August 11, 2003

A broad-based campaign to advance the barley industry in eastern Australia by solving disease and quality problems and delivering improved varieties is starting to pay dividends.

A Queensland Department of Primary Industries team has made breakthroughs in researching the problem of colour defects in barley grain ­ especially black point ­ which cause some 10 per cent of Australian malting barley to be downgraded in most years.

Working on a Grains Research & Development Corporation Strategic Initiative, the team used controlled environment tunnels at Warwick's Hermitage Research Station to identify emerging barley lines with black point resistance.

As well the team's research indicates:

• no direct relationship between resistance to black point and fungal staining, dormancy or pre-harvest sprouting in barley,
• black pointed barley grain appears to germinate at a different rate from unaffected grain,
• black point resistance could be highly heritable, and
• opportunities for identification of molecular markers for black point, allowing their use in breeding programs in conjunction with field screening.

QDPI research scientist Maria Sulman said the team used ground and overhead mist irrigation to maintain high humidity at flowering time in the controlled environment tunnels at Hermitage Research Station.

"A number of recent studies have suggested that black point is not the result of a fungal disease, rather that it is associated with a biochemical reaction, in particular phenolic acid metabolism, specifically in the area of the germ of the grain," Ms Sulman said.

" In developing varieties with resistance, our previous studies concluded that a high humidity environment produces conditions that trigger high levels of black point in the field.

"We tested germplasm from Australian barley breeding programs ­ elite lines from Western Australia, New South Wales, Tasmania, South Australia, Victoria and Queensland ­ alongside three doubled haploid populations and some commercial and barley cultivars.

" We found a number of genotypes in Australian breeding programs that exhibited levels of black point below the industry cut-off point of 10 per cent, and better resistance than the overseas varieties Harrington and Chevron, which are our most resistant benchmarks.

"But even cultivars showing black point levels of up to 15 per cent in our work could be considered to have good levels to black point, as the environment we created in our tunnels at Hermitage would be considered challenging for any genotype."

Project leader Glen Fox said germination studies conducted during the research showed black point had an effect on the germination rate of barley, and an understanding of the phenolic compounds involved in black point formation could throw some light on the dormancy-like condition of black pointed grain.

However a number of important issues remained to be resolved for black point in Australia and the QDPI team's research would continue.