. Hybrid Hysun 33 produced maximum grain yield perhectare. For the interaction of C x N maximum grain yield per hectare wasproduced in plots of hybrid Hysun 33 that received 160 kg N/ha. Oil contentpercentage was significantly affected by cultivar and nitrogen levels. Oilcontent percentage decreased with increase in nitrogen levels. Hysun 33produced more oil content.