Grains Research and Development

Date: 01.03.2016

Variety the spice of early crop life

Author: Nicole Baxter

National trials show early sowing with an appropriate variety is a profit-booster in most areas, particularly in years providing early establishment opportunities

Image of James Hunt

Dr James Hunt, former CSIRO Agriculture senior research scientist, says early sowing works best when there is a full profile of moisture. Dr Hunt, who recently became a senior lecturer at La Trobe University, says there are new varieties under development that may assist in widening the sowing window for growers in areas with a shorter growing season.

PHOTO: Nicole Baxter

National trials show improved yield and profit can be expected in most areas when appropriate wheat varieties are sown early to take advantage of March and April rainfall.

Former CSIRO Agriculture senior research scientist Dr James Hunt, who now works as a senior lecturer at La Trobe University, says sowing earlier than 25 April is a tactic that complements dry sowing.

“For the past 20 years, wheat breeding has focused on developing mid-to-fast-maturing varieties, which are only suited to sowing from late April to May,” he says.

“Sowing earlier requires slow-developing varieties with a strong vernalisation or cold requirement, usually found in winter wheats, or varieties with a strong photoperiod or day length requirement, which is characteristic of slow-developing spring wheats.”

Previously, Dr Hunt’s New South Wales research demonstrated slow-developing varieties sown early could yield more than mid-to-fast varieties sown later when they flower at the same time. This is because early sowing increases plant rooting depth and water use, reduces evaporation and increases transpiration efficiency.

As such, Dr Hunt says early sowing of slow-developing varieties opens the door for improved yield potential and profit with little extra investment.

By way of example, he says if a grower in NSW who usually grew Condo – the highest-yielding Australian Hard wheat in southern NSW – had planted a portion of fallow country to the winter wheat EGA Wedgetail on the back of early rains at Easter in 2015 (3 to 6 April), the benefit of the decision would have been an additional $330 per hectare.

To test the benefits of early sowing, Dr Hunt has worked with a team of collaborators from across Australia to set up trials at a range of locations.

Western Australia

At Brookton, Western Australia, there was plenty of seedbed moisture at all sowing dates and the seed germinated shortly after sowing.

Research collaborators from the consultancy Living Farm deliberately located the trial in a frost hollow and frost-induced sterility and grain damage were measured in the early flowering treatment.

Dr Hunt says the frosted treatments (italics in Table 1) were assessed on 8 September, but he suspects other treatments, such as Mace sown 23 May, were also damaged later in spring.

Of the varieties tested, EGA Eaglehawk and Whistler sown 15 April and Magenta sown 29 April yielded the highest.

At Cunderdin, WA, 20 millimetres of rain was recorded between 7 and 12 April, with no further rain until 17 May. As a consequence, Dr Hunt says the first plants sown experienced severe early drought stress (Table 2).

He says a new Australian Grain Technologies-developed ‘fast’ winter wheat, known as RAC2341 and derived from Mace, was the only variety at this site sown on 14 April that came close to the yields of Magenta sown 28 April and Mace sown 22 May.

At Doodlakine, WA, there was sufficient seedbed moisture at the first sowing but the second sowing needed to be irrigated with 8mm for germination.

Although there appeared to be sufficient seedbed moisture at the third sowing, Dr Hunt says emergence was staggered and the trial was water stressed until early July.

Frost was not a major issue and, as a consequence, Magenta and LongReach Lancer sown 28 April produced the highest yields. Mace and Magenta also performed well across all times of sowing (Table 3).

At Kojonup, WA, seedbed moisture was sufficient for all treatments and the germination was even. Similar to the Cunderdin site, birds damaged fast-developing varieties at the first sowing (Table 4).

Dr Hunt says the varied gravel layers at the trial site had an impact, with the highest yields coming from EGA Eaglehawk sown 16 April and Magenta sown 4 May, although many treatments (such as Mace sown 22 May) were not significantly different.

