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RESEARCH AND APPLIED TECHNOLOGY

RECHERCHE ET TECHNOLOGIE APPLIQUÉE

INVESTIGACIÓN Y TECNOLOGÍA APLICADA

New approach to germplasm exchange for a sustainable increase of rice biodiversity and production in Africa

R.G. Guei and K. Traore

West Africa Rice Development Association (WARDA), 01 B.P. Bouaké 01, Côte d'Ivoire

INTRODUCTION

Both consumption of rice and the adoption of new rice varieties are increasing faster than any other food crop in many African countries. It is the staple food crop in Côte d'Ivoire, the Gambia, Guinea, Guinea-Bissau, Liberia, Madagascar, Mauritania, Senegal and Sierra Leone, among others (Matlon, Randolph and Guei, 1998). Fortunately, considerable potential exists on the continent for expanding the rice-producing areas and increasing productivity. Rice in Africa is subjected to several stresses that are specific to the continent. The rice yellow mottle virus, the African rice gall midge and the cosmopolitan rice blast are among the major biological stresses. Other important insect pests include Diopsis and Maliarpha. Among abiotic stresses, mid-altitude low temperatures, infertile soils and iron toxicity have prominence.

Rice genetic diversity at the farm community level in Africa is composed of both wild and cultivated species. Cultivated rice species include Oryza glaberrima, the indigenous African rice species and Oryza sativa, a rice species introduced to Africa from Asia. Oryza sativa encompasses landraces and improved varieties. Traditional rice varieties, although long-maturing, tall and low-yielding, are mainly cultivated by upland rice farmers (Becker, 1991; Becker and Diallo, 1992). They constitute a good source of unique genes for stress tolerance.

During the last decade, several improved varieties have been released in Africa and the adoption rate is increasing rapidly (Adesina and Seidi, 1995; Adesina and Zinnah, 1992, 1993). Most of the new lines are adapted to low input management and are more weed-competitive and input-responsive. Hence, new emerging commercial varieties are becoming more and more competitive and adapted to the new farming environments and mentality. As a consequence, landraces are gradually disappearing and the total area planted to local varieties is decreasing (Guei, 2000). Fortunately, other types of genetic material being made available to farmers are contributing to the reconsti-tution of a new genetic diversity. Since 1992, the West Africa Rice Development Association (WARDA) successfully crossed O. glaberrima and O. sativa for African upland rice farmers (Jones, Semon and Aluko, 1997). Several interspecific progenies have been derived from these crosses and are being grown by farmers. These interspecific hybrids, named "New Rice for Africa (NERICA)", have increased on-farm agrobiodiversity as they are being widely spread in upland and lowland rice-growing ecologies of Africa. NERICAs are more robust, stress-tolerant and weed-competitive. This new rice constitutes a new plant type that has enriched the total genetic diversity at community levels. Genetic materials distributed in Africa come from sources worldwide, although 72 percent are generated by the breeding programmes of WARDA, the International Institute for Tropical Agriculture (IITA) and the national agricultural research programmes of Africa. However, most of the parental materials used in crosses have been introduced from Asia, Latin America and other parts of the world.

The International Network for Genetic Evaluation of Rice (INGER-Africa), a germplasm exchange and evaluation network now being operated by WARDA, has a mission to ensure a wide and rapid dissemination of new rice germplasm in Africa. This network was created because most national research programmes in Africa have limited access to diverse genetic materials and rely on international centres to broaden their genetic base.

Although national research institutions in Africa have benefited from this network for several years, shortcomings were identified by them in 1990 and a new germplasm exchange approach (new INGER-Africa) was initiated by WARDA in 1991. The objective of this paper is to show how this innovative germplasm exchange approach has hastened the dissemination and adoption of new and better varieties in Africa in the past ten years and to show its contribution to increased biodiversity at the farm community levels.

HISTORICAL BACKGROUND

In 1975, the International Rice Research Institute (IRRI) launched the International Rice Testing Pro-gramme (IRTP) as a systematic global programme for the collection, distribution and testing of rice genetic materials. This programme was later redesignated the International Network for Genetic Evaluation of Rice (INGER) (Chaudhary et al., 1998). The overall objec-tives of INGER have been to link national rice improvement programmes and international centres and to promote genetic diversity for different ecosystems through global exchange, evaluation and utilization of improved breeding materials originating from sources worldwide.

The old INGER-Africa mechanism

Before its transfer to WARDA in April 1997, INGER-Africa had 16 types of regional rice evaluation trials/nurseries targeted for upland, irrigated, rainfed lowland and mangrove ecosystems and the biological stresses of blast and rice yellow mottle virus. For each ecosystem, there were four types of nursery: the preliminary screening set (PSS), the observational nursery (ON), the advanced trial (AT) and the stress nurseries.

