Seed size matters

National herbicide-sustainability organisation Weedsmart has alerted growers that the size of sown seed can be important in managing herbicide resistance.

It has listed crop competition as an important strategy in its 10-point plan, adding it was not all about row width and seeding rate.

Wagga Wagga-based NSW DPI research and development agronomist Rohan Brill, along with colleagues at Trangie and Tamworth, has been teasing apart whether the improved early performance of canola hybrids over open-pollinated cultivars came from the generally-larger seed size of hybrids or from hybrid vigour.

“It seems that most of the improved early growth in hybrids lies in the larger seed size, with heterosis providing an additional benefit,” he said.

“Our study showed that sowing large canola seed, regardless of the cultivar, was key to strong early crop growth and the crop’s ability to compete with weeds.

“A 10 percent difference in seed diameter produces a 33 percent difference in seed volume.”

For more information about managing herbicide resistance visit the Weedsmart website, www. weedsmart.org.au.