Horses for courses: Matching sorghum hybrids to sites

  • In sorghum what really matters is to understand how to match hybrids and agronomy to site and seasonal conditions
  • Farmers from the Northern Grains Regions can choose from a large range of high yielding hybrids having contrasting maturity types, tillering type, yield potential, and yield stability
  • Choosing the right hybrid for the right target yield and environment can make the difference between good yields and exceptional yields, particularly during the better seasons

GRDC-funded research (projects UQ00075 and UQ00074) is producing sorghum hybrid type recommendations for the Northern Grain Region that are helping growers understand how commercially available hybrids can be managed to maximize yield, and water use efficiency. This work is being carried out by the Queensland Alliance for Agriculture and Food Innovation (QAAFI) at the University of Queensland, in collaboration seed companies.

In rain fed cereals yield gains over time have been the result of improvements in hybrids, improvements in agronomy, and improvements in the cropping system, and their interactions. In Australia’s Northern Grains Region climate variability offers growers challenges, but also the opportunity to match hybrids and agronomy to best matches site, as well as prevailing and expected seasonal conditions. Water and nitrogen availability at planting together with expected in-crop rainfall all will contribute to the final yield result. Some of these variables are known or measurable before planting, others, e.g. seasonal climate forecasting, still not that reliable.

We conducted on farm research trials at 19 locations across Queensland investigating the performance of twelve commercial and experimental hybrids representing the major types available, sown at a wide range of plant densities and row spacing. More than 2000 plots were planted between 2014 and 2016. MR-Buster was sown at all sites as a check. Comparing the best and worst yields at each site showed a 3-fold increase in water use efficiency i.e. from 5 to 16 kg/mm/ha.

Commercially available hybrids can be characterised by their yield response when grown across environments of different yield potential, e.g. low yielding (drier sites or seasons) – to high yielding (wetter sites or seasons).  Then hybrids could be characterised by their yield potential (high or low) and their type of yield stability (dynamic or static). For example in static stability the yield of the hybrid remains relatively constant across a range of low to high yielding sites. While in dynamic stability, the yield response of the hybrid to better yielding environments is steeper (Fig 1).

We evaluated the yield potential and yield stability of most available hybrids in the Northern Grains Region and compared that against that of the most popular (older) hybrid in the region MR-Buster (Fig. 2). Results showed that:

 

1.       Most hybrids yielded more than MR-Buster in both high and low yielding environments. In Fig 2 this is shown as most hybrids are to the right of the vertical dotted line determined by the black circle (MR-Buster).

2.       Some hybrids were higher yielding than MR-Buster and also showed dynamic stability. This can be seen in Fig 2 as some hybrids are above the horizontal dotted line determined by the black circle (MR-Buster) – top right quadrant.

3.       While other hybrids were higher yielding than MR-Buster and also more stable, showing static stability. This can be seen in Fig 2 as some hybrids were below the horizontal dotted line determined by the black circle (MR-Buster), bottom right quadrant.


Fig 2. Characterisation of sorghum commercial hybrids by their yield potential in low yielding (left panel), and high yielding (right panel) sites. Hybrids to the right of the vertical dotted line yielded more than MR-Buster, hybrids over the horizontal dotted line showed more dynamic stability than MR-Buster, and hybrids below the dotted line were higher yielding and more stable than MR-Buster. Hybrids that yielded less than MR-Buster are not named.

Key points:

  • We do have high yielding sorghum hybrids in the Northern Region that are able to achieve values of water use efficiency between 16 and 20 kg/mm/ha.
  • These high yielding hybrids also show different types of yield stability. Hybrids showing dynamic stability are better suited for irrigation or high yielding sites and season
  • Hybrids showing static stability will be more stable and will trade yield in the better sites and seasons for yield in the poorer sites and seasons.
  • The most dynamic – higher yielding hybrids were also medium-late and late maturity hybrids (Pac2 and Pioneer G22).
  • Sorghum growers from the Northern Grain region do have options to chase yield or to chase stability. Though they also need to be aware of the trade-offs.

 

 

 Article written by A/Prof Daniel Rodriguez

Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland

T 0434075094 E d.rodriguez@uq.edu.au W https://www.qaafi-fsr.info/