The Breeder’s Dilemna and the Future of Biofortification: A Case Study of Golden Rice

by Mackenzie Sweeney

Introduction: The Breeder’s Dilemna

The main goal for both Strampelli and Borlaug, the two main innovators of the Green Revolution, was to increase crop yields in order to feed more people. Strampelli effectively used cross-breeding among varying wheat strains to achieve strains with short-strawed, early maturing, rust resistant, and high-yielding properties (Salvi et al. 2-3). One in particular, the Mentana, was used by Norman Borlaug when he was implementing his own famous program of cross-breeding as pathologist in the Rockefeller Foundation Project in Mexico, which selected further for traits such as pest resistance and resistance to various diseases (Salvi et al. 3). Borlaug’s efforts were recognized with a Nobel Peace prize, awarded for saving millions of people from starvation (1).

The drive behind the research of both men was to provide additional food in order to counteract food shortages – for Strampelli, it was the shortage in Italy in the early 1900s; for Borlaug, it was the shortage throughout the world in the 1960s. This consideration was effective in accomplishing the goal of preventing starvation and increasing self-sufficiency in many countries throughout the world, but it neglects the matter of nutritional quality. It has been found that selecting crops based entirely on factors of increased yield may actually counter-select for nutrition. This unique challenge has been termed the “Breeder’s Dilemna,” and it is a necessary consideration for the prevention of malnutrition ranging from severe in countries where many people are almost entirely dependent on these high-yielding varieties (HYVs) to moderate in countries where Green Revolution crops have contributed to but do not supply the majority of food for the population (Sands et al. 378).

Not every trait of HYV crops has been shown to lead to nutrient deficiency. The strongest correlation by far is the trait of pest resistance. According to Morris and Sands, most insects naturally seek out the most nutritious plants using internal feedback mechanisms; therefore, making plants undesirable to pests also naturally reduces their nutritional quality (1079). This is an especially concerning fact when coupled with the reality that the three primary cereal grains – wheat, corn, and rice – account for 75% of total caloric intake of the entire human population. These crops have poor nutritional profiles for the human diet, lacking a complete balance of essential amino acids, essential fatty acids, vitamins, and minerals. (Sands et al. 378-379). Plant breeders are utilizing already suboptimal sources of nutrition and further depleting their nutritional qualities.

The Issue of Malnourishment and Vitamin A Deficiency

In 2009, over 1 billion people throughout the world were severely malnourished. (379). Coupled with a rapidly increasing world population, the trend for breeding patterns to produce crops with increasingly reduced nutritional content will only exacerbate this already prominent issue, leading to severe problems in the future. This is especially true for areas mostly dependent on cereal grains for the majority of their diets, and therefore will affect impoverished and less developed areas more than those with additional resources.

One particular nutrient which is depleted by the selection for pest resistance is vitamin A. According to information compiled by Al-Babili and Beyer from the World Health Organization in 2005:

…VAD [vitamin A deficiency] represents a public health problem in more than 118 countries and affects between 140 million and 250 million preschool children worldwide. It is estimated that between 250 000 and 500 000 vitamin A-deficient children become blind every year, half of them die within 12 months of loosing their sight. VAD is the primary cause of childhood blindness worldwide and is now recognized as a major contributing factor in an estimated 1 million – 3million child deaths each year. In addition, nearly 600 000 women die from childbirth-related causes each year, the vast majority of them from complications that could be reduced through better nutrition, including provision of vitamin A (566).

           The problem of VAD remains largely unsolved, still affecting a large number of people throughout the world (Perez-Massot et al. 29-30). VAD is not necessarily the most prominent nutrient deficiency arising from the Breeder’s Dilemna, but it is a deficiency which has resulted in some of the most radical technological innovations, including the creation of Golden Rice, which will be the focus of this paper (Sands et al. 380).

What is Golden Rice?

