Interaction of Genotype, Environment and Herbicides in wheat (Triticum aestivuum L.) and barley (Hordeum vulgare L.) across a range of environments in Australia

Abstract

Wheat and barley cultivars can display differential tolerance to herbicides used in Australian cereal production. Seasonal variability can be seen across single cultivars in response to herbicide application. However, it is unknown how much herbicide damage can be explained by seasonal variability, and whether cultivars respond similarly across a range of environments. Currently five Australian states are conducting herbicide by cultivar tolerance research projects; however crossover between these projects has been limited due to differing nature of cultivar and herbicide uses in each state. To overcome this, from 2010 to 2012, a series of genotype x environment x herbicide trials were simultaneously conducted across five states (NSW, QLD, SA, WA and Vic). Trials comprised of barley cultivars Hindmarsh and Buloke and wheat cultivar Janz with eight herbicide treatments and an untreated control to ensure uniformity across all states. Observations made throughout the year included normalized difference vegetative index (NDVI), grain yield, grain protein, small grain screenings and test weight. Results identified that environmental effects can significantly impact the herbicide response of barley and wheat cultivars with considerable amounts of variation observed site-to-site and year-to-year. Grouping of barley cultivars Hindmarsh and Buloke showed similar trends in results, suggesting that herbicide responses can be repeated from one season to the next.
The limited correlation between the sites highlighted the degree of variation in herbicide response across environment and genotype, and therefore agro-ecological region specific testing over longer periods would be advantageous to gain increased confidence in identifying levels of herbicide tolerance.