Barley boon in doubled dabble

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NSW DPI staff, Michael McCaig and Rick Graham, inspecting doubled haploid barley plants.

A new research project aims to improve barley varieties used by NSW farmers so they are more disease resistant and able to thrive in acid soils.

Barley Breeding Australia’s (BBA) national resources are being used to develop new varieties for NSW, with a focus on high yielding varieties that combine elite malting quality with improved disease resistance and tolerance to acid soils.

One aspect of this project is the development of doubled haploid barley populations, specifically targeted for southern NSW, Victoria and Tasmania.

NSW Department of Primary Industries (DPI) barley breeding technical officer, Rick Graham, said doubled haploid technology was a tremendously valuable tool in plant breeding and could significantly reduce the time it took to breed new varieties.

In a doubled haploid laboratory, plants are generated from haploid cells such as pollen cells (containing only one half of the paired chromosome complement of normal cells), and the chromosomes are doubled artificially to restore normal chromosome numbers.

Doubled haploids are useful because when they are generated from a hybrid parent, the genetic make-up of each plant is fixed by the chromosome doubling process.

Each doubled haploid plant is then 100 per cent true breeding, which means successive generations of that plant will have the same genetic characteristics and qualities.

"The essential step of generating fixed lines following crossing of parental varieties is reduced from four years typical of conventional breeding methods, to less than 12 months with doubled haploid technology and plant tissue culture techniques," Mr Graham said.

This project has been made possible by the Department of Agriculture and Food Western Australia (DAFWA) barley breeders, Dr Reg Lance and Dr Chengdao Li, and doubled haploid staff, Sue Broughton, Ian Watson and Li Liu.

"In NSW, myself and Michael McCaig from the NSW DPI barley evaluation unit are responsible for the transplanting, monitoring and day-to-day management of the doubled haploid plants," Mr Graham said.

The plants will be produced using plant tissue culture techniques at DAFWA, then flown to Wagga Wagga Agricultural Institute in small plastic tubs containing plant tissue culture medium.

"On arrival at the institute, we carefully transplant the plantlets to seedling trays and grow them under controlled conditions until they are ready to be transferred to the field or glasshouse," Mr Graham said.

"Doubled haploid populations from four elite crosses were sent to Wagga in April and June.

"These crosses involve advanced acid soil tolerant NSW breeding lines crossed with Western Australian and Victorian parents.

"The project commenced on a small scale with approximately 950 plantlets transplanted to seedling trays.

"They were placed in a controlled environment room for six weeks before being transplanted to the field in a bird-proof enclosure.

"In 2008 the doubled haploids will be tested in a disease nursery at the institute, to identify lines resistant to scald, which can be a problem in southern NSW."

The next stage of the barley project will attempt to incorporate multiple disease resistance to diseases such as scald, leaf rust and powdery mildew.