From 1985 to 1996, INGER-Africa distributed about 3 726 nursery sets to African countries. In West Africa, Côte d'Ivoire, the Gambia, Ghana, Liberia, Nigeria and Senegal were the highest recipients while Burundi, Cameroon, Ethiopia, Kenya, the United Republic of Tanzania and Zambia were the major recipients in the eastern, central and southern African regions.

Shortcomings of the old INGER-Africa mechanism

The old INGER-Africa mechanism only allowed for a fixed number of nurseries (16) and a fixed number of entries per nursery (20, 100, 150, etc.). Entries within a nursery set included different plant characteristics, notably plant height, growth duration, disease and insect resistance, and grain size. Furthermore, nursery sets were compiled according to criteria based on the results of previous nurseries, without the full participation of national agricultural research systems (NARS) scientists, the main beneficiaries of INGER-Africa's nurseries. The same entries per nursery were dispatched to all countries regardless of their varietal preferences and their capacity to handle the volume in their breeding programme. As a result, national breed-ers were often overloaded and, while hundreds of entries were introduced, only a few varieties adapted to local conditions would be selected. Moreover, not all nurseries received were effectively conducted by NARS scientists.

The new approach to germplasm exchange (new INGER-Africa)

The shortcomings of the old INGER-Africa mechanism were recognized by national rice scientists in West and Central Africa in 1990. In order to improve its effectiveness in African conditions, a new germplasm exchange mechanism was initiated in 1991 to modify certain operational aspects of the old INGER-Africa. This mechanism was formalized in 1994 by the creation at WARDA of the Germplasm Exchange Unit.

Changes in the old INGER-Africa operations were needed to make it more adapted to the specific conditions and needs of African NARS. These include:

With the new approach, nurseries are designed to fit NARS' needs, and composed according to the principles that they should:

Along with the above principles, the new nurseries have the following objectives:

This approach brings more flexibility and responsive-ness to the diverse needs of different national programmes. Contrary to the former mechanism, where the same nurseries were sent across boundaries, with this approach nurseries are tailored to meet the specific needs of every national programme. Moreover, nurseries are supplied on the basis of requests by NARS scientists and taking into account the plant characteristics best suited to their particular environ-mental conditions. It is noteworthy that since the creation of WARDA research task forces in 1991, every year members of task forces who are also members of the new INGER-Africa come together during their annual meeting to plan their activities and report on their activities over the previous year. This mechanism, which did not exist previously, has contributed tremendously to increasing the interaction among scientists and has improved the rate of return of trial results.

ACHIEVEMENTS

Increased NARS participation

International centres are the main sources of rice germplasm in Africa. Nevertheless, since the creation of the Germplasm Exchange Unit at WARDA, the level of interaction between breeders and their participation in the regional germplasm exchange network has increased. They recognize the need to use the new mechanism to evaluate their own materials in a wide range of environmental conditions. They are gradually nominating their own bred or selected lines for inclusion in regional nurseries (Figure 1).


FIGURE 1

Percentage of varietal nomination from national agricultural research systems versus international agricultural research centres

From very few varietal nominations prior to 1994, the nominations from national programme scientists had grown to 62.4 percent by 1996. This clearly indicates that the germplasm exchange and evaluation network in Africa was no longer a one-way germplasm flow from international centres to the national programmes, a development that has helped to increase genetic diversity.

Increased flexibility in germplasm request and supply

As indicated above, to avoid overloading NARS and to increase their efficiency in conducting regional trials, the criteria for composing nurseries are now determined with greater participation of national breeders and not by the INGER-Africa coordinator alone. National breeders are therefore given the opportunity to determine the number of entries they can handle. They can specify the varietal characteristics of interest, such as plant height, grain quality, growth duration and stress reactions. Seeds are supplied only on request.

Increased proportion of useful genetic materials

National programmes use their own criteria (breeding objectives, farmers' preference, market demand) to request genetic materials of interest to them. The number of entries and plant characteristics are indicated. This has substantially increased the number of useful materials at national levels, contributing to a rapid increase of genetic variability which leads to a faster genetic gain.

Increased genetic diversity at regional and national levels

The underlying principle in nursery composition is to provide genetic diversity. The number of sister lines is kept to a minimum in a particular nursery and for a particular country. As stated above, only NARS varietal preferences are taken into account; nurseries are composed to meet their specific needs so that they do not necessarily receive the same entries or the same nurseries. Also, rice germplasm distributed to a particular nursery comes from several countries or institutions in Africa, Asia, Latin America, Europe and the United States.

