Several researchers in the UCD weed science program have been working on various aspects of glyphosate-resistant junglerice (Echinochloa colona) for the past few years.   One of our undergraduate student interns, presented a poster at the 2018 Plant and Soil Conference (the California Chapter of the American Society of Agronomy) earlier this month in Fresno. 

Drew reported on the (still in process) results of an experiment in which we grew seven populations of junglerice in growth chambers at 20, 30, and 40 C (~68, 86, 104 F) and treated them with a range of glyphosate doses (0, 0.5, and 1 lb ae/A).  Drew, Sarah, and other lab members collected data on growth (biomass production) and on activity of the EPSPS enzyme that glyphosate affects.

Although still processing a mountain of samples at the time the poster was prepared, the data Drew presented were pretty interesting and we're looking forward to digging into the full data set once it's complete.   At the whole plant level there were dramatic differences in how the biotypes responded to the herbicide - at least anecdotally, it appeared that the GR plants were slightly injured at the cooler temperatures but very little stunting was observed at 30 and 40C. 

Drew noted the clear differences among the biotypes in their response to glyphosate in terms of shikimic acid accumulation which indicates the inhibition of the EPSPS enzyme (higher shikimic acid = highly inhibited) at 30 C.  We'll have to see how the 20 and 40 C data look in comparison to see if this helps explain the whole plant response.  

The research poster, is linked at the bottom of this post (or click on the thumbnail photo). 

Congratulations to Drew for winning an undergraduate  award at the conference for his effort and presentation of this research!  He'll have opportunities to further sharpen those skills as he continues on with a master's thesis project focused on the biology and management of threespike goosegrass over the next several years.

Take care,

Brad