Ground work proving messina
Researchers are getting closer to identifying an annual legume species that will grow in saline and waterlogged soils.
Messina (scientific name Melilotus siculus) is showing plenty of promise with trials in the ground this year.
Last August, _Countryman _ reported on its stunning results in the glasshouse.
Messina comes from marshy areas of the Mediterranean where it is grazed as part of the native flora but hasn't been cultivated and will be a new species for agriculture.
Researchers from the Department of Agriculture and Food (DAFWA), the South Australian Research and Development Institute, the Future Farm Industries Cooperative Research Centre and the University of WA (UWA) are working together to narrow down a list of 21 messina varieties to find the one best suited to agriculture.
DAFWA senior pasture scientist Phil Nichols said messina was identified six years ago as showing promise in waterlogged and saline sites.
To understand the mechanisms behind the tolerance traits, they began to work with UWA researcher Natasha Teakle.
Her work has found that the messina root system has a spongy layer called phellem, which has spaces for oxygen to help it breathe under water and also restricts damaging sodium and chloride ions making their way to the shoots.
She also found messina formed a gas film on the leaves which helped it tolerate flooding.
Last year Dr Teakle's research confirmed the legume could grow in sea water and survive when other pasture legumes, such as balansa clover, died.
"A lot of my research is providing the science behind what makes messina tolerant," she said.
"Some of my work is feeding directly into the breeding program which is aiming to release this plant to farmers in the next couple of years."
Dr Nichols' work has taken the glasshouse research out into the field where the 21 varieties are being trialled in Tambellup and Darkan, as well as in South Australia.
The varieties were trialled last year but failed due to the drought and were replanted this year.
"The aim is to run the trials for the next three years to measure feed production and persistence in these environments and select the best one for agriculture," Dr Nichols said.
Seed production will be measured along with the ability to regenerate seedlings in the second and third year.
But the process hasn't all been plain sailing.
In the beginning, researchers noticed problems with the rhizobia, the soil bacteria that fixes nitrogen for the plant.
"Commercially available rhizobia used on annual medics will work with messina but they don't persist over the summer when the soil surface is most saline," Dr Nichols said.
"What we had to do is try and select a rhizobium that is more salt tolerant to match with the messina."
Eighty strains of rhizobia were examined and the nine shortlisted are being tested with the messina.
"The aim is in three years to have the best plant matched to the best rhizobia," Dr Nichols said.
Release of a messina variety means farmers will have a new option for utilising non-productive, saline soils.
In high rainfall areas, it is likely to fit in with tall wheat grass and puccinellia and in low-medium rainfall areas, will be suited for planting in between saltbush.
A likely option for saline areas will be a pasture legume mix that incorporates messina with balansa clover and burr medics, as each species will occupy patches that suit it best.
Before commercialisation, there will still need to be feed tests with livestock as well as an agronomic package outlining how to manage it, when to graze, which herbicides to use as well as fertiliser and the best way to produce seed.
"Because the seeds stay on the plant, we think a header could quite easily harvest the seeds like a cereal crop and we don't anticipate any seed production problems," Dr Nichols said.
And for Dr Teakle, who grew up on a farm surrounded by salinity, it could help improve the profitability of pasture systems.
"If farmers can see that saltland pastures can be profitable, it could lead to a greater adoption of them," she said.
"Many don't invest in planting saltbush or puccinellia because of the time and cost but if they can incorporate a legume and see it is profitable, I think it will encourage more farmers to take action."
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