Bild 1

1

• Background
• Weeds negative ecological and/or economic
  effect
• Improved knowledge more effective
  control strategies of weeds

• Results
• Competition reduced biomass (Fig 1 and 2)
• Sorghum weeds weeds biomass differed
  significantly with different water regimes

Competition between
Sorghum bicolor (crop)
Parthenium hysterophorus (weed)
Tagetes minuta (weed)

• Aims
• Do crop and weeds affect each other?
• Do the weedy species differ in competitive effect
  and response?
• Can differences in reactions to water stress
  explain the difference between the weeds
  variation in competitive effect and response?

Verbesina encelioides (weed)
-along a water gradient representing different
levels of water stress for six weeks of growth
No competition
Competition
Figure 1. Sorghums effect on the weeds
Parthenium
Verbesina
Tagetes
Figure 2. Weeds effect on Sorghum. Line
average of Sorghum without competition.
2
Weed-crop competition during early growth along a
water gradient Åsa Jönsson Final thesis
International Master Programme Applied Biology
2008

• Conclusions
• Weeds and crop competed significant
  reduction in biomass
• Weeds differed in their way they responded to
  competition from Sorghum and how they affected
  Sorghum
• Weeds different responses to competition from
  Sorghum was dependent on that they responded
  differently to different levels of water stress

Contact info Emailasajo842_at_gmail.com Homepage
https//cms.ifm.liu.se/edu/biology/master_projects
/2008/presentation-of-master-th/web-pages/jonsson-
asa/
Acknowledgements I would like to thank my
supervisors Dr Laila Karlsson and Prof. Per
Milberg for their help during the project.