Grain size distribution: computation, interpretation and utilisation for minimising small grain screenings in cereals

Document Type

Conference Proceeding

Publication Date


Conference Title

Australian Society of Agronomy 16th Annual Conference 2012: Capturing Opportunities and Overcoming Obstacles in Australian Agronomy

Place of Publication

Armidale, NSW


Screenings; wheat; grain size; cereals; grain size distribution; rainfed agriculture; seasonal conditions


Agricultural Science | Agronomy and Crop Sciences


Small grain screenings, grain narrower than 2 mm, is a major constraint to profits from rainfed wheat and barley crops grown in Australia and overseas. Drying and warming climate as predicted for most parts of WA wheatbelt is likely to further increase this risk. Screenings for a variety can be higher for any one of three reasons; inadequate average grain weight, faulty grain shape and grain position effects due to asynchronous kernel growth. Kernel weight, the traditionally used parameter for classifying cultivars has often failed and we have previously proposed the use of the Grain Size Distribution (GSD) for overcoming this limitation. We now have developed functions in the R Statistical System ready for placing in public domain that cereal breeders and agronomists can use. The new set of scripts is usable irrespective of whether the distribution data was collected using a physically grading machine such as Sortimat or an electronically measuring machine such as Single Kernel Characterisation Systems (SKCS). In this paper, we will demonstrate i) how these functions can be used to calculate the parameters of the GSD; ii) how the GSD can be used to separately capture the defects of size, shape and position of kernels; iii) the strategies that breeders can use from the resulting information for screening breeding material; and iv) strategies on how agronomists and farmers can use the GSD parameters for matching inputs and crop management levels of new varieties in order to minimise the risk of small grain screenings.