Round leaf cassia (Chamaecrista rotundifolia) cv. Wynn is an important legume in light textured soils in sub-tropical Queensland and forage evaluators in other regions of the tropics frequently wish to include in their evaluation trials this cultivar plus other accessions which represent the variation in the species. Provenance data of a world collection of 130 accessions of round leaf cassia were examined and a core set of 26 accessions selected

Hacker, J B

Maass, B L

Pengelly, B C

Thomas, B D

English

University of Kentucky

Session 1 - Conservation, Evaluation and Utilization of Plant Resources    1-25ID NO. 368ORIGIN OF THE WORLD’S COLLECTION OF THE TROPICAL FORAGE LEGUMECHAMAECRISTA  ROTUNDIFOLIAB.C. Pengelly1, B. L. Maass2, B.D. Thomas1 and J.B. Hacker11 ATFGRC, CSIRO, Division of Tropical Crops and Pastures, 306 Carmody Rd, St Lucia, Qld 4067, Australia2 CIAT, Apartado Aéreo 6713, Cali, ColombiaABSTRACTRound leaf cassia (Chamaecrista rotundifolia) cv. Wynn is animportant legume in light textured soils in sub-tropical Queenslandand forage evaluators in other regions of the tropics frequently wishto include in their evaluation trials this cultivar plus other accessionswhich represent the variation in the species. Provenance data of aworld collection of 130 accessions of round leaf cassia were examinedand a core set of 26 accessions selected.KEYWORDSChamaecrista rotundifolia, germplasm, plant geography, corecollectionINTRODUCTIONRound leaf cassia (Chamaecrista rotundifolia) cv. Wynn is animportant forage legume for the light textured, acid soils of sub-tropical Queensland. This particular cultivar is an early flowering,heavy seeding short-lived perennial which is persistent under grazingand is most frequently used as a legume sown into native speargrass(Heteropogon contortus) pastures. The species is widespreadthroughout tropical America and is found in savannas, campos, llanos,openings in woodlands and is an abundant coloniser of disturbedareas (Irwin and Barneby, 1982). In a comparative study of 18accessions of the species from which cv. Wynn was selected forcommercial release (Strickland et al., 1985), variation inmorphological and agronomic attributes including yield, floweringtime, seed weight and broad adaptation were clearly related togeographic origin. More recently, Whitty et. al., (1994) were able torelate variation within the species to geographic origin using RAPDanalysis. However relationships between phenotypes of C.rotundifolia and geographic origin have been difficult to establish inother studies (Irwin and Barneby 1982, Maass and Cárdenas (pers.com.). Wynn was collected from Sao Paulo, Brazil in 1964 andreleased in 1983. Since its release, the number of accessions held inthe world’s major tropical forage genebanks has increased to 130.This paper reports the geographic origin of those accessions andidentifies a core collection of the species. Using that core collectionin future evaluation studies should result inefficiencies in utilisationof the collection and, because of the reduced number of accessionsfor which large quantities of seed need to be available, improvedefficiencies in seed multiplication and maintenance of the collection.METHODS AND MATERIALSProvenance data for C. rotundifolia accessions held at the two majortropical forage germplasm centres (CIAT and ATFGRC) wereassembled. Data were examined to identify duplicate accessions,mapped and studied to identify the range of latitudes, mean annualrainfall, altitude, soil texture, soil pH and associated species at thesite of collection. A core set of accessions was selected on the basisof provenance data. It includes accessions from the geographic rangeof the species as well as accessions from the extremes of rainfall,altitude and soil reaction (Table 1). CPI 34721, cv. Wynn, is includedin the core set because of its cultivar status.RESULTS AND DISCUSSIONLatitude. Site of collection is available for 117 of the 130 accessions.C. rotundifolia accessions have been collected from North, Centraland South America with latitude ranging from 22°55' N in Jalisco,Mexico to 28°53' S in Corrientes, Argentina (Map 1). Some accessionshave been collected from Ghana and Nigeria in West Africa.Hutchinson and Dalziel (1958) and Lock (1989), however, considerthe species to have been introduced into Africa from the Americas.On the basis of seed size reported by Strickland et al., (1985), itwould appear that the origin of the west African material is possiblyBrazilian. However Whitty et. al., (1994) suggested differencesbetween the African and American germplasm based on RAPD analysis.Mean annual rainfall. C. rotundifolia has been collected from siteswith mean annual rainfall ranging from 400mm to 3720mm. Mostaccessions were collected from sites with a mean annual rainfall ofca. 1000mm which is reflected in the adaptation of C. rotundifoliato the sub-humid and semi-arid areas of Africa (Tarawali 1994). Themajority of accessions from dry sites (<1000mm) were collected fromthe states of Bahia, Rio Grande de Norte, Pernambuco in northernBrazil while the wetter sites were almost invariably located inColombia.Altitude. The majority of accessions were collected from below 0.9m altitude although 6 accessions were collected from altitudes>1000m - from Jalisco in Mexico and from District Federal