Keywords

1 Multiple Origins of Agriculture

Did you know that the oldest bee pollinators from 100 million-years ago were found in pieces of amber? Scientists also found evidence that human ancestors used fire one million years ago. According to fossils of starch grains from grinding stones and cooking pots found in archaeological sites, archaeologists stated that the history of plant breeding and cultivation of major cereals started about 10,000 years ago.

1.1 Emergence of Agriculture

The adaptation of crop plants to human needs and cultivation is a slow process evolving on a time scale of millennia. Wild cereals could have been cultivated for over one millennium before the emergence of domesticated landraces (Tanno and Willcox 2006). Human domestication of plants can be divided into three stages: “gathering,” in which people gathered plants from wild stands; “cultivation,” in which wild plants were systematically sown in fields of choice; and “domestication,” in which mutant plants with desirable traits were raised (Weiss et al. 2006).

Based on recent DNA studies and radiocarbon dating of archaeobotanical remains, farming arose several times in several locations once the Ice Age had ended and climatic and environmental conditions were favourable for farming. Soon after humans adopted a sedentary existence agriculture arose (Tanno and Willcox 2006). These discoveries show the greatest revolution in human history: the transition from gathering foods from the wild to producing them on farms.

Foremost among the creations of ancient plant breeders are the cereals—rice, wheat, and maize, provide more than 50% of the calories consumed by humans today (Ross-Ibarra et al. 2007). However, 70% of the calories consumed by humans come from only 15 crops, which were domesticated in different countries worldwide. The Neolithic transition, which broadly describes the shift from foraging to farming, is one of the most important events in human history. Agriculture happened first in the early villages of the Near East in the Fertile Crescent, a region from the Mediterranean Sea to Iran including modern-day Israel, Syria, Jordan northeastern Iraq and southeastern Turkey and subsequently occurred in different parts of the world including China, Mesoamerica and the Andes, Near Oceania, sub-Saharan Africa, and eastern North America (Riehl et al. 2013; Meyer and Purugganan 2013). As early as 13,000 years ago, hunter-gatherers first began to gather and plant seeds from wild cereals and legumes, such as wheat, barley, and lentils and began their cultivating more than 11,500 years ago. Plants were domesticated gradually and independently by people in many different parts of the world. Japonica rice, a subspecies of Oryza sativa, was bred about 10,000 years ago in the upstream region of the Yangtze River in China. Key crops such as rice and soybean originated in eastern Asia. This region is also the original home of several minor crops, such as certain types of millet. Maize eaten today by over 1 billion people was domesticated approximately 10,000 years ago in southwestern Mexico. For further information refer to the book «1491» by Charles C. Mann. Starting from 12,000 years ago in the Middle East, the Neolithic lifestyle spreads across Europe via separate continental and Mediterranean routes (Rivollat et al. 2020).

1.2 The ‘Domestication Syndrome’

The dawn of agriculture, as well as of crop domestication, was a process of trials and errors. During domestication, humans subjected several key events to selection that make up the ‘domestication syndrome’. During this process, ancient farmers, either consciously or unconsciously, saved seeds from plants with favoured characters to be sown the next year. The ‘domestication syndrome’ defined as phenotypic traits associated with the genetic change to a domesticated form of an organism from a wild progenitor form include loss of seed falling (shattering), decreased dispersal, loss of seed dormancy, increased number of seeds, change in seed shape, compact growth habit (reduced branching, reduced plant size, dwarfism), increased size of fruits, adaptation of flowering time to local areas, and reduced content of toxic compounds (safer food). Humans have also selected crops for disease-resistance.

The cereals—botanically a grass, from which the fruit which is called a caryopsis (grain) is harvested—, and most other crops, share a feature—a character or trait—central to domestication: their grains remain attached to the plant for harvest by humans rather than falling from the plant, as required by wild species to produce their next generation. For example, domestication of maize involved a plant architecture transformation from the wild ancestor (progenitor), Zea mays ssp. parviglumis resulting into an unbranched plant with seed attached to a cob, thereby making maize dependent on humans for cultivation. Subsequent to domestication, maize has been subject to intensive improvement efforts, culminating in the development of hybrid maize lines that are highly adapted to modern agricultural practices.Understanding the origins and domestication of crops is of evolutionary interest. Understanding crop origins also allows the identification of useful genetic resources for crop improvement. Thus, domesticated plants provide a model system for studying adaptation of plants to their environment (the concept of adaptation is central in Darwin’s work). Domestication shapes the genetic variation that is available to modern breeders as it influences diversity at the DNA level. Indeed, scientists today can follow how domestication proceeded at the level of DNA sequence change, from wild ancestors (progenitors) to cultivated crops. Insights into the domestication process reveal useful DNA information (at the gene level) for future crop breeding.

