Water stress in four sunflower (Helianthus annuus L.)‎ cultivars : 1.effect of different water intervals on vegetative characteristics

الملخص EN

This experiment was carried out during 2003 / 2004 and 2004 / 2005 seasons, on sandy clay loam Soil in the Demonstration farm, Faculty of Agriculture, Omdurman Islamic University, to investigate the effect of three different irrigation intervals on some vegetative characteristics of four sunflower cultivars. The results revealed that the irrigation every 10 days increased significantly plant height at all growth stages, except at 75 days form sowing.

Also the present data showed that the number of internodes per plant and stem dry weight increased significantly at 45 days.

However, irrigation every 10 days increased significantly the number of leaves / plant, stem diameter and number of internodes / plant at 90 days from sowing. The results showed that the fortnightly irrigation caused significantly increased of leaf area per plant, dry weight of stem, and leaves, total dry weight at 60 days form sowing and heads dry weight at 90 days form sowing.

Whereas, irrigation every 20 days increased significantly the number of leaves / plant at 45 days from sowing.

Hungarian- A cultivar surpassed the other cultivars significantly increased plant height at all growth stages, number of Internodes / plant at 75 and 90 days from sowing, the number of leaves / plant, stem diameter and total dry weight at 45 days from sowing. However, Hysun- 33 cv.

surpassed the other cultivars significantly in total dry weight at 60, 75 and 90 days from sowing. Also the result revealed that the Hysun -33 cv.

Significantly exceeded the other cultivars in number of leaves / plant, leaf area / plant, leaf area index and (stem- leaves) dry weight at 75 and 90 days from sowing. Irrigation Hysun – 33 cv.

fortnightly resulted to the highest total dry weight at 60 days from sowing.

Whereas irrigation Hungarian – A every 10 days increased significantly plant height and number of leaves / plant / at 90 days from sowing.