8 billion . . . and counting

This is the latest estimate of the world’s population announced by the United Nations on 15 November 2022. Can you imagine? I was born 74 years ago when the population was just over a quarter of what it is today.

So many more mouths to feed, so many challenges to overcome. And population growth fastest in many of the world’s poorest countries.

The UN’s latest prediction is that another billion will be added by 2037, and that . . . half of the world’s population growth will be concentrated in just nine countries: India, Nigeria, the Democratic Republic of the Congo, Pakistan, Ethiopia, the United Republic of Tanzania, the United States of America, Uganda and Indonesia (ordered by their expected contribution to total growth).


In 2021, the Food and Agriculture Organization of the UN or FAO reported that 193 million people in 53 countries or territories were facing acute food insecurity. And while conflict and the effects of the Covid pandemic are contributors to this state of affairs, there is no doubt that weather extremes are also a major contributing factor, affecting many more people worldwide. More frequent storms. Too much water—or too little. Rising temperatures reducing the agricultural productivity in many regions.

Sustainable food and agricultural production were appropriately important themes at the latest climate change conference—COP27—in Egypt. The Consultative Group on International Agricultural Research or CGIAR, the Food and Agriculture Organization of the UN or FAO, and the Rockefeller Foundation together were prominent at COP27 with the aim of putting agrifood systems transformation at the heart of the conference.

So, whether you are a believer in climate change or a denier (I’ve never been a climate change denier—quite the opposite, in fact), surely you have to accept that something strange is happening to our climate.

More than 30 years ago, two University of Birmingham colleagues—Brian Ford-Lloyd and Martin Parry—and I organized a workshop to discuss the impact of climate change on agriculture and the conservation of plant genetic resources (and how they could, and should, be used to mitigate the effects of a warming climate). The proceedings were published in 1990. Twenty-five years later, in 2014, we followed up with a second volume reflecting how the science of climate change itself had progressed, and how better we were equipped to use genetic resources to enhance crop productivity.


So while agriculture has been—and continues to be—one of the contributors to climate change (livestock, methane from rice paddies, use of fertilizers and the like) it can and has to be part of the solution.

Since more than half of the world’s population are now urban dwellers, they do not produce their own food. Or at least not enough (even if they grow their own vegetables and such on small holdings or allotments) to support many others.

Subsistence farming is not a solution either, even though these farmers can increase productivity by adopting new agricultural practices and higher-yielding crop varieties, if appropriate and affordable. And those campaigners who advocate the abolition of livestock farming (and I have seen one young person state that all farming should be stopped!) have little notion of how that would affect the lives of farmers globally, or where the rest of us would source our food.

There has been much talk recently about diversification of farming systems and adoption of so-called ‘orphan crops’ as part of the solution. Of course these approaches can make a difference, but should not diminish the role and importance of staple crops like wheat, maize, rice, potatoes, sorghum, and many others.

So what are the options? Investment in plant breeding, among others, has to be central to achieving food security. We will need a pipeline of crop varieties that are better adapted to changing environmental conditions, that are one step ahead of novel pest and disease variants. Crop productivity will have to increase significantly over the next few decades.


My first encounter with plant breeding—or plant breeders for that matter—was during a visit, in July 1969, to the Plant Breeding Institute (PBI) in Cambridge during a field course at the end of my second year undergraduate degree course at the University of Southampton. We heard all about wheat breeding and cytogenetics from Dr Ralph Riley FRS (right) no less (later knighted and Director of the PBI from 1972 to 1978). Our paths crossed again several times during the 1990s when he was associated with the CGIAR.

During my third and final year at Southampton, 1969-1970, I enjoyed a plant breeding module taught by genetics lecturer Dr Joe Smartt whose original research background was in peanut cytogenetics. He had spent some years in Africa as a peanut breeder in Zambia (then known as Northern Rhodesia).

It was in that course that I was introduced to one of the classic texts on the topic, Principles of Plant Breeding by University of California-Davis geneticist, RW Allard (first published in 1960). Sadly I no longer have my copy that I purchased in 1969. It was devoured by termites before I left the Philippines in 2010.

I’ve never been actively involved in plant breeding per se. However, the focus of my research was the conservation of genetic resources (of potatoes and rice, and some other species) and pre-breeding studies to facilitate the use of wild species in plant breeding.


It’s been my privilege to know and work with some outstanding plant breeders. Not only did they need a knowledge of genetics, reproductive behavior, physiology and agronomy of a plant species, but this was coupled with creativity, intuition and the famous ‘breeder’s eye’ to develop new varieties.

Perhaps the most famous plant breeder I met in the early 1990s was 1970 Nobel Peace Laureate (and ‘Father of the Green Revolution’) Norman Borlaug, who spent a lifetime breeding wheat varieties, first with the Rockefeller Foundation and then with the International Center for the Improvement of Maize and Wheat (CIMMYT) in Mexico. I wrote about that encounter here.

Explaining how rice seeds are stored in the International Rice Genebank at IRRI to Nobel Peace Laureate Norman Borlaug

In the potato world I met Stan Peloquin from the University of Wisconsin, George Mackay in Scotland, and John Hermsen from Wageningen University. I worked alongside Peruvian potato breeder and taxonomist Carlos Ochoa (below) for several years.