2 The Toolbox of Crop Improvement: Hybrids and First Biotechnologies

To accomplish the objectives for crop improvement plant breeders develop various tools and methods to broaden the possibilities for breeding new plant varieties: conventional breeding such as hybridization and mutation breeding, to advanced breeding techniques such as genetic modification.

The work of Charles Darwin (1859) and Georg Mendel (1866) created the scientific foundation for plant breeding (Fedoroff 2004). The Austrian monk Gregory Mendel showed the importance of statistics in breeding experiments and the predictability in selective breeding. In 1866 he formulated the laws of inheritance on garden peas and discovered of unit factors (later defined as genes). Previously, the French family of the Vilmorins, who established the first seed company in 1727 in France (today part of the Limagrain Cooperative), introduced the pedigree method of breeding in 1830 (based on selected individual plants). The first seed company in North America was established by David Landreth in 1784. He published a catalog of vegetable seeds in 1799. The twentieth century efforts were devoted to improving the productivity, reliability, and nutrition of crops: maize (George Beadle and Paul Mangelsdorf), fruits, vegetables, and ornamental flowers (Luther Burbank) to cite some. Indeed since the beginning of the 20th-century the plant breeder’s toolbox has been developed to cause specific and permanent changes (genetic modifications): from first-generation hybrids (of maize and many other crops), wide-species crosses, mutation breeding, to genetic engineering. The new tools and methods are more and more rapid in their ability to create varieties with new and interesting traits.

2.1 Hybridization (Crosses Between Plants or Species)

The transfer of traits between genetically distant or closely related species is not a new technique. Hybridization which is a cross between two parental plants which carry interesting traits has been achieved in numerous crops. It takes almost 15–20 years to create a new hybrid variety such as in sunflower, maize, oilseed rape, or wheat. In these wide crosses thousands of genes are affected while in transgenic plants one to six genes can be added (for the moment).

In 1919 in Connecticut Donald F. Jones developed the double-cross method in maize, which involved a cross between two single crosses (four inbred lines generated from the mating of parents who The domestication syndrome can be defined as the characteristic collection of phenotypic traits associated with the genetic change to a domesticated form of an organism from a wild progenitor form.are closely related genetically are used). This technique made the commercial production of hybrid maize seed economically-viable. In 1923 in Iowa, Henry C. Wallace developed the first commercial hybrid maize. In 1926, he then founded the Hi-Bred Maize Company (today Pioneer Hi-Bred, a DuPont Company).

Hybrid seed technology generates heterozygous plants with improved yield and disease resistance by adding traits from two different parents. Average maize yields over the past 40 years have doubled in the USA, but this did not occur everywhere in the world.

2.2 Chemical- and Radiation-Induced Mutagenesis

Chemical- and radiation-induced mutagenesis (using Gamma-rays and X-rays since ca.1920) increases the frequency of genetic variations which can be used to create new mutant varieties. A mutant is a plant/organism in which a base-pair sequence change occurs within the DNA of a gene or chromosome resulting in the creation of a new character or trait. These mutations can be interesting for crop improvement, such as reducing the height of the plant, changing seed colour, or providing tolerance or resistance to abiotic (e.g. salinity and drought) and biotic (e.g. pests and diseases) stresses. In the UK, much of the beer was produced using a mutant variety of barley (the ‘Golden Promise’ variety, salt-tolerant spring barley with semi-dwarfness in stature). Wheat varieties developed through mutation breeding technique are used today for bread and pasta (e.g. induced mutability for yield). Many physiological and morphological mutants have been obtained (in banana, cassava, cotton, date palm, grapefruit, pea, peanut, pear, peppermint, rice, sesame, sorghum, and sunflower … and also horticultural plants, see https://mvd.iaea.org/.) Over 3332 crop and legume varieties developed through chemical or radiation induced mutagenesis have been released worldwide in more in 73 countries: Seeds of tomato variety Bintomato-7 irradiated with gamma ray (370 Gy) were released in 2018 for cultivation in winter season (November-February) of Bangladesh, The mutant variety of wheat with low amylose was developed by treatment with chemical mutagen sodium azide (NaN3) in Japan; the first mutant semi-dwarf table rice ‘Calrose 76’ released in the US, a mutated indica rice stain developed by irradiation of seeds with gamma rays (250 Gy) with short stature (95 cm against 120 cm of Calrose), shortening of all internodes. In organic agriculture farmers use the ‘Calrose 76’ strain of brown rice, also developed through mutagenesis. Lewis J. Stadler of the University of Missouri was the first to use X-rays on barley seeds in 1920s and ultraviolet radiation on maize pollen in 1936. Different kinds of mutagens are used in plant breeding, such as chemical mutagens like EMS (ethyl methanesulfonate) to generate mutants.

