Nitrogen use efficiency, yield and other characteristics of sunflower (Helianthus annuus L.) hybrids as affected by different levels of nitrogen

Abstract

To assess the nitrogen use efficiency of hybrid sunflower (Helianthus annuus L.), an experiment was conducted at New Developmental Farm, Khyber Pakhtunkhwa, Agricultural University Peshawar-Pakistan. Randomized complete block (RCB) design with split plot arrangement, replicated four times, was used. Sunflower hybrids (Suncross, Gulshan-98, Aritar-93, and Peshawar-93) were allotted to main plots while nitrogen levels (0, 45, 90, 135, 180, and 225 kg $ha^ {-1}$) to the sub-plots. Statistical analysis of the data revealed that nitrogen had significant effects (P≤0.05) on all parameters under study. Days to button formation and flowering decreased with increase in nitrogen levels. The delayed button formation (35.63) and flowering (52.06) were observed in controlled plots, while earlier button formation (31.94) and flowering (48.56) were noted when 225 kg N $ha^ {-1}$ was applied to the crop. Among hybrids Peshawar-93 took less days (45.29), while Gulshan-98 took more days (56.42) to flowering. Maximum plant height (87.54 cm), seed yield $ha^ {-1}$ (1302.75 kg) and leaf area $plant^ {-1}$ (9909.5 $cm^ 2$) was recorded in plots with highest dose of nitrogen (225 kg $ha^ {-1}$). Maximum leaf area $plant^ {-1}$ (8777.53 $cm^ 2$) has produced by Suncross. Values of nitrogen use efficiency were higher in controlled plots (342) and lower (5.83) in plots with highest dose of nitrogen (225 kg $ha^ {-1}$). Out of tested hybrids, Suncross produced maximum yield with maximum dose of nitrogen. It is therefore suggested that Suncross should be sown in Peshawar Valley by farmers with N application at the rate of 225 kg $ha^ {-1}$.