Genetic Resources of Tropical Legumes

GENETIC RESOURCES OF TROPICAL LEGUMES Jos van der Maesen van der Maesen, L.J.G. 1988. GeneticResources of TropicalLegumes. Acta Univ. Ups. Symb. Bot. Ups.XXVIII(3):79-91 .Uppsala . ISBN91-554-2348-5 . The Leguminosae constitutes oneo f the important plant families widely studied both taxonomically and agronomically. Both in well-known and locally impor tant legumes various levels of knowledge are extant, but many details need to be filled in. In tropical areas, floras do not extend to all regions and many gen era require further taxonomie scrutiny. The taxonomie framework enables fur ther detailed collection inorde rt osafeguar d genetic resources oflegumes , first lythos e needed to improve important legumes such as Phaseolus beans,Pisum peas, Cicer chickpeas, Viciaf aba bean s and vetches, as well asso-calle d minor legumes and those for other than food purposes. Of the major important le gume crops, taxonomy has reached a fairly stable, yet not always unequivocal status. For Arachis, taxonomy is seriously wanting. The genetic resources at hand inlivin gshap e areonl y abudant for the major crops, but not inothe r cases norfo r thewil d relativeso f major grain legumes.Continue d attention and fund ing are required. Jos vander Maesen, Department of PlantTaxonomy, P.O. Box 8010, 6700ED, Agricultural University Wageningen, the Netherlands. The important of Leguminosae for food, an provided by systematic botany, which in imal fodder, fuel and wood, as restorers of cludes the classification of cultigens. soil fertility and for toxic or medicinal prop The systematics of the Legume family are erties is well understood. In tropical areas in relatively good shape. After two interna the key role of legumes is probably larger tional gatherings in 1978 and 1986 of the than inth e temperate zone,sinc e for reasons many scientists who continue to work in le of religion, seasonal lack of availability or gume taxonomy and many other aspects, at poverty animals proteins are not or less fre tention to classification is adequate (Polhill quently eaten. The role of legumes is impor & Raven 1981, Polhill & Zarrucchi, in tant even if sometimes quantitatively over press). Cultivated legumes and their wild emphasized, as it is not always realized that relatives receive considerable attention, if the bulk of food proteins are supplied by the not always including taxonomy, but in many cereals, but few people manage to eat cere cases taxonomie data can be considered suf alsi nth e absence of additionssuc h aspulses , ficient (Polhill &va n der Maesen 1985).Th e vegetables, fat or spices. ILDIS (International Legume Database and Information Service), intended to become The key to all knowledge of plants is the available within afe w years,wil lprovid esci name of the species involved. The names are entistswit h accepted or provisionally accept- Symb.Bot. Ups. XXV1U:3 80 L.G.J. VAN DER MAESEN ed names from one edited source. This ini disappearance of old cultivars and narrows tiativei sprobabl y the first establishment ofa the genetic base by producing uniformity. taxonomie database of a single important The possibility of gene transfer by genetic plant family with worldwide coverage. Part engineering, it may be speculated, will in of the database is operational, such as for crease the search for somewhat more distant Glycine max, the soybean (contributed by relatives of cropplants , and that emphasizes Newell, St. Louis). Only the input of many the need for up-to-date systematics. Here specialists and availability of existing data RNA and DNA variation in, e.g. cell ribo- bases can make this project succeed. A pilot somes and chloroplasts, offer new objective project in Vicieae, the Vicieae database, is tools for classification and phylogeny, to as operational at the University of Southamp sist gene transfer programs tolocat e suitably ton and with BIOSIS, York. compatible germplasm. In cultivated plants classification incultiva r Taxonomy is the basis for most aspects of groupsver ymuc h tailored bycurren t practical tropical research in plants and animals. Scien needs is needed from time to time. The nam tistsinvolve d with organisms should know ex ing, classification and documentation also of actlyth ename so f those theyinvestigate .Fol k disappearing cultivars is needed to assist ge taxonomy andth estud yo fvernacular s areim netic conservation of old landraces and obso portant ethnobotanical linkst oforma l scientif lete cultivars. In comparison to a number of ictaxonomy , which in itself isa startin g point 25000 0 species of flowering plants, a similar for basic and applied research. Even if names number has been estimated for cultivars for of certain well-known plants are taken for merly and presently in cultivation. Cultivars granted, scrutiny of names and classification, and groupsthereo f maybeenvisage d eithero n particularly at infraspecific level, is needed. a regional scale,o r involvingal lmateria lwith Thestud