Cocoyam Programme

Cocoyam Programme is one of the seven crop-based programmes at the National Root Crops Research Institute, Umudike.   Cocoyam became a mandate crop for research during   the mid seventies when the Institute was charged specifically to study and improve holistically important root and tuber crops in Nigeria.  Cocoyam ranks third in importance after cassava and yam among the root and tuber crops cultivated and consumed in Nigeria. Currently, Nigeria is the world’s leading producer of cocoyam (taro), accounting for up to 3.7 million metric tones annually.  Cultivars of two species, Colocasia esculenta (taro) and Xanthosoma sagittifolium (tannia) are generally grown for food.  Nutritionally cocoyam is superior to cassava and yam and taro starch is also more readily digested.

PROGRAMME OBJECTIVES:

• Development of improved genotypes that possess desirable agronomic and culinary qualities as well as resistance to diseases.

• Multiplication and dissemination of healthy planting materials of elite  cultivars.

• Development of farmer-friendly and yield-enhancing low-cost cultural management practices.

• Development of environmentally-friendly technologies for the control of pre- and post-harvest biotic and abiotic stress factors.

• Diversification of value-added products obtained from corms and cormels to increase shelf life of ccoyam products and meet consumers acceptability.

RESEARCH HIGHLIGHTS:

Although no new improved genotypes of cocoyam have been developed largely due to difficulties not unconnected with conventional breeding methods in the crop, 10 distinct cultivars, of which three are Xanthosoma  species and seven Colocasia species, identified from germplasm collections at NRCRI, Umudike, are recommended for cultivation.    Concerted efforts by scientists in Cocoyam Programme over the years have resulted in the development of production packages that are beneficial to cocoyam farmers.  They include:

Cocoyam minisett technique for enhanced multiplication of cocoyam planting materials.

  Advantages include:

• Drastic reduction in seed outlay from 2 t/ha in farmers’ field to 0.5 t/ha, without compromising yield.

• Reduced cost of planting material by 40%.

• Increased yield output from 6-7 t/ha in farmers’ field to 15–20 t/ha.

• Manipulation of cormel size in Xanthosoma species through plant spacing in the field.

Development of improved field production package for high yield involving:

• Early planting

• Application of appropriate levels of inorganic and organic soil amendment materials.

• Mulching in open fields.

• Suitable inter-crops and time of introduction.

Cultural control of Cocoyam Root Rot Blight Complex (a devastating disease that attacks Xanthosoma sp) by: 

• Early planting (April/May)

• Use of fertilizer rich in potassium (80N, 30P and 100K)

• Well drained soil with no water logging

• Use of clean planting material.

Development of value-added products to extend shelf life and meet consumer acceptability from targeted cultivars.

• Examples:

• Cocoyam crisps/flakes

• Soup thickener powder

• Flour (for confectionary)

• Starch.

CURRENT CHALLENGES:

In spite of the advances made in cocoyam research, several factors remain as challenges to sustained cocoyam production in Nigeria.

• The ignorance of the nutritive value and diversities of food forms from cocoyam by a large percentage of the populace is a major limiting factor to general acceptability and extensive production of the crop.  The notion that cocoyam is a poor man’s crop is still prevalent and needs to be   dispelled through the extension of proper information about the crop.

• The recycling of planting material (corms/cormels) year by year results in the accumulation of pathogens in them and this translates to yield decline with time.  The 11% drop in national production figures between 2000 and 2004 (FAO 2001, 2004) may not be unconnected with this phenomenon.  Generation of ‘clean’ planting material through meristem tip culture and multiplication of these will not only stem this process but increase yield as well.

• A breakthrough in conventional breeding or through biotechnology is necessary to develop cultivars with more desirable traits, particularly resistance to diseases, other than those found in the local cultivars.  This will widen the current narrow genetic base in the country.

• Nigerian cocoyam needs to enter the international trade market and generate foreign exchange for Nigeria.  This will in turn stimulate production.

On-going studies:

• Induction of  flowering in cocoyam cultivars by chemical treatment

• Assessment of cassava starch-gelled medium for in vitro multiplication of cocoyam

• Efficiency of small-holder cocoyam production and storage in Anambra State

• Effect of post-harvest treatment on the control for rot in stored cocoyam planting materials

• Cost and return analysis of cocoyam production at NRCRI, Umudike.

 Scientists in the Programme

Name                                                           Qualification       Specialization                         E-mail Address

Dr.E.N.A.Mbanaso(Coordinator)                    Ph.D                    PlantPhysiol./TissueCulture        embanaso@yahoo.com 

 Mr, O Onwubiko                                          MSc.                    Agronomy

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