CHICKPEA germplasm with potential improved tolerance to chilling temperature and acid soils are in the works as part of new research being conducted by The University of Western Australia (UWA) to cross wild and domestic varieties.
A team of researchers from UWA's Centre for Plant Genetics and Breeding have spent the past five years undertaking Grains Research and Development Corporation and UWA co-funded research to cross wild chickpeas from Turkey with domestic varieties.
The foundations of the research date back to 2013 when, for a brief moment, a ceasefire in the disputed Kurdish region of Turkey where chickpea originates enabled the GRDC to co-fund a collection mission.
Since then, there has been a lot of work going on behind the scenes, particularly from Dr Jens Berger, at CSIRO, collaborators at the Turkish National Genebank and Dr Sally Norton, at the Australian Grains Genebank (AGG), to bring the collected material from Turkey to Australia.
UWA senior research fellow Janine Croser said getting the material into Australia had taken time, but the result was hundreds of new accessions of wild chickpea relatives into the AGG.
"At UWA in 2015/16, we started to work with the wild collection as it became available," Dr Croser said.
"We're working mostly with the initial 2013 collection which had members of different species but the two of interest to us were Cicer reticulatum, which are the most closely related to domestic chickpeas and Cicer echinospermum which are the next most closely related.
"The benefit of them being closely related is that you can, with varying degrees of success, cross both of these wild species with a domestic chickpea."
The crossing efforts at UWA were led by Dr Maria Pazos-Navarro who had access to a LED-based platform developed by the university that could get domestic chickpeas to flower in about 25 to 30 days.
Dr Croser said Dr Pazos-Navarro then wanted to find out if she could get the same response from wild chickpeas which can take more than 100 days to flower at their site of origin.
"Dr Pazos-Navarro grew them under the LED light spectra, extended day-length and temperature conditions we had developed for chickpea and we were very pleased to see that there was a very similar response in the wild as what we had seen in the domestic chickpeas," Dr Croser said.
"That meant we could develop a platform where we could get everything to flower at once, when you're crossing you need flowers on both the parents at the same time and that can be really tricky to achieve if you don't have a prediction of when the wild one is going to flower."
Research technician Simone Wells developed a robust cloning protocol so that many plants could be developed from just one successful hybrid.
The team had excellent success in developing a range of hybrids and UWA senior research fellow Dr Judith Lichtenzveig took the lead in using hybrids and their progeny to understand the genetic barriers to compatibility.
Dr Croser said the three researchers did a great job in establishing the platform to rapidly transfer genes from the wild to domestic and develop new populations of plants that have characteristics of both the wild and of the domestic.
"Those materials have been delivered to the AGG at a fixed stage, we were the first team in the world to get to F5, so the fifth generation after you cross which is when the traits are fairly fixed," Dr Croser said
"So we were able to deliver an F6 population derived from the most closely related wild Cicer reticulatum and a F5 population from Cicer echinospermum.
"The AGG is now bulking that seed and it will be made available to breeding programs and pre-breeders, on a case by case basis, so they can start to screen it for traits which might be useful."
As part of a separate project undertaken by the GRDC using the AGG collection, phenotyping was conducted by various other universities around Australia.
"At the University of Southern Queensland they found there was likely to be root lesion nematode resistance, if you can have a chickpea which is resistant to that then you benefit the following cereal crop," Dr Croser said.
"At Murdoch University they saw there were acid-tolerant accessions within the population, those lines will be of particular interest in WA where acid tolerance is a major barrier to chickpea expansion."
This is while researchers at Curtin University have been looking into ascochyta blight resistance.
Critically, work being done by UWA and in Turkey has shown there is also good potential for chilling tolerance at the reproductive stage which is the number one abiotic production constraint in Australia for chickpeas.
Chilling tolerance is when the plant has started to flower and it gets temperatures that are less than 15 degrees when averaged out across the day and night, which is enough of a stress for chickpeas to start to lose yield.
Dr Croser said the original wild relatives of chickpeas in Turkey were winter plants and they experienced growth in a cool environment.
"As they've been taken further and further away from Turkey, after domestication, they have adapted to spring growing conditions and in the process we lost traits like chilling tolerance that made them a winter chickpea.
"What we're hoping is that by going back to the original source material, we can pick up not just the chilling traits but also other traits that got lost along the way.
"It's a kind of treasure box of genes that were lost along the way that we can now reach back through history and put them into our domestic chickpeas."
In total, the project at UWA has led to the development of more than 5000 individual lines which can be looked at for new potential genetic combinations.