In addition, although most of these rice germplasm were created or selected in Africa, their parents came from a wider range of sources. The most common origins of cross-parents used in the past 20 years are Argentina, Bangladesh, Brazil, China, Colombia, Côte d'Ivoire, the Democratic Republic of the Congo, the Gambia, Guinea, India, Indonesia, Mali, Mozambique, Nigeria, the Philippines, Senegal, Sierra Leone, Sri Lanka, Thailand, Taiwan Province of China and the international research centres such as IRRI, IITA, WARDA and the International Institute for Tropical Agriculture (CIAT) (Table 1). Figures 2 and 3 show the quantity of seed samples and nurseries dispatched and evaluated at regional levels, per ecology, in recent years. Table 2 shows the total number of varieties dispatched to each country from 1995 to 2000. As a result, a greater diversity of improved varieties has been introduced, released and grown by rice farmers in Africa.


FIGURE 2

Number of nurseries dispatched in the region per year and per ecology, 1992-2000


TABLE 1

Varieties selected through New INGER, released and grown by farmers in Africa

Variety

Cross

Source

Selection criteria

Ecology

Year of release

Burkina Faso

IR 64

GP 15 / TN 1

IRRI

Poor soil, low nutrient

Irrigated

1989

ITA 123 (FKR 28)

MUTANT OF OS 6

IITA

Grain quality

Irrigated

1983

RP 1125-1526-2-2-3 (FKR34)

VIKRAM / PTB 2

India

High yield

Irrigated

1984

SAHEL 108 (IR 13240-108-2-2-3)

IR 305 / BABAWEE // IR 36

IRRI

High yield, blast, high input

Irrigated

1992

TOX 728-1

MAHSURI / IET 1444

IITA

Adaptability, blast, lodging

Rainfed

1984

FARO 43 (CAN 6675)

IREM 293-B / IAC 81-176

Brazil

Blast, lodging

Upland

1992

FARO 45 (ITA 257)

IRAT 13/DOURADO PRECOCE# 689 // TOX 490-1

Nigeria

High yield

Upland

1987

TOX 1011-4-A2

IRAT 13/DP 689 // TOX 490-1

WARDA

Blast, drought

Upland

1992

WAB 56-125

IDSA 6 / IAC 164

WARDA

Blast, drought

Upland

1992

WAB 56-39

IDSA 6 / IAC 164

WARDA

High yield, blast

Upland

1992

WAB 56-50

IDSA 6 / IAC 164

WARDA

Acidity, blast, drought

Upland

1982

Cameroon

BKN 7033

 

Thailand

High yield

Irrigated

n.a.1

BKN 7167

 

Thailand

High yield

Irrigated

n.a.

IR 46

IR 1814 // IR 1366-120-3-1/IR 1539-37-3-1

IRRI

High yield

Irrigated

n.a.

WAB 384-B-B-1-2

ITA 184 / ROK 16

WARDA

High yield

Upland

n.a.

WAB 96-1-1

ITA 257 / YS 121

WARDA

Low input, weed

Upland

n.a.

Chad

BW 348-1

 

Sri Lanka

High yield

Rainfed

1997

CT 6240-12-2-2-3-6P

N GOVIE / IRAT 124 // COL.1 / M 312A

CIAT

High yield

Rainfed

1996

FARO 20

BPA 76

Philippines

High yield

Rainfed

1996

TOX 728-1

MAHSURI / IET 1444

IITA

Adaptability, blast, lodging

Rainfed

1993

Côte d'Ivoire

WITA 1

ITA 212 / IR 13149-19-1

WARDA

Iron toxicity., blast

Irrigated

1997

WITA 3

11975 / IR 13146-45-2-3

WARDA

Iron toxicity., blast

Irrigated

1997

WITA 7

TOX 891-212-1-201-1-105 / TOX 3056-5-1

WARDA

RYMV,2 blast

Irrigated

1997

WITA 8

TOX 891-212-1-201-1-105 / TOX 3056-5-1

WARDA

RYMV

Irrigated

1997

WITA 9

IR 2042-178-1 / CT 19

WARDA

RYMV

Irrigated

1997

WAB 638-1

DR 2 / DR 2

WARDA

Quality

Rainfed

1997

WAB 450-11-1-P31-1-HB (NERICA 2)

WAB 56-104 / CG 14

WARDA

Weed, early

Upland

2000

WAB 450-I-B-P-38-HB (NERICA 1)

WAB 56-104 / CG 14

WARDA

Weed, early

Upland

2000

WAB 56-104

IDSA 6 / IAC 164

WARDA

Blast

Upland

1997

WAB 56-125

IDSA 6 / IAC 164

WARDA

Blast, drought

Upland

1997

WAB 56-50

IDSA 6 / IAC 164

WARDA

Acidity, blast, drought

Upland

1997

WAB 96-1-1

ITA 257 / YS 121

WARDA

Low input, weed

Upland

1997

Gambia

IR 28128-45-3-3-2

IR 36 / IR 10154-23-3-3 // IR 9129-209-2-2-2-1

IRRI

Poor soil

Irrigated

n.a.

