Interference between Avena sterilis, Phalaris minor and five barley cultivars.

Field experiments were carried out in Northern Greece from 1994 to 1997 to study interference between Avena sterilis L. or Phalaris minor Retz. and five autumn-sown barley cultivars. Weed:crop interference began in early April. Avena sterilis at 120 plants m−2 showed greater interference against barley than P. minor at 400 plants m−2. The greatest grain yield and ear number reduction due to interference by either weed was recorded for cvs Klipper and Plaisant, and the least for cv. Athinaida; with cvs Carina and Thermi intermediate. Yield reduction due to A. sterilis for cvs Athinaida, Carina, Thermi, Klipper and Plaisant was 8, 16, 27, 61 and 67%, respectively, while corresponding losses to P. minor were 1, 8, 14, 45 and 55%. These results clearly indicate that growth and consequently yield components of cv. Athinaida were unaffected by the presence of either weed species, while those of cv. Carina were affected by A. sterilis, but not by P. minor. However, dry weight and panicle number of both weed species were severely reduced by interference with cvs Carina, Athinaida and Thermi compared with cvs Klipper and Plaisant. The order of interference of the five barley cultivars tested against A. sterilis and P. minor was Athinaida > Carina > Thermi > Klipper ≥ Plaisant.