Following their discovery of two genes which control the size of plant seeds, CSIRO researchers are investigating how that knowledge can be used to produce larger seeds across a wide range of crops.

The two seed-size genes have been isolated in the model plant Arabidopsis and in initial tests, where the genes have been ‘turned down’, seed size has been reduced by up to 30 per cent.

The challenge now for the CSIRO team led by Dr Abed Chaudhury and Dr Ming Luo is to ‘turn up’ the activity of the genes to try and increase seed size.

'For farmers bigger seed means healthier crops, more productive farms and potentially higher returns,' Dr Chaudhury says.

'The genes we identified in Arabidopsis are likely to have equivalent counterparts in other plants, so what we learn from these genes and how they influence seed size may be applied to a whole suite of other plants.'

Food like bread, pasta, rice, cornflakes, peanut butter, canola oil, margarine, soymilk and even coffee and chocolate are all made from seeds.

There is huge variation in seed size in different plants, from orchids, with seed the size of a speck of dust, right through to coconuts – the world’s largest seeds.

Plant breeders have long recognised the importance of larger seed in the production of food crops and have been breeding for the trait.

'Manufacturers and industry often pay a premium for large seeds like chickpeas or lentils, because they are easier to handle and are often preferred by consumers,' Dr Chaudhury says.

'Farmers prefer larger seeds because for certain crops, especially wheat and canola, large seeds mean more food for the seedling, early germination and vigorous plants that are more likely to produce higher yields.'

The CSIRO team hope to understand how the seed-size genes work and what they do to affect seed size.

'We’re also interested in a third gene that looks like it might be responsible for controlling the two other genes,' he says.

“Understanding how these genes operate in plants could help us find ways to develop plants that consistently produce larger seeds.”

This work is published in the Proceedings of the National Academy of Science, November 29 2005, vol. 102 no. 48, 17531-17536