IR 64

GP 15 / TN 1

IRRI

Poor soil, low nutrient

Irrigated

1993

ITA 212

BG 90-2*4 / TETEP

IITA

Salinity

Irrigated

1992

ITA 222

MAHSURI / IET 1444

IITA

Salinity

Irrigated

1992

ROHYB 4

RH 2 / T 52-10-1

WARDA

High yield

Mangrove

n.a.

ROHYB 6

CCA / RH 22

WARDA

High yield

Mangrove

n.a.

ROK 5

SR 26 / WELLINGTON

Sierra Leone

Salinity

Mangrove

1990

WAR 1

IR 4595-4-1-5 / PA FANT 213

WARDA

Salinity, acidity, high input

Mangrove

1992

WAR 115-108-1-8

ROHYB 15/WAR 3-3-B-2 // IR 14753-120-3

WARDA

High yield

Mangrove

1993

WAR 77-3-2-2

IR 4595-4-1-5 / PA FANT 213

WARDA

Salinity, lodging, acidity, high input

Mangrove

1992

WAB 56-50

IDSA 6 / IAC 164

WARDA

Acidity, blast, drought

Upland

1995

Ghana

         

TOX 3108-56-4-2-2-2

DJ 12-539 / IR 46

IITA

Grain quality, Insect/disease resistance

Rainfed

1997

Variety

Cross

Source

Selection criteria

Ecology

Year of release

Guinea

GAMBIACA

 

Benin

Shallow rainfed

Irrigated

1975

B 38 D2

 

Sierra Leone

Salinity

Mangrove

1995

BW 295-5

OB 678 / BW 254-1

Sri Lanka

High yield

Mangrove

1997

ROHYB 6

CCA / RH 22

WARDA

High yield

Mangrove

1993

ROK 5

SR 26 / WELLINGTON

Sierra Leone

Salinity

Mangrove

1992

WAR 1

IR 4595-4-1-5 / PA FANT 213

WARDA

Salinity, acidity, high input

Mangrove

1998

WAR 73-1-M-1

RICE MILL / I. MAHSURI

WARDA

Salinity

Mangrove

1996

WAR 77-3-2-2

IR 4595-4-1-5 / PA FANT 213

WARDA

Salinity, lodging, acidity, high input

Mangrove

1996

BG 90-2

(PETA 3 * TN 1) / REMADJA

Sri Lanka

High yield

Rainfed

n.a.

BOUAKE 189

B 189B-52-8-3-1

Indonesia

Favorable, high yield

Rainfed

n.a.

SUAKOKO 8 (ROK 24)

SIAM 25 / 3*MALUNJA

Liberia

Iron toxicity

Rainfed

1994

CK 7

 

Brazil

High yield, blast

Upland

n.a.

IDSA 16 (IRAT 216)

IRAT 11 / IRAT 13

Côte d'Ivoire

High yield

Upland

n.a.

IDSA 6

COLOMBIA / M 312A

Côte d'Ivoire

Blast, high yield, drought

Upland

1995

IDSA 85

ARAGUAIA / CUIABANA

Côte d'Ivoire

Grain quality

Upland

1998

IRAT 112

IRAT 13 / DOURADO PRECOCE

Côte d'Ivoire

Blast

Upland

1985

IRAT 114 (FARO 39)

IRAT 13 / IRAT 10

Burkina Faso

Blast, drought

Upland

1985

LAC 23

Local selection

Liberia

Drought

Upland

n.a.

TOX 1011-4-A2

IRAT 13/DP 689 // TOX 490-1

WARDA

Blast, drought

Upland

1995

WAB 450-I-B-P-28-HB (NERICA 3)

WAB 56-104 / CG 14

WARDA

Weed, early

Upland

1998

WAB 450-I-B-P-38-HB (NERICA 1)

WAB 56-104 / CG 14

WARDA

Weed, early

Upland

1998

WAB 450-I-B-P-91-HB (NERICA 4)

WAB 56-104 / CG 14

WARDA

Weed, early

Upland

1998

WABIS 675

 

WARDA

Weed, high yield

Upland

1998

Guinea Bissau

BG 367-4

BG 280-1*2 / PTB 33

Sri Lanka

High yield

Mangrove

1994

BG 380-2

BG 90-2*4 / OB 677

Sri Lanka

High yield

Mangrove

1994

BG 400-1

OB 678 / IR 20/H 4

Sri Lanka

High yield

Mangrove

1994

CK 4

TCHINKAN 30 / IR 4422

Guinea

High yield

Mangrove

1993

DJ 684-D

 

