Barley trials hone variety management
GroundCover™ Issue: 114 | Author: Bob Freebairn
Improved management of different barley varieties and their varying responses to seeding rates and nitrogen has come a step closer after a series of national trials.
The trials, as part of the GRDC co-funded barley agronomy projects in the western, southern and northern grains regions, compared grain yield and quality responses of current and potential malting varieties.
The trials, initiated in 2012, compared the response of eight varieties – Bass, Buloke, Commander, Flinders, Granger, La Trobe, Skipper Australia and Wimmera – with three different seeding rates (75, 150 and 300 plants per square metre) and three different levels of nitrogen application (0, 30 and 90 kilograms of nitrogen per hectare).
In 2013, the trials were repeated and included Compass (undergoing malt accreditation), which is an early mid-season variety closely related to Commander.
Rick Graham, New South Wales Department of Primary Industries (DPI) Condobolin-based research agronomist, has been coordinating the research in the southern region with Rob Wheeler from the South Australian Research and Development Institute and Simon Craig from BCG. Dr Guy McMullen, the NSW DPI research leader for Northern Farming Systems based at Tamworth, is overseeing the northern region component of the trial. Blakely Paynter, from the Department of Agriculture and Food, Western Australia (DAFWA), is coordinating the western component.
Initial findings from 2012 showed that La Trobe, a sister line to Hindmarsh undergoing malt accreditation, performed well across a range of environments, showing a yield advantage over the other varieties tested. Longer-season varieties Bass, Flinders and Granger exhibited potential in medium-rainfall environments.
In 2013, Compass produced similar grain yield to La Trobe in trials at Parkes and Condobolin in central NSW. Both Compass and La Trobe are showing good adaptability in low to medium-rainfall environments.
Nitrogen yield response
Findings from these trials (nine locations under dryland conditions across WA, SA, Victoria and NSW in 2012), including one at Condobolin, found that although varieties differ in yield, their response curves to applied nitrogen are similar on nitrogen-responsive sites.
The meta-analysis so far has also shown there is a curvilinear yield response for nitrogen treatments for all genotypes, with a significant increase in grain yield for nitrogen applications of up to 30kg nitrogen/ha, but no significant response from the higher 90kg/ha treatment.
Mr Graham reports that grain protein in response to nitrogen fertiliser rates is far more variety specific.
He notes that grain protein concentration (GPC) has been found to be the most critical factor affecting malt receival standards. This is particularly important as quality specifications require protein of between 9 and 12 per cent, while also achieving physical grain quality criteria related to grain size, weight and uniformity. In addition to sensitivity to management inputs, GPC showed a large genotype-by-environment response.
Although grain protein showed a linear trend to increasing rates of nitrogen for all varieties assessed, there were differences in respect to the range of the increase. Commander, for example, a known low-protein achiever, was less responsive and Bass was more responsive.
On limited data, La Trobe, Buloke, Skipper Australia and Wimmera followed the established inverse relationship between yield and protein (lower grain protein as yield increases when varieties are compared at given sites), while Bass and Flinders appear to be more protein responsive (Figure 1).
Apart from some small variations in physical quality parameters (test weight, retention or screenings), GPC was the major factor influencing the failure of cultivars to meet malt receival standards.
Overall, BassA exhibited a significantly higher test weight than Commander, while both Bass and Skipper Australia achieved better grain size (lower screenings and higher retentions). La Trobe was very adaptable, performing well over a range of locations and treatments.
Nitrogen application increased test weight for rates of up to 30kg/ha, with increasing seed rates decreasing test weight. Bass and Skipper Australia had significantly lower screenings than Commander. Compass, included in 2013 trials, performed similarly to Commander in terms of grain-quality parameters.
High rates of nitrogen and seed increased the level of screenings for all genotypes. Wimmera had the lowest seed weight and Buloke the highest, while low nitrogen and low seed rate gave higher seed weights.
In 2012, malt specifications were not achieved for all sites because of environmental constraints – dry spring finishing conditions and/or high starting soil nitrogen profiles.
La Trobe was the only cultivar to achieve malt specifications at all trial sites other than at sites affected by the dry spring and/or high soil-nitrogen levels. The results highlighted its potential as an early maturing malt variety.
Seeding rate response
Flinders showed a significant incremental increase in grain yield from increasing seed rate, while all other cultivars showed an increase in yield only up to the targeted 150 plants/m2.
These findings have potential implications in terms of nitrogen management and could include canopy management strategies, such as earlier sowing and delayed application of nitrogen in lower-grain-protein varieties such as Commander. Varieties inherently low in grain protein might also be useful in conditions of excessive soil nitrogen or in situations where nitrogen is applied to optimise yield.
This research is highlighting that varieties differ in their sensitivity to management practices and may need to be managed differently. Importantly however, growers need to consider both agronomic merit and market potential when making a decision to adopt a new malting variety, as its successful uptake will ultimately depend on its agronomic performance and market demand.
More information:Rick Graham,
0428 264 971,
Ground Cover will report on the 2014 trials when all the data is in.
GRDC Project Code DAW00224, DAN00173, DAN00167
Region South, West, North