Plant biotechnology : A key tool to improve crop production in Rwanda

Rwanda’s economy relies on agriculture; nevertheless, crop production remains insufficient for both local consumption and exportation. Overall, enough agriculture yields in Rwanda to ensure food security has not yet been achieved regardless of more than 87% population engaged in agriculture activities. In this context, this study aimed at gathering the information on Rwanda’s agriculture based on different research reports and Rwandan’s government established policies to identify constraints to agricultural production faced by farmers and applicability of plant biotechnology. It was revealed that intensive and appealing discussions about agriculture economic importance, production of improved crops and the use of all necessary resources to ameliorate agricultural production need more attention. This review attempts to discuss the current problems facing agriculture in Rwanda and feasible solutions stressing that planning strong-long term policies, promoting crop breeding and use of plant biotechnology tools together with modern agriculture resources can boost up and transform economic developmental progress of Rwanda.


INTRODUCTION
The current population growth in Rwanda makes it impossible to keep the balance between food production and consumption rate.According to FAO reports, more than 2/3 of African countries are among the most vulnerable to adapt to climate uncertainties (Mikova, 2015).In Rwanda, as in all other Sub-Saharan African countries, food inadequacy is very obvious despite the availability of natural agricultural resources, and it is unlikely that the situation will change if new measures are not taken (FAO, IFAD, UNICEF, 2017).Food inadequacy causes numerous problems including malnutrition and low incomes that barely satisfy daily needs for those who entirely depend on agricultural income.The problem might be the people's culture itself that fail to adapt to the current needs of the people and speed of development, the political policies that are not practical, or merely the misallocation of funds (Ndiritu, 1999).In 2016, the number of chronically undernourished people in the world was estimated to have increased to 815 million, up from 777 million in 2015 although still down from about 900 million in 2000 (World Population Prospects 2017Revision, 2017).Food scarcity has worsened particularly in sub-Saharan Africa, south-eastern Asia, and western Asia and this situation was mostly found in places with *Corresponding author.E-mail: dusengeleonce@yahoo.fr.
Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution License 4.0 International License conflicts together with regions where droughts or floods have appeared (FAO, 2011).
It is indeed known that the solutions to the current and future need of food require producing much more food and that more productive agriculture is urgently needed especially in Sub Saharan African countries.Most African countries including Rwanda have significantly prioritized and allocated funding to the agriculture industry to increase food productivity.In Rwanda, current agricultural policies advocate crop intensification and production of high valued crops and the use of biotechnology in animal production (Gahakwa et al., 2012).
Rwanda's social economic development highly depends on agricultural production.Rwandan government policies on agriculture have always been prioritized because agriculture is the maindrive of economic growth and employing more than 87% of the population in 2017 (FAO, IFAD, UNICEF, 2017).Despite the efforts made in the past years, agriculture has faced challenging problems mainly shortage and inconsistent rainfall, soil infertility, soil salinity, lack of land management, urban development, abrupt climate change which causes erosion in some parts of the country because of Rwanda's mountainous landscape (Brink et al., 1998;Gahakwa et al., 2012;Mikova, 2015).All these challenges have negatively impacted agriculture performance causing low food production as well as low exportation.With all these challenges in place, Rwanda together with other Sub-Saharan African countries are urged to solve these problems with new methodologies to tackle this difficult task of eradicating hunger, malnutrition and all diseases related to being chronically undernourished (FAO, IFAD, UNICEF, 2017).
All documents (articles, reports and other information's) relevant to this study were accessed from different online database resources, and the main keywords were: Rwanda, crops improvement, agriculture in Rwanda, food security, plant biotechnology.In this narrative literature review article, different suggestions about current constraints facing agriculture and plant biotechnology implementation in Rwanda providing possible key solutions were critically discussed.
In Rwanda, current agriculture is dominated by conventional practices and mostly owned by smallholder farmers.However, due to food security demand in recent years and increasing population, there is urgent need for adequate quantity and quality of food.Unlike other countries where most revenue is from agricultures, in Rwanda it is the opposite (Figure 1).Despite 87% population practicing agriculture on a daily basis, only 17% is the agriculture's contribution to GDP (National Institute of Statistics of Rwanda, 2017).

