THE VEGETABLE SECTOR AND ITS CHALLENGES IN GHANA

Vegetables play significant role by ensuring nutritional balance in the diet of humans and a rich source of micro nutrients- minerals, vitamins and sources of fiber for enhanced digestibility.
Inadequate vegetable intake has been blamed for growth retardation, poor cognitive development and mortality in children under 5 years of age, late pregnancy and early lactation nutritional disorders.
In Ghana, the major sources of vegetables in the diet are the traditional leafy vegetables that appear not to receive research attention as compared to the ones of widespread cultivation (tomato, eggplant, onions, cabbages, carrots, lettuce, etc.)
Broadly, the latter face some common challenges of production, post-harvesting and marketing such as the use of inappropriate varieties, lack of quality seeds, pests and diseases, inappropriate use of ago-chemicals and inadequate clean water.
Intense labour engagement is also a challenge, especially in cases where family labour is not in use. These conditions offer the opportunity to use enhanced conventional and modern biotechnology approach to address these challenges.

POSSIBLE ROLE OF MODERN BIOTECHNOLOGY

Biotechnology has been defined by the Convention on Biological Diversity as “any technological application that uses biological systems or derivatives thereof, to make or modify products or processes for specific use”. The biological system can be a plant, an animal and micro-organisms e.g. bacteria and yeasts. The tools in biotechnology includes:
• Tissue culture (micro-propagation) used in the production of large quantities of planting material (clones) that are free of disease organisms like bacteria and viruses.
• Molecular characterization which enables true identification of vegetable types according to the genetic makeup.
• Accurate identification of diseases of plants or animals.
• Development of vaccines (recombinant) that are more specific in action.
• Development of transgenic (GM) organisms.

Molecular or DNA characterization assists the identification of genes (actually, biological markers to the genes) in plant breeding thereby accelerating conventional plant breeding. New varieties of vegetables can be produced in a much shorter time period than would be the case in normal breeding.
Genetic engineering or GM development enable the introduction of genes that are not available in the gene pool of the species of interest. Here the desired genes may be identified in an organism of a different species and not compatible for breeding but moved to the species of interest. This has enabled the development of new varieties of vegetables resistant to insects, fungi or bacteria or more drought tolerant varieties. It has also helped in the development of plants with a higher nutrient content such as bananas with high carotene or iron content.
For instance, essential nutrients such as calcium (Ca) could be limiting in plant-based diets. Consequently, genetically engineering vegetables containing increased Ca levels may boost Ca uptake, thereby reducing the incidence of Ca deficiencies such as osteoporosis (Dias and Ortiz, 2012).
Despite the merits of GM technologies concerns have been raised over the safety of GM crops, farmer access to seeds and possible adverse effect on the environment through a change in plants, animals or micro-organisms. Bio-safety and food safety protocols are in place to address GM crop (vegetable) safety to both the environment and humans or animals. GM crops are the most regulated. For 19 years since GM crops were commercialized there has not been any case reported and scientifically proven of a health or environmental damage attributable to them. As far as safety is concerned GM crops are not different from their non-GM counterparts.
The scientific potential to develop new vegetable varieties to addresses various challenges is now available and has been done at the research level. However, very few commercialized vegetables are on the market. This include, squash, sweet corn and eggplant. The high regulatory cost has largely accounted for the low commercialization of GM vegetables.
The Ghana CSIR-Crops Research Institute in Kumasi has a permit to test on the field high protein sweet potato developed in the US. This has not taken off due to inadequate funding.

ASSESSMENT OF THE POTENTIAL IMPACT OF GM VEGETABLES IN GHANA

The International Food Policy Research Institute (IFPRI) with headquarters in Washington DC, in a 2006 study, assessed the potential economic impact of of the following genetically modified crops in Ghana: tomato, garden eggs, cabbage and cassava. The study identified generally low yields in vegetable production in Ghana compounded by stresses due to drought, pests and diseases. Vegetables are the most susceptible to these biotic constraints compared to other crops.
A major benefit of genetically resistant varieties, stated by the study, is the expected reduction of pesticide use. Pesticide use has been ineffective leading farmers to apply high dosages. The misuse of chemical pesticides is of much concern to public health from residues and direct contact by farmers. The general adverse effect from pesticide drifts includes effect on non-target organisms.

Tomato

Tomato is a major vegetable crop in Ghana and the rest of West Africa. It is a rich source of Vitamins A and C. Despite widespread production, tomato production still does not meet the high demand, so tomatoes are imported from Burkina Faso five to six months of the year (Horna et al 2006). A major constraint facing tomato production in Ghana identified by the study is the prevalence of a virus transmitted by the white fly (Bemisia tabaci). The disease, known as Tomato Yellow Leaf Curl Virus (TYLCV), causes yellowing and curling of the leaves hence its name. It is a devastating disease of tomato in Ghana. Spraying to control the white fly is not effective if the disease has set in. Recycling of seeds commonly practised by farmers worsens the problem as infested seeds prevail. A GM option for the control of the disease is an option that is receiving attention at the research level in the US.
Seed for GM virus-resistant (VR) tomato is expected to cost as much as 50 percent more than the typical certified seed.
The main reduction in costs from the use of VR tomato seed is from inputs and labour. VR tomato seed would require lower doses of pesticide to control the vector.
The use of GM virus-resistant tomato will produce economic gains but cannot eliminate spraying with insecticides as other pests of tomato occur that will require spraying.

Eggplant

The fruit and shoot borer is a devastating insect pest of eggplant, a major vegetable crop in Ghana. Insecticide sprays have not been effective to control the larvae of this insect, a moth. A GM approach is an option to deal with this pest. Bangladesh officially released GM eggplant (Brinjal) in 2014 (James, 2014).

Eggplant damaged by insect borer

Cabbage

Cabbage is a common vegetable grown largely in urban and peri-urban areas. It is severely attached by an insect known as the Diamond Back Moth against which spraying with insecticides is not effective but it is the only option available to farmers. Large quantities of insecticides with a high risk for pesticide residues in market vegetables occur. A GM option is worth considering. In the 2006 study by IFPRI in Ghana, farmers opted for a GM option if that was available.

Diamond Back Moth caterpillar.

SUGGESTED WAY FORWARD

For seed sector challenges it is necessary to develop appropriate variety development for different markets. This is especially true of tomato where product differentiation for canning or use as fresh fruits market is required.
Public-private partnership in variety development and marketing should be encouraged. Vegetable variety development is a specialised technology with expertise for commercial varieties with the private sector. The current Plant Breeders Right Bill before parliament when passed will encourage greater private sector investment in the vegetable seed sector in Ghana.
Increased farmer awareness creation and training in modern practices in vegetable production is to be encouraged.
Enhanced research and development activities over the entire value chain, is to be encouraged. Public research institution alignment with global companies will promote local expertise development.

REFERENCES
Clive James, 2014 Brief 49: Global Status of Commercialized Biotech/GM Crops: 2014
Dias, J. S. and Ortiz, R. 2012. Transgenic Vegetable Breeding for Nutritional Quality and Health Benefits Food and Nutrition Sciences, 2012, 3, Published Online September 2012 (http://www.SciRP.org/journal/fns)
Horna, J.O, Timpo, S, Al-Hassan, R. M. Falck-Zepeda, Smale, M and Gruere, G. 2006. Ex-Ante Economic Impact of GM Technology in Ghana: Comparing Potential Benefits and Risks across commodities. IFPRI Briefs 1-5.

By: Prof Walter Sandow Alhassan
Director, Biotechnology and Stewardship for Sustainable Agriculture in West Africa (BSSA)
(Former Director-General, Ghana CSIR)