«Biotechnology-Assisted Participatory Plant Breeding: Complement or Contradiction? PPB Monograph No. 3 Ann Mane Thro and Charlie Spillane 1 7 ...»
The rapid propagation of desirable genotypes using in vitro cultu re of shoot tips or meristems (often referrcd to as tissue culture) is a relatively low-cost and h ence 'appropriate' biotcchnology which is already delivering tangible benefits to many fa rmers in both developed a nd developing countries (Bryan, 1988; Van Uyen and vander Zaag, 1993 ; Govil and Gupta, 1997 ; Sasson, 1998). Tissue culture can allow rapid response to demand for ¡arge quan tities of high-qual ity plan ting material in vegetatively propagated crops. Th rough in vitro c10nal thermotherapy, it can also be used to generate discasc-free plantin g material s. Large yield gain s have been reported from the use of tiss ue culture to eliminate di seases from existing farmers ' cultivars, many of which have low yields due to the high d isease load that has buil t up over t he generalions (Delgado and Rojas, 1993; Garcia e t al, 1993; Zok, 1993; Maban za et al, 1995). There are nu merou s examples oftissue culture projec ts th at are p roving highly successful in dehvering ruseasefree planti ng materials to rcsourcc-poor far mers (Sasson, 1998).
Tissue culture tcchniques have now been develo ped for a wide range of crops. In many Latin Am erican and Car ibbean cou n tries, IargescaIe ti ssue cul ture is used for crops such as cofTee, banana, planta in, taro, cOCQa, cocoyam, sweet potato, apple, blueberry, raspbeny, pineapple, citrus, grapes, pa paya, mango, guaYa, potato, ki.wi, cherry, pcar, ornamen ta ls, a nd yams (Sasson, 1998). In Asia, China h as now developed tissue culture for more than 100 crop s pecies. In the country's Gu an gdong Province, 3-4 mi.llion micropropagated banana plantlets are produced annually, 1 m iUio n of which are exportcd. In 1994 it was estimated tha t farmers in Guangxi had carned an extra US$723,000 by adopting a pproximately 600,000 disease-free plantlets.
Similarly, 100/0 of China's potato area was plantcd with viru s-free tissu e cultu re materials in the early 1990s, with yi elds that are reported to have increased by up to 2000/0 (Sasson, 1998). Tissue cu lture capacity is less weU developed in most African countrics, where it has the poten ti al to benefit farmers greatly if integra ted with other efforts to boost the production and delivery of plan ting ma terials. A few s u ccessful projects h a ve been launch ed in the 1990s, inc1uding one on ba nanas in Kcnya (Box 9 ).
Although biotechnology is often not conside red in cases of disaster relief(FAO, 1996). tissue culture ha s becn uscd for the rapid sup ply of cassava varietics in post-war AngoIa a nd in post-flooding di saster aid in Ecuador (Boxes 10 and 11 ). Sorne of the world's poorest farmers a nd most ma rginal croppi ng arcas coulcl make use of ti ssue culture to propagate much -nceded planting materials.
Biolechnology as a Set of Tools for Formal and Informal Plan! Breeding
Box 9 Tisaue culture ud small-scale banana producers in Kenya Tissue·cultured banana plants are Cree oC the damaging weevils and nematodes that ¡nCest most bananas grown by resource·pooT Carmers throughout the world.
In 1996, the Intemational Service for the Acquisition of Agrobiotechnology Applications (ISAAAj brokered a project involving a wide range of Kenyan institutions, including the Kenya Agricultural Research Institute (KARI), in the development oC tissue culture to rejuvenate banana orchards in Kenya and Uganda. The project tapped the considera ble experience in banana tissue culture and mass propagation obtained in South Africa, where the public and povate sector had worked together to lay the basis fo r a profitable plantlet export industry.
Project scientists worked with 12 representative farmers (including women) in Kenya's main banana growing regions. These fanners grew demonstration plots oC 120 in vitro plants of each oC three varieties. They were trained in plot management by KARI officers and a visiting technieal advisor (rom the Insutute of Tropical and Subtropical Crops (ITSC), South ACriea. Each C arme r had a group of 50 other Carmers using his or her plot as their focal poiot fo r leaming. These 50 farmers each purchased between 10 and 500 in vitro plants Cor their own plots.
They then disseminated information and clean planting material to other farroers in their areas. The original supply of plantlets is being met by a Kenyan private· sector bioteehoology company. Genetic Technologies Umited (GTL).