When I joined IRRI in the Philippines in 1991 as head of the Genetic Resources Center, one of my close colleagues was 1996 World Food Prize Laureate Gurdev Khush (below left) who led the institute’s breeding program. He and his team bred more than 300 varieties of rice, some of which—like IR36 and IR72—have been grown over millions of hectares and saved countless millions from starvation.

And another rice breeder (and 2004 World Food Prize Laureate) famous for NERICA rice was Monty Jones (above right) at the Africa Rice Center in West Africa. Monty was a graduate at Birmingham and I was the internal examiner for his PhD thesis in 1983.


Plant breeding has come a long way since I first became interested 50 years ago. Breeders now have access to a whole new toolbox to accelerate the development of new varieties, some of which were not available just a few years ago.

A decade ago I asked my friend and former colleague at IRRI, Ken McNally to contribute a review of genomics and other ‘omics’ technologies to discover and analyse useful traits in germplasm collections to the 2014 genetic resources book that I referred to earlier [1]. I’m sure there have been many useful developments in the intervening years.

One of these is gene editing, and Nicholas Karavolias (a graduate student at Berkeley University) has written an interesting review (from which the diagram above was sourced) of how the CRISPR gene editing tool is being used to improve crops and animals.

Among the climate change challenges that I mentioned earlier is the likelihood of increased flooding in many parts of the world. Just last year there were devastating floods along the Indus River in Pakistan where rice is an important crop, as it is in many Asian countries. Although grown in standing water in paddy fields, rice varieties will die if totally submerged for more than a few days when floods hit.

Rice paddies near Vientiane, Laos.

Over several decades, submergence tolerant rice varieties were developed in a collaborative project between US-based scientists and those at IRRI using marker-assisted selection (not genetic engineering) to identify a gene, named Sub1 (derived from an Indian rice variety) and incorporate it into breeding lines. My former IRRI colleagues, plant physiologist Abdelbagi Ismail and breeder David Mackill have written about response to flooding. In the video below you can see the impact of the Sub1 gene [2]. And the impact of that gene is readily seen in the video below which shows two forms of the rice variety IR64 with and without the Sub1 gene.

To date, the impact of genetic engineering in crop improvement has not been as significant as the technology promised, primarily because of opposition (environmental, social, and political) to the deployment of genetically-modified varieties. I wrote about that issue some years back, and focused on the situation of beta-carotene rich rice known as ‘Golden Rice’. After many years of development, it’s gratifying to see that Golden Rice (as the variety Malusog) has now been grown commercially in the Philippines for the first time, and can now deliver real health and nutritional benefits to Vitamin A impoverished communities in the Philippines and hopefully elsewhere before too long.

In recent weeks there have been interesting news releases about the development of perennial rice and its potential to mitigate some climate change effects, and reduce labor usage. Researchers at the John Innes Centre in the UK have identified a gene that they hope will make wheat varieties more heat-resistant. The need for trait identification has never been greater or the importance of the hundreds of thousands of crop varieties and wild species that are safely conserved in genebanks around the world. Fortunately, as mentioned earlier, there are now better and more efficient tools available to screen germplasm for disease and pest resistance, or for genes like the wheat gene just discussed.

In terms of adaptation to a changing climate through plant breeding, I guess much of the focus has been on developing varieties that are better adapted to changing environment, be that the physical or biotic environment.

But here’s another challenge that was first raised some years back by one of my former colleagues at IRRI, Melissa Fitzgerald (right) who was head of the Grain Quality, Nutrition, and Postharvest Center, and is now Professor and Interim Head of the School of Agriculture and Food Sciences at the University of Queensland, Australia.

And it’s to do with the potential global savings of carbon. Melissa and her colleagues were looking at the cooking time of different rice varieties. This is what she (and her co-authors wrote in an interesting 2009 paper):

The cooking time of rice is determined by the temperature at which the crystalline structures of the starch begin to melt. This is called gelatinization temperature (GT). Lowering the GT of the rice grain could decrease average cooking times by up to 4 min. Although this might initially seem entirely insignificant, by computing the number of times rice is cooked in any one day by millions of households around the world, a decrease of just 4 min for each cooking event could save >10,000 years of cooking time each day. This represents massive potential for global savings of carbon and is of particular relevance to poor, rural households that depend on scarce local supplies of fuel.

Now there’s a huge breeding challenge.

Anyway, in this post I’ve really only scratched the surface of the topic, but hopefully for those readers not familiar with plant breeding, what it entails, and what it can promise, I hope that I’ve explored a few interesting aspects.


[1] McNally, KL. 2014. Exploring ‘omics’ of genetic resources to mitigate the effects of climate change. In: M Jackson, B Ford-Lloyd & M Parry (eds), Plant Genetic Resources and Climate Change. CABI, Wallingford, UK. pp. 166-189

[2] Ismail, AM & Mackill, DJ. 2014. Response to flooding: submergence tolerance in rice. In: M Jackson, B Ford-Lloyd & M Parry (eds), Plant Genetic Resources and Climate Change. CABI, Wallingford, UK. pp. 251-269.

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