Boron deficiency is rare in cereals in Western Australia (WA) and will impact broadleaf crops such as lupin and canola before affecting cereals like wheat and barley. Boron does not easily move around the plant therefore a deficiency is most likely to be seen in the younger tissues first.
Links
[1] http://soilquality.org.au/factsheets/boron
[2] https://www.agric.wa.gov.au/crops/production-postharvest/plant-nutrition