It takes more than ten years to create a variety with such mutations, which will be then crossed with an elite variety adapted to local agronomical and climatic conditions. Such varieties carry a huge number of genes affected. The random results of this genetic technique illustrate how spontaneous mutations create the genetic diversity that drives evolution (one of the Darwin’s concept), and the material upon which selective breeding can operate.

2.3 Other Techniques: In Vitro Techniques, Genome Sequencing and Gene Mapping

Other breeding techniques using in vitro tissue culture—micropropagation, and embryo rescue—permits the crossing of incompatible plants and allows the production of uniform plants.

Thanks to the knowledge at molecular (DNA) level and bioinformatics the latest step of innovation in plant breeding, dating from the 1980s, came from biotechnologies. Molecular marker–assisted selection (MAS) is now widely used to localize characters or traits on the genetic map of the crop and select commercially important characters or traits. In MAS for example, a DNA marker closely linked to a disease resistance locus can be used to predict whether a plant is likely to be resistant to that disease (Tester and Langridge 2010).

In 1944, DNA as the genetic material was discovered in pseudococcus by Oswald Avery, Colin MacLeod, and Maclyn McCarty, from the Rockefeller Institute in the USA. Then in 1953 James Watson, Francis Crick, Rosalind Franklin, and Maurice Wilkins determined the structure of DNA. Since the 50s DNA sequencing has seen rapid progress. The first sequencing of a natural gene from yeast was made in 1965 and took 2.5 years. In 1976, the first genome was sequenced (a bacteriophage). In 2008, the first human genome (6 billion base pairs of DNA of James Watson’s genome) was sequenced in four months and cost less than US$ 1.5 million. The price is dropping rapidly due to new DNA sequencing technologies. According to the National Human Genome Research Institute (USA) today the cost to generate a whole-exome sequence is generally below US $1,000.

A complete genome sequence is available for several crops since the late 1990s: bread wheat, rice, maize, papaya, grape, apple, soybean, potato, sorghum, strawberry, date palm, cassava, cacao, foxtail millet, cotton, banana… The latest sequenced genomes of 2013 are of chickpea, peach, sweet orange, and wild rice.

2.4 The Green Revolution

Since 1940, foundations such as the Ford, the Rockefeller, the Howard Buffet or the Bill and Melinda Gates Foundations have played a major role in collaboration with governments for breeding of crops. The Green Revolution started in 1943 when the Mexican government and the Rockefeller Foundation co-sponsored a project, the Mexican Agricultural Program, to increase food production in Mexico, in particular wheat production. Using a double-concept (interdisciplinary approach and international team effort), the scientific team headed by an American wheat breeder at the Rockefeller Foundation, Norman E. Borlaug, started to assemble genetic resources (germplasm) of wheat from all over the world. The life and legacy of the father of the Green Revolution, Borlaug, who received the Nobel Peace Prize in 1970, is celebrated in 2014 for the 100th anniversary of his birth.

After the famine of 1961 in India, Borlaug advanced the development of high-yielding varieties such as IR8—a semi-dwarf rice variety, along with expansion of irrigation infrastructure, and modernization of management techniques, distribution of hybrid seeds, fertilizers, and pesticides to farmers.

Today almost two billion people suffer from chronic hunger and malnutrition in developing countries. This makes agricultural development in developing countries a pressing need as they have the fastest population growth rate and they are also more at risk from resource shortages and the effects of climate change. Increasing food supply without deforestation or a net change in land use means increasing production. This makes agricultural development through crop improvement a pressing need. As deplored by Paarlberg (2009), modern agriculture—including biotechnology—has recently been kept out of Africa).

3 Advanced Breeding Techniques: Genetic Modification Technologies

In 1946 J. Lederberg and E. L. Tatum were the first to discover that DNA naturally transfers between organisms. Genetic engineering, also known as genetic modification (GM), exploits recombinant DNA technology as new tool for plant breeders. As a technique that is faster and able to deliver genetic changes that would never occur through conventional methods, GM is uniquely useful in the plant breeder’s toolbox.

