AcknowledgementsThis study was performed with financial support of European Social Fund co-financed project 2009/0218/1DP/1.1.1.2.0/09/APIA/VIAA/099.

Cereal breeding for organic farming:aspect of competitiveness against weedsDace Piliksere1, Vija Strazdina2, Zaiga Vicupe2, Zaiga Jansone2 1State Priekuli Plant Breeding Institute, Latviadacepil@gmail.com2State Stende Cereals Breeding Institute, Latvia

IntroductionAssessing weed suppression ability of crops became more important with the development of organic plant breeding.This report introduces with first results on the project Development, improvement and implementation of environmentally friendly and sustainable crop breeding technologiesThe aim is to develop the methodology for an estimation of cereal varieties and breeding lines for their competitive capacity against weeds, to establish more effective criteria of the selection by significant crop characteristics in the breeding process.Material and MethodsThe investigation is carried out at State Priekuli Plant Breeding Institute and at State Stende Cereals Breeding Institute in Latvia. In organic growing conditions With different varieties and breeding lines of such cereal species as:Barley (fig. 1)oatwinter triticalewinter wheat

Different crop, as well as some weed flora characteristics are taken into account, to evaluate cereal varieties for their competitiveness:field germinationcrop growth habit at tillering and at stem elongationcrop tillering capacitycanopy height at the beginning and at the end of stem elongation and crop plant height before the harvestingbeginning of such crop phenological phases as tillering, stem elongation, heading and fully ripening, (in days from sowing)crop and weed ground cover several times from tillering to maturityweed dry weights at cereal flowering or maturitycrop yields. Harrowing was not used in the trials, to exclude the impact of this factor.Linear correlation method was used for statistical data analysis.

ResultsCereals suppress weed growth, as it is evident from field trials (fig. 2). However, diverse cereal genotypes could have different competitiveness against weeds, that depends on crop growth and above-ground characteristics. Therefore we look for the most relevant crop traits that influence weed growth and can be of value in organic crop breeding. Results from first investigation year are shown below (fig. 3).

Figure 2. Pure-weed plot versus barley-weed plot at stem elongation.Figure 1. Diverse genotypes of barley differ in their characteristics (stem elongation)Figure 3. Significant correlations between weed observations and different crop traits. Photo by L. LegzdinaPhoto by L. LegzdinaFirst ConclusionsThe first years results of investigation show that some crop traits are signifficantly correlated with weed growth. However, these results should be reviewed for correctness in next at least two years more of experiments.

Detection of the most important crop characteristics, which provide the competitiveness against weeds for cereal breeding aims in organic growing conditions, is stressed as a desired result.

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