Even  “dodgy” outsiders got a gallop in three years of extensive searching for new lucernes that are easier to establish, easier to manage and easier to remove in dryland cropping rotations. 

New South Wales Department of Primary Industries (NSWDPI) lucerne breeder Rex Williams leads the search for a new generation of lucernes that will allow growers – not the usual decline of the stand – to decide when a lucerne paddock goes back under crop.

Supported by the Grains Research and Development Corporation (GRDC) with $1.15 million over five years, the “Lucerne Alliance” project also involves Queensland’s Department of Primary Industries and Fisheries (QDPI&F and SeedMark.

Dr Williams’ research team compared 60 existing lucerne varieties and breeders lines – including those “dodgy” ones –  in three replications at 15 sites in NSW and southern Queensland.

“We’re not likely to carry out such extensive testing again, but it was crucial for us to understand how existing lucernes performed throughout the cropping zone in northern NSW and southern QLD before launching into a major new crossing program,” Dr Williams said.

“As usual, we wanted to identify the best varieties and breeding lines, but we also wanted to use the trials to learn more about the environments in which lucerne will have to perform and the traits we need to breed into our new varieties to ensure they’re even more successful.

“And we didn’t just sow the elite lines; we put in some of the dodgy ones, like the old Hunter River variety, for instance, because susceptible lines can tell us whether pests or diseases like phytopthora root rot and aphids are a problem.

“The process helped identify the challenges in different environments, because any lines that go through to commercial release will  have to perform well across a wide range of conditions.” 

Dr Williams said all sites were managed as cutting trials and evaluated for three years using annual counts of stand density.

Breeding lines and cultivars varied in their performance across sites, with NSWDPI bred cultivars Genesis, Aurora and Venus performing well under trial conditions.

Several breeding lines produced high yields and persisted extremely well across sites and one – a new, highly, winter-active line – was being considered for commercial release.

Other trends identified by the team through its three years of trials were:

• generally the more winter-active the lucerne, the higher the forage yield across sites, although this was more the case in the north than the south, possibly reflecting the ability of the highly winter active types to take advantage of longer growing seasons.

• high winter-activity alone did not guarantee high yields,

• the more persistent lucernes were not necessarily low yielding, but tended to be those with lower levels of winter activity, and

• improved pest and disease resistance delivered no consistent benefits to lucerne persistence or productivity across the 15 dryland sites, suggesting that general adaptation to dryland conditions was more important to field success.

“While the incidence of pests and diseases in these trials was quite low, the aphid susceptible cultivar Hunter River was still one of the worst performers across sites,” Dr Williams said.