Table 1 Brookton, WA, results, 2015.
 Variety  Grain yield (t/ha) and time of sowing
15 April
29 April
23 May
EGA Wedgetail
3.1 2.5 2.4
EGA Eaglehawk
3.5 2.7 2.2
Whistler 3.3 3.1 2.6
LongReach Lancer
1.5 2.8 2.4
Magenta 2.3 3.4 3.1
Mace 1.9 2.1

2.7

Note: P-value = <0.001, LSD (P=0.05) = 0.3

Table 2 Cunderdin, WA, results, 2015.
 Variety  Grain yield (t/ha) and time of sowing
 15 April
 29 April
22 May
 EGA Wedgetail
 2.2 1.7 1.2
 EGA Eaglehawk
 2.2 2.0 1.5
 Whistler  2.5 2.3 1.6
 RAC2341  3.1 2.6 2.1
 LongReach Lancer
Birds 3.3 2.7
 Magenta Birds 3.3 2.8
 Mace Birds 3.2 3.3

Note: P-value - <0.001, LSD (P=0.05) = 0.3

Table 3 Doodlakine, WA, results, 2015
 Variety  Grain yield (t/ha) and time of sowing
15 April
28 April
22 May
EGA Eaglehawk
1.9 2.0
1.1
EGA Wedgetail
2.0 2.1 1.0
Whistler 2.4 2.5 1.5
LongReach Lancer
2.3 2.7 1.9
Magenta 2.6 2.9 2.2
Mace 2.6 2.4 2.4

Note: P-value = <0.001, LSD (P=0.05) = 0.2

Table 4 Kojonup, WA, results, 2015.
 Variety  Grain yield (t/ha) and time of sowing
     
  16 April
4 May
22 May
EGA Wedgetail
4.4 4.2 3.9
EGA Eaglehawk
5.1 4.8 4.3
Whistler 4.7 4.7 4.2
LongReach Lancer
Birds 4.8 4.1
Magenta
Birds 5.1 4.6
Mace Birds 4.0 4.8

Note: P-value - <0.001 = 0.6, LSD (P=0.05) = 0.6

South Australia

In South Australia, South Australian Research and Development Institute researchers established early sowing trials at Cummins, Minnipa, Port Germein and Conmurra. The Hart Field Site Group set up another early sowing trial funded by its members. Each trial had three times of sowing: mid-April, late April and mid-May. Tested were six commercail wheat lines planted into a moist seedbed, which produced an excellent germination.

The results show LongReach Trojan sown in mid or late-April was the highest or equal highest yielding variety (Table 5). Dr Hunt says LongReach Trojan sown in its optimal window (late April) out-yielded Mace sown in its optimal window (mid-May) at three of the four sites where the two were grown (mean yield advantage 0.6t/ha).

“Slow-developing varieties bred in other states (EGA Wedgetail, EGA Eaglehawk and Rosella) showed poor adaptation to all sites,” he says. “When sown early these varieties flower too late in many SA environments.”

Dr Hunt says the winter wheat RAC2341 showed promise at Minnipa, where its yield was close to LongReach Trojan and Cutlass at all times of sowing, despite flowering later and carrying less frost risk.

“If released, this variety would give SA growers an option for taking advantage of any establishment opportunities arising from March through to late April when it becomes safe to sow currently adapted spring wheats,” he says.

“It would also provide the first-ever adapted dual-purpose cultivar for SA, which would increase productivity on mixed farms.”

At Conmurra, the highest yields came from LongReach Trojan and LongReach Cobra sown 15 May and Manning sown late April.

Dr Hunt says 2015 was the second consecutive year where there was no advantage in sowing earlier than mid-May, because of disease pressure from barley yellow dwarf virus (BYDV) and Zymoseptoria tritici.

“Growers in this environment wishing to sow early and graze should use Manning for its superior resistance to BYDV, Z. tritici and leaf rust, although fungicides will still be needed for Z. tritici and stripe rust.”

