Wheat - Phalaris spp. competition/interference studies using an additive design series

摘要

A glasshouse experiment was conducted using an additive design to determine the approximate onset of competition between Phalaris spp. and wheat, the density of Phalaris plants necessary to reduce wheat yield significantly and to investigate the comparative aggressiveness of Phalaris minor and Phalaris paradoxa relative to spring wheat. Seed of Phalaris spp.were sown in tanks at densities between 0 and 400 /m~2 whereas the density of wheat cv. Axona was maintained constant (350/m~2). Wheat height wassignificantly reduced in the presence of P. minor 28 days after sowing, whereas such a reduction occurred one week earlier in competition with P. paradoxa. Wheat fresh weight was significantly reduced by P. minor at a seed density of 400/m2 whereas a similar reduction occurred at 100 plants /m~2 in competition with P. paradoxa. Overall it was found that the number of leaves, dry weight, penetration of photosynthetically active radiation below the crop and weed canopy and dry weight of wheat ears decreased with the increasing weed density.