hybrids (zea mays l. ) effects of different levels of drought stress on yield and yield components of corn

abstract to determine the effects of different levels of drought stress on yield and yield components of corn hybrids as well as to determine the correlation between the characteristic and yield in different level of stress a experimental study was done in split plot with 15 corn hybrids placed in gharakheil. the main plot was contained different levels of stress(a1:irrigation after 50mm evaporation from small tub evaporation. a2: irrigation after 90mm evaporation from small tub evaporatio. a3: irrigation after 130mm evaporation from small tub evaporation. a4:irrigation after 170mm evaporation from small tub evaporation. ) and sub plot contained corn hybrids. in normal ,mild and severe stress conditions osgt14 hybrid respectively with 9. 445,9. 270 and 8. 352 ton/hac had the highest yield. in the severest stress condition spgt12 hybrid with 7. 445 ton/hac had the highest yield. in the yield components, the weight of 1000 grains,the number of grains in rows,the number of grains in an ear of corn,biological yield,harvest indices and the geight and thickness of an ear of corn showed the most correlation with yield. . in other word,this characteries are having the most important effect on the yield. the correlation between tolerance indicies can be a factor in choosing the best hybrid and the best indices. where as there is a high correlation between mp, gmp, harm and sti, in the other hand, these indices are having the highest correlation with yield in normal condition and different level of stress ,they can be called the most important indices. with the help of these indicies, probable delicate variaties can be distinguished.