Table 5 South Australian results, 2015.
 Cummins
 Variety  Grain yield (t/ha) and
time of sowing
10 April
29 April
14 May
EGA Wedgetail
3.3 2.5 3.1
Rosella 2.8 2.6 2.8
EGA Eaglehawk
3.3 2.7 2.8
Cutlass 4.3 3.8 4.0
LongReach Trojan
4.7 4.1 3.9
Mace 4.0 4.1 4.0

Note: P-value = 0.012, lSD (p=0.005) = 0.5

Table 5 South Australian results, 2015 (continued).
 Minnipa  
 Variety Grain yield (t/ha) and
time of sowing
13 April
29 April
13 May
EGA Wedgetail
2.8 2.5 1.9
EGA Eaglehawk
2.9 2.3 1.8
RAC2341 3.4 3.6 2.7
Cutlass 3.5 3.6 2.9
LongReach Trojan
3.3 3.9 3.0
Mace 2.9 3.8 3.2

Note: P-value = 0.001, LSD (p=0.005) = 0.3

Table 5 South Australian results, 2015 (continued).
 Port Germein
 Variety Grain yield (t/ha) and
time of sowing
8 April
27 April
19 May
EGA Wedgetail
2.7 ;2.3 1.6
 Rosella 2.7 2.3 1.4
EGA Eaglehawk
2.9 2.6 1.4
Cutlass 4.1 3.8 2.3
LongReach Trojan
4.5 4.0 2.6
Mace 4.4 4.3 3.1

Note: P-value = 0.001, LSD (p=0.005) = 0.2

Table 5 South Australian results, 2015 (continued).
 Hart
 Variety Grain yield (t/ha) and
time of sowing
10 April
30 April
15 May
EGA Wedgetail
3.6 3.4 2.8
LongReach Trojan
3.7 4.0 3.3
Mace 2.9 3.4 3.5

Note: P-value = 0.001, LSD (p=0.005) = 0.3

Table 5 South Australian results, 2015 (continued).
Conmurra 
 Variety Grain yield (t/ha) and
time of sowing
13 April
28 April
15 May
Manning 4.6 5.1 4.4
SQP Revenue
4.3 4.4 4.4
Forrest 4.0 4.1 4.5
Bolac 3.4 4.1 4.7
LongReach Trojan
1.6 4.5 5.5
LongReach Cobra
2.1 4.2 5.4

Note: P-value = 0.001, LSD (p=0.005) = 0.5

Victoria

At the Birchip Cropping Group main site at Berriwillock, Victoria, the soil was completely dry and all plots were irrigated with 8mm of water. Emergence was assisted by 14mm of rain from 17 to 18 April. Treatments sown on 8 May were established into a moist seedbed and germinated shortly after sowing.

Temperature data showed multiple frost events at the site from the end of tillering onwards. Some varieties such as LongReach Scout sown 9 April suffered 10 to 15 per cent frost damage but still yielded similarly to other varieties (Table 6). Drought and heat were more damaging than frost at this site in 2015.

Dr Hunt says slow-developing spring wheats such as Bolac and LongReach Lancer sown 9 April flowered too early and too late when sown on 8 May.

He says experience suggests these varieties have a very narrow sowing window that extends from 15 to 25 April, reducing their flexibility and suitability for the Mallee, although yields in this trial did not reflect these concerns.

Varieties sown on 8 May had significantly higher protein levels because of yield concentration effects and most varieties had higher screenings, evidence of the hot and dry finish (Table 7).

