Phenology research offers growers valuable yield insights
April 3, 2018
Maximising wheat yields in the southern New South Wales cropping belt starts with one key discipline – knowing your variety.
An understanding of a variety’s genetic make-up can help growers assess the potential impact of environmental influences such as vernalisation and photoperiod which affect early development phases and flowering, and match a sowing date accordingly.
A collaborative research investment between the Grains Research and Development Corporation (GRDC) and NSW Department of Primary Industries (DPI) has been investigating the phenology and yield responses to sowing date for a core set of wheat genotypes in southern NSW.
The research is part of a broader GRDC investment aimed at optimising grain yield potential in the northern grains region through better matching sowing management with likely varietal responses to environmental conditions. Last year’s trial work involved field experiments at eight sites stretching from southern NSW to northern NSW, central and southern Queensland.
NSW DPI crop physiologist Dr Felicity Harris said a diversity of geographic sites was chosen to give researchers critical data about how different varieties, perform in different regions with a focus on time of sowing, flowering and yield responses.
“The geographic diversity of trial locations is a key element of this project and will allow us to provide growers with data that helps inform on-farm decision making in terms of varietal selection and time of sowing” she said.
While 2017 trial results from some sites are still being assessed, Dr Harris presented the results from three southern NSW sites – Wagga Wagga, Cudal and Condobolin – at a recent GRDC Grains Research Update.
At each of the sites, a range of genotypes with varied development and with different combinations of vernalisation and photoperiod genes were sown on three dates — April 20, May 5 and May 18, with an additional early sowing at the Wagga Wagga site on April 10.
Dr Harris said the trial work showed differences in grain yield responses to sowing time of wheat genotypes across growing environments in southern NSW, suggesting that particular varieties could be exploited by grain growers.
“Genotypes vary in their response to vernalisation and photoperiod which influences early development phases as well as flowering time,” Dr Harris said.
“The extreme frost conditions experienced in 2017 had a significant effect on grain yields at the three experimental sites and highlighted the importance of the timing and length of pre-flowering development phases.
“Matching variety and sowing time to achieve flowering at an appropriate time for each growing environment is currently the most effective management strategy in optimising grain yields.
“That said, future research will investigate the contribution of pre-flowering phases to yield development which will give growers an even wider spectrum of information on which to base variety management decisions.”
Genotypes responsive to vernalisation require a period of cold temperatures (accumulated most rapidly in the range 3°C to 10°C) to progress from vegetative to reproductive development, whilst time to flowering is accelerated during long-days in photoperiod sensitive genotypes.
The range in development patterns in Australian wheat varieties, due to responses to vernalisation and photoperiod, provides growers with flexibility in their sowing window according to Dr Harris.
“Grain yield is maximised when genotype and sowing date are matched so that flowering occurs when the risk of early frost damage and later, heat and moisture damage, is low,” she said.
“Generally, in southern NSW, winter wheat can be sown from early March through to April, slow developing spring wheat from late-April to early May and mid-fast developing wheat from early May onwards and all flower within an optimal window.”
A copy of Dr Harris’ GRDC Grains Research Update paper can be downloaded from the `Resources and Publications’ section of the GRDC website.