CHALLENGES OF AGRICULTURE IN RWANDA
In Rwanda, the majority of the agricultural produce is Dusengemungu et al. 69 food crops instead of export crops which results in generating low incomes for the farmers (Muvunyi et al., 2017).Primarily due to numerous challenges that result in low crop production including shortage of arable land and mismanagement of available land, inadequate rainfall (climate uncertainties), soil infertility, pest and disease control, limited technology base, to cite a few.

Shortage of cultivatable land and mismanagement of available land
Rwanda is known as one of the countries with the highest population densities in Africa; so, the Rwandan government has decided to put in place some policies that can alleviate the lack of land problems.2018).

Lack of quality planting materials
Rwanda's farming suffers shortage of quality planting materials due to few production companies or organizations of good quality seeds (Musebe et al., 2017).Good quality planting material affects crop yield and income of farmers.It is desirable for farmers to use quality seed that are of high value that can benefit them.That is why more proper seed storage units, tissue culture production units and other possible alternative methods to increase the number of quality planting materials are needed.

Soil infertility and crop nutrient deficiency
Because Rwanda's soil is at high risk of erosion, soil fertility has been declining, and the rate of production in a local area where smallholder farmers use most cultivable land has also been affected.Malpractice of traditional agriculture, the low utilization of modern agricultural methods as well as the economic policies have practically done little to encourage agricultural transformation.Now research-based policies are in place to transform the production rate.Rwanda's soils need chemical fertilizer inputs since some parts of the country are characterized with low quantity of inorganic matter like nitrogen, sulfur, phosphorus and potassium along with the regular popular use of organic manures which are low in nutrient content (Ministry of Agriculture and Animal Resources, 2009, 2018).In studied areas, in Rwanda, soil fertility was imbalanced and caused low yields in maize and groundnuts (Kabirigi et al., 2016).So frequent and intensive application of necessary fertilizers (N, P, and K) is to be encouraged, and it has started with distribution of agro-chemicals fertilizers rich in the organic nutrients to the local farmers to support one cow per low-income family program which involves distributing heifers to needy families and ensuring the use of both natural organic nutrients and agrochemicals for better yields of food crops by smallholder farmers (Ministry of Agriculture and Animal Resources, 2009Resources, , 2018)).Modernization of agricultural practices and irrigation in different areas of the country is also an alternative that has started in different areas of the country, and this needs to be encouraged more.Research in the area of alternative means of fertilizing the soil, along with the use of herbicide tolerant varieties is also an area of interest and opportunity for young researchers.

Inadequate rainfall
Inconsistent and poor rainfall leads to flooding and prolonged drought, and it has been a constraint to the growth of agriculture in Rwanda since 90% of agriculture production depends on rainfall (Mikova, 2015).The inconsistency of rainfall is attributed mainly to deforestation of the country since more than 80% of cooking energy comes from trees, and since wood and charcoal are the main source of fuel for Rwandan households (REMA, 2012).Luckily, overgrazing has been managed from the last decade when the government implemented a policy (Zero-grazing system) where cattles and other livestock have to be fed in order to allow improvement of pastures, increase of organic manure, promoting improved livestock breeds and reduction of environmental degrations problems (Twagiramungu, 2006).This policy has been useful, but more attention needs to be developed to be able to produce plant hybrids that can adapt to dramatic climate change (drought), and it can be more beneficial for Rwanda to be the hub and pioneers of these plant hybrids in Sub-Saharan African countries.Africa's harsh climatic conditions are affecting people's lives and need immediate attention (Kathiresan, 2011;National Institute of Statistics of Rwanda, 2017).Use of greenhouse technology to grow crops can also be an alternative method to resolve this inadequate rainfall problem.

Pest and diseases control
Recently, in Rwanda, crop-devouring caterpillars known as fall armyworms damaged 17% of maize crop in just a few months.The fall armyworm pest originated from Americas but has recently spread throughout African countries: Nigeria, Saotome, Malawi, Zambia, Zimbabwe, South Africa, Namibia, Uganda and Democratic Republic of Congo.This has significantly directly affected the revenue of farmers and high loss of harvest (Goergen et al., 2016).In Rwanda, most cultivable land is apportioned for production of major consumable crops like cassava, beans, sweet potato, and maize and due to diseases attacking these crops from time to time their yield is still low (Nduwumuremyi et al., 2016).Many developing countries have been affected by the different outbreaks of diseases, and numerous crops have been affected (Munganyinka et al., 2017).Even though African countries spend enormous expenses purchasing herbicides, fungicides and insecticides, this does not inhibit the considerable crop losses due to pests and diseases.It proves that this option does not sustain the increase of productivity and opting for biotechnology based diseases control methods can be a better option.