Table 6 Berriwillock, Victoria, results, 2015.
Variety Grain yield (t/ha) and time of sowing
9 April
8 May
LongReach Scout
1.78 1.09
Kiora 1.68 0.98
RAC2341 1.57 0.99
Bolac 1.51 0.87
LongReach Lancer
1.44 0.99
EGA Wedgetail
1.40 0.70

 Notes: P-value <0.004 = 0.6, LSD (P=0.95) = 0.14

 

Table 7 Berriwillock, Victoria, results, 2015.
 Variety Time of sowing
Protein %*
 Screenings %#
9 April
8 May
9 April
8 May
Bolac 14.0 15.5 14.3 13.3
Kiora 13.8 15.6 7.4 6.5
LongReach Lancer
14.5 15.8 5.9 6.5
RAC2341 14.7 14.9 3.5 6.2
LongReach Scout
13.7 14.7 5.8 9.5
EGA Wedgetail
15.3 15.2 5.6 6.7

Notes: *P-value = <0.001, LSD (P=0.05) = 0.4
#P-value = <0.01, LSD (P=0.05) = 2.2

New South Wales

In New South Wales, Dr Hunt says the major lesson learned was that the yield advantage of early-sown winter wheat varieties is greatest when the soil profile is full of water.

At Rankins Springs, NSW (Table 8), AgGrow Agronomy and Central West Farming Systems established an early-sowing trial on an 18-month fallow. April to October rainfall was 285mm and as a consequence EGA Wedgetail produced the highest yields at 6.2t/ha.

By contrast, an early sowing trial at Temora, NSW, was planted into a much drier soil profile. Although 270mm of rain was recorded in April to October, EGA Wedgetail sown 20 April only just equalled the yields of Suntop sown 7 May (Table 9).

In another trial at Temora, established by PhD student Bonnie Flohr, the unreleased fast winter line RAC2341 out-yielded every other variety sown on 17 April (Table 10). However, at all other sowing dates Condo, the control variety, was the standout, even when flowering early at a time of high frost risk.

Table 8 Rankin Springs, NSW, results, 2015.
  Grain yield (t/ha) and time of sowing
15 April
14 May
EGA Wedgetail
6.2 4.9
Kiora 6.1 5.1
LPB11-0140 6.0 5.2
Wylah
6.0 5.0
Bolac 5.9 4.3
V07041-39 5.9 5.1
LongReach Lancer
5.8 4.9
EGA Gregory
5.3 4.0
Sunvale 5.3 4.8
EGA Eaglehawk
5.1 4.5
Condo 3.0 4.7

Notes: P-value = <0.001, LSD (p=0.05) = 0.5

Table 9 Temora, NSW, results, 2015.
  EGA Wedgetail sown 20 April
EGA Gregory sown 7 May
Suntop sown 7 May
Plant density (plants/m2) Defoliation at GS30 46kg/ha nitrogen broadcast at sowing  46kg/ha nitrogen top-dressed at GS30 46kg/ha nitrogen broadcast at sowing 46kg/ha nitrogen top-dressed at GS30 46kg/ha nitrogen broadcast at sowing   46kg/ha nitrogen top-dressed at GS30
 48
Defoliated
3.5
3.9
Not tested
Not tested
Not tested Not tested
 48 Undefoliated 3.6 3.8 Not tested
Not tested Not tested  Not tested
 74 Defoliated 4.0 3.7 Not tested
Not tested Not tested Not tested
 74 Undefoliated 4.0 3.7 3.8 3.8 4.2 3.8

 Notes: P-value = 0.041, LSD (P=0.05) = 0.3

Table 10 Temora, NSW, results, 2015.
 Variety Grain yield (t/ha) and time of sowing
17 April
27 April
7 May
15 May
EGA Wedgetail
4.3 4.1 3.7 3.2
RAC2341 5.5 4.9 4.4 4.3
 EGA Gregory
4.7 4.8 3.9 3.8
Condo 4.7 5.8 4.9 4.4

Note: P-value = <0.001, LSD (P=0.05) = 0.4
SOURCE: Bonnie Flohr, CSIRO and ANU, 2016

Queensland

At Emerald in Central Queensland researchers irrigated the entire early sowing trial site with 25mm of water to enable establishment.