Senegal

High yield

Mangrove

1993

RD 15

 

Sierra Leone

High yield

Mangrove

1992

ROHYB 4

RH 2 / T 52-10-1

WARDA

High yield

Mangrove

1993

ROHYB 6

CCA / RH 22

WARDA

High yield

Mangrove

1993

ROK 5

SR 26 / WELLINGTON

Sierra Leone

Salinity

Mangrove

1984

WAR 1

IR 4595-4-1-5 / PA FANT 213

WARDA

Salinity, acidity, high input

Mangrove

1993

WAR 102-1-3-1

DJUKEME / IR 3464-96-3-3-1-1

WARDA

High yield

Mangrove

1993

WAR 115-111-2-3

ROHYB 15/WAR 3-3-B-2 // IR 14753-120-3

WARDA

High yield

Mangrove

1993

WAR 77-3-2-2

IR 4595-4-1-5 / PA FANT 213

WARDA

Salinity, Lodging Acidity, High input

Mangrove

1993

WAR 81-2-1-2

MINIKU 33A / BAYER PUTIH 462-10

WARDA

High yield

Mangrove

1993

BG 90-2

(PETA 3 * TN 1) / REMADJA

Sri Lanka

High yield

Rainfed

1990

IDSA 16 (IRAT 216)

IRAT 11 / IRAT 13

Côte d'Ivoire

High yield

Upland

1997

IRAT 109

IRAT 13 /IRAT 10

Côte d'Ivoire

High yield

Upland

1997

IRAT 110

IRAT 13 /IRAT 10

Côte d'Ivoire

High yield

Upland

1997

IRAT 112

IRAT 13 / DOURADO PRECOCE

Côte d'Ivoire

Blast

Upland

n.a.

PEKIN

 

Gambia

High yield

Upland

1997

WAB 56-50

IDSA 6 / IAC 164

WARDA

Acidity, blast, drought

Upland

1997

Liberia

WAB 56-104

IDSA 6 / IAC 164

WARDA

Blast

Upland

1998

WAB 56-50

IDSA 6 / IAC 164

WARDA

Acidity, blast, drought

Upland

1998

WAB 96-1-1

ITA 257 / YS 121

WARDA

Low input, weed

Upland

1998

Madagascar

WITA 10

IR 2042-178-1./.CT 19 / IR 9828-91-2-3

WARDA

RYMV

Irrigated

n.a.

Year

Cross

Source

Selection criteria

Ecology

Year of release

Mali

AD 9246

ADT 31 / AD 198

India

High yield

Irrigated

2000

BG 90-2

(PETA 3 * TN 1) / REMADJA

Sri Lanka

Grain quality, high input, lodging

Irrigated

1987

ECIA 36-2-2-1-4

CARIBE 1 / P 896-8-7-3-2-1

Cuba

High yield

Irrigated

1999

IR 1561-228-3-3

IR 579-48-1-2 / IR 747B2-6-3

IRRI

High yield

Irrigated

n.a.

IR 32307-107

IR 13240-108-2-2-3 / IR 9129-202-2-2-2-1

IRRI

High yield, grain quality

Irrigated

1995

LEIZHONG 152

 

Taiwan Province of China

High yield

Irrigated

1999

RPK N2

   

High yield, grain quality

Irrigated

1999

BG 90-2

(PETA 3 * TN 1) / REMADJA

Sri Lanka

High yield

Rainfed

n.a.

BOUAKE 189

B 189B-52-8-3-1

Indonesia

Favorable, high yield

Rainfed

n.a.

KHAODAWK MALI 105

 

Thailand

Grain quality

Rainfed

1998

Mauritania

SAHEL 108 (IR 13240-108-2-2-3)

IR 305 / BABAWEE // IR 36

IRRI

High yield, blast, high input

Irrigated

1996

SAHEL 20 (BW 292-3)

IR 2071-586 / BG 400-1

Sri Lanka

High yield, blast, high input

Irrigated

1996

SAHEL 202 (ITA 306) (FARO 37)

TOX 494-3696 / TOX 711 / BG 6812

IITA

High yield, blast, high input

Irrigated

1996

Niger

BG 90-2

(PETA 3 * TN 1) / REMADJA

Sri Lanka

Grain quality, high input, lodging

Irrigated

1982

IR 1529

IR 305-3-17-1-3 / IR 661-1-140-3

IRRI

High yield

Irrigated

1970

IR 54

NAM SAGUI 19/IR 2071-88 // IR 2061-214-3-6-20

IRRI

High yield

Irrigated

1982

WITA 8

TOX 891-212-1-201-1-105 / TOX 3056-5-1

WARDA

RYMV

Irrigated

1997

WITA 9

IR 2042-178-1 / CT 19

WARDA

RYMV

Irrigated

1997

BG 90-2

(PETA 3 * TN 1) / REMADJA

Sri Lanka

High yield

Rainfed

n.a.