Limited technological base and insufficient resources
The use of a hoe and other traditional agriculture methods has served the Rwandan Agriculture Industry for a long time, but these means prove to be time-consuming, frustrating and limiting the production capacity of the people (Gahakwa et al., 2012).This conventional practice of agriculture has not changed in quite a long time now due to the lack of trained workforce, difficulties in getting an agricultural credit, academic research results that do not reach the people.Therefore, urgent need of forwardthinking techniques to augment agricultural yield and diminish losses at the same time conserving the environment are highly required.

Post-harvest deterioration
As in many African countries, post-harvest management and handling is still quite a challenge due to a few industrial food processing units.Most produce deteriorates right after few days of harvest.In Rwanda, initiatives to manage the processing of pineapple postharvest losses has started and should escalate to more food crops (Ministry of Agriculture and Animal Resources, 2018; Nduwumuremyi et al., 2016).

CROP PRODUCTION PERFORMANCE IN RWANDA
Crop production is practiced by the majority of Rwandese households.Each household produces at least one type of crop and the majority produce either vegetables or fruits.According to the data by National Institute of Statistics, the percentage of households engaged in Dusengemungu et al. 71 agriculture does not make much contribution to the GDP (Figure 1) mainly due to the challenges discussed in this review.
Conventional agriculture is a term used to designate farming techniques that are done traditionally (United States Department of Agriculture, 2015).In East Africa and particularly in Rwanda, conventional agriculture methods are still the main drive of the agriculture industry, and this results in poor productivity causing Africa to depend on international food aid and agriculture assistance from developed countries to support small and large-scale farmers (Blein et al., 2013).
Most of the Rwandese population and labor force are engaged in traditional agriculture.Traditional agriculture practices are mainly characterised by crop rotation, use of compost and burning of fields to maintain soil fertility by increasing nitrification.In Rwanda, cultivation of most food crops has always been dominated by smallholder farmers who do it to survive and no surplus production for the market.As a result, the income of the farmer and the country, in general, is deficient compared to other Asian countries where Green agriculture revolution has been applied.Therefore, appropriate measures should be put in place to address these problems adequately (Kathiresan, 2011).
Although soil fertility in Rwanda has been maintained for a decade, due to rapid urbanization and increase in population, climate change and the traditional practices of agriculture lead to low production.In these circumstances, agriculture improvement is highly critical to the present and the future economic growth and the wellbeing of Rwandese and other developing countries population.Changes in agricultural production that meet the needs of people are urgently needed to raise the standard of living and to minimize poverty.