After 72mm of April to October rain, the highest yields came from LongReach Lancer and EGA Gregory sown 20 April (Table 11).

Dr Hunt says the winter wheats did not vernalise and that growers in warm environments such as this need slow-developing spring wheats if they wish to sow early.

At Brookstead, in southern Queensland, there was plenty of moisture available at all times of sowing and seed germinated shortly after being sown.

The highest yields came from EGA Eaglehawk and EGA Gregory sown 10 May (Table 12). Dr Hunt says the yield response to sowing time was flat at both Queensland sites, which is not unusual in a summer-dominant rainfall environment.

Table 11 Emerald, Queensland, results, 2015.
Variety Grain yield (t/ha) and time of sowing
20 April
1 May
11 May
 EGA Eaglehawk
1.3 1.7 2.1
 EGA Wedgetail
0.3 0.3 0.2
Wylah 0.2 0.4 0.2
LongReach Lancer
3.1 3.0 2.2
 EGA Gregory
3.1 2.8 2.3
 Suntop 2.5 2.4 2.3

 Note: P-value = <0.001, LSD (P=0.05) = 0.3

Table 12 Grain yield (t/ha) at Brookstead, Queensland
 Variety  Grain yield (t/ha) and time of sowing
;10 May
25 May
10 June
EGA Eaglehawk
4.4 3.9 4.0
EGA Wedgetail
4.0 3.2 3.2
Wylah 3.9 3.4 3.4
LongReach Lancer
4.0 3.6 3.8
EGA Gregory
4.3 3.7 4.0
Suntop 3.9 3.5 3.7

Note: P-value = <0.001, LSD (P=0.05) = 0.2

Future varieties

The winter wheat RAC2341, which is still under evaluation, was tested at Cunderdin, WA, Minnipa, SA, Berriwillock, NSW, and Temora, NSW, where it showed a 35 per cent yield advantage over EGA Wedgetail averaged across all times of sowing.

When sown in mid-April, Dr Hunt says it had, on average, a 25 per cent yield advantage over EGA Wedgetail.

“Averaged across the four locations, RAC2341 produced a 17 per cent yield advantage over the locally adapted spring wheat control sown at optimal time and flowering, which is representative of current practice,” he says.

According to Dr Hunt, the ‘fast’ winter habit of RAC2341 may offer more flexibility than EGA Wedgetail, which is too slow in many medium-to-low-rainfall environments across Australia. Provided yield, disease and quality are acceptable, RAC2341 is scheduled for 2018 release.

Early sowing reminders

Former CSIRO Agriculture’s Dr James Hunt (now at La Trobe University, Victoria) suggests the following to maximise the yield potential of early-sown crops.

  • Avoid dry sowing slow-developing varieties such as EGA Wedgetail because they will flower too late if not established early. Ensure the seedbed is moist and there is some stored soil water for growth to winter.
  • If growing winter wheat (EGA Wedgetail) and not grazing, defer nitrogen inputs until after GS30.
  • Plant into clean paddocks because winter wheat is not competitive with ryegrass.
  • Early sowing exacerbates common root diseases, so pick clean paddocks following a break crop.
    • To protect against barley yellow dwarf virus apply imidacloprid to seed and follow up with in-crop insecticides at the start of tillering if aphid pressure is high.
    • In some areas, Zymoseptoria tritici may be an issue. Choose varieties with a good level of resistance such as Manning, and consider adding flutriafol to fertiliser and applying foliar fungicides at GS30 and GS39.
    • Many slow-developing cultivars have poor resistance to stripe rust. Add flutriafol to fertiliser and apply foliar fungicide at GS39.

More information:

Dr James Hunt,
03 9032 7425,
j.hunt@latrobe.edu.au,
@agronomieiste (Twitter)

Next:

Trials show cost of varieties mismatched with sowing time

Previous:

Risk rankings add new pieces to frost jigsaw

GRDC Project Code CSP00178, CSP00160

Region North, South, West