The fate of morphologically different populations of Arrhenatherum elatius transplanted into arable and semi-natural habitats

Abstract Fates of three morphologically distinct populations of Arrhenatherum elatius were monitored following seedling transplantation into a winter wheat crop, or an Italian ryegrass ( Lolium multiflorum ) and red clover ( Trifolium pratense ) ley. Two populations were corm-forming, the third was not. One corm-forming population was an arable weed, the other two populations were collected from semi-natural grassland. Survival within all populations of A. elatius was greater in wheat than grass and clover ley. Ramet numbers of all A. elatius populations increased following cultivation of the wheat plots. Productivity, measured in terms of tiller number and plant biomass, partially reflected site of origin. Non-corm-forming plants were most productive in the grass and clover ley habitat, and plants of arable origin were most productive in the wheat habitat. Mean productivity of corm-forming plants of semi-natural origin was least in both habitats. Arable bulbous plants produced more corms than semi-natural plants. Productivity was generally greater in wheat than grass and clover ley, when comparisons could be made. Non-corm-forming plants, by definition, had lower maximum stem diameters than those which formed corms. The maximum diameter of corms from the population of arable origin was significantly greater than that of the corm-forming population of semi-natural origin in ley, and tended to be greater in wheat. Phenotypic categorisation highlighted differences between the non-corm-forming population and the corm-forming populations. Mean phenotype of non-corm-forming plants in grass and clover ley plots changed over time, plant stems becoming marginally thicker. The two corm-forming populations could not be distinguished by phenotype in ley plots, although in wheat there was a tendency for plants of arable origin to have a more bulbous phenotype. Corm-forming plants delayed regrowth from corm reserves until late spring, whereas non-corm-forming plants grew throughout the winter. This life-cycle difference may explain their different niches.