OPPORTUNITIES AND PROPOSED SOLUTIONS FOR RWANDAN AGRICULTURE
Rwanda has an arable soil and abundance of water that can surely promote agricultural production if used well, but to guarantee the nutritional and food security of Rwanda, it is a big challenge which requires the involvement of multisectoral firms (Kathiresan, 2011; Figure 2).With current population growth, young generation should consider the current challenges as an opportunity to enter into this sector and respond to the rising demand for agricultural products globally.
Improving agricultural production incomes can encourage the use of local products and services thereby promoting the growth in the rest of Rwanda's economy and moreover, potentially create jobs.Nearly all farmers still use traditional agricultural methods mainly because of lack of funds to buy the modern agriculture inputs such as agricultural machinery and chemical fertilizers, pest and disease control inputs; so, the introduction of new alternatives for conventional agricultural practices is also an open opportunity (Ye et al., 2002).
Even though suitable policies are in place to tackle agriculture problem, their implementation needs a speed up, and new measures have to be put in place.Rwanda as any other Sub-Saharan African countries are in need of free-disease plantlets for highly cultivated crops and to achieve this, plant biotechnology holds the key to high agricultural productivity (Musebe et al., 2017).Use of plant biotechnology has to be highly considered as a means to solve some agri-related problems (Figure 2) since its benefits can speed up the economy and stimulate the research processes.China can be a good example with the Bt Cotton experience proving the direct and indirect benefits of its investments in plant biotechnology research and product development (Hautea and Escaler, 2004).In 2002, Bt Cotton was grown in 2.1 million hectares by around five million farmers in the world (Innes, 2006).The average Bt Cotton farmer has reduced pesticide sprays for the Asian bollworm from 20 to 6 times per year and produces a kilogram of cotton for 28% less cost than the farmer using non-Bt varieties in Asia (Huang et al., 2002).Instant detection of disease attacks by using ELISA and PCR techniques is also required for better management of farms.The use of biotechnology tools to protect seed distributed among farmers, biological control agents and testing varieties of seed identity and purity before their distribution are primary tools that can benefit African farmers.In this context, it is recommended for developing African countries to start thinking about pursuing gene transfer to breed-disease and introduction of pestresistant varieties in order to meet the future food's needs.
Rwanda's current vision is to promote agricultural productivity through reforms of using modern agriculture methods and animal production, increase in agriculture budget, education of farmers on how to use new agricultural methodologies because the conventional agricultural research does not keep equal distribution between the high demand of food and the supply chain (Ministry of Agriculture and Animal Resources-Rwanda, 2009).
Plant biotechnology and genetic engineering are the primary drive of agriculture progress in developed countries (Huang et al., 2002).Despite the difficulties in sharing information between scientists across the country, the information gathered about the current status of plant biotechnology in Rwanda from some researchers in Rwanda Agriculture Board (RAB) have reported the use of tissue culture: in vitro cultivation of cash crops like banana, coffee, potato, sweet potato, pineapple, passion fruit, Tamarillo also known as a tree tomato (Gahakwa et al., 2012).Several private companies (FAIM.CO) have also initiated in vitro production of crops including bananas.The effort made still does not provide enough for the high demand of plantlets from the farmers.Disseminating resistant varieties produced using plant breeding technology is highly recommended since most of the varieties that are brought from abroad sometimes fail to adapt (Gahakwa et al., 2012).More research is needed to identify and use suitable domestic breeding techniques for popular varieties in the country, and this should be widespread to other crops since the only crops receiving research attention are common beans, bananas, cassava and sweet potatoes (Karangwa, 2018).
After the genocide of Tutsi in 1994, plant breeding and tissue culture budget were merged.However, today efforts are made for the allocation of research funds to many biotechnology tools of which introduction of genetically modified hybrid research, use of DNA markers in plant breeding and optimization of current tissue culture protocol to minimize the cost of tissue culture products, therefore, improving the income of smallholder farmers and agriculture productivity in general (Ministry of Agriculture and Animal Resources, 2004).

