Wheat leaf rust

Wheat leaf rust
Symptoms of wheat leaf rust
Common names	Brown rust Leaf rust
Causal agents	Puccinia triticina
Hosts	wheat
EPPO code	PUCCRT
Distribution	Worldwide

Brown rust

Puccinia dispersa f. sp. tritici Erikss. & E.Henn. 1894
Puccinia recondita f. sp. tritici (Eriks. & E.Henn.) D.M.Henderson

Wheat leaf rust is a fungal disease that affects wheat, barley and rye stems, leaves and grains. In temperate zones it is destructive on winter wheat because the pathogen overwinters. Infections can lead up to 20% yield loss exacerbated by dying leaves which fertilize the fungus. The pathogen is Puccinia rust fungus. Puccinia triticina causes 'black rust', P.recondita causes 'brown rust' and P.striiformis causes 'Yellow rust'. It is the most prevalent of all the wheat rust diseases, occurring in most wheat growing regions. It causes serious epidemics in North America, Mexico and South America and is a devastating seasonal disease in India. All three types of Puccinia are heteroecious requiring two distinct and distantly related hosts (alternate hosts). Rust and the similar smut are members of the class Pucciniomycetes but rust is not normally a black powdery mass.

Plant breeders have tried to improve yield quantities in crops like wheat from the earliest times. In recent years, breeding for the resistance against disease proved to be as important for total wheat production as breeding for increase in yield. The use of a single resistance gene against various pests and diseases plays a major role in resistance breeding for cultivated crops. The earliest single resistance gene was identified as effective against yellow rust. Numerous single genes for leaf rust resistance have since been identified, the 47th genes prevent crop losses due to Puccinia recondite Rob. Ex Desm. f.sp. tritici infections, which can range from 5–15% depending on the stage of crop development.