30 tonnes of tolerant seed in four years

Plant breeders in two States report very promising developments in boron-tolerant malting barley lines and durum wheat.

Boron is widespread in soils in the southern (and western) cropping belt and is associated with toxic conditions which limit root growth, and hence moisture and nutrient uptake in plants.

Some wheat varieties, including the widely grown Frame, are more tolerant of boron than others but now senior barley breeder David Moody of Agriculture Victoria, Horsham, is hopeful that similar attributes will be available in malting barley.

"The breeding of potential boron-tolerant lines has been fast-tracked using a combination of NIR technology, a rapid hydroponic assay for boron resistance, summer seed increases, and knowledge gained from the CRC for Molecular Plant Breeding. The overseas variety Sahara is the source of tolerance," Mr Moody said.

Related work at the University of Adelaide has identified a suite of genes and their molecular markers for boron-tolerance (see p1 southern edition of this Ground Cover). Field trials in Sloop on the Eyre Peninsula have yielded good results despite the stresses of dry years. This breakthrough in identifying genes that affect yield on boron-toxic soils should add considerable speed and accuracy to future crossing work.

Meanwhile, "one of the most promising lines so far is VB9953, a potential malting variety which is also cereal cyst nematode-resistant. This line has progressed from being a single seed in 1996 to about 30 tonnes being harvested this year".

Mr Moody said in trials it was out-yielding Schooner in the Wimmera by an average 8 per cent and producing similar yields in the Mallee. Grain size was also better than Schooner.

"Seed of this line is being multiplied to enable commercial production trials in 2001 and commercial malting and brewing trials during 2002," he said.

"Due to quality similarities with Sloop it is expected that only one year of commercial brewing trials will be necessary."

Tolerant durums

Also, two new boron-tolerant durum wheat lines are at an advanced testing stage.

The lines have been bred at the University of Adelaide. Wheat breeder Tony Rathjen said one of the lines was a boron-tolerant back-cross derived mainly from Yallaroi.

He said it had out-yielded the very widely grown Tamaroi variety in conditions associated with high soil boron. The other was a Tamaroi derivative.

"If continued testing, especially grain quality trials, is successful, these lines should be available to seed producers in 2001," Dr Rathjen said.

Program 1.3.1 Contact: Mr David Moody 03 5362 2111 email: david.moody@nre.vic.gov.au

Program 1.6.2 Contact: Dr Tony Rathjen 08 8303 7216