Cereals 2010: First wheat variety choice affects take-all build up

Research suggests that growers could increase second wheat yields by 1.5-2t/ha by growing the correct first wheat variety.

Rothamsted Research investigations, as part of the Wheat Genetic Improvement Network (WGIN) have identified some varieties, when grown as a first wheat, build up more take-all inoculum than others. The amount of take-all inoculum in the soil has a strong correlation to the amount of take-all seen in the following crop.

That original research found differences between two old varieties, Avalon, which built up a lot of take-all around its roots, and Cadenza, which didn’t, Kim Hammond-Kosack of Rothamsted Research explained.

A follow-up experiment grew those two varieties, plus 62 different crosses from the two as first wheats in 2008, and then over-sowed the plots with Oakley last season.

The results showed big differences in the levels of take-all in the Oakley crop and its yields. For example, the 2008 Cadenza plots had just 5 and 10% take-all levels in last season’s Oakley plots and yielded 9.9 and 9.4t/ha respectively, while the 2008 Avalon plots had take-all scores of 50 and 70% and yielded 7.8 and 6.6t/ha.

It was likely that the differences were caused by differing amounts of take-all inoculum being built up in 2008, Prof Hammond-Kosack suggested.

A first year of trials investigating Recommended and National List varieties has identified a number of varieties, particularly those with Cadenza in the parentage, that might be used commercially by growers as a first wheat to minimise take-all in following crops, she added. “But we need another year of trials to confirm these findings.”

Potential genes responsible for the build up of take-all had been identified, she said. “We now have markers for these genes, which mean breeders can remove material from breeding programmes that build up take-all. Ultimately we should be able to fix to only be the low take-all build up varieties.”

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