Golden Rice (Oryza sativa, GR), is the general name for rice which has been genetically modified (GM) to reactivate the pathway for β-carotene production in its endosperm (Al-Babili & Beyer 565). Β-carotene is also commonly known as provitamin A because it is converted to vitamin A after absorption and is therefore useful in alleviating the burden of VAD. GR was created using recombinant DNA technology, which involves the combination of DNA sequences from multiple organisms to create a hybrid organism. For GR, DNA sequences from the daffodil plant which code for phytoene synthase (PSY) were inserted into the genome of the Taipei 309 line of rice to allow the rice to produce the carotene phytoene. Next, the bacterial carotene desaturase CRTI was introduced to the genome to allow direct conversion of phytoene to lycopene. This reactivated the pathway for β-carotene synthesis, allowing this strain of rice to produce β-carotene in the endosperm of the plant, in addition to the leaves, where it is produced naturally (Al-Babili & Beyer 565). Preliminary analysis revealed β-carotene content ranging from 1.6 µg/g to 6.0 µg/g for the first strain of golden rice, now known as GR1. This amount, while beneficial, would not truly be very beneficial when put into large scale production. In order to increase β-carotene content, the pathway for β-carotene synthesis was analyzed extensively. In 2005, Paine et al. hypothesized that the daffodil gene encoding PSY was the limiting step in the pathway. A new PSY was identified in maize which substantially increased carotenoid accumulation and this PSY was introduced into the GR1 genome (to function alongside the first) to create Golden Rice 2 (GR2). A maximum of 37 µg/g was observed for GR2, with 31 µg/g being β-carotene. This was at least a 19-fold increase compared with the most pessimistic evaluation of GR1 (482).

GR was created by plant scientist Ingo Potrykus, formerly of the Swiss Federal Institute of Technology in Zurich, and biochemist Peter Beyer of the University of Freiburg in Germany in an effort to combat VAD in poor countries (Schiermeir 551). Development began in 1990, and the first official seeds of the plant were shipped to the International Rice Research Institute (IRRI) in Los Baños, Philippines in 2001 to undergo preliminary testing for biochemical safety, as well as yield under local conditions. Subsequent shipments were made to non-commercial research institutes in China, India, Africa, and Latin America soon after the first shipment.

Opposition to Golden Rice

Despite estimated benefits, extreme opposition from the EU and non-governmental organizations (NGOs) such as Greenpeace and Friends of the Earth has kept GR from being widely adopted throughout the world, especially in some of the poorer areas, where proponents claim it would be most beneficial (Baggott 29, Miller 130, Potrykus 472, Adenle 1, Perez-Massot et al. 29). Greenpeace is perhaps the strongest NGO opponent of GR. The extensive list of major arguments by Greenpeace against GR is as follows: (1) GR is a ploy by conglomerate industries to gain increased GM acceptance, (2) GM crops are unsafe to eat and/or grow, (3) GR does not address the underlying issues which cause malnutrition, economic want, or inequity, (4) GR threatens biodiversity and would encourage reliance on single staple crops rather than varied vegetables, aggravating malnutrition in the long run, (5) existing supplemental programs work fine; no other supplements are necessary to combat VAD since other leafy vegetables can provide vitamin A, (6) GR might not have enough bioavailable vitamin A to be effective in combating VAD,  and finally (7) other substances such as zinc and fats might not be present in adequate amounts for conversion of β-carotene into vitamin A in the malnourished diets GR seeks to improve (Greenpeace 2010). These arguments are fairly representative of those generally raised against GR, so each will be addressed in turn in order to better understand the potential benefits and limitations of GR in combating VAD, as well as the obstacles preventing its introduction into commercial agriculture.

GR is a ploy by conglomerate industries to gain increased GM acceptance and GM crops are unsafe to eat and/or grow.

The claim that GR is a ploy by conglomerate industries to gain increased GM acceptance may be valid. If GR gains wide acceptance throughout the world and proves to be as effective as proponents have estimated, then it will almost certainly open the doors to further adoption of GM crops. However, this is only a negative consequence of GR acceptance if GM crops are indeed unsafe to eat and/or unsafe to grow. Observed benefits include: increased crop yields exceeding 100% annual increases following initial adoption, reductions in the necessity and subsequent use of insecticide sprays as high as 50%, and substantially enhanced farm incomes. While there have been significant benefits identified, there is a lack of evidence to support any claims for safety risks posed by GMOs (Adenle 1). The World Health Organization (WHO) and the Food and Agriculture Organization of United Nations (FAO), among other national regulatory organizations, have released conclusions stating that there is no scientific evidence that GM technologies represent a danger to humans or the environment (2).

