دور شدة الانتخاب لتحسين حاصل الذرة الصفراء

Abstract EN

A field experiment was conducted in the Department of Field Crop Sci.

Farm, College of Agriculture ,University of Baghdad ,Abu-Ghraib, during spring and fall seasons of 2007 and spring season of 2008.

The objectives were to determine the optimum selection pressure used were to improve maize( Zea mays L.) Buhuth 106 by mass selection were 5,10,15 and20%.The trial was carried out by using a randomized complete block design with five replications.

Significant differences were found among all selection pressures and original population .

Buhuth 106 for all studied characters except grain yield .In plant height , grain weight and number of grains per ear were the most important characters .The selection pressure in 20% is superior in plant height (188.92 cm) and grain weight ( 0.254 gm) .

The selection pressure in 15% is superior in number of grains per ear (477.40 grain).

It was found that genetic gain selection was higher at 5% then decreased gradually at selection pressure 20% .

It was concluded that selection pressures 15% and 20% are superior to other selection pressure and cultivar Buhuth 106 for characters plant height, grain weight and number of grains per ear .This is a well known fact because it could not obtain a Significant differences in grain yield from one generation of agriculture on narrow areas in comparison with grid system where the work of additive gene principle is clear.

So, less number seasons selection.

In conclusion increase in grain yield maize should be dependent on hundred of plant groups during selection ,because differentiate plant depend on the size of changes in population, chance of appearance of these changes in the population and dependence of grid system method in selection .

In this program additive gene action was dependent because it works independent from the plant intensity.