#millicent smith

Taro (Colocasia esculenta cv.) is a tropical plant primarily grown for it’s sweet, starchy, edible corms, which are a hugely important food crop globally. A staple food in African, PNG, Asian, Caribbean and in particular Polynesian cultures, taro is believed to be one of the earliest cultivated plants. In 2018 global production was over 10 million tonnes.

Despite this global importance, the crop remains somewhat neglected in scientific research, particularly when compared to commodity crops like wheat. “Taro fits in what we call ‘orphan crops’, where all the research funding attention in Australia focuses on larger staple crops at the expense of others. It means we can make advances with these ‘orphan crops’ quickly, as there’s less improvements that have been made already” says plant physiology researcher at the University of Queensland, Dr Millicent Smith.

As part of the research project, Millicent and her team of researchers have been taking different taro plants (collected over a 20-year project!) and subjecting them to varying degrees of salinity, and seeing who survives.

Various taro seedlings are placed into containers not unlike self-watering pots, and then submitted to different degrees of salinity, precisely calibrated. Their reactions are recorded on cameras.

Parallel to this is detailed genetic mapping, looking to correlate particular genetic “markers” in taro with better performance in salinity. Once these genetic markers are identified, it makes it easier to identify them in other taro varieties.

“We observe how plants react to these salinity treatments. Plants can adjust to salinity osmotically (through diffusion of water/fluid-pH), but toxic ions still build up. Some plants like saltbush have a strategy for dealing with these ions. We’re finding out what the key traits are for taro to survive this salinity. We want to find the mechanism. Once we do that, we can bring any mechanism we find back through plant breeding”.

Salinity can reduce a plant’s ability to absorb water, resulting in symptoms like drought; stunted growth, poor germination, leaf burn, wilting and death. Salinity can also affect nutrient availability and uptake.

“We try to understand the process of how these plants were domesticated, and through that we’re trying to find traits that may have inadvertently selected against in the past, that may help”.

But the search for the taro of the future doesn’t stop within the confines of existing taro cultivars. All along the Brisbane River and surrounding tributaries, taro thrive on muddy embankments, thought to be escapees from gardens and farms.

The hope is these Brisbane-brand emancipated taro populations may hold the key to keep the crop going in a not-so-distant future climate.

Perhaps nowhere is the reality of climate change clearer than in the Pacific Ocean. As sea levels rise, small island nations like Tonga, Samoa and Fiji find themselves increasingly dealing with rising soil salinity. Coincidentally, many of these countries also rely on the taro as a staple food, grown largely in coastal areas. As salinity in arable areas increases, the future of this essential food is under threat.

Dr Brad Campbell is a molecular biologist at the University of Queensland which has been working in partnership with the national scientific body of Fiji to address this very problem.

The future of growing food in a changing climate is uncertain, but one thing is definite; crops everywhere will need to get by in harder, more changeable conditions. It’s humbling to think that the answer to feeding millions of people may be sitting on the muddy banks of the Brisbane River, waiting patiently to be discovered.

Featured Plant:

TARO - Colocasia esculenta cv.