Effect of different irrigation intervals and potassium fertilization on yield components and protein yield of sunflower (Helianthus annuus L.)‎

الملخص EN

-This research was conducted at the Agriculture Experiment Station at Sana'a University, Faculty of Agriculture during the 2006 and 2007 seasons.

The objective of this study was to investigate the effect of water stress of three different irrigation intervals (9, 18, and 27days) with average amount of water applied for each treatment being fixed at 4000m3/ha/season and different rates of Potassium fertilization (100, 200, and 300 kg K2O/ha) on yield components and protein content of sunflower (Euroflor cultivar).

The results obtained in the first season 2006 indicated that , decreasing irrigation intervals from IR3(27day) to IR1(9days) increased seed yield, head seeds weight, seed number per plant, 1000- seed weight, heads yield, leaves number/plant, plant height and seed protein content, whereas the potassium treatments have significant effect on protein yield only.

However, seed protein content decreased with decreasing irrigation intervals from IR3 to IR1.

Significant differences between irrigation treatments in 1000- seed weight, leaves number, plant height, and seed protein content in the second season 2007, potassium treatments have affected protein yield, and the results indicated the reduction in 1000- seed weight, leaves number and plant height with increased irrigation intervals from IRI to IR3.

The decrease in irrigation intervals decreased seed protein content.

The first treatment (IR1) gave higher values of all traits, except in seed protein content which gave lowest values.

Whereas the third irrigation treatments IR3 (27 day) gave the highest value in seed protein content.

Protein yield was affected by potassium treatments in the second season 2007, and the increase in potassium rates increased protein yield, and the interaction between Potassium fertilization treatments and irrigation intervals on protein content, during 2007 season.

It is recommended to use the second irrigation interval (18 day) with a total amount of water 3600 m3/ha/Season.

It is enough to increase the seeds yield and yield components use of the second potassium rate (200 kg K2O/ha) also enough to increase protein yield.

Keywords: Potassium fertilization., Sunflower, different irrigation intervals.