Despite these statements, the EU’s precautionary principle has been largely effective in preventing adoption of GM crops in Europe and surrounding areas, such as Africa. “…this precautionary principle can be stated as: action can be taken against potential hazards if the scientific information does not prove lack of risk” (2). This principle is unnecessarily wary, as there will always be risk associated with food consumption. Even traditional foods present some health risks, which to this point have not exceeded those shown by GM foods. The situation is much different in the United States, where the FDA has approved substantial use of GM foods. USDA data shows that “93 percent of all soybeans, 78 percent of all cotton, and 70 percent of all corn grown in the USA in 2010 were genetically modified to be herbicide tolerant” (4). With the widespread adoption of GM crops in the USA, it seems that potential risks would have manifested themselves to some extent, however, no scientific evidence has been presented for any such risks as of 2011 (4).

Another concern regarding GM crops is the potential for unintended gene flow from GM crops to wild varieties. Initial studies on non-target species have shown gene flow which is quite similar to that which is seen in traditional agricultural products (1). According to information presented on goldenrice.org: “Oryza species with different genome types have significiant reproductive isolation, making them unlikely to hybridise with each other. Hybridisation between species in different genera within the tribe Oryzeae is extremely difficult, even using artificial conditions, such as embryo rescue.” More recent evidence has shown that introgression of crop alleles between commercially grown rice and weedy rice does occur over time (Han-Bing et al. 10). This is an essential consideration when determining the long-term effects of adopting GR commercialization. If introgression occurs in significant proportions, then it could result in the subsequent biofortification of weedy rice, which is unfavorable for commercial rice agriculture (Han-Bing et al. 10). Additional data suggests that changing levels of CO2 in the environment could increase outcrossing from 0.22% to 0.71% (Ziska et al. 1). Even if the rate of introgression is small, the potential for weedy rice and other harmful variants to become genetically fortified by gene introgression must be acknowledged.

GR does not address the underlying issues which cause malnutrition, economic want, or inequity.

These underlying issues are identified as being governmental infrastructure necessary for the programs which Greenpeace has traditionally used to address issues of VAD, including supplementation and fortification programs (Greenpeace 2010). While it is true that the creation of GR is in no way targeted at addressing government infrastructure, it is equally clear that it does not need to. Biofortification has been identified as being an effective alternative to supplementation and fortification programs for the purpose of alleviating the burden of VAD in areas which lack the necessary government infrastructure for these programs (Perez-Massot et al. 30).

GR threatens biodiversity and would encourage reliance on single staple crops rather than varied vegetables, aggravating malnutrition in the long run.

The argument that adoption of GR threatens biodiversity goes hand in hand with the argument against single staple crops. Both arguments can be addressed at the same time. First it is important to understand that there are three major strategies for addressing the issue of malnutrition. (Perez-Massot et al. 30). The first and most desirable strategy is to increase the diversity of diets (increase biodiversity). The second strategy involves artificial supplementation of food intake, either through diet supplements such as pills, or through fortification, as in the cases of iodine-fortified salt and wheat flour double-fortified with iron and folate. The third strategy is biofortification, which can be accomplished either through complex breeding programs, or through genetic engineering (GE) technologies (30).

The first approach, while being the most desirable, is also the one which is most frequently impractical in developing countries, particularly for the low-income populations most affected by VAD. The second approach has been shown to be effective in a number of case studies (Greenpeace 2010). However, these cases were largely made possible by effective government infrastructure for the implementation of education and supplementation programs. In areas where sufficient government infrastructure has not yet been established, such programs are very difficult to implement. Even though GR is likely to reinforce patterns of reduced biodiversity (Johns & Pablo 1-24), the same can be said for supplementation and fortification programs, and there are cases where both approaches prove to be more effective solutions than the simple approach of farming for biodiversity.

Existing supplemental programs work fine; no other supplements are necessary to combat VAD since other leafy vegetables can provide vitamin A.

Existing supplemental programs have only been found to work well in selected case studies in locations where sufficient government infrastructure is present for the distribution and incentivizing of these programs. In areas where government infrastructure is poor, GR has been identified as an effective alternative, wherein subsistence farmers could be provided with self-pollinating seeds which could proliferate their benefits over many subsequent generations, providing a feasibly long-term benefit over traditional varieties of rice. In addition, GR2 has been estimated to be more cost effective than vitamin A supplementation (Stein et al. 1201).