The shorter time to maturity and the superior quality and quantity of bananas produced by the tissue·cultured trees have made this biotechnology popular everywhere it has been demonstrated. The I ~year-old trees produce bunches weighing about 40-60 kilograms, compared to 10·20 kilograms (rom traditional trees after 2 years. By mid-1999 it was clear that mosl farmers were prepared to pay C the pLantlets because they were confident that they would be able to OI' inerease th eir incomes from them. Farmers do, however, need to nurture the plantlets carefully, providing them with adequate nutrients and water. Micro· credit achernes are being introduced to enable farmers to invest in the plantlets and the improved management they require.
The demonstration and difCusion strategy adopted by the project is cnsuring that orchards in most banana growing regions of Kenya are now being, or will soon be, rejuvenated. The ultimate aim ia to spread the technology to other ACrican countries, s tarting with Uganda and Tanzania. A banana growers' association is being established to help provide marketing ¡nformation. Socioeconomic studies are in progress to heJp fanners identify and tailor their product to reliable market outlets.
SOURCES: F. Wambugu, S. Sharrock (pers. cornms.).
The application of tissue culture to local varieties and landraces of root and tuber crops could not only in crease yields also lirnit the genetic erosion caused by the 10ss of clona! varieties to systemic pathogens and other problems (F. Engelmann, pers. comm.J. Links need to be developed between genetic resources conservation and tissue culture initiatives, so Biotechnology -Assisted PPB: Complement or Contradictiort?
Coastal Ecuador was inuodated with torrential El Niño rai os for almost 12 mon ths during 1997-98, when rrunfall was 400%-450% more than normal.
The rains wiped out all crops and left deep ravines and landslides where fields aod roads had beeo. By early 1998, savings had beeo exhausted. Meo and young people migl'ated from the countryside to nearby cilies in scarch of \York.
caN supported the participatory dcvelopment of a relief proposaJ by thc Unión de Asociaciones de Trabajadores Aglicolas, Productores y Procesadores de Yuca (UATAPPV), lhe Universidad Tecoiea de Manabi (UTM), the Instituto Nacional Autónomo de Investigación Agropecuaria (INIAP). and C IAT. ¡ndependent proposals from all the partners were synthesized by a representative group ioto an integrated project to restore smaJI -scale cassava production and processing capacity and re-cstablish markets lost as a res ult of crop failure and the destruction of infrastructure. The proposal was funded by USAlO's Office of Disaster Assistance.
The project is unique because it combines cassava germplasm testing, tissue culture, and new management skills to (i) reconstruct local food security and economic opponunity and (¡jI establish a locally managed in situ genetic resources conservation effort. Restored and rescued local cassava germplasm and elite cassava clones are being used in combination with new concepts in microenlcrprise development to jump start a disaster-struck rural ecooomy. Tissue culture i8 an essential lool for lhe project. It is bcing used to conserve cassava gennplasm collected by the farmen and characterized using oral history and DNA fingerprintin g. It IS also being uscd to repatriale the Ecuadorian nationa! cassava collection. which was destroyed by the noods, from the duplicate collection held at ClAT.
SO URCE : Thro et al (1999bJ.
as to bring about a rapid increase in the supply of planting materiaJs of a wide range of genotypes, including those of endangered species.
There is considerable potentiaJ for integrating the periodic supply of disease-free gcrmplasm from genebanks with deceotralized farm cr-Ied tissue cultu re and dissemination efforts.
Tissuc culture is well suited to practice by 'meticulous noo scientists' (D. Duvick, pers. comm.) and ca n therefore be condu cted by farmcrs or villagc groups. Allhough the tcchnology is a laborious one for working [armcrs, the low cost of labor in many areas, together with the potcntial [or developing low-cost locally adapted in vitro propagation methods, could create significant commerciaJ opportunities (0.0.
Henshaw, pers. comm.). In most countries, several important Biotechnologyas a Set of Tools for Formal and Inf ormal Plartl Breeding
In 1996, over 14,000 in vitro cassa va planUets were produced at JITA, airlifted to Angola, transplanted and acclimatized before delivery to rapid multiplication centers. Of the 216 genotypes shipped, 16 had been selected by liTA for immediate distribution to farmers, while the rest were to be evaluated by Angolan cassava researchers. An liTA researcher based in Angola was n~sponsible for transplanting the initially delicate plantlets from g1ass tu bes to starter pots and training World Vision stafr to care for and multiply them. High s urvival rates were achieved.
