Genetic diversity will improve rhyncho resistance

A collaborative project is aiming to provide more diverse genetic resistance to rhynchosporium in barley, to stay one step ahead of the pathogen.

The project is funded by the Technology Strategy Board and carried out by the James Hutton Institute, in collaboration with the University of Hertfordshire, KWS, Dupont and Agrii. The goal is to bring improved resistant varieties to market within 10 years.

“There is heavy asymptomatic infection on resistant varieties, with high levels of the pathogen on the leaves.

“We are trying to map as many genes as possible to discover the one that enables the plant to deal with the presence of this infection without showing symptoms,” said Adrian Newton, plant pathologist at the James Hutton Institute.

“One gene on chromosome seven controls the amount of plant growth and disease symptoms separately, which is the one that we are interested in primarily.”

Traditionally, breeders have selected for lack of symptoms, however, discovering this gene will enable them to build a more complex resistance to the disease that will be more difficult for the pathogen to overcome.

“It is much like combining many different modes of action when applying fungicides. The rhynchosporium will require more mutations to overcome the resistance due to the diversity of the genetics,” said Prof Newton.

“We are also looking at a secondary gene pool from barley’s close relative, hordium bulbosum, which we also hope will bring different resistance genes into mainstream varieties,” he added.

The project is also aiming to discover the interaction of different varieties with fungicides in the presence of asymptomatic infection, which will improve fungicide recommendations in the short term.

“It is sometimes difficult to establish whether a T0 is worth applying, but using assays to monitor levels of rhynchosporium infection on the leaf and the affect on final yield will enable us to make an improved judgement,” said Prof Newton.

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