Flowering and grain fill

Date posted: 04 December 2013

It is an exciting time for our barley crop... We’re now at growth stage 60-69: flowering. 

Stem elongation is basically finished, so the plants are just about fully grown, and the head has fully emerged from inside the stem. Flowering can take only a few hours per plant and tends to happen on a sunny day in the morning. 

Makin’ grain! 

Pollen (which is the male reproductive part of the plant) has been developing inside the head of the barley plant over the past few months. If you dissect the flower you will be able to see the yellow anthers which produce the pollen (male) and the fluffy stigma and ovules (which are the female parts of the plant). Have a look at our photo album for an up close look!

During flowering, the powdery pollen is released is caught by the stigma of an awaiting barley flower.  

Sometimes, barley can ‘self pollinate’, meaning the anthers remain within the closed barley flower allowing the pollen to simply connect with the stigma of the same flower.  

Other times, barley can be open pollinated. In this case, the anthers are pushed outside the flower allowing the pollen to become windborne. The pollen can travel a few metres where it can land on an awaiting stigma of a neighbouring plant and cross pollination then occurs.  

In either case, once the pollen and stigma connect the fertilisation process beings and the fertilised cells beginning their journey to becoming a grain. The cells rapidly divide and fill, leading us to the next growth phase... 73 to 89: grain filling. 

Did you know?

  • Barley pollen can survive up to 26 hours once released for fertilisation...
  • Pollen grains are tiny and are 35-45 micros in size, whereas a pin head is around 1000! 
  • Fertilisation occurs within about 5 minutes of the pollen touching the stigma.
  • Barley tends not to be insect pollinated, it is predominantly wind pollinated or self pollinated. 
Reference: The Biology of Hordeum vulgare L. (barley) (2008). Produced by the Office of the Gene Technology Regulator.