PGR News from the Pacific

Posted 5:38 PM by Tevita

Discovered: New technique to boost yam production

From: Businessday ( Courtesy of Luigi)

Nigeria is the centre of origin of the white yam (Dioscorea rotundata) because of the immense genetic diversity of this species in Nigeria. It therefore behoves Nigeria to have a pride of place in spearheading the development of yam production and processing technologies in the world like Brazil is doing in cassava.

Ndubisi Igwilo

It is in this vein that note is taken of the Minisett Technique of seed-yam multiplication developed by the National Root Crops Research Institute (NRCRI), Umudike, which has reached mass adoption stage within and without the frontiers of Nigeria.
Recently, the Dry- season Yam Production Technique was also developed in Nigeria, which is discussed hereunder.

Yam is a sun-loving crop and the tuber yield is increased by the amount of sunshine to which the crop is exposed. The bottleneck in achieving this increase is that yam tubers have only one month of the year when most of them sprout, irrespective of method of storage- that is the month of February. A few precocious tubers sprout in January and some laggards in March. When the tubers sprout in February, they remain vining in the barn of the upland farmers until the rainfall resumes in March/April in the Rain-Forest and Guinea Savanna zones of Nigeria.

But the onset of the rainy-season marks the beginning of increase in atmospheric cloudiness. In the months preceeding the rainy season is the dry-season with abundant sunshine.
It then becomes logical that the best time to plant yam tubers is at the beginning of the dry-season in order to increase yam tuber yield by combining the sunshine of the dry season with that of the early phase of the rainy season. White yam takes 7-8 months from sprouting to tuber maturity when the yam vines dry up.

Scientists at the Institute of Agricultural Research and Development (IAR&D), University of Port Harcourt, have developed a technique for changing the sprouting time of yam tubers to any month desired, instead of the month of February only.

When the seasonal growth cycle of yam is changed, it remains permanent because there is a natural mechanism in the yam plant to sustain the perpetuity of this change. When the yam tuber is changed to sprout towards the end of September and the sprouted tubers are planted about the middle of October, which is towards the end of the rainy season, the sprouts emerge early in November and begin to grow under maximum possible sunshine and mature in May. The young yam plant makes use of the residual soil moisture left by the rainfall. Watering, 2-3times a week, starts in December and ends in February. Mulching with dry grass reduces the frequency of watering .

In locations like Port Harcourt near large bodies of water, occasional convectional rains occur in the dry season to re-charge the soil. Planting on beds is better than planting on mounds in the dry season, suggesting that yams can now be grown at the backyard watered from the tap with hose, watering can or bucket like vegetable gardens.

The rains take over in the month of March till maturity in May. By the month of May, some of the upland yam farmers may still be planting. Thus Nigeria can now have two crops of yam in a year- the dry season crop (October -May) and the rainy season crop (March-October), ensuring availability of fresh tubers in the market all the year round.

By changing the seasonal growth cycle of yam, every part of Nigeria can now grow yams by irrigation or watering. Yams planted in the dry season do not require stakes to support the yam vines. Previous research results at NRCRI, Umudike, had shown that the reason why yams are staked is to remove the yam vines from the physiological damage which flood water causes unstaked yams during the rainy season in the Rain-forest zone of Nigeria. Yams are grown without stakes in the Guinea Savanna zone. Hence staking of yams in the dry season does not increase the tuber yield of yams.

It has been estimated that staking constitutes 25 per cent of the total outlay in yam production and cutting stakes from the bushes and secondary forests impacts negatively on the ecosystem. Planting yams without stakes in the dry-season therefore eliminates a major cost item in yam production and saves the ecosystem. Yield of dry season crop is also double the yield of the rainy season crop because of exposure to brighter and longer duration of sunshine, contributing to make the farming effort more profitable.

In the seasonally- flooded locations along the River Niger such as Otuocha/Aguleri in Anambra state, farmers plant their yams around December/January. These tubers continue to remain dormant in the ground until the obligate sprouting time of February. The sprouts then emerge and begin to grow and develop because there is adequate residual moisture in their soils to sustain yam growth throughout the dry- season.

The yam plants are exposed to the sunny period of February to May/June and that explains why Otuocha/Aguleri farmers produce large, ceremonial tubers. This location and their neighbours contribute the bulk of the yams sold in the Nigerian markets between the end of July and November.

These yams which sprouted in February should mature in September/ October but they are usually harvested prematurely early in July 2-3months before full maturity. A close look at the tail of these tubers will show that they are light-yellow in colour, suggesting that they were still growing when they were harvested.

The premature harvesting is caused by the fear of the River Niger overflowing its banks in July, August and September, causing flooding. It requires only 3-4 days of flooding for yam tubers to get rotten in the ground.