Conventional breeding today encompasses all plant breeding methods that do not fall under current regulations for GMOs. For example in Europe, the European legal framework defines GMOs and specifies various breeding techniques that are excluded from the GMO regulations (the European Directive 2001/18/EC on the deliberate release of GMOs into the environment). Excluded from this GMO Directive (and thus may be viewed as conventional breeding) are hybridization (cross breeding), in vitro fertilization, polyploidy induction, mutagenesis and fusion of protoplasts from sexually compatible plants. In the USA transgenic (GM) plants are deregulated and not labeled as GMOs (except in some States). Edited plants are deregulated in the USA. The case of Europe is examined in the Joachim Schiemann’s chapter.

3.1 Genetic Engineering Technologies

Transgenic techniques provide genetic modification or genetic engineering of a recipient plant with one or more foreign genes. These foreign genes can come from plant or non-plant organisms. Transgenic plants are used for precise crop improvement because of transfer of limited genetic material as oppose to conventional breeding in which one half of the genome from each parental line is combined after hybridization. Genetic engineering also makes possible genetic changes, including between animals and plants, which would be highly unlikely or would never occur using mutagenesis or other conventional breeding techniques.

Advances in molecular biology in the 1970s made it possible to identify the specific gene responsible for a trait, isolate it, and transfer it, from any type of organism, to plant cells. Instead of making tens of thousands of genetic changes (cross or mutation breeding), with transgenesis a gene with a known single beneficial trait is inserted into the plant genome. Plant breeders embraced transgenesis because it offered this precision and a quicker way of obtaining a desired trait in a plant.

Ethical questions on growing GM crops were addressed by scientists involved molecular biology research. The first GM experiment, published in 1972, described the insertion of bacteriophage genes into an animal viral DNA. Consequently scientists raised questions about potential risks of recombinant DNA to human health and organized the Asilomar Conference in 1975 in California in the USA, attended by scientists, lawyers and government officials to discuss the technology. They concluded that experiments could proceed under strict guidelines drawn up by the US National Institutes of Health (Berg et al. 1975).

There are several vectors to genetically engineer plants: (i) infecting plant tissue by recombinant Agrobacterium tumefaciens carrying a gene of interest will lead to integration of this gene in the plant DNA, a mechanism of genetic engineering discovered by Marc Van Montagu and Jeff Schell (in Belgium) and Mary-Dell Chilton (in the USA) in 1977, or (ii) shooting plant tissue with a ‘particle gun’ carrying tungsten or gold particles coated with the gene to be transfered (also called as biolistic particle delivery system; developed in 1984 by John Sanford, Edward Wolf, and Nelson Allen in the USA).

Introduced genes fall randomly amid the DNA strands. Plant mutation breeding (discussed above, 2.2) may induce more changes than transgene insertions through genetic engineering. Regeneration of a genetically engineered plant is a rather fast process, however, since such a variety need to be crossed with elite varieties adapted to specific agronomical and climatic conditions, it takes a few years to create a variety with added transgenes.

A special feature of genetic modification is that it allows the transfer into crop plants of one or a few genes from unrelated organisms (microorganisms such as bacteria, animal or human). Conventional breeding (hybridization between very distinct plants even from different genus) cannot form plants with genes coming from different kingdoms. Additional techniques of modern plant breeding are discussed in the second chapter by Surinder Chopra.

3.2 Traits Expressed by the Genetic Engineering Technologies

The first GM plant produced was an antibiotic-resistant tobacco plant in 1982. The first commercialized GM crop was the FlavrSavr® tomato in 1994 in the USA. It contained a trait that suppressed early ripening in tomato to maintain flavor and taste. In the UK, a concentrated tomato paste using these GM tomatoes went on sale in 1996 (by Zeneca). It received an award in France for the best innovation. The earliest crops produced by transgenesis (insect-resistant and herbicide-tolerant varieties) have been commercially cultivated since 1995. A GM variety of maize developed to express a protein from Bacillus thuringiensis, (‘Bt maize’) protects maize against the European maize borer and some other lepidopteran insects. Bt, originally discovered in 1911 in the province of Thuringia in Germany, has been used as a spray by organic farmers. The Bt genes produce insecticidal CRY proteins which are an alternative to chemical pesticides. These are introduced in more than a thousand elite varieties of maize, but also in cotton, cowpea, soybean and sugarcane as examples.

