Wheat variety update — 2018

Take home messages

• Across a wide sowing date range and variable seasonal weather conditions, mid-season maturing wheat varieties were generally the highest yielding in 2017.
• Scepter (Australian Hard (AH)), Beckom (AH), Mace (AH), Longreach Havoc (AH) and Trojan (Australian Premium White (APW)) were the highest yielding varieties across 2017 South Australian (SA) wheat National Variety Trials (NVT) sites.
• Foliar disease had little impact on varietal performance, but a delayed opening (Eyre Peninsula), spring frosts (Murray Mallee/Mid North) and early waterlogging (South East) affected many trials in 2017.
• The new durum, DBA-Aurora again produced high yields.

2017 South Australian wheat crop

The SA area sown to wheat in 2017 was estimated by ABARES (December 2017) at 1.97 million hectares compared to 2.0 million the previous year (Figure 1). Despite below average growing season rainfall in many districts, total wheat production is estimated at 3.65 million metric tonnes (MMT), which is slightly below the 10 year average of 3.921 MMT and represents a statewide average grain yield of 1.85t/ha. These production figures are approximately 55% lower than 2016 but very similar to the national 10 year mean grain yield of 1.78t/ha.

Figure 1. ABARES values for South Australian wheat production in metric tonnes (black upper line) and hectares sown (grey lower line).

2017 NVT and wheat varietal performance

Despite an erratic opening to the cropping season and then very low, early winter rainfall, good rains in mid-winter combined with a dry but mild spring to produce surprisingly good yields and grain quality in many SA districts.

In 2017, wheat variety trial yields across 17 SA main-season sown NVT sites, averaged 2.72t/ha, which is considerably lower than the 4.29t/ha recorded in 2016, but more consistent with the five year (2012 to 2016) average of 3.19t/ha. The individual NVT site yields ranged from 0.59t/ha at Penong to 5.38t/ha at Wokurna on Yorke Peninsula, with sowing dates ranging from 2 May at Mitchellville to 20 June at Cummins and trials evenly split between May and June sowings. The wide range of sowing dates reflected the variable seasonal weather conditions and lack of opening rain. This, together with stock grazing and waterlogging, resulted in the abandonment of trials at Poochera, Nangari, Wolesley and Conmurra. In addition, severe spring frosts affected relative varietal performance at Spalding, Wanbi, Wunkar, Pinnaroo and Geranium. The results from these sites were considered invalid for ‘head to head’ variety comparisons but are available in a special abandoned trials report obtained at: https://www.nvtonline.com.au/. Several newly introduced early sown wheat varieties were sown commencing 21 and 22 April at Pinnaroo and Kimba, respectively, but again the Pinnaroo trial was severely frosted. All other trials returned statistically acceptable results and regional mean data is shown in Table 1. The dry conditions commencing in August and proactive disease control saw no impact from stripe rust or any other disease in trials. It must be reminded that wheat NVT trial sites are managed for disease control, using up-front (Impact®) and in-crop fungicides where diseases are detected and have the potential to cause significant yield losses.

A total of 34 wheat varieties and 34 breeding lines were evaluated in the SA main season NVT series. Overall, the 2017 seasonal conditions tended to favour mid flowering and maturing varieties, although sowing dates outside the ‘usual’ window, were seen to influence varietal rankings across sites. While most early and late flowering varieties yielded relatively better or poorer, respectively, with June sowing dates surprisingly, Scepter was found to perform relatively better with later sowing compared to early sowing and no difference was observed with the later flowering Cutlass.

Across all main-season sown NVT trial sites in SA, the newly released mid-season flowering AH quality variety, Scepter, produced the highest average yield of 3.0t/ha, 3% above the new Longreach variety, LRPB Havoc (2.92t/ha) and 5% above the popular commercial variety, Mace (2.86t/ha) and Beckom. Corack and Longreach Trojan closely trailed these varieties. Table 1 lists the average yield of these and other varieties within trials in each SA region and shows that Scepter was dominant in most regions (noting only one valid trial in the Mallee and South East districts). Derived from the popular commercial variety Mace and released in 2015, Scepter significantly outyielded Mace in seven out of 17 NVTs and continues to assert itself as a widely adapted alternative to Mace having improved levels of stripe rust resistance, albeit with significantly lower powdery mildew resistance.

The second ranked variety, LRPB Havoc, was released to WA grain growers in 2017 and is also derived from Mace. While its average yield was 2% above Mace, within individual sites it only significantly outyielded Mace in two of the 17 NVT comparisons and performed best within Mid North trials. This is the second year of NVT evaluation of this new variety, where it has shown wide adaptation with improved resistance to stripe rust over Mace and Scepter, however it is susceptible and hence below industry standards for stem and leaf rust resistance in eastern Australia.

The most widely grown commercial variety, Mace, generally ranked third and continues to perform well in most regions but is losing some favour in districts prone to eyespot and septoria triticiblotch. The new AGT mid-season variety Beckom ranked equal with Mace, with best performance in lower Eyre Peninsula sites. Derived from Annuello and Young, which historically have had good adaptation to Victorian Mallee and Wimmera environments, Beckom could see some adoption in the more favourable South East region of SA where its smaller grain size would be of less concern.

Longreach Trojan was not expected to perform well in 2017 given its mid to late maturity but yielded well, particularly within the low yielding sites across Upper Eyre Peninsula and the high yielding sites across Yorke Peninsula. It was again generally the best among the group of varieties with similar maturity such as Cutlass, Estoc and Yitpi.

The new imidazolinone (IMI) tolerant APW variety derived from Wyalkatchem, Chief CL Plus, continues to lead other IMI tolerant alternatives and was about 5% higher yielding than both Grenade CL Plus and Kord CL Plus in 2017 NVT. Chief CL Plus has moderate susceptibility to stripe rust but good levels of resistance to most other foliar diseases, potentially making it a good option for many situations where IMI tolerance is sought.

The relative grain yield of selected commercial varieties in 2017 NVT is summarised in Table 1. The grain yield for each variety is expressed as a percentage of the regional individual trial mean yields. While these mean values are a guide to the general performance of varieties across the state in 2017, results in individual sites and seasons do vary. This detail can be better explored via the long term results reports found at National Variety Trial Results. Note that long term results found on the NVT website are derived from a Multi-Environment Trial (MET) analysis which incorporates all southern trial data for the past five years, and therefore, gives the best indication of relative varietal performance.

Durum wheat

Across the five central region durum NVT sites (Spalding frosted), average site yields were 3.66t/ha. The now widely grown commercial variety, DBA Aurora produced the highest average yields of 3.85t/ha across all Mid North and Yorke Peninsula trials , but was jostled for top position by Saintly and DBA Vittaroi within Mid North trials.

DBA Vittaroi was developed for the irrigated durum producing areas of NSW and QLD and is yet to be widely tested or classified for southern Australia. DBA Aurora continues to be adopted by growers seeking a new variety with high yields and improved grain quality relative to older varieties.

Table 1. Mean grain yield (%) from 2017 SA NVT. Yield expressed as a function (%) of region trials. Mean yield is shown for each region. The two highest ranked varieties in each region are highlighted with bold (varieties omitted from means were not tested at all locations, varieties listed in alphabetic order within classification grade, number of trials in italics).

AH = Australian Hard, ANW = Australian Standard Noodle Wheat, APW = Australian Premium White, SFT = soft, DR = durum.

Contact details

Rob Wheeler
robwheeler@grdc.com.au