Therefore, if the farmers of Otuocha/Aguleri adopt this technology and plant sprouted yams in October/November, they will harvest mature tubers in May/June, long before the River Niger overflows its banks from the end of July.

To catch the early market, the farmers may still harvest their yams prematurely in March/April. The farmers will also grow their yams without stakes and harvest increased tuber yield because of exposure to more insolation, making the farming exercise more profitable. These yams harvested in May/June will sprout in October/November to continue the cycle.
In all the seasonally- flooded plains along the major rivers of Nigeria- the fadamas- yams can be grown with this new technology. Indeed, it has been estimated that the fresh -water zone of the Niger Delta has the potential of producing 30 million metric tonnes of yam tubers in the dry-season annually.

This potential exists not only in the flooded pains of the River Niger but also of River Benue and other rivers. Infact the dry- season yam production activity can exist conveniently in relay with swamp rice in these seasonally inundated areas.

Some dams exist in Nigeria especially in the north and yams should be included in the dry- season crop production programme of these irrigated areas.Water supply through the boreholes is rapidly increasing in Nigeria and farmers in the upland locations can grow yams in the dry-season by watering.

In Nigeria, yams are grown traditionally during the rainy-season in upland and lowland areas. When this production is added to that produced in the dry-season by irrigation, Nigeria will be harvesting a basket full of yams for domestic food self- sufficiency and surpluses for processing and export.