MODERN AGRICULTURE AND PLANT BIOTECHNOLOGY STATUS IN RWANDA
Rwanda's plant biotechnology is mostly dominated by tissue culture of medicinal plants and micropropagation of disease-free food crops mainly bananas, potato, sweet potato and cassava (Nduwumuremyi et al., 2016).To ensure food security, appropriate measures to increase the capacity of plant biotechnology should be a priority.
Tissue culture practiced in Rwanda is one of the techniques that is believed can solve agriculture production problems because it has so many advantages, one of them being the high multiplication of plantlets in a short time and space (Smith, 2013).The plants produced with tissue culture techniques are also known to be free of viruses and other diseases; thus, are all with high survival rate in the field.They grow with uniformity, and as a result, they increase yield and quality (Hautea and Escaler, 2004).Currently, many developing countries are adopting this technique but it is not yet highly spread throughout because the plantlets resulting from tissue culture are still expensive and not every farmer has access to them.Unlike developing countries, Dusengemungu et al. 73 developed countries have taken one step ahead from tissue culture techniques into high agricultural technologies like plant genetic engineering, plant breeding with DNA molecular markers and these techniques have replaced the conventional plant breeding.By mastering the above technologies, the capacity to start transgenic plants research will be achieved.
Conventional methods for food production in Rwanda do not suffice the market need, and it has been discovered that plant biotechnology tools can be used to alleviate current agricultural productivity problems (Roberts, 1984).In Rwanda as well as in other Sub-Saharan African countries, few institutions are conducting research and implementation of Agriculture Biotechnology.In Rwanda, University of Rwanda (UR), Rwanda Agriculture Board (RAB), INES-Ruhengeri, FAIM.CO are all among the few organizations that have undertaken the biotechnology program, and it has been a few years now, but the impact of that program on Rwandan people's livelihood is still debatable.Further, it is mainly because the research that is conducted does not initiate the production of affordable products that can reduce the need of costly agrochemicals and deleterious effect of diseases and weeds thus promoting agricultural productivity (Wandui et al., 2013).
For example, to embark on the problem of lack of freedisease planting material and rapid crop multiplication, tissue culture practice is now a common practice in most African countries including Rwanda.In Rwanda, there are a number of laboratories that are involved in multiplication of banana, pineapple, potato and coffee plantlets (Gahakwa et al., 2012).It has been done so because the demand of these products were high and it has become a source of high income for these plant growers.The practice now is targeting the small-scale farmers and it is hoped to increase productivity, therefore, contributing to the food security and poverty eradication.Choosing the right high productive and reliable breed of cultivated plants is very recommended and should be more exploited by all sectors involved in agriculture (Musoni, 2016;Muvunyi et al., 2017).
In Rwanda, some of them are to master the novel traditional biotechnology method: tissue culture techniques and aeroponics that can help in the multiplication of different essential plants.Adapting to tissue culture was because the above mentioned crops are among the most important in the country and are daily affected by numerous challenges.
DNA molecular markers are also among the biotechnological techniques that can be applied in various forms to construct linkage maps of different crops thereby locating the particular gene of relevance to the improvement of the quality of crops; It can also influence rapid crop and livestock breeding production.Mapped markers are useful in speeding up selection of traits for use in conventional cross-breeding procedures (Ndiritu, 1999).In common bean improvement, some efforts are also going on at RAB (Rwanda Agriculture Board) to improve efficiency in developing multiple constraint resistance and marketable bean varieties in Rwanda using marker assisted selection (MAS), and, to implement and strengthen capacity of scientists and technicians in applying MAS technologies (Annuarite and Alice, 2018;Tamara et al., 2018).With MAS, Pythium root rot resistance genes have been successfully introgressed in certain Rwandan popular bean varieties (Nzungize et al., 2011).Other MAS programs in common beans to produce the beans varieties resistant to Bean Common Mosaic Necrotic Virus are also being tried by Scientist at RAB (Worrall et al., 2015).The potential of MAS technologies to produce sweet potatoes and cassava varieties resistance to different viruses are also being tested in RAB (Munganyinka et al., 2017;Njeru et al., 2008).Even though the need to use biotechnology programs and its applications to benefit the people is urgent, a number of critical elements have to be reviewed because this new agriculture technology is very sophisticated, expensive and location-specific; therefore, policymakers have to set priorities that favor the growth of agricultural biotechnology industry (Hautea and Escaler, 2004).Funds need to be allocated to research to try and test both conventional and modern agricultural methods.Crops that are most affected by diseases and environmental challenges should gain more interest.
Plant biotechnology has increased the quality and quantity of agricultural production industry in developed countries as well as in developing countries for those who have chosen to use plant biotechnology products (Mackey, 2003).It has dramatically increased farm income, and has allowed the insertions of genes with desirable agriculture characteristics from one organism to another, which includes: increased level of proteins, fat and carbohydrates levels and stimulation of post-harvest maturations of plants.All biotechnology resources cannot be used to solve the current Agri-related problems in Rwanda.Policymakers should identify which technology can and cannot benefit the farmers and should also be aware that biotechnology advancement is not a short income process, is costly, and its benefits might not be noticeable in a short-term period.

