PERFORMANCE OF THE EGYPTIAN WHEAT VARIETIES TO STEM RUST AND DYNAMICS OF VIRULENCE OF THE CAUSAL ORGANISM

Abstract

Wheat (Triticum aestivum L.) is one of the most important food crops in Egypt and World. Wheat is liable to attack by many diseases pmiicularly rust diseases. The present investigation aimed to build up useful data on the race identification of the causal organism.ln addition to determine the frequencies of virulence on Sr genes and local wheat varieties. Also, the study dealt with gene postulation in some Giza wheat varieties under greenhouse conditions.

Under field conditions this investigation included studying the effectiveness of stem rust resistance genes, the performance of some local wheat varieties as well as identification of adult plant resistance gene (s) of stem rust in the previous varieties under disease stress in the field.

Race identification:

The identification of physiologic races was don following adopted by Roelfs and Martens (I 988) in which 12 wheat stem rust monogenic differentials were used throughout the three growing seasons i.e. 2001/02, 2002/03 and 2003/04. This procedure gave evidence to the pressens ofrace groups i.e. RR and RT the most fi•equent ones which gave 9.58 % frequency.