Results Introduction Materials and methods Discussion

VARIATION IN GRAIN SIZE IN SOME AUSTRALIAN WHEATS Yuanfeng

1 Yang ,

Miranda

1 Mortlock ,

Lee

2 Hickey ,

Glen

2 Fox

1School

of Agricultural & Food Sciences, The University of Queensland, St Lucia, Qld, 4067 2Queensland Alliance for Agriculture & Food Innovation, The University of Queensland, St Lucia, Qld, 4067

Introduction

Results

• The Australian wheat industry uses screenings as a receival standard to assess the grain size of delivered wheat.

Q: What do screenings tell us about grain size distribution of wheat? A: Not much, but there is G and E influencing the production of large grain.

• There are many factors that influence the proportion of screenings: environment (E), management (M) and wheat genotype (G). Grain size is a heritable trait1.

 Agtator: all varieties across the four sites had screenings less than 5.0% indicating all sites had low screenings. Low screenings suggests high retention of > 95.0%. However, no information is available on the distribution of the grain > 95.0%.

• The standard process of testing screenings uses a single sieve with 2.00 mm slots and rocking motion for a set period. The results provided are percentage of grain less than 2.00 mm (screenings) – also providing the percentage of grain greater than 2.00 mm. • Major issue: the size distribution of the grain greater than 2.00 mm is unknown.

 Sortimat: provided data for screenings plus grain size distribution > 2.0 mm. Figure 3 clearly shows the distribution of grain > 2.00 mm for all ten varieties at each site. All sites had a percentage of grain larger than 2.5 mm than the 2.2 mm fraction.

• In this study we investigate the grain size characteristics for a selection of Australian wheat varieties grown at four locations in the 2012 National Variety Trials (NVTs).

Materials and methods

 Seedcount: provided size and shape data, including distributions, however, there was a poor correlation between Sortimat screenings and fraction results or Agtator screenings.

 Grain was sampled from ten wheat varieties (listed below) by three plot replicates, grown at Biloela, Bungunya, Kilcummin and Kingsthorpe in Queensland NVTs in 2012 (Figure 1).

 Protein content increased as grain size increased. For example, the variation in protein content between Sortimat fractions for Suntop is displayed in Figure 4.

 The 120 samples were assessed for grain size distribution using a Sortimat (Figure 2b), which separated the grain into four fractions: < 2.00 mm (screenings; S1), 2.00 – 2.20 mm (S2), 2.20 – 2.50 mm (S3) and > 2.50 mm (S4). The Sortimat uses a sideways rocking motion for 1 min to seive the grains.

100

Proportion of whole grain sample (%)

 In addition, each fraction was scanned in a Foss 6500 near infrared (NIR) spectrometer to predict protein content using the Qld DAFF in-house calibration.  The Agtator (Figure 2a) data for the ten varieties was obtained through Qld DAFF.

Kingsthorpe Bungunya

Figure 1. Location of selected NVT sites

Kilcummin

Kingsthorpe

60 40 20 0 100 80 60 40 20 0 S1

S2

S3

S4

S1

S2

S3

S4

Grain size fraction

Figure 3. Sortimat distribution for all varieties at four sites. 16

Protein content (%)

Biloela

Varieties tested • Baxter • Crusader • Dart • EGA Gregory • Kennedy • Lang • Spitfire • Suntop • Sunguard • Wallup

Bungunya

80

 Each fraction along with the original samples were imaged using the Seedcount (Figure 2c). The Seedcount uses a pixel based algorithm to calculate grain size and shape. The grain size is reported as: < 1.6 mm, 1.60 – 2.00 mm, 2.00 – 2.20 mm, 2.20 – 2.50 mm, 2.50 – 2.80 mm and > 2.80 mm.

Kilcummin

Biloela

Biloela

Bungunya

Kilcummin

Kingsthorpe

14 12 10 8 S1

S2

S3

S4

S1

S2

S3

S4

S1

S2

S3

S4

S1

S2

S3

S4

Grain size fraction

Figure 4. Protein content within each Sortimat fraction for Suntop at four sites.

Discussion • Having low screenings (