Nigeria

BG 380-2

BG 90-2*4 / OB 677

Sri Lanka

High yield

Mangrove

n.a.

ROHYB 4

RH 2 / T 52-10-1

WARDA

High yield

Mangrove

n.a.

ROHYB 6

CCA / RH 22

WARDA

High yield

Mangrove

1992

WAR 77-3-2-2

IR 4595-4-1-5 / PA FANT 213

WARDA

Salinity, lodging acidity, high input

Mangrove

n.a.

WAR 81-2-3-3-3-1

MINIKU 33A / BAYER PUTIH 462-10

WARDA

High yield

Mangrove

1993

CISADANE (FARO 51)

PELITAI 1 // IR 789-98-2-3/IR 2157-3

Indonesia

ARGM3, blast

Rainfed

1997

WAB 36-2L-FX

IRAT 144 / OS 6

WARDA

High yield

Upland

n.a.

WAB 36-34-FX

IRAT 144 / OS 6

WARDA

High yield

Upland

n.a.

WAB 56-125

IDSA 6 / IAC 164

WARDA

Blast, drought

Upland

n.a.

Senegal

BG 90-2

(PETA 3 * TN 1) / REMADJA

Sri Lanka

Grain quality, high input, lodging

Irrigated

1997

BR 51-46-5

IR 20 / IR 5-114-3-1

Bangladesh

Grain quality, high input, lodging

Irrigated

1997

BW 248-1

 

Sri Lanka

High yield, blast

Irrigated

1997

ITA 123 (FKR 28)

Mutant OF OS 6

IITA

Grain quality

Irrigated

1997

SAHEL 108 (IR 13240-108-2-2-3)

IR 305 / BABAWEE // IR 36

IRRI

High yield, blast, high input

Irrigated

1994

SAHEL 201 (BW 292-3)

IR 2071-586 / BG 400-1

Sri Lanka

High yield, blast, high input

Irrigated

1994

SAHEL 202 (ITA 306) (FARO 37)

TOX 494-3696 / TOX 711 / BG 6812

IITA

High yield, blast, high input

Irrigated

1994

ROK 5

SR 26 / WELLINGTON

Sierra Leone

Salinity

Mangrove

n.a.

WAR 1

IR 4595-4-1-5 / PA FANT 213

WARDA

Salinity, acidity, high input

Mangrove

1997

WAR 77-3-2-2

IR 4595-4-1-5 / PA FANT 213

WARDA

Salinity, lodging acidity, high input

Mangrove

1997

WAR 81-2-1-3-2

MINIKU 33A / BAYER PUTIH 462-10

WARDA

Quality, salinity

Mangrove

1997

BG 90-2

(PETA 3 * TN 1) / REMADJA

Sri Lanka

High yield

Rainfed

1997

BW 248-1

 

Sri Lanka

Blast

Rainfed

1997

BW 248-1

 

Sri Lanka

Blast

Rainfed

1997

TOX 728-1

MAHSURI / IET 1444

IITA

Adaptability, blast, lodging

Rainfed

1997

Year

Cross

Source

Selection criteria

Ecology

Year of release

Sierra Leone

MASHURI (ROK 25)

TAICHUNG 65 / 2*MAYANG EBOS 80

Malaysia

High yield

Irrigated

1998

ROHYB 4

RH 2 / T 52-10-1

WARDA

High yield

Mangrove

1992

WAR 1

IR 4595-4-1-5 / PA FANT 213

WARDA

Salinity, acidity, high input

Mangrove

1991

WAR 81-2-1-2

MINIKU 33A / BAYER PUTIH 462-10

WARDA

High yield

Mangrove

1993

SUAKOKO 8 (ROK 24)

SIAM 25 / 3*MALUNJA

Liberia

Iron toxicity

Rainfed

n.a.

LAC 23

Local selection

Liberia

Drought

Upland

n.a.

WAB 96-1-1

ITA 257 / YS 121

WARDA

Low input, weed

Upland

1998

Togo

IR 46

IR 1814 // IR 1366-120-3-1/IR 1539-37-3-1

IRRI

High yield

Irrigated

n.a.

