Evaluation of some bread wheat mutants for adult plant resistance to stem rust

الملخص EN

Stem rust disease is a drastic factor to bread wheat (Triticum aestivum, L.

) production in Egypt and several countries in the world.

This study was carried out to evaluate twenty-two bread wheat mutant-lines in M₅ and M₆ generations as well as five check bread wheat cultivars Gemmeiza11, Sids12, Sakha 93, Sakha94 and Morocco, for high yield and an adequate level of adult plant resistance to stem rust under stress of the disease in the field.

The epidemiological parameters; final rust severity (FRS% ), average coefficient of infection (ACI) and area under disease progress curve (AUDPC), were used to characterize adult plant resistance to stem rust in the tested genotypes, as well as, some yield traits; grain yield, biological yield, No.

of grains / spike and 1000-kernel weight were also recorded for the studied genotypes.

The results showed that Sakha94 (Sk94) cultivar and the nine mutant lines, i.

e.

(Mut1, Mut2, Mut11, Mut25, Mut26, Mut28, Mut38, Mut59, Mut161), were resistant to stem rust.

Negative correlation coefficient values existed between disease parameters and yield traits under study, showing harmful effect of stem rust on plant characteristics.

Grain yield showed negative and significant correlation with ACI (r= -0.694**), AUDPC (r= -0.679**) and FRS% (r=-0.665**), while positive and significant correlation were found with biological yield (r = 0.889**), number of grains/spike (r= 0.411*).

The best mutant lines, having an adequate levels of adult plant resistance to stem rust, combined with desirable yield traits could be introgressed into adapted Egyptian wheat cultivars; to develop durable resistance to stem rust in wheat.