Combating no-show lupins in Liebe region

In-house germination testing for lupin establishment.

In-house germination testing for lupin establishment.

IN recent seasons, growers have been experiencing issues with poor germination of lupin crops from retained seed and as such, want to better understand the contributing factors behind this.

Manganese (Mn) deficiency, variety, harvester settings and moisture at harvest have all been identified as contributing factors behind poor establishment, however there is limited information available to growers and advisors as to the most important and controllable factors in modern farming systems that could be managed differently, to improve lupin germination percentages.

Some research was done in the 1970s but farming practises have changed drastically since then.

The issue was raised in the Geraldton zone at the Regional Cropping Solutions Network (RCSN) meeting in June 2019 after issues in 2018 with retained seed from the previous season.

While it is widely accepted that Mn deficiency is a contributing factor towards poor germination due to its expression in lupins as split seed, it is unclear under what circumstances Mn deficiency is most prevalent and what other factors contribute.

Harvest operations are considered the other likely contributing factor as the threshing mechanisms within the header can damage the seed coating - an effect possibly exacerbated by grain moisture, harvesting conditions or variety.

As such, the Liebe Group launched a two-year project, with Grains Research and Development-investment (the effect on lupin establishment as a result of reduced seed coat integrity) in 2019, that will assist all stakeholders in the lupin industry including growers, advisors, researchers and breeders to ensure the issue is better managed in future seasons.

The Liebe Group started the project by collecting seed from 27 locations, including five different varieties and seed with foliar, compound and no Mn applied.

 There was a great attendance for the AgChats Series with a strong interest from growers around lupin agronomy.

There was a great attendance for the AgChats Series with a strong interest from growers around lupin agronomy.

At each location, a representative sample was handpicked from the paddock.

This sample was then compared to another matching sample taken from the grower's silo that had been harvested in their conventional manner.

Mn composition and germination tests were conducted on the samples and a range of other factors were recorded.

The Liebe Group also performed its own germination testing, both in the environment-controlled lab and outside, to see how feasible it would be for growers to test their own seed.

p AgChats

The first of the AgChats series for 2020, supported by Grain Growers, saw amazing attendance and a very strong interest in the lupin agronomy topic, with 31 growers and industry representatives attending the breakfast and presentation at Liebe's office in Dalwallinu.

Liebe's research and development co-ordinator Judy Storer began the AgChats session by presenting the group's in-house germination testing and pointing out the very low correlation between Liebe's results and DDLS's (Development Diagnostic Laboratory Services, a branch of DPIRD and nationally recognised germination test provider) official test results.

This highlighted the difficulties in getting an accurate representation of your seeds' germination potential by doing your own testing during adverse seasonal conditions (testing cold season seeds in midsummer) and showcased the value of getting official germination testing done.

From there, the AgChats workshop moved inside and some of the interesting trends in the data were highlighted for the attendants, including the 12 per cent average drop in germination between the pre and post-harvest samples and the 9pc drop in germination seen between two samples harvested from the same paddock when the rotor speed was increased by 330.

An engaging discussion was then had between all attendants and experts Bob French, the Department of Primary Industries and Regional Development and Alan Meldrum, GrainGrowers, who answered growers' questions about their lupin crop, lupin agronomy and their business decisions on increasing profitability when growing lupins.

Some of the more interesting discussion topics brought up were the correlation between liming and poor lupin growth, a project to measure seed coat thickness, the benefits of inoculating and whether is was necessary and how stressed plants seem to better convert biomass to seed.

There was also very strong interest shown by all attendants in establishing further projects and demonstrations around lupin agronomy, so the Liebe Group will be looking into those possibilities as it goes forward.

For details on this project as it progresses, contact Judith Storer at research@liebegroup.org.au or call 9661 1907.