IR 841

IR 262-43-8-11 / KDM 105

IRRI

High yield

Irrigated

1990

WITA 4

11975 / IR 13146-45-2-3

WARDA

Drought, Iron Toxicity

Rainfed

1999

IDSA 6

COLOMBIA / M 312A

Côte d'Ivoire

Blast, high yield, drought

Upland

1997

IRAT 112

IRAT 13 / DOURADO PRECOCE

Côte d'Ivoire

Blast

Upland

n.a.

IRAT 13

MUTANT OF 63-83

Côte d'Ivoire

Blast

Upland

n.a.

1n.a. = not available.

2RYMV = rice yellow mottle virus.

3ARGM =African rice gall midge.


FIGURE 3

Number of seed samples dispatched in the region per year and per ecology, 1992-2000


TABLE 2

Number of varieties dispatched to each country, 1995-2000

Country

Upland
rice

Rainfed
lowland rice

Irrigated
rice

Mangrove
swamp rice

Total

Benin

113

293

178

 

584

Burkina Faso

247

116

176

 

539

Cameroon

246

333

176

 

755

Chad

138

277

123

 

538

Côte d'Ivoire

105

134

217

 

456

Gambia

240

312

159

243

954

Ghana

383

432

218

 

1 033

Guinea

326

242

134

69

771

Guinea-Bissau

386

300

76

181

943

Liberia

155

     

155

Mali

63

333

271

 

667

Mauritania

   

84

 

84

Niger

35

132

232

 

399

Nigeria

299

306

177

197

979

Senegal

87

53

125

391

656

Sierra Leone

291

749

103

891

2 034

Togo

215

87

214

 

516

Grand total

12 063

Fast release of new improved varieties

The Consultative Group for International Agricultural Research (CGIAR) germplasm impact studies conducted by Dalton and Guei (1999) in seven of the most important West African rice-producing countries indicated that despite the limited regional resources invested annually in varietal improvement, 197 improved varieties have been released with more than 122 targeted for release in the next five years. It was noted that regional collaboration produced a considerable number of new varieties for all ecologies and particularly for mangrove swamps and irrigated. Out of the 197 varieties, 60 percent were the product of international collaboration involving international research centres. Some of the varieties were lines introduced and selected as varieties; others were varieties developed by NARS with parents obtained from international research centres.

The studies also showed that of the 197 released varieties, 150 (76 percent) were released in the 20 years from 1975 to 1994, with an average of seven varieties per year. The former INGER-Africa mechanism was operating in Africa during part of this period (1985-94). With the new approach, 47 varieties (24 percent) were released in the four years from 1995 to 1999, with an average of 12 varieties per year. This is about five years after the germplasm exchange mechanism was created. It is projected that 122 varieties will be released during the period 2000-2004, with an average of 30 varieties per year. These results relate to only seven of the 17 WARDA member countries, and indicate the efficiency and effectiveness of the new approach to germplasm exchange and evaluation. They also show that better varieties are being bred or selected by scientists for a sustained yield increase, yield stability and stress tolerance.

CONCLUSIONS

Through the germplasm exchange mechanism, national programmes have had quick access to valuable rice germplasm for high yield and stress tolerance. During task force meetings national programme scientists make their nursery requests. They specify the type of nursery they need, the number of varieties per nursery, the varietal characteristics and the deadline by which the seeds should be sent to them. This approach presents several advantages: nurseries are tailored to the individual country's needs; each country only receives useful genetic materials adapted to its environmental characteristics and farmers' preferences; genetic benefits are achieved quickly and good varieties can reach farmers' fields in a shorter period of time.

A number of varieties have been released or are scheduled for release in several countries. Other outstanding varieties, including the new interspecific progenies for upland and lowland ecosystems requested and tested by NARS scientists, have already been released and are being cultivated by farmers. These results show that the new germplasm exchange approach has proved itself to be better adapted to the African research context and should contribute to accelerating the African green revolution.

BIBLIOGRAPHY

Adesina, A.A. & Seidi, S. 1995. Farmers' perceptions and adoption of new agricultural technology: analysis of modern mangrove rice varieties in Guinea-Bissau. Q. J. Int. Agric., 34(4): 358-71.

Adesina, A.A. & Zinnah, M.M. 1992. Using farmers' perceptions to re-orient varietal technology development strategies: case study of mangrove swamp rice in West Africa. Paper presented at the Rockefeller Foundation Social Science Fellows meeting, International Maize and Wheat Improvement Center, Mexico, 9-13 November 1992.

Adesina, A.A. & Zinnah, M.M. 1993. Technology characteristics, farmers' perceptions and adoption decisions: A tobit model application in Sierra Leone. Agric. Econ., 9(4): 297-311.

Becker, L. 1991. Characterization of the rice growing agroecosystems in Côte d'Ivoire. In WARDA 1990 annual report. Bouaké, Côte d'Ivoire, West Africa Rice Development Association.