	A blog maintained by Tevita Kete, PGR Officer Secretariat of the Pacific Community (SPC), Suva, Fiji Islands
This weblog documents the activities of Pacific Agricultural Genetic Resources Network (PAPGREN), along with other information on plant genetic resources (PGR) in the Pacific. The myriad varieties found within cultivated plants are fundamental to the present and future productivity of agriculture. PAPGREN, which is coordinated by the Land Resources Division of the Secretariat of the Pacific Community (SPC), helps Pacific countries and territories to conserve their crop genetic diversity sustainably, with technical assistance from the Bioversity International (BI) and support from NZAID and ACIAR. SPC also hosts the Centre of Pacific Crops and Trees (CEPaCT). The CEPaCT maintains regional in vitro collections of crops important to the Pacific and carries out research on tissue culture technology. The CEPaCT Adviser is Dr Mary Taylor (MaryT@spc.int), the CEPaCT Curator is Ms Valerie Tuia (ValerieT@spc.int). PAPGREN coordination and support IPGRI ACIAR NZAID CTA SPC PAPGREN CEPaCT Click on the thumbnail to see a map of the locations of Pacific genebanks. Click here to download a regional directory of genebanks in the Pacific, including information on their location, contact details and holdings. PAPGREN partners Mr William Wigmore Director of Research Ministry of Agriculture Department of Resources & Development P.O. Box 96 Rarotonga Cook Islands Tel: (682) 28711-29720 Fax: (682) 21881 Email: cimoa@oyster.net.ck Mr Adelino S. Lorens Chief Agriculture Pohnpei Office of Economic Affairs P.O. Box 1028 Kolonia Pohnpei 96941 Federated States of Micronesia Tel: (691) 3202400 Fax: (691) 3202127 Email: pniagriculture@mail.fm Dr Lois Englberger Island Food Community of Pohnpei Research Advisor P.O. Box 2299 Kolonia Pohnpei 96941 Federated States of Micronesia Email: nutrition@mail.fm Mr Apisai Ucuboi Director of Research Ministry of Agriculture, Fisheries & Forest Koronivia Research Station P.O. Box 77 Nausori Fiji Islands Tel: (679) 3477044 Fax: (679) 3477546-400262 Email: apisainu@yahoo.com Dr Maurice Wong Service du Developpement Rural B.P. 100 Papeete Tahiti 98713 French Polynesia Tel: (689) 42 81 44 Fax: (689) 42 08 31 Email: maurice.wong@rural.gov.pf Mr Tianeti Beenna Ioane Head, Research Section Division of Agriculture Ministry of Environment, Lands and Agricultural Development P.O. Box 267 Tarawa Kiribati Tel: (686) 28096-28108-28080 Fax: (686) 28121 Email : agriculture@tskl.net.ki; Beenna_ti@yahoo.com Mr Frederick Muller Secretary Ministry of Resources & Development P.O. Box 1727 Majuro 96960 Marshall Islands Tel: (692) 6253206 Fax: (692) 6257471 Email: rndsec@ntamar.net Mr Herman Francisco Director Bureau of Agriculture Ministry of Resources & Development P.O. Box 460 Koror 96940 Palau Tel: (680) 4881517 Fax: (680) 4881725 Email: bnrd@pnccwg.palaunet.com Ms Rosa Kambuou Principal Scientist PGR NARI Dry Lowlands Programme Laloki Agricultural Research Station P.O. Box 1828 Boroko National Capital District Papua New Guinea Tel: (675) 3235511 Fax: (675) 3234733 Email: kambuou@global.net.pg Ms Laisene Samuelu Principal Crop Development Officer Crops Division Ministry of Agriculture, Forests, Fisheries & Meteorology P.O. Box 1874 Apia Samoa Tel: (685) 23416-20605 Fax: (685) 20607-23996 Email: lsamuelu@lesamoa.net Mr Jimi Saelea Director of Research Department of Agriculture and Livestock P.O. Box G13 Honiara Guadalcanal Solomon Islands Tel: (677) 27987 Mr Tony Jansen Planting Materials Network Kastom Gaden Association Burns Creek, Honiara P.O. Box 742 Honiara Solomon Islands Tel: (677) 39551 Email: kastomgaden@solomon.com.sb Mr Finao Pole Head of Research Ministry of Agriculture & Forests P.O. Box 14 Nuku'alofa Tonga Tel: (676) 23038 Fax: (676) 24271 Email: thaangana@hotmail.com Mr Frazer Bule Lehi Head of Research Department of Agriculture & Rural Development Private Mail Bag 040 Port Vila Vanuatu Tel: (678) 22525 Fax: (678) 25265 Email: flehi@hotmail.com Other links Other CROP agencies Forum Secretariat University of the South Pacific SPREP Pacific biodiversity Biodiversity hotspots Breadfruit Institute Hawaiian native plants Intellectual property rights Nature Conservancy PBIF PestNet SIDS WWF South Pacific Program Other Pacific organizations Foundation of the Peoples of the South Pacific Micronesian Seminar Te Puna web directory Pacific news Cafe Pacific CocoNET Wireless Island Directory Pacific Islands News Pacific Islands Report Pacific Islands Travel Pacific Time South Pacific travel Time Pacific Interested in GIS? DIVA-GIS	Wednesday, May 30, 2007 Posted 5:38 PM by Tevita Discovered: New technique to boost yam production From: Businessday ( Courtesy of Luigi) Nigeria is the centre of origin of the white yam (Dioscorea rotundata) because of the immense genetic diversity of this species in Nigeria. It therefore behoves Nigeria to have a pride of place in spearheading the development of yam production and processing technologies in the world like Brazil is doing in cassava. Ndubisi Igwilo It is in this vein that note is taken of the Minisett Technique of seed-yam multiplication developed by the National Root Crops Research Institute (NRCRI), Umudike, which has reached mass adoption stage within and without the frontiers of Nigeria. Recently, the Dry- season Yam Production Technique was also developed in Nigeria, which is discussed hereunder. Yam is a sun-loving crop and the tuber yield is increased by the amount of sunshine to which the crop is exposed. The bottleneck in achieving this increase is that yam tubers have only one month of the year when most of them sprout, irrespective of method of storage- that is the month of February. A few precocious tubers sprout in January and some laggards in March. When the tubers sprout in February, they remain vining in the barn of the upland farmers until the rainfall resumes in March/April in the Rain-Forest and Guinea Savanna zones of Nigeria. But the onset of the rainy-season marks the beginning of increase in atmospheric cloudiness. In the months preceeding the rainy season is the dry-season with abundant sunshine. It then becomes logical that the best time to plant yam tubers is at the beginning of the dry-season in order to increase yam tuber yield by combining the sunshine of the dry season with that of the early phase of the rainy season. White yam takes 7-8 months from sprouting to tuber maturity when the yam vines dry up. Scientists at the Institute of Agricultural Research and Development (IAR&D), University of Port Harcourt, have developed a technique for changing the sprouting time of yam tubers to any month desired, instead of the month of February only. When the seasonal growth cycle of yam is changed, it remains permanent because there is a natural mechanism in the yam plant to sustain the