The global area cultivated with GM varieties was over 191.7 million hectares in twenty-six countries (21 developing and 5 industrialized countries) in 2018. A total of 26 countries adopted GM crops through cultivation and 44 additional countries imported. Crops grown commercially today contain traits for mainly herbicide tolerance, insect resistance, or both. These have been developed for commodity crops such as soybean, cotton, maize, oilseed rape and alfafa. It is estimated that, for example, 88% of the cotton grown in India is now GM due to its greater resistance to pests. The cultivation of GM insect-resistant crops, particularly varieties of cotton, in India and China, is also reducing the exposure of farmers to harmful organo-phosphate insecticides. There are a lot of products from GM crops in the food chain. In Europe it is estimated that 90% of some animal feed (maize and soybean) is derived from GM varieties because of their low cost and large amount available.

The list of approved GM crop varieties modified by transgenesis (gene transfer or silencing using RNAi) is long: alfalfa, Argentine canola, apple, bean, canola, carnation, creeping bentgrass, cotton, cowpea, eucalyptus, flax, maize, melon, miscanthus, papaya, petunia, plum, Polish canola, potato, rice, rose, squash, safflower, sorghum, sugar beet, sugarcane, sweet pepper, soybean, tobacco, tomato, wheat (for updated data visit https://www.isaaa.org/gmapprovaldatabase/default.asp). The list of edited crop varieties which are deregulated includes e.g. alfafa, bahiagrass, camelina, citrus, chrysanthemum, flax, maize, pennycress, Petunia, potato, rice, setaria (wild millet), soybean, tobacco, tomato or wheat.

Many genes of interest have been discovered including pest and disease (fungi, virus, bacterial) resistance genes, and new ones are being discovered at a rapid rate. Some of these genes have been incorporated into commercial varieties to breed for specialty traits and these include heat and drought tolerance, nitrogen use efficiency, modified alpha amylase, male sterility, modified amino acid, modified flower color (in dianthus), modified oil/fatty acid, and virus resistance. In Pamela Ronald’s laboratory in UC Davis (USA) the discovery of the gene XA21 confers resistance to a bacterial disease, and the discovery of a gene of submergence tolerance of rice allows drowning weeds without drowning the rice, providing a method for weed management without relying on a herbicide (Ronald and Adamchak 2008).

Radical innovations concern nutritional benefits. Healthier vegetable oils with fewer trans-fats are being developed. Bio-fortifying key crops including cassava in Africa or rice in Asia illustrate the potential of genetic engineering to fight malnutrition. In developing countries, especially in Asia, vitamin-A deficiency causes childhood blindness. The most famous attempt to combat this deficiency is the development of ‘Golden rice’ by Ingo Potrykus in Switzerland and his colleagues (Zeigler 2014). They genetically transformed rice plants with carotenoid biosynthetic genes that result in more vitamin-A precursors. Today, geneticists are also trying to reduce allergens in foods using genetic engineering. Technologies such as genomic selection, genome editing and the role of bioinformatics could be galvanized by using speed breeding to enable plant breeders to keep pace with a changing climate and environment in plant adaptation to environmental and biotic contraints,

The ability to manipulate plant genes to produce certain human enzymes is not new. Interest in deriving pharmaceuticals from plants (known as ‘bio-pharming’), first took off in the 1990s after scientists showed that monoclonal antibodies could be produced in tobacco plants. Plant-derived biologic treatments have proven successful in drugs given to animals in recent years and today in human patients suffering from Gaucher disease or development of vaccines against COVID-19 (discussed in Kathleen Hefferson’s chapter). This led to genetic engineering of plants to produce vaccines, antibodies and proteins for therapeutics.