Becker, L. & Diallo. R. 1992. Characterization and classification of rice agroecosystems in Côte d'Ivoire. Research report. Bouaké, Côte d'Ivoire, West Africa Rice Development Association.

Chaudhary, R.C., Sehcu, D.V., Alluri, K.,Cuevas-Perez, F., Lopez, V.C. & Khush, G.S. 1998. INGER derived rice varieties directly released in various countries. Manila, the Philippines, IRRI.

Dalton, T.J. & Guei, R.G. (In press.) Ecological diversity and the impact of rice genetic enhancement in West Africa.

Guei, G.R. 2000. Participatory varietal selection and rice biodiversity at community levels. Paper presented at the participatory varietal selection workshop, West Africa Rice Development Association, 13-21 April 2000.

Jones, M.P., Dingkuhn, M., Aluko, G.K. & Semon, M. 1996. Using backcrossing and doubled haploid breeding to generate weed competitive rices from O. sativa L. × O. Glaberrima Steud. Genepools, interspecific hybridi-zation: Progress and prospects, Bouaké, Côte d'Ivoire, WARDA/ADRAO.

Jones, M.P., Semon, M. & Aluko, G.K. 1997. Diversity and potential of Oryza glaberrima Steud in upland rice breeding. Breeding Science, 47: 395-98.

Matlon, P., Randolph, T. & Guei, R.G. 1998. Impact of rice research in West Africa. In L. Prabhu & M.H. Pingali, eds. Impact of rice research. Los Baños, the Philippines, IRRI.

Nouvelle approche à l'échange de matériel génétique pour un accroissement durable de la biodiversité et de la production de riz en Afrique

En Afrique, les obtenteurs des Systèmes nationaux de recherche agricole (SNRA) se sont toujours reposés sur les centres internationaux pour élargir leur base génétique par l'introduction de nouveau matériel génétique. Le volet africain du Réseau international d'évaluation génétique du riz (INGER-Africa) a été créé en 1985. En 1990, des scientifiques nationaux spécialistes du riz des pays membres de l'Association pour le développement de la riziculture en Afrique de l'Ouest (ADRAO) se sont rassemblés pour créer avec d'assez bons résultats des équipes spéciales et pour instaurer une nouvelle méthode d'échange de matériel génétique en 1994. Les principes suivants ont été adoptés:

1) les pépinières ne sont données que sur demande et sont adaptées aux besoins particuliers des pays; 2) chaque pays ne reçoit que du matériel génétique spécifique adapté aux conditions locales et aux préférences des agriculteurs; 3) les obtenteurs nationaux peuvent préciser les caractéristiques qu'ils souhaitent pour les plantes. Par conséquent, au cours des cinq dernières années, plus d'une douzaine de nouvelles variétés ont été distribuées en moyenne chaque année dans sept pays, contre sept en 20 ans (1975-1994) avec l'ancien système. Pour cette région, les projections (2000-2004) prévoient la distribution de plus d'une trentaine de nouvelles variétés en moyenne chaque année. Les résultats prouvent que l'approche à l'échange de matériel génétique par une équipe spéciale est mieux adaptée au contexte de la recherche africaine.

Un nuevo enfoque del intercambio de germoplasma para un aumento sostenible de la biodiversidad y la producción de arroz en África

Los fitogenetistas de los sistemas nacionales de investigaciones agronómicas de África siempre han confiado en centros internacionales a la hora de ampliar su base genética mediante la introducción de germoplasma nuevo. En 1985 se creó la sección africana de la Red internacional para la evaluación genética del arroz (INGER-África).

En 1990, científicos especializados en el arroz de los países miembros de la Asociación para el Desarrollo del Cultivo del Arroz en el África Occidental (ADRAO) se reunieron para crear unos grupos de acción y dar un enfoque nuevo al intercambio de germoplasma en 1994. Este enfoque recurre a los principios siguientes: sólo se proporcionan semilleros cuando se solicitan, y éstos se adaptan a las necesidades exactas del país; cada país sólo recibe materiales genéticos específicos, ajustados a las condiciones medioambientales del lugar y las preferencias de los agricultores; se ofrece a los mejoradores de cada país la posibilidad de indicar las características de la planta que ellos deseen. Durante los últimos cinco años, se entregó un promedio anual de más de 12 variedades nuevas en siete países, en contraste con las siete variedades que se entregaron en 20 años (1975-1994) con el mecanismo antiguo. Las proyecciones (2000-2004) para la región contemplan la entrega de un promedio de más de 30 variedades nuevas al año. Estos resultados muestran que el enfoque del intercambio de germoplasma de los grupos de acción ha demostrado adaptarse mejor al contexto investigador africano.

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