Australian graingrowers deciding which wheat varieties to plant could soon have another characteristic to consider besides disease resistance and grain quality – a variety’s ability to extract maximum grain value from available soil water.

The Grains Research and Development Corporation (GRDC) is supporting Queensland Department of Primary Industries and Fisheries plant physiologists Jack Christopher and Ahmad Manschadi in a study of the effect of roots on crop performance in water limited environments.

The project “Improved performance of cereal roots in Australian farming systems” aims to match plant roots to cropping systems in northern New South Wales and Queensland.

The project focuses around the idea that growers can reduce their production risk by using genotypes with a root system that matches the crop environment, as defined by the interaction of climate, soil and management.

Dr Christopher says the QDPI&F team has identified some differences – lateral root development, for instance, and the distribution of roots at depth – between the root systems of the high yielding, drought tolerant CIMMYT wheat line SeriM82 and the current cultivar Hartog.

Dr Manschadi has been using the computer simulation model APSIM to test the value of these traits in the northern region using historical data for the past 100 years. 

That should help the scientists determine which root traits are most important for growers in the northern region.  As further traits are identified these will also be tested.

Dr Christopher says work on the GRDC project, which began last July, is building on a wider QDPI&F effort to find high yielding winter cereals for the north.

One characteristic identified in some wheat and barley varieties by his team is a “stay-green” trait similar to the more widely known one in sorghum.

Under drought conditions, cereal lines with the “stay-green” characteristic maintain green leaves longer during the critical grain-filling phase.

“Stay-green” in winter cereals appears to be related to certain differences in root structure, but the mechanisms that cause the effect are not well understood.

It’s also likely that they are not the same for all “stay-green” lines, because scientists know of at least five different patterns of the trait in different crop species.

Dr Christopher says complex interactions exist between climate, management systems and genetically controlled traits such as “stay-green” and root characteristics but a better understanding will allow scientists best to match winter cereal cultivars to the changing environment and management systems of the northern grains region.