The Effect of Different Nitrogen Doses on Growth Attributes of Some Sunflower (Helianthus annuus L.) Cultivars Grown as Second Crop

Abstract

Objective: The current study investigated the impact of different N doses on growth traits of some sunflower (Helianthus annuus L.) cultivars grown as second crop. Materials and Methods: The experiment was conducted according to randomized complete block design with split-plot arrangements and three replications. Three sunflower cultivars (‘Bosfora’, ‘P64LE119’, and ‘LG5582’) and four N doses (0, 50, 100, 150, 200 kg ha-1 pure N) were included in the study and data relating to different growth traits were recorded. Results: The results revealed that individual effects of cultivars and N doses exerted significant impacts on the studied growth traits, whereas their interactive effects were significant for some of the studied parameters. The earliest emergence duration was recorded under 150 and 200 kg ha-1 N. Similarly, the earliest head formation, flowering initiation and seed filling duration were recorded for ‘Bosfora’ cultivar with 200 kg ha-1 N. Conclusion: The earliest physiological maturity was recorded for ‘P64LE119’ cultivar, whereas the widest head diameter and the highest head weight was noted for ‘LG5582’ cultivar under 200 kg ha-1 N application. Overall, ‘Bosfora’ cultivar under 200 kg ha-1 N application performed better for head formation, flowering initiation, and seed filling duration, whereas cultivar ‘LG5582’ under 200 kg ha-1 N application performed better for head diameter and head weight.It is recommended that cultivars ‘Bosfora’ and ‘LG5582’ should be provided 200 kg ha-1 N for better growth in southeastern Anatolia.