Seed size makes ma­jor dif­fer­ence to her­bi­cide re­sis­tance

Central and North Burnett Times - - RURAL WEEKLY -

CROP com­pe­ti­tion is an im­por­tant strat­egy in the Weeds­mart 10 Point Plan to man­age her­bi­cide re­sis­tance – but it’s not all about row width and seed­ing rate – the size of the seed sown makes a dif­fer­ence too.

Ro­han Brill, Re­search and De­vel­op­ment agron­o­mist, NSW DPI, based in Wagga Wagga, along with col­leagues at Trangie and Tam­worth, has been teas­ing apart whether the im­proved early per­for­mance of canola hy­brids over open-pol­li­nated (OP) cul­ti­vars comes 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, is key to strong early crop growth and the crop’s abil­ity to com­pete with weeds.”

As a re­li­able rule of thumb, Mr Brill rec­om­mends clean­ing and grad­ing all farmer-re­tained OP canola seed to col­lect plant­ing seed that is 2mm in di­am­e­ter or larger.

In both glasshouse and field ex­per­i­ments fol­low­ing this rule led to im­proved open-pol­li­nated TT canola emer­gence and early biomass pro­duc­tion.

Seed size had a greater ef­fect on early biomass pro­duc­tion than did cul­ti­var type (hy­brid vs OP).

“A 10 per cent dif­fer­ence in seed di­am­e­ter pro­duces a 33 per cent dif­fer­ence in seed vol­ume, so it is very im­por­tant not to skimp on the 2 mm di­am­e­ter rule,” he says.

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

Newspapers in English

Newspapers from Australia

© PressReader. All rights reserved.