Annual Bluegrass Suppression Through the Utilization of Phosphorus Sensitive SIZ1 Transgenic Creeping Bentgrass.

Annual bluegrass [Poa annua (L.)] is a problematic grassy weed in turfgrass ecology and many management strategies have been researched, particularly for creeping bentgrass putting greens.  The goal of the research project is to examine the suppression and growth of annual bluegrass through fertility management.  SUMO E3 ligase SIZ1 transgenic creeping bentgrass was developed and found to be tolerant to extremely low phosphorus levels in the soil. To further examine the effects of phosphorus levels and annual bluegrass suppression a preliminary study was conducted.  Low phosphorus levels in a sand root-zone suppressed annual bluegrass germination growth.  Results from that study found that 1 and 10 µM P resulted in significantly lower total biomass than 100 µM P treatments.  To further observe the suppression of annual bluegrass under low phosphorus environments a second study was conducted.  SIZ1 transgenic creeping bentgrass and annual bluegrass were established in a pure sand root-zone under 4 phosphorus levels (10, 20 40 & 80 µM P).  Total biomass and nutrient concentration will be measured to assess the performance of transgenic creeping bentgrass and annual bluegrass under low P levels.  Ideally, transgenic creeping bentgrass populations would out-compete annual bluegrass.  This research could provide another management tool for annual bluegrass control to turfgrass managers in the future.