dalma.castillo@inia.cl, bsagredo@inia.cl, imatus@inia.cl, fcorreas23@gmail.com, v.munozquiroz.inia@gmail.com

Wheat is one of the most important crops in South America. In 2023 the production rise 24.10 MT, and the main producers’ countries were Argentina, Brazil, Chile, Paraguay, Uruguay, and Peru. Since 2017, the production has been under threat because of the presence of yellow rust (Puccinia striiformis) in a significant area of production.

If no fungicides are employed, this disease might result in a 40% or a total loss of production. In some cases, the farmers require at least three applications per season, realizing that P. striiformis is one of the limiting factors for the sustainable production of this cereal.

Many studies show that P. striiformis populations have been constantly changing with high capacity for adaptation to new environments, features that are concomitant with more aggressiveness of races producing high quantity of urediospores in shorter period of time.

These characteristics added long-distance dispersal of yellow rust populations, and the rapid evolution of new races, have led to the rapid erosion of effective resistance genes. This has significantly reduced the number of sources of resistance for the development of new varieties. In Chile the situation became very complex, the epidemics are frequent, and there is a high genetic diversity for the P. striiformis populations collected.

Further, the wheat breeding program has reported that the area affected by this pathogen has increased, with higher number of wheat fields infected for P. striiformis each season, as well as the species affected, such as bread wheat, durum wheat, triticale, and rye, causing total losses in some cases. In this scenario we need to identify the races of P. striiformis that explain this new pattern of the disease in Chile. We collected yellow rust samples in different seasons, from diverse sites of the cereal production of the country from bread wheat, durum wheat, winter triticale and spring triticale.

An isolate obtained from pustule was used to extract total DNA to be sequenced. Its genome will be compared with known genome sequenced available at database. Both known reference genes and SSR markers will be used to infer about genetic diversity and races exist in Chile.