Effect of wheat (Triticum aestivum) cultivars and seeding rate on yield loss from Galium aparine (cleavers)

Galium aparine L. is a troublesome broadleaved weed in winter wheat fields and other winter-sown crops in Eurasia and North America. Field experiments were conducted in Havza and Kavak, Samsun-Turkey, to evaluate the effect of different densities of G. aparine on the productivity of four wheat cultivars and to determine the effects of different seeding rates of wheat cultivars on the competitive ability of G. aparine. In experiments over 3 years, the wheat cultivar Panda was taller at maturity than other cultivars at both sites. Although Bezostaja was naturally shorter than other cultivars, its height decreased less due to competition from G. aparine than other cultivars. Wheat grain yields increased with seeding rate, either in the presence or in the absence of G. aparine at both locations. Based on wheat yields the relative competitiveness of the wheat cultivars was Bezostaja>Momtchill=Panda>Kate A-l. G. aparine biomass and seed numbers were reduced by an increase in the wheat seeding rate and by cultivar effects.