STUDIES ON THE COMPLEMENTARY EFFECT OF THE RESISTANCE GENES TO LEAF RUST OF WHEAT

Abstract

Leaf rust of wheat caused by Puccinia recondira f. sp. tritici IS a widespread disease in Egypt and most countries of the world. In Egypt, this disease was the cause of eliminating many wheat varieties, in 1970's, because of their susceptibility. However in 1980's many varieties of high level of field resistance were produced and reduced the disease incidence. In the last few v.ears , particularly. A progressive increase in rust severity was observed

at the last season. Consequently, one of the most important and essential objectives was to suney and study the distribution frequency of virulence gene(s) in the causal organism populations and to study the interaction of genes of resistance in the currently used varieties.

Two main goals of the present study were covered.

The first goal was to study the distribution frequency of virulence gene(s) in the causal organism populations between 1993 and 1996 seasons. Cultures of leaf rust fungus, collected between ( 1993 and 1996) aeason, were tested against a set of monogenic lines of leaf rust ((17 lines) and local varieties (23 varietie.