SPRING WHEAT (TRITICUM-AESTIVUM) GROWTH AND YIELD AS INFLUENCED BY DURATION OF WILD OAT (AVENA-FATUA) COMPETITION

The effect of duration of wild oat competition on spring wheat yield a nd growth was determined in time-of-removal experiments conducted over a three year study period in Saskatchewan, Canada. Failure to remove wild oat reduced wheat yield 28 and 39% at wild oat populations of 64 and 188 plants per m(2), respectively. Wheat yield was not reduced by wild oat densities of 64 or 118 plants per m(2) until the six- and sev en-leaf stage of wild oat, respectively. Removing wild oat at 64 plant s per m(2) before the seven-leaf stage and 118 plants per m(2) before the five-leaf stage did not increase wheat culm or fresh weight produc tion.