Precision plant breeding and genetic biofortification: A crop game changer

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A diverse group of distinguished speakers contributed to the theme of the 13th Southern African Plant Breeding Symposium, each by elaborating on plant breeding in the Fourth Industrial Revolution.

A diverse group of distinguished speakers contributed to the theme of the 13th Southern African Plant Breeding Symposium, each by elaborating on plant breeding in the Fourth Industrial Revolution. The Southern African Plant Breeders’ Association (SAPBA) hosted the symposium at the University of Pretoria’s Future Africa Campus from 8 to 11 March this year.

The event showcased how the Fourth Industrial Revolution is driving digital transformation throughout the entire agricultural industry, and changing the way agricultural stakeholders live and work within the multidisciplinary nature of plant breeding.

Precision breeding for the modern farm

Richard Fly, head of breeding at Bayer South Africa, discussed precision breeding for the modern farm. “We are going to have an extra 2,2 billion people on earth by 2050, which means we need 50% more food than we currently consume. There is a massive amount of pressure on our ecosystems and resources, which means we have to start thinking differently about how we do things,” he said.

According to Richard, the science of plant breeding has improved by leaps and bounds over the last 100 years. “If you look at the area it took to cultivate ten bushels of maize in 1940 compared to what we are cultivating now, we have really made impressive advances. However, we need to focus on doing the small things really well, and set new standards in terms of sustainability to make sure we pioneer digital transformation and improve our overall productivity.”

Richard Fly, head of breeding at Bayer South Africa, discussed precision breeding for the modern farm.

Improving your breeding programme

Richard explained that enhanced precision translates into better resource allocation, which will improve any breeding programme. “By considering which type of traits or alleles are interacting best in a particular climate and environment, we can gain insight into which type of alleles would be better suited to each country. This will enable us to leverage our global germplasm library effectively, which ultimately lays the foundation for our ability to develop new genetics and commercialise new plant cultivars across global markets.”

According to Richard, Bayer is currently having the largest impact on the following areas of plant breeding:

  • The use of homozygous doubled haploid (DH) plants to create populations.
  • Self-pollination of those populations.
  • Different processes that enable the best cultivar selections.
  • Predictive analytics.

“With regard to innovative field testing and seed logistics, we are testing under more diverse conditions to understand the stability of the products that we are developing. We are also centralising our seed operations to enhance our overall accuracy.”

Genetic biofortification of crops in Africa

Prof Maryke Labuschagne of the University of the Free State discussed genetic biofortification of crops in Africa.

According to Maryke, approximately 792,5 million people across the world are malnourished, of which 780 million live in developing countries. In addition, around 2 billion people suffer from hidden hunger caused by inadequate daily intake of essential micronutrients. One of the possible solutions to this global concern is genetic biofortification of crops.

“Biofortification is the process during which the nutrient density of food crops is increased through conventional plant breeding, improved agronomic practices, biotechnology or a combination of all of these factors, without sacrificing plant characteristics preferred by farmers and consumers,” she explained.

Prof Maryke Labuschagne of the University of the Free State discussed genetic biofortification of crops in Africa.

Fighting hidden hunger

The biofortification approach involves fixed one-time costs in developing breeding methodologies, breeding nutritional quality traits into current crop varieties, and adapting these varieties to diverse environments. This approach will require minimum recurrent investments and the benefits can be made available globally, especially to all developing countries. Most importantly, breeding for higher trace mineral density in the consumed plant parts will not incur a yield penalty.

“Biofortification through conventional breeding offers a cost-effective, long-term and sustainable approach for fighting hidden hunger. About 300 biofortified crop varieties have been released for commercial production, with most of these produced through conventional breeding. At this stage, the crops have mostly been biofortified with minerals like zinc and iron, or provitamin A.

“The agronomic approach focuses on optimising the application of mineral fertiliser and improving the solubilisation and mobilisation of the mineral elements in the soil. This is the simplest method among all the biofortification methods, but the success rate is highly irregular due to differences in mineral mobility, mineral accumulation among crops, soil composition and the location of each crop. However, this approach is not very cost effective,” she explained.

According to Maryke, biofortification through conventional breeding is the most accepted method of biofortification. Nevertheless, you must have sufficient variation in the traits of interest for it to be feasible. In instances where genetic variability is limited, mutagenesis can be considered as an alternative.

Limitations of conventional breeding

Since the uptake and accumulation of micro-nutrients are controlled by polygenes and are dependent on genetic diversity for their traits, the conventional breeding-based biofortification approaches have not always been successful in all crops. According to Maryke, there are also no quick fixes, seeing as conventional plant breeding is a very lengthy process.

Transgenic approaches are an alternative to conventional breeding. “Transgenic technologies improve the genotypes by changing focused metabolic pathways. These technologies pave the way for modified proteins, vitamins, carbohydrates, minerals and other metabolites.

“Ample research has been done on transgenics, but relatively few cultivars have been released so far. In contrast, research on conventional breeding has been limited with a higher number of cultivars available. When looking at the three biofortification approaches of agronomics, transgenics and conventional breeding, you can see that cereals have benefitted the most, followed by legumes, vegetables, fruit and oilseeds,” she added.

Transgenics: What is the hold up?

The biggest problem is consumer acceptability, seeing as modified crops may physically differ from normal varieties that people have come to know and trust. Marketing therefore plays a very important role prior to commercial release. Regulatory processes are also very expensive and time consuming, especially in an African context. Many countries do not yet have supporting legislation in place, which causes a lot of delays. – Claudi Nortjé, Plaas Media