There is a researcher Raoul Robinson who favored the use of multiple genetic resistance because when it could breakdown the effects were not a highly susceptible reaction. He suggested that defeated resistance genes give a ghost level of partial resistance and if several of these genes are pyramided the effect is multi gene stable resistance. I am attaching a work which suggests if multiple Asian defeated resistance genes from Asian rust can be incorporated with genes working in Brazil the net result will be a stable multiple gene resistant type. Hope these concepts are useful for your breeding program.

Thanks Paul Reed. Hepperly. “Robson said in the past: Resistance isn’t black or white bit the shaddow of the gray”. This is true. Partial resistance durable but major genes or complete resistance isn’t durable. Soybean rust has many races. Until fungicides reduced the efficiency in Brazil after 18 years. Mutations in the pathogen population is a common background. In Brazil we have the mix population from Asia, America and Africa.

Agree with Paul & Juliatti

Partial resistance is the solution to sustainable management,

but unfortunately it is difficult to achieve

Para ter avanços na obtenção de plantas com resistência parcial aos fitopatógenos é necessário trabalhar com progênies ou famílias nas gerações segregantes e não com plantas individuais. A maioria dos melhoristas trabalham com a seleção de plantas individuais, onde o escape predomina. O trabalho é árduo mas vale a pena.

Sim, concordo! Neste caso, a seleção deverá ser feita com plantas sintomaticas.

Também é importante o desenvolvimento de multinhas ou variedades compostas....