and thestate of Goias in Brazil. The accessions from Jalisco, Mexico werecollected from near the northern extremes of the species’ distribution,at ca. 20°N and these accessions are likely to be the most cold tolerantaccessions in the collection.Soil texture and pH. Data for soil texture, fertility and pH at thesite of collection are limited. In the 52 cases where soil texture datawere available, 3 accessions were collected from stony soils, 28 werefrom sands, 13 from loams and 8 from clay loams or clay soils. Theseresults confirm the observation of Irwin and Barneby (1982) that thespecies is largely confined to light-textured soils. While mostaccessions were collected from slightly acid soils (pH 5.0-7.0), sixaccessions were collected from soils with pH 5.0 and these could beof particular value for developing cultivars for acid soils in the tropics.No accessions were collected from alkaline soils.Associated legumes. 59 accessions of C. rotundifolia were collectedin association with various pioneer legumes adapted to open anddisturbed environments, including Stylosanthes guianensis, S. scabra,S. humilis, Desmodium barbatum, D. incanum and Centrosemabrasilianum. In 48 of these, the associated legume species includedStylosanthes spp. Also, most accessions of C. rotundifolia (ca. 70%)were collected from roadsides and together, these data indicate thatthe species is a strong coloniser.CONCLUSIONAlthough there is conflicting evidence on the relationship betweenmorphological variation and geographic origin, the results fromStrickland et. al., (1985) and Whitty et. al. (1994) justify the selectionof a core set of accessions based on geographic origin and otherprovenance data. A core collection of 26 accessions of C. rotundifolia,which takes into account the geographic origin, soil, mean annualrainfall and altitude at the site of collection has been identified (Map1, Table 1.). No representatives from Africa are included in the coreset since most evidence points to the species being adventive in thatcontinent. There are a number of regions of the Americas where C.Session 1 - Conservation, Evaluation and Utilization of Plant Resources 1-26rotundifolia is reported and which are yet to be sampled. Importantamong these are Cuba, Honduras, coastal Ecuador and Bolivia.REFERENCESHutchinson, J. and Dalziel, J.M. 1958. Flora of West TropicalAfrica. Royal Botanic Gardens, Kew. p 452.Irwin, H.S. and Barneby, R.C. 1982. The American Cassiinea.Memoirs of the New York Botanical Gardens. 35: 1-918.Lock, J.M. 1989. Legumes of Africa: A Check List. Royal BotanicGardens, Kew. p 33.Strickland R.W., Greenfield, R.G., Wilson, G.P.M. and Harvey,G.L. 1985. Morphological and agronomic attributes of Cassiarotundifolia Pers., C. pilosa L., and C. trichopoda Benth., potentialforage legumes for northern Australia. Aust. J. Exp. Agric. 25: 100-108.Tarawali, S.A. 1994. The yield and persistence of selected foragelegumes in sub-humid and semi-arid west Africa. Trop. Grasslands28: 80-89.Whitty, P.W. , Powell, W. and Sprent, J.I. 1994. Molecularseparation of genera in Cassiinae (Leguminosae), and analysis ofvariation in the nodulating species of Chamaecrista. Mol. Biol. 3:507-515.Table 1Core accessions of Chamaecrista rotundifolia selected on the basis of geographic origin, rainfall, altitude and soil data.Accession* Country State Latitude Longitude Altitude (m) Rainfall (mm) pHCPI 86162 Mexico Jalisco 20.37N 105.15W 10 1500 6.5CPI 86178 Mexico Jalisco 19.35N 104.25W 1000 850 6.5CPI 85836 Mexico Guerrero 16.45N 99.30W 50 1400 6.5CIAT7091 Panama Chirique 8.43N 82.37W 770 2720CIAT7288 Venezuela Anzoategui 8.37N 63.50W 130 1080CIAT18252 Venezuela Zulia 8.29N 72.29W 10 2730 4.8CIAT8158 Colombia Arauca 6.23N 71.36W 280 2680CIAT21715 Colombia Meta 4.03N 73.27W 340 3700CIAT20715 Colombia Huila 3.50N 75.06W 550 1090 6.9CIAT17958 Colombia Meta 3.38N 73.44W 380 2850 4.6CIAT17440 Brazil Roraima 2.22N 61.10W 80 1930CIAT8389 Brazil Paraiba 7.06S 36.17W 570 400Q10057 Brazil Paraiba 7.22S 36.30W 580 420CIAT9847 Brazil Mato Grosso do Sul 11.37S 50.40W 250 1580CIAT8556 Brazil Goias 12.24S 46.27W 690 1510 5.0CIAT8994 Brazil Bahia 13.53S 40.01W 200 690CIAT8559 Brazil Goias 15.23S 47.32W 1220 1600CIAT17002 Brazil Bahia 18.01S 39.51W 90 1510CIAT17000 Brazil Espirito Santo 18.46S 39.51W 70 1420CIAT9735 Brazil Mato Grosso do Sul 20.23S 54.32W 580 1450 4.5ATF2208 Paraguay Nuevo Asuncion 20.57S 61.48W 300 500 6.0CPI 34721 Brazil Sao Paulo 22.54S 47.03W 800 1390ATF2222 Paraguay Concepcion 23.17S 57.20W 250 1300 7.0CPI 92985 Brazil Parana 25.36S 49.48W 790 1260ATF2228 Paraguay Itapua 27.14S 56.04W 260 1600CPI 78355 Argentina Corrientes 28.53S 58.45W 80 1320CPI =  Australian Commonwealth Plant Introdusction numberCIAT = Centro Internacional de Agricultura Tropical, ColombiaATF = Australian Tropical Forages Genetic Resource CentreFigure 1Distribution of the world genertic resource collection of Chamaecrista rotundifolia together with those accessions selected on the basis ofprovenence data as being part of the core collection.

Origin of the World\u27s Collection of the Tropical Forage Legume Chamaecrista Rotundifolia

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Origin of the World\u27s Collection of the Tropical Forage Legume Chamaecrista Rotundifolia

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