perpetuity of this change. When the yam tuber is changed to sprout towards the end of September and the sprouted tubers are planted about the middle of October, which is towards the end of the rainy season, the sprouts emerge early in November and begin to grow under maximum possible sunshine and mature in May. The young yam plant makes use of the residual soil moisture left by the rainfall. Watering, 2-3times a week, starts in December and ends in February. Mulching with dry grass reduces the frequency of watering . In locations like Port Harcourt near large bodies of water, occasional convectional rains occur in the dry season to re-charge the soil. Planting on beds is better than planting on mounds in the dry season, suggesting that yams can now be grown at the backyard watered from the tap with hose, watering can or bucket like vegetable gardens. The rains take over in the month of March till maturity in May. By the month of May, some of the upland yam farmers may still be planting. Thus Nigeria can now have two crops of yam in a year- the dry season crop (October -May) and the rainy season crop (March-October), ensuring availability of fresh tubers in the market all the year round. By changing the seasonal growth cycle of yam, every part of Nigeria can now grow yams by irrigation or watering. Yams planted in the dry season do not require stakes to support the yam vines. Previous research results at NRCRI, Umudike, had shown that the reason why yams are staked is to remove the yam vines from the physiological damage which flood water causes unstaked yams during the rainy season in the Rain-forest zone of Nigeria. Yams are grown without stakes in the Guinea Savanna zone. Hence staking of yams in the dry season does not increase the tuber yield of yams. It has been estimated that staking constitutes 25 per cent of the total outlay in yam production and cutting stakes from the bushes and secondary forests impacts negatively on the ecosystem. Planting yams without stakes in the dry-season therefore eliminates a major cost item in yam production and saves the ecosystem. Yield of dry season crop is also double the yield of the rainy season crop because of exposure to brighter and longer duration of sunshine, contributing to make the farming effort more profitable. In the seasonally- flooded locations along the River Niger such as Otuocha/Aguleri in Anambra state, farmers plant their yams around December/January. These tubers continue to remain dormant in the ground until the obligate sprouting time of February. The sprouts then emerge and begin to grow and develop because there is adequate residual moisture in their soils to sustain yam growth throughout the dry- season. The yam plants are exposed to the sunny period of February to May/June and that explains why Otuocha/Aguleri farmers produce large, ceremonial tubers. This location and their neighbours contribute the bulk of the yams sold in the Nigerian markets between the end of July and November. These yams which sprouted in February should mature in September/ October but they are usually harvested prematurely early in July 2-3months before full maturity. A close look at the tail of these tubers will show that they are light-yellow in colour, suggesting that they were still growing when they were harvested. The premature harvesting is caused by the fear of the River Niger overflowing its banks in July, August and September, causing flooding. It requires only 3-4 days of flooding for yam tubers to get rotten in the ground. Therefore, if the farmers of Otuocha/Aguleri adopt this technology and plant sprouted yams in October/November, they will harvest mature tubers in May/June, long before the River Niger overflows its banks from the end of July. To catch the early market, the farmers may still harvest their yams prematurely in March/April. The farmers will also grow their yams without stakes and harvest increased tuber yield because of exposure to more insolation, making the farming exercise more profitable. These yams harvested in May/June will sprout in October/November to continue the cycle. In all the seasonally- flooded plains along the major rivers of Nigeria- the fadamas- yams can be grown with this new technology. Indeed, it has been estimated that the fresh -water zone of the Niger Delta has the potential of producing 30 million metric tonnes of yam tubers in the dry-season annually. This potential exists not only in the flooded pains of the River Niger but also of River Benue and other rivers. Infact the dry- season yam production activity can exist conveniently in relay with swamp rice in these seasonally inundated areas. Some dams exist in Nigeria especially in the north and yams should be included in the dry- season crop production programme of these irrigated areas.Water supply through the boreholes is rapidly increasing in Nigeria and farmers in the upland locations can grow yams in the dry-season by watering. In Nigeria, yams are grown traditionally during the rainy-season in upland and lowland areas. When this production is added to that produced in the dry-season by irrigation, Nigeria will be harvesting a basket full of yams for domestic food self- sufficiency and surpluses for processing and export. * Comments: Post a Comment	Archive October 2002 November 2002 December 2002 January 2003 February 2003 March 2003 April 2003 May 2003 June 2003 July 2003 August 2003 September 2003 October 2003 November 2003 December 2003 January 2004 February 2004 March 2004 April 2004 May 2004 June 2004 July 2004 August 2004 September 2004 October 2004 November 2004 December 2004 January 2005 February 2005 March 2005 April 2005 May 2005 June 2005 July 2005 August 2005 September 2005 October 2005 November 2005 December 2005 January 2006 February 2006 March 2006 April 2006 May 2006 June 2006 July 2006 August 2006 September 2006 October 2006 November 2006 December 2006 January 2007 February 2007 March 2007 April 2007 May 2007 June 2007 July 2007 August 2007 September 2007 October 2007 November 2007 December 2007 January 2008 February 2008 March 2008 April 2008 May 2008 June 2008 July 2008 August 2008 September 2008 October 2008 November 2008 December 2008 January 2009 February 2009 March 2009 April 2009 May 2009 June 2009 July 2009 August 2009 September 2009 October 2009 November 2009 January 2010 RSS Feed Alternative feed Contact Tevita Something new: Agrobiodiversity Weblog: For discussions of conservation and sustainable use of the genetic resources of crops, livestock and their wild relatives. PestNet: For on-line information, advice and pest identification for the Pacific and beyond. Contact: Grahame Jackson. Pacific Mapper: For on-line mapping of point data over satellite images of the Pacific provided by Google Maps. DIVA-GIS: For free, easy-to-use software for the spatial analysis of biodiversity data.