Acta Agrobotanica (Sep 2017)
Weed suppression and yield of thirteen spring wheat (Triticum aestivum L.) varieties grown in an organic system
Abstract
The aim of this study was to determine the relationships between morphological features, canopy parameters, weed infestation, and grain yield of spring wheat varieties. The study was conducted in the period 2011–2013, on fields managed organically at the Experimental Station of The Institute of Soil Science and Plant Cultivation – State Research Institute, Osiny, Poland. Thirteen spring wheat varieties were sown in a randomized complete block design with four replications. Weed density and dry matter production were estimated as well biometric features of the wheat varieties at tillering (BBCH 22–24) and dough (BBCH 85–87) stages. The analyses of variance showed that the year had a stronger effect than varieties on the level of weed infestation. Pearson’s correlation analysis indicated that weed number was influenced by the height of wheat plants and their aboveground biomass at the tillering stage and additionally by number of tillers at the dough stage. A significant correlation (r = −0.328, siginfficant at p < 0.05) was shown between the number of weeds and wheat grain yield. Different morphological features and canopy parameters influenced the competitive abilities of the spring wheat varieties tested. A cluster analysis detected one set of varieties with the largest (‘Bombona’, ‘Brawura’, ‘Hewilla’, ‘Kandela’, ‘Katoda’, ‘Łagwa’, and ‘Żura’) and another with the smallest (‘Monsun’, ‘Ostka Smolicka’, and ‘Parabola’) competitive abilities against weeds. The main outcome of the research is information for farmers as to which varieties are highly competitive against weeds and also high yielding. Among the varieties with the highest competitiveness, Triticum aestivum ‘Żura’ was the highest yielder (3.82 t ha−1 on average), whereas ‘Bombona’ yielded only at an average level (3.03 t ha−1). The suppressive ability of spring wheat varieties against weeds and yield potential should be both taken into account in the selection of varieties suitable for an organic farming system where weed control is absent.
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