Plant science ‘should focus on stem, leaf and root crops’

Mark Reader, farm economist at the Rural Business Unit, Department of Land Economy, University of Ca

Mark Reader, farm economist at the Rural Business Unit, Department of Land Economy, University of Cambridge - Credit: Archant

Efforts to develop foods to deal with malnutrition and climate change should be focused on stem, leaf or root plants rather than grain crops, a farm economist says.

Mark Reader, a researcher at the Rural Business Unit at Cambridge University’s Department of Land Economy who has worked in Australia and Peru, believes that plant science could help achieve a “climate-friendly, waste-free, and wilderness-rich” world if research funders adopt avenues of study which were already proven and readily feasible.

There were already plants producing oil, starch and amino acids, all important to the human diet, he pointed out.

“Basically I’m saying that with deprivation and climate change and also waste we should really take advantage of the technologies that have been available for a long time and do the things like breed high oil crops that are not in seeds,” he said. “There are avenues of research that have been around for a long time.”

Starch yields are greatest in crops where the product is in vegetative tissue rather than reproductive tissue, he argued, because seeds need a balance of nutrients if they are to be viable. Meanwhile, tonne for tonne, vegetable crops produced much more per acre than grain crops.

“Sugar beet, for example, yields an average of 11-12 tonnes of pure sugar per hectare, in some years across the whole of eastern England, which might be compared to average yields of wheat in England, that are at best 8-9 tonnes per hectare. There is thus huge scope to develop higher-yielding staple crops,” he said.

Sugar beet was developed in the 19th century from a wild plant that was slightly sweet, but nothing like the crop today. Similarly, starches and proteins could be enhanced in plants such as spinach, he said.

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“It’s all highly speculative,” he admitted, but starch is concentrated in vegetative tissue in vegetables such as turnips, swedes, celeriac, beets, and many more.

“Potato yields, it is perhaps worth noting, have been stagnant in England for almost 40 years owing to inconsistencies in research funding, and to sales of cheap but exceedingly poor quality potatoes,” he said, which meant some consumers were going back to antique varieties with reliable quality.

“Current oil crops are limited, in yield, by the concentration of economic product in reproductive tissue, with the exception of oil palm,” he said.

“However there are genera where oils are secreted in vegetative tissue, and that fix atmospheric nitrogen also. For example, the wax-berries myrica cerifera and myrica pensylvannica are fatty-acid secreting temperate species, that fix nitrogen and might be bred to produce substantial quantities of oil in the same way that oil palm was selected, in the 1950s, for high oil in vegetative tissue and so today oil palm is the world’s leading oil crop.”

Those same vegetative and high yielding staples could also be selected for nutritional quality, he argued, principally levels of the amino acids lysine and methionine, which are essential nutrients for humans, but are deficient in grains and potatoes.

“This has already been done using genetic modification by Monsanto with corn (maize), and by the Indian scientist Chakraborty with Amaranthus protein in potatoes but those varieties are not marketed, and there is virtually no awareness of the possible savings and benefits of ‘nutritionally complete staples’ which could quickly reduce the figure of 25% of the world’s children (World Health Organisation) who are stunted,” he said.

This situation, where “obvious and feasible” technologies are disregarded, is “short-sighted”, he said, but many people felt it was inevitable given that we have an economic model which depends on growth, leading to over-consumption and waste.

“I think that this is self-defeating. We should grow up and stop using resources that pollute the planet just because we could not be bothered coming up with a better allocation system,” he said.