3.3 Development of New Breeding Techniques

In the past two decades, additional applications of biotech and molecular biology in plants have emerged, with the potential to further enlarge the plant breeder’s toolbox. Making precise changes in the genomes of organisms is challenging for most techniques. Several recently described genome editing techniques allow for site-directed mutagenesis of plant genes (to knock out or modify gene functions) and the targeted deletion or insertion of genes into plant genomes. New breeding techniques have rapidly emerged in the 2000s. Compared to the early versions of gene editing tools, such as ODM (oligonucleotide directed mutagenesis), meganucleases (MNs), zinc finger nucleases (ZFNs), and transcription activator-like effector nucleases (TALENs), clustered regularly interspaced short palindromic repeat (CRISPR) system is capable of altering a genome more efficiently and with high accuracy. In 2012, researchers transformed a bacterial immune system (CRISPR system) into a fast and versatile tool for genome editing. The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Chemistry 2020 to Emmanuelle Charpentier (Max Planck Unit for the Science of Pathogens, Berlin, Germany) and Jennifer A. Doudna (University of California, Berkeley, USA) for the development of a method for genome editing. Since 2014 plants were edited with CRISPR-cas9 and notably the hexaploid wheat (Ricroch 2017). Regarding plant species and countries in which the research is performed, one can note the importance of rice, mainly in China, which is in accordance with the Chinese research and economic contexts, while the application of CRISPR/Cas systems in maize is more prevalently studied in the USA (Ricroch et al. 2017). China is now taking the lead in the industrial and agricultural applied sectors and in the total number of patents per year (Martin-Laffon et al. 2019). Another innovative trend is the use of transgenes solely as a tool to facilitate the breeding process. In this application, transgenes are used in intermediate breeding steps and then removed during subsequent crosses, eliminating them from the final commercial variety (null segregants). Among new tools are accelerated breeding techniques, where genes that promote early flowering are used to speed up breeding, and reverse breeding, a technique that produces homozygous parental lines from heterozygous elite plants (Lusser et al. 2012). New tools also concern three techniques: cisgenesis, intragenesis, and the zinc finger nuclease-3 technique (ZFN-3). Cisgenesis is the genetic modification of a recipient organism with a gene from a crossable–sexually compatible organism (same species or closely related species). Intragenesis is a genetic modification of a recipient organism that leads to a combination of different gene fragments from donor organism(s) of the same or a sexually compatible species as the recipient. ZFN-3 allows the integration of gene(s) in a predefined insertion site in the genome of the recipient species. In 2012, the researchers transformed a bacterial immune system into the fast and versatile tool for genome editing (CRISPR system).

A search-and-replace method, also known as prime editing, was developed that can introduce user-defined sequence into a target site without requiring double-stranded breaks (DSBs) or repair templates (Anzalone et al. 2019). For precision breeding of crops this genome engineering using prime editing system was developed in rice (Hua et al. 2020) and wheat (Lin et al. 2020). China and the USA lead scientific research in crop editing while Nigeria being headquarters to numerous research consortia mainly using transgenesis (Ricroch 2019).

4 How to Meet 70% More Food by 2050?

Global population has risen from 2.6 billion in 1950 to around 7.8 billion in 2020, and is predicted to rise to a world population of near 10 billion people by 2050. According to the Food and Agricultural Organization of the United Nations, the demand for food could rise by 70% by 2050. To meet this goal an average annual increase in production of 44 million metric tons per year is required, representing a 38% increase over historical increases in production, to be sustained for 40 years.

This accomplishment will be particularly challenging in the face of global environmental change. The challenge for major changes in the global food system is that agriculture must meet the double challenge of feeding a growing population, with rising demand for meat and high-calorie diets, while simultaneously minimizing its global environmental impacts (Seufert et al. 2012).

Today farmers will have to hit targets for reducing greenhouse gas emissions, improving water use efficiency and meeting the demands of consumers for healthful food and high-value ingredients. In this context, new plant breeding techniques are needed to contribute to improvements in crop productivity and sustainability in a climate-smart agriculture framework.

New technologies must be developed to accelerate breeding through improved DNA methods and by increasing the available genetic diversity in breeding germplasm (collection of wild types and varieties). Scientists underline the importance of conserving and exploring traditional germplasm. Introgression of characters or traits (pest and disease resistances or adaptation to salinity, cold or heat temperatures for example) into locally adapted varieties is expected to considerably enhance productivity in protecting crops from new pests and diseases due to climate change variability and under abiotic stress conditions (e.g. drought). The most gain will come from delivering these technologies in developing countries, but the technologies will have to be economically accessible and readily disseminated.

With governments, the private sector, foundations, and development agencies faced with feeding a growing and hungry world, research to increase agricultural productivity and access to affordable and safe medicines is needed including against COVID-19. The rush to develop a vaccine for COVID-19 the disease caused by the novel coronavirus SARS-COV-2 has extended to public and private laboratories, where scientists are using the tools of genetic engineering to develop edible vaccines in plants. The challenges of intellectual property rights and genetic resources preservation that play major roles in the plant breeding enterprise. The twenty-first century will witness radical plant innovations.