Triticum aestivum and Lolium multiflorum interaction during drought

A greenhouse experiment compared the vegetative growth in pure cultures and mixtures of winter Triticum aestivum cultivar 'Mit' and Lolium multiflorum cultivar 'Marshall' in continuously watered controls and drought treatment s. Central L. multiflorum in pure culture 14 wk after planting produced mor e leaf area, tillers, and dry weights of stem and root than control T. aest ivum in pure culture. The greater seed size, Larger initial leaf area, and height allowed T. aestivum to 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 mi xtures compared to controls. The ability of I: aestivum to maintain a great er leaf expansion rate during drought and a greater leaf area afterward tha n L, multiflorum allowed T. aestivum to attain greater growth than L, multi florum in pure cultures exposed to temporary drought followed by watering. Conversely, drought and its relief enhanced the relative competitiveness of L. multiflorum compared to controls in mixtures with I: aestivum. During 4 wk of watering following the drought, L. multiflorum in mixtures grew vigo rously and was similar to T. aestivum in all measures except in height and dry stem weight. Thus, L. multiflorum was similar in root growth with I aes tivum in control and drought mixtures and had its aboveground competitivene ss amplified by the cycle of drought and watering in this study There was n o evidence of an allelopathic interaction between the two species.