الفهرس 
Acknowledgments
Effect of growth regulators on yield and yield componentsOnly 14 pages are availabe for public view
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Abstract
In this thesis we carried out an experiment which contains two parts:
A-Field Experiment:
Two field experiments were conducted in the Experimental Farm, Faculty of Agriculture, Assiut University, during the two seasons of 2004/2005 and 2005/2006, to study the effect of some growth regulators, Gibberellic acid (GA3) and Ascorbic acid, on the growth and yield and yield components of two Egyptian wheat cultivars, represented the two species of Triticum aestivum vulgare (Giza 168) and Triticum durum (Beni-suef 1).
Each experiment contained for each variety and concentrations. The split-split plot design was used. The wheat cultivars were six treatments (100,200,300) and control allotted in the main plots and the growth regulators were allotted in sub-plot and concentrations were arranged in sub-sub plot. This variable was practiced after harvesting corn directly. Wheat seed were soaked on different concentrations of GA3 and Ascorbic acid (100 ppm, 200ppm, 300ppm) for 8 hours which control soaked with water then the seeds were sown on the field. The fertilization was conducted according to the recommended doses.
The results obtained in this part of study could be summarized as follows:
1. Effect of growth regulators on yield and yield components:
The growth traits such as plant height, spike length, grain yield / plant, grain weight / spike, seeds weight, grain yield (ard/fed) and 1000 grain weight were significantly enhanced by two growth regulators in both seasons. It could be observed, in general, that Ascorbic acid and Gibberllic acid at 200ppm were more effective in increasing growth characters, yield and its components for two wheat cultivars.
2 - Effect of growth regulators on physical and chemical properties of the grains and flours:
2. 1. Protein percentage, gluten percentage and fermentation test:
The results indicated that growth regulators exerted a significant influence on these traits. These groups of traits were more enhanced when Ascorbic acid and Gibberllic acid applied at 200ppm
2. 2. Flour, fine bran and coarse bran (%):
The results observed that these traits were slightly affected by two growth regulators for two wheat cultivars but these increase were not significant.
B- Laboratory Experiment:
The two varieties of wheat grains tested, Giza 168 and Beni-suef 1 which were obtained from the Ministry of Agriculture, Department of certification, were sieved and cleaned from dust, husk or any inert materials. Four replicates of 100 grains were set to germinate on filter paper in Petri dishes as 25 grains in each dish. Grains were watered with 6 ml distilled water, Gibberllic acid at (100ppm ,200ppm, 300ppm) and Ascorbic acid at (100ppm ,200ppm, 300ppm) followed by 4 ml after 3 days. Grains were incubated at 200 c for ten days.
The results obtained in this part of study could be summarized as follows:
1. Effect of growth regulators on grain viability and seedling growth:
1. 1. Germination Power percentage, germination percentage and speed of germination:
The results indicated that the maximum rate of Germination Power percentage and germination percentage were recorded when Ascorbic acid and Gibberllic acid applied at 200ppm for two wheat cultivars. It is also indicated that growth regulators resulted in a significant increase in germination speed for Giza 168 cultivar but was not significant for Bani-sweef cultivar.
1. 2. Length of shoot and primary root (cm):
The mean length of shoots and primary roots were significantly affected by growth regulators for two wheat cultivars. The maximum highest of shoot and root length were recorded when Ascorbic acid and Gibberllic acid applied at 200ppm.
1. 3. Abnormal seedlings (%):
The results revealed that growth regulators resulted in a significant decrease in abnormal seedlings for Giza 168 cultivar but was not significant for Bani-sweef cultivar.