Net blotch-busting research
Aims to map and mark resistant genes for breeders to introduce
IT IS a sight any barley grower dreads.
There, on the drooping green leaves, unmistakeable—the brown streaks or small circular dots which indicate the presence of net or spot types of net blotch, a fungal disease caused by the Pyrenophora teres pathogen.
And according to a 2010 report, if there were no control measures in place, yield losses would be up to 30 per cent and cost growers $300 million, so this is a fungus not to sneezed at.
However, research being conducted by the Centre for Crop Disease Management in Western Australia holds out hope that within a few years genetic markers can be laid down for new genes or combinations of genes resistant to the fungal disease which breeders can then introduce into their lines.
Centre senior research officer Dr Nola D’Souza said the team was at about the halfway point of their research, which has been testing lines from international cultivars that have shown field resistance to net blotch against a group of eight domestic isolates.
The research is hoping to find “durable” resistance across the life cycle of the plant, characterised by a combination of genes, as opposed to a single gene, which the fungus can adapt to a lot easier.
If these resistant genes can be found, mapped and marked, breeders can do a DNA analysis on the line as opposed to field trials, where success may not be known for several growing seasons.
“It helps with resources, it’s a way of getting results faster,” Mrs D’Souza said.
“It’s much better than looking for a needle in a haystack.”
She said introducing genetic resistance to net blotch into barley lines is preferable to the current method of treating the disease with fungicides, as pathogens tend to build resistance over time to the fungicides.
The research has been helped by a process known as doubled haploid breeding.