A greenhouse experiment compared the vegetative growth in pure cultures and mixtures of winter
Triticum aestivumcultivar Mit and Lolium multiflorumcultivar Marshall in continuously watered controls and drought treatments. Control L. multiflorumin pure culture 14 wk after planting produced more leaf area, tillers, and dry weights of stem and root than control T. aestivumin pure culture. The greater seed size, larger initial leaf area, and height allowed T. aestivumto produce greater final leaf area and dry stem weight in control mixtures than L. multiflorum.Watering following drought shifted the relative performance of the two species in pure cultures and mixtures compared to controls. The ability of T. aestivumto maintain a greater leaf expansion rate during drought and a greater leaf area afterward than L, multiflorumallowed T. aestivumto attain greater growth than L. multiflorumin pure cultures exposed to temporary drought followed by watering. Conversely, drought and its relief enhanced the relative competitiveness of L. multiflorumcompared to controls in mixtures with T. aestivum.During 4 wk of watering following the drought, L. multiflorumin mixtures grew vigorously and was similar to T. aestivumin all measures except in height and dry stem weight. Thus, L. multiflorumwas similar in root growth with T. aestivumin control and drought mixtures and had its aboveground competitiveness amplified by the cycle of drought and watering in this study. There was no evidence of an allelopathic interaction between the two species.