International varieties hold hypocotyl answer

Speaking at the Grains Research and Development Corporation Updates forum at Wagga Wagga, CSIRO researcher Matthew Nelson, Perth, said the project was the first of its kind anywhere in the world.

Dr Nelson said one of the biggest challenges with canola was unreliable establishment, which often led to increased weed pressure, reduced yield potential, and in some cases resowing.

"How bad it is varies a lot, but the numbers that come up frequently are about 50 per cent to 60pc," he said.

"It's estimated about 100 to 200 million dollars a year in lost opportunity or direct cost."

Dr Nelson led a CSIRO and GRDC project from 2019 to 2023 focused on identifying the critical targets for genetic improvement of canola.

"At the start of the project ... we went out and did a survey asking growers what they thought was causing poor establishment," he said.

"The top answers were marginal soil moisture, sowing too deep or too shallow, so the difficulty in getting it right.

"One of the conclusions we made was one of the things we can to do improve establishment is to have longer hypocotyls (the stems of emerging seedlings).

"That gives us the ability to sow deeper in the soil, that moisture is going further down in the profile as a general trend so we get the seed into a more favourable environment.

"We normally sow at about one and half to two centimetres, so quite shallow."

Dr Nelson said the first part of the research was to find the length hypocotyls could grow to, with 255 varieties collected from various growing areas of the world.

The maternal environment was controlled to ensure the seed lots were comparable.

"We were looking at the genetic potential of the seedlings to grow a hypocotyl without the influence of soil resistance," he said.

Dr Nelson said the lab experiment revealed the Australian varieties grew much shorter hypocotyls than the internationals.

Field tests were then conducted at eight sites in Western Australia and NSW to test establishment.

A total of 20 varieties were selected, plus five current varieties, and sown at depths of 20 millimetres and 50mm with emergence counted.

Dr Nelson said the Australian varieties only had about half coming up from the deeper sowing, while the international varieties with long hypocotyls came out at much higher rates

"We've taken a lot of encouragement from this that long hypocotyls is a good trait to get better emergence, which is an important factor in establishment," he said.

Now moving into a new project Dr Nelson and his team wee focused on breeding the genes from the international varieties into Australian varieties.

The idea was to create options for breeders with longer hypocotyls and improve establishment.

"We're looking at 10 to 12 years before we expect to see a variety," he said.