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Abstract

Spring wheat is less competitive against weeds than rye, oat or barley. This is mainly probably an effect of less vigorous growth early in spring, but it is not possible to role out that allelopathy also may be involved. It is a well known fact that straw residues of both rye and barley have inhibitory effects on weeds in the following crop and there are also several studies showing that root exudates may be involved. In a screening of more than 800 different genotypes from a world collection of spring wheat, Swedish cultivars both, old and new, showed low allelopathic activity against rye grass (Lollium perenne L.) if compared with e.g. barley or even most of the foreign wheat cultivars. Two foreign cultivars were also identified to be as allelopathic as the most allelopathic Swedish barleys and are now used in a breeding program. Since the cultivars are not adapted to Swedish conditions several steps with crossings and back-crossings followed by repeatedly allelopathy selections are thus needed to get a useful breeding material. From a breeding point of view it is important, at an early stage, to evaluate how important allelopathy is for the weed competitive ability. Therefore four breeding lines (not completely stable and only back-crossed once) were in 2007 studied in an organic yield trial together with the Swedish parent and other advanced normal breeding lines. As in most studies including weeds standard errors were rather high, but still genotypic differences in weed biomass could be observed. Interestingly, the only single trait found that correlated with the differences in biomass was the allelopathic activity measured as the root growth inhibition of rye-grass. Neither early biomass growth nor early plant height or straw length was correlated with weed biomass. There was also a correlation between the allelopathic activity of the four breeding lines plus the Swedish parent and the weed biomass. However, it is too early to draw any conclusions from this single field study with a very limited number of lines. Hopefully new studies during 2008 including more lines with variable allelopathic activity will through more light on the question how effective a breeding for higher allelopathic activity really is. The Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (Formas) is acknowledged for funding this research

Keywords

Allelopathy; wheat; weed competition

Published in

Publisher: The joint WG4-EWRS meeting

SLU Authors

UKÄ Subject classification

Agricultural Science

Permanent link to this page (URI)

https://res.slu.se/id/publ/20239