None of these cassava genotypes would have been as rapid1y accessible to Angolan farmers or researchers ir they had not arrived as in vitre plantle ts, enabling tbem to be certified as cüsease-free.
SOURCES: lITA (1997); P. Ilona, S.Y.C. Ng (pers. comms.).
vege tatively propa gated crops could benefit from the development of 'barefoot' tissue culture operations.
Tissue culture need not be expensive or require very sophisticated technologies. Kitchen-based micropropaga tion kits are sold to amateur horticulturalists in the USA (e. StifT, pers. comm.). Basic design s for very simple aseptic culture hoods (involving plastic sheeting, bulldog clips, and file folder supports) that can be constructed and folded away in minutes have been developed (T.M. Horn, pers. comm.). There a re many formula tions for cheap growth mediums using table sugar, coconut milk, and so on. Recycled glass jars can be used as sterile containers.
To date, few technology development or tran sfer organization s have become involved in the promotion of 'low-tech' methodologie s and rnaterials for use by farmers or farmers' groups in developing countries.
Sorne taro farmers in Samoa have becorne a dept at bas ic tissue culture (M. Taylor, pers. cornrn.) as also h a ve pota to farmers in the Dalat province of Vietnam, cassava farmers in Colombia, and stra wberry growers in the Dominican Republic. In sorne recent cases th ere have been efIorts to involve farmers' organizations in the design and running of tiss ue culture schemes. ClAT's small-scale cassava micropropaga tion work with NGOs and farrncrs' organizations in Colombia is an example (Box 12). Much experience in adapting tissue culture to the village or district level has been gained in the ongoing wor k on pa tato initia ted by the CIP and national program stafT and now conducted independantly by farmers in Dalat province ofVietnam (Box 13). The farmer participatory FLASH system successfully developed for po tato Biotechnology·Assisted PPB: Complement or Contradiction?
Box12 Low-cost rustlc tlssue culture ror cassava and other Indigenous root crops in Colombia Cassava in Colombia'g Cauca region is grown by resource · poor fanners for home consumplion and sale to sma ll·scale local starch extraction plants. The crap is a good source of future income and rural employment, provided local producers can compete with those of Brazil and Thailand.
In 1999 an NOO, the Fundación para la Investigación y Desarrollo Agrícola (FIDAR) and local fanners ' organizations in Cauea, including the Asociación de Agricultores de ?ítal, the Asocia ción de Productores Agropecuarios de Pescador, and the Orupo Comunitario Mi Lucha, began working with CrAT under a project funded by the SWp·PROA. Ca u ca's cassava fanners had alrt:ady worked with CIAT and FrDAR for about a decade in participatory cassava varietal selection, But in the late 1990s it became c1ear tha t the limited supply of planting materiaIs was preventing this work from having an impacto ¡nterest in other local root crops, such as achira (Cana s pp.), aracacha (Aracacha spp.), and local varieties of batata Of camote (q,omoea spp.), is increasing, but for these crops too a shortage of planting materials is e~cted to constrain development. Remaining stocks are in very small plots, often diseased, and gene rally inadequate in quantity and quality to allow propagation te be scaled up adequately to deve lop new markets.
To meet the need for high· quality planting material, FIDAR, through CBN, invited C IAT researchers to JOLn with Cauca farmers' associations to explore affordable tissue culture methods. 'Ole idea is to organize tissue culture as household micro·enterprises or as prajects for fanners' associations. Fanners will provide k-nowledge of local materials and information 00 the social and economic contC..1:, in addition to their skills and labor. ClAT biotechoologists will provide technical informa tion on cassava in vitro c u lture, and collaborate with the farmers in proposing and tes ting med ia and methods. FIDAR is to coordinate farrncrs ' partici pation in technology and enterprise development, to monitor and evaluate (he projecl, and to as sess its impact.
Cassava plantlets will be used for the production vegetative planting materials (stakes). These will be distributed at a price yet lO be dete nnined, but which may be subsidized in the ¡¡rst year, when the vaJue of the technology is not yet es tablished. Production will be moni tored to assess (i) the agronomic and socio· economic vallle of the techn ology and (ii) how frequently on·fann plan ting malerial ShOllld be replaced to maintain yield and quality levels.
Timely access to high-quality planting material wiIl enable local fanners to use their own varieties more fu lly, to get access to new varieties from other sources, and to respon d rapidly and flexibly to market signaIs and changes in the agro· economic environment.