The idea that leafy vegetables can provide adequate vitamin A is not invalid, however, it leads back to the essential problem which led to lack of biodiversity in the first place: poor areas are often malnourished in terms of calories, ensuring that yield is the primary consideration; only when caloric needs are met will nutrition become a priority. Single staple crops are the natural solution to this problem, which is why they have been adopted so widely and have been so successful in alleviating starvation throughout the world. While encouraging subsistence farmers to rely on vegetables may seem like an adequate solution in the short run, it is very likely that it will not solve the problem of nutrient deficiency in the long run. Even assuming large-scale reversal of single staple crop adoption could be achieved, it still seems likely that when the need for increased calories becomes more prominent, past trends of abandoning low calorie vegetable crops in favor of single staple crops will likely increase in prevalence, resulting in the same problems currently being seen. For this reason, it seems likely that reliance on biodiversity as a panacea for nutrient deficiency will prove disastrous when single staple crops become necessary to prevent large-scale starvation in the face of a rapidly growing world population with ever-increasing life spans.

GR might not have enough bioavailable vitamin A to be effective in combating VAD.

According to Al-Babili & Beyer: “The conversion factor for β-carotene from a mixed diet is 12. Using this conversion factor and a conservative estimation of only 24 mg/g of provitamin A, 72 g of dry GR2 polished rice would provide 50% of the RDA for children It is therefore expected that GR2 will be able to contribute to alleviating VAD” (570). Preliminary analysis of benefits in the Philippines conducted by Zimmerman and Qaim in 2004 estimated annual health improvements ranging in worth from $16 million to $88 million US dollars and rates of return on R&D ranging from 66% and 133% (147). Additional findings released in 2006 by Stein et al. indicate that widespread consumption of GR2 could reduce VAD by as much as 59% worldwide. Even the most pessimistic circumstances should reduce VAD by at least 9%. In terms of cost-effectiveness, GR2 is much more cost effective than vitamin A supplementation and as much as one tenth as costly as the 2006 World Bank benchmark, making GR2 a very cost effective method of alleviating death and suffering from VAD (1201).

Other substances such as zinc and fats might not be present in adequate amounts for conversion of β-carotene into vitamin A in the malnourished diets GR seeks to improve.

Golden Rice has also been genetically modified to produce up to 38.3 nmol/g additional folic acid, up to 32 additional µg/g DW of Fe, and up to 76 additional µg/g DW of Zn (Perez-Massot et al. 32). These results indicate that concerns about bioavailability of β-carotene can be addressed using further genetic modification.

Conclusion: A More Balanced Approach is Necessary

The Breeder’s Dilemna which arose from selecting crop strains for pest resistance during the Green Revolution has exacerbated problems of malnutrition associated with reliance on single staple crops. Given the rapidly increasing world population and ever elongating life spans of humans, it is quite likely that the primary consideration of plant scientists will continue to be high yield. Therefore the current problems associated with lack of biodiversity are unlikely to be combatable through avenues involving reversal of current trends stemming from the Green Revolution. The remaining alternatives appear to be supplementation and fortification programs and biofortification. While the former has been shown to be effective in some populations, this method of alleviating micronutrient deficiency falls short in areas where insufficient government infrastructure is present to encourage such wide scale and costly innovations. Biofortification has the potential to be a very useful aid in the struggle to overcome micronutrient deficiency in areas such as these, as well as in areas where traditional methods have been used to good effect. Despite the potential benefits, there has been strong opposition to technologies involving genetic modification, especially from the European Union and non-governmental organizations such as Greenpeace.

Arguments on both sides have been exaggerated, and a middle ground incorporating both traditional technologies of supplementation and fortification programs as well as biofortified crops will be necessary in order to combat the dual problems of producing sufficient calories to feed the world population in the coming years and ensuring malnutrition does not come to outweigh the benefits of increased caloric production. Rather than ostracizing each other and choosing to proceed as opposing parties, proponents of GR and opponents such as Greenpeace would both benefit from a more rational approach to the problem of VAD. Such a viewpoint would recognize that traditional technologies of cross-breeding, supplementation, and fortification programs are effective in some areas, but biofortification also holds distinct promise for the future of nutrition.

 

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