yo ftaxonom y toregiste r man'snatu in a species on a world scale. Cultivar names ralheritag ei sa non-goin gaffair . Eveni fi n20 0 can also carry names in languages other than years or so nearly all species of flowering English, French, Spanish and German. Most plants would have been described (Raven et of the crop-oriented International Research al. 1971), the knowledge needs to be updat Institutes have been assigned or took up a ed so study of taxonomy cannot be left to mandate for one or more pulse crops (Table computers and libraries. Identification, even 1). Several national genetic resources centres with the aid of computers, has to be doneb y carry large numbers of cultivated legume ac people.Th e rate of evolution isfaste r inspe cessions, and small numbers of wild relatives cies with rapid generation turn-over, e.g. of pulses. Numerous Botanical Gardens list Arabidopsis thaliana, but in20 0year sthi sin wild or cultivated, often ornamental, legumes crease would not be so enormous as to and exchange these, but the accompanying equate theprobabl e rate ofextinctio n ofspe datavar ygreatly ,an dth estatu so fth esample s cies, for which very pessimistic forecasts are is not always clear. Attempts are made to fo probably true (Koopowitz & Kaye 1983). A cus on well-documented samples of authenti large increase in taxonomieunit s can be pre cated wild origin. dicted in new crop cultivars. On-going ef This paper attempts to highlight some of forts to improve and diversify edible (and or the achievements of legume classification namental) crops bybreedin g counteracts the and the use made thereof in genetic re- Symb.Bot. Ups. XXVIII:3 GENETIC RESOURCES OF TROPICAL LEGUMES 81 Table 1. International Agricultural Research Institutes and their crop mandates in Leguminosae. Institute Crops CIAT, Cali, Colombia Phaseolus beans, fodder legumes ICARDA, Aleppo, Syria Chickpea, Lentil, Fababean, fodder legumes ICRISAT, Patancheru A.P. India Groundnut, Chickpea, Pigeonpea UTA, Ibadan, Nigeria Cowpea, Vigna spp. Note: for the numerous national and regional gene banks see IBPGR directories. Strong national programs with international links exist e.g. on soybean, pea and groundnut. sources and breeding. The multitude of uses get re-identified correctly, but that informa of Legume species overlaps almost all topics tion rarely gets back into the original data of this Symposium. Just as Systematic bot base, an aspect several curators worry about. any is the key science for tropical research, Documentation involves screening, and the conservation of genetic resources is the gene bank personnel usually carry out charac key to further improvement of crops, me terization and preliminary evaluation. Special dicinal or other technical plants, the study of ists such as phytopathologists and entomolo ecology, nutrition and many other disci gists apply special-purpose screenings to select plines. resistant accessions for further use in breed ing,breeder s search for special plant types and high yield. Biochemical screenings, such as for Available resources protein, are obscured by season and location Documentation effects, but it isimportan t that high yield is not accompanied by reduced protein content. Documentation provides us with the back ground of data concerned with the accessions Geographical information. Delimitation to incollections , and the status of the various col purely tropical plants and crops is not easy, lections. The last ten to fifteen yearswer e very where especially in the Papilionoideae sub important for the genetic resources of food le family several crops of the cool season ex gumes. The other legumes, for fodder, timber tend into the summer season of the temper and pharmaceutical use have not received so ate zone or vice-versa. Wild relatives some much attention. Several legumes have more times have a larger ecological and geograph than one usage, and classification in use cate ical amplitude than the crop itself; on the gories can be made in many ways. Genetic other hand, crop species have often a wider conservation is applied to very different de range of distribution than the wild species. grees to overcome narrowing the genetic base Temperate legume species are grown at for breeding and to save part of nature's van higher altitudes in the tropics and are of local ishing diversity. commercial importance or even exported. Documentation of the various accessions in The use of temperate vegetables is spreading botanical collections and gene banks is a mat in the tropics, if these cannot be grown im ter of concern. Taxonomie verification is very portation is common for the high-income important. After seed exchange samples may population groups. Vegetables such as fresh Symb. Bot. Ups. XXVIIU 82 L.G.J. VAN DER MAESEN Table 2. Publication status of the major recent Floras in tropical regions. Country Papilionoideae Caesalpinioideae Mimosoideae N. AFRICA Algeria Nouv. Fl. Alg. 1(1962) do.

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