REASON FOR CONTROVERSY ABOUT ADAPTING TO GM CROPS
Africa's agricultural development and growth have been slowing down for a long time now even though most biotechnologists prefer GMO crops over conventional crops and claim that GMO crops are potentially healthier and more productive (Huang et al., 2003); also, there are so many claims now that biotechnology products can revolutionize not only agriculture but also medicine and environmental problems.
Conversely, critics of biotechnology argue that GMO crops might affect human health and damage the environment and that it might be little or nothing to facilitating the elimination of poverty in developing countries.Regardless of critics that are associated with GMO crops, their increase since 1990 has not diminished at all; from 1996 to 2010, it exceeded 1 billion hectares which are equivalent to the total area of USA or China, which demonstrate that biotech crops will be here for a long time (Clive, 2009).
The reason why farmers in most developed countries have adopted the use of GM crops is because they have seen a very positive income.Adopting GM crops will come with a lot of tangible benefits cutting down the number of herbicides, fungicides and other chemicals to control pests.With the concern and critics of GM crop's security, the technology has not stopped and continues to prosper in developing countries whereby now more precision technology to transform are in place.Whereas technologies like CRISPR/Cas9 allows scientist to target very specifically a desired loci in the plant genome, this technology allows making the tiny changes, therefore, eliminating the concerns of leaving exogenous DNA in the plant or another fingerprint (In Stewart, 2016).Using this particular technology will benefit both large and small scale farmers by both growing economy and employment rates as it has been the case in the US and Argentina (Burachik, 2012).
Applying biotechnology is looked up as costly, requires expertise, hard to accomplish, high technology-based, and argued that it probably comes with high risk to human health (FAO, IFAD, UNICEF, 2017); however, it was proved to improve and generate high production rate of inexpensive food for developed countries, and it has helped these countries in many ways to fight and eliminate the hunger and malnutrition problem (Wang and Zhang, 2001).Only a few African countries have managed the production of transgenic plants.In Tanzania, Mikocheni Agricultural Research in Dar es Salaam, a plant virologist has genetically transformed cassava to resist potential viruses like cassava mosaic virus though the products are still in field trials (Guardian Weekly, 2013); and for the moment, only three countries in Africa have GM crops that have reached the commercial level (Clive, 2009).While the effect of GM crops has positively affected the economic growth of developed countries by reducing the cost and introducing better farming practices that benefit both the farmers and the environment; in developing countries, it has not yet been achieved, and the quantity, quality, and safety of foods are currently the primary needs of the people.The great importance of plant biotechnology tools combined with other agricultural tools can solve hunger problem.

CONCLUSION AND RECOMMENDATIONS
Considering the potential benefit that plant biotechnology holds, it should be considered in the framework of the agricultural sector at large perceiving scientific, technical, regulatory, socio-economic and political evolution (Heffer, 2000).
To take a step further in the development of agriculture, hard choices from policymakers, government officials and the citizens have to be made because the economy of most developed and developing countries main drive is agriculture.Thus, it will be very wise to allocate necessary funds for experimentation and research of applicability of modern biotechnology programs: tissue culture, genetic engineering, use of GM crops, use of plant molecular markers especially in developing countries since the demand to apply that technology will always be high, and the future of agriculture will definitely depend on modern plant biotechnology.Biotechnology programs that deal with agriculture and health problems of the people should be supported and promoted.
To revolutionize plant biotechnology industry in Rwanda and Africa as a whole, initiatives to build strong long-term policies to promote this technology starting by training individuals and increasing the scientific capacities and infrastructures that specializes in plant biotechnology should be recommended.Rwandan government should reinforce its current agricultural policies: documenting the available plant breeds by increasing the number of community gene bank and installing proper research units in the whole country, renovating and improving the current plant breeding techniques and training the new generation of plant breeders, limiting the use of agrochemicals to protect the environment, soil management, plan for irrigation in cases of irregular rainfall, and of course implementation of plant biotechnology to ensure a substantial future agriculture are all among the few recommendations to enhance farmers' agriculture productivity.As for the production of modified food crops, it has allowed the production of improved crops resistant to disease and with improved resistance to environmental factors and their stability.The production of transgenic crops holds great promise for improved quality food crops and low production of pharmaceuticals and disease-free strains.Although this new technology can be useful to overcome different problems that agriculture faces in Rwanda, practicing this technology for the moment requires debatable and ethical considerations before full application.

Figure 1 .
Figure 1.Status of agriculture's contribution to the gross domestic product (GDP) compared to other activities.Data source: www.statistics.gov.rw(National Institute of Statistics Rwanda, 2017).