Barley Agronomy and Industry Development Project, Agriculture Western Australia, Northam^A, Esperance^B, Katanning^C and Albany^D.

Abstract

Gairdner barley is a new two row, malting barley for the higher rainfall areas of Western Australia. Both Crop Variety Testing (CVT) and barley agronomy trials have shown that Gairdner is a very high yielding variety under a wide range of situations, however grain size is extremely variable. The limited combination of management factors and sowing dates that are typified by the CVT program failed to identify conditions to which Gairdner is suited. By contrast the agronomy research program which uses combinations of sowing date, plant density, nitrogen rate and soil type, was able to demonstrate the conditions under which Gairdner is likely to produce grain of an acceptable quality. The close relationship between this barley agronomy program and barley breeding is proving to be a successful partnership in the development of the barley industry in Western Australia.

The Gairdner management package contains these essential elements. Gairdner can produce high grain yields and meet the malting specification for grain size if sown in mid to late May on soils with good moisture holding capacity during spring, at up to 150 plants/m², in the absence of spot type net blotch and with enough fertiliser nitrogen to maximise grain yield.

Introduction

Production of total barley and malting grade barley has doubled and nearly tripled since 1992. Annual production of barley in Western Australia has increased from around half a million tonnes to over 1 million tonnes, with production peaking at 1.8 million tonnes in 1997/98. Over 80% of the area sown to barley is sown to varieties with a malting classification. Between 60% and 70% of the total barley delivered is received as malting annually.

In September 1998, a new malting barley was registered in Western Australia. Gairdner is locally bred, two row, semi-dwarf variety originating from a cross between a well adapted feed variety, Onslow and a sib (Tas ‘83-587’) to the long seasoned malting variety, Franklin. Gairdner was classed as malting after three years of commercial evaluation, edging out another locally bred line Fitzgerald.

Evaluation of Gairdner barley by Agriculture Western Australia has shown that Gairdner is well suited to the high rainfall areas (> 450 mm) of the south coast and central wheatbelt and the medium rainfall areas of the southern mallee (325 – 450 mm) (Figure 1). Gairdner outyields Stirling, Harrington, Schooner and Franklin in these areas, with yields similar to the two main feed varieties, Onslow and Skiff.

Figure 1. Areas of Western Australia potentially suited for the production of Gairdner barley.

A consolidated research and extension project exists in Western Australia dedicated to studying the agronomy and physiology of barley, as well as providing specialist barley industry development. Gairdner barley is a case study for the benefits of having a breeding program well supported by agronomic research such as exists in Western Australia.

Traditionally barley varieties are released in Western Australia solely on their performance in variety evaluation trials run by the CVT. CVT provides an excellent analysis of the relative grain yield performance of new lines, but is weak in the area of grain quality and producing grain within the malting specification. Agronomy research is strong in the area of grain quality and producing grain within the malting specification. This paper describes the outcome of research with Gairdner barley and how agronomic research was able to unravel the grain quality weaknesses and strengths of the variety. Conventional testing of Gairdner in variety evaluation trials did not differentiate between low and high grain quality sites.

Grain size

Gairdner produces grains of a similar average grain weight to Stirling under a wide range of conditions (Figure 2). Gairdner grains are however, longer and narrower than Stirling grains. The amount of Gairdner grain passing through a 2.5mm slotted sieve is therefore nearly always greater than Stirling. In some situations the amount of grain passing through a 2.5mm screen is significantly higher than Stirling. The success of Gairdner as a malting variety in Western Australia is clearly dependent on managing grain size, as high grain yields occur in most situations.

Figure 2. Average grain weight (mg, db) of Stirling and Gairdner barley under the same management and the amount of grain passing through a 2.5mm slotted sieve at any given grain weight.

Soil type and date of seeding

Gairdner has shown a propensity to produce high screenings when grown on inappropriate soil types and sowing dates (Table 1). Overall Gairdner is best suited to mid May to late May sowing in all areas. Early May sowing, particularly on the south coast, increases the risk of Gairdner lodging. June sowing is considered risky unless there is significant September and October rainfall. Gairdner is best suited to soils that are able to store and provide moisture during the grain filling period. Differences exist between the south coast and the central, high rainfall areas in the soils on which Gairdner can produce grain of an acceptable quality.

Growing Gairdner on south coast soils

In the high rainfall areas, Gairdner has performed well on medium and deep sands over both gravels and clay and on shallow sands over well structured clay. Gairdner has given variable results on shallow gravelly soils with screenings being affected by waterlogging and below average spring rains. In the medium rainfall areas, Gairdner had performed well on grey clays when sown into wheat stubbles and on shallow duplex soils with reasonable structure in the underlying clay. Gravelly soils are likely to produce high screenings in this region.

Growing Gairdner on central, high rainfall soils

In the central, high rainfall areas, Gairdner has performed well on red-brown sandy duplex soils, good sands, sandy gravels and gradational soils. The screenings risk on all these soils increases with June sowing. The valley floor, grey sandy duplex soils that are prone to waterlogging and the gravelly sands overlying cemented lateritic rock are considered risky for Gairdner even with May sowing.

Table 1. Interaction between soil type and date of seeding on screenings (% < 2.5mm) for Stirling, Gairdner and Sloop barley at Darkan, Western Australia (central high rainfall).

Seeding rate and date of seeding

The optimum plant density for grain yield is between 120 and 150 plants/m². For Gairdner the optimum plant density to minimise screening levels shows a strong interaction with date of seeding (Table 2). Gairdner can be sown at up to 150 plants/m² with May sowing with little impact on screenings. Benefits from sowing Gairdner at a higher density include improved grain yield, better recovery from waterlogging and better competition with weeds. Should Gairdner be sown in June or on an inappropriate soil type, plant establishment should be reduced to 100 plants/m².

Table 2. Interaction between plant density and date of seeding on screenings (% < 2.5mm) for Stirling, Gairdner and Sloop barley at Badgingarra, Western Australia (central high rainfall).

Fertiliser nitrogen

Screening levels in Gairdner are more sensitive to high nitrogen supply than Stirling (Table 3). Rates of applied nitrogen higher than recommended for maximum grain yield increase screening levels in Gairdner.

The practice of soil testing and then determining the optimum nitrogen rate with the ‘Nitrogen Calculator’ developed by Agriculture Western Australia is the best way to keep protein at the desired level and avoid excessive screenings.

Table 3. Influence of level of applied nitrogen on screenings (% < 2.5mm) for Stirling, Gairdner and Sloop barley at Piesseville, Western Australia (central high rainfall).

Leaf disease

Gairdner barley has good levels of resistance to scald, powdery mildew and net type net blotch. Gairdner however is susceptible to the emerging leaf disease spot type net blotch (STNB) (Table 4). Increases in levels of STNB appear to be associated with an increase in the use of zero tillage, stubble retention and the widespread planting of the STNB susceptible variety, Franklin. STNB has a significant effect on the capacity of Gairdner to produce plump grains. Whilst Stirling is also susceptible to STNB, small changes in average grain weight due to the disease have little impact on screenings levels as observed in Figure 2. As STNB has no chemical control and is carried over on stubble, Gairdner should not be sown next to infected stubble and there should be an interval of three years between re-cropping of Gairdner in a paddock.

Table 4. Impact of spot type net blotch (STNB) on screenings (% < 2.5mm) for Stirling, Gairdner and Sloop barley at two sites on the south coast of Western Australia.

Acknowledgments

Agriculture Western Australia and the Grains Research and Development Corporation support this research. Technical assistance was provided by David Dodge, Peta Dunkerton and Ray Tugwell.