View metadata, citationTropical and Grasslands similar papers (2008) at Volume core.ac.uk 42, 40–53 brought40 to you by CORE provided by CGSpace Characterisation of a collection of perennial Panicum species MARK VAN DE WOUW, Introduction MARIA ALEXANDRA JORGE, JÜRGEN BIERWIRTH and JEAN HANSON Several of the Panic grasses have high forage Forage Diversity Project, International Livestock potential. Guinea grass (Panicum maximum Research Institute (ILRI), Addis Ababa, Ethiopia Jacq.), blue panic (Panicum antidotale Retz.) and coloured Guinea grass (Panicum coloratum L.) are some of the better-known and used species. Abstract P. maximum plays an important role as feed and forage in intensive livestock systems in the tropics A collection of 74 perennial Panicum accessions, and subtropics, especially in Brazil, where it is belonging to 6 different species, maintained at grown extensively and has received a lot of atten- the fi eld genebank of the International Livestock tion recently (Souza 1999; Carnevalli et al. 2006; Research Institute, was described using 49 agro- Andrade et al. 2006; Santos et al. 2006). morphological characters in a multivariate analysis. Panicum is a very diverse genus, with its Fifty-four accessions, for which coordinates of natural range of distribution in the tropics and warmer temperate regions. It is one of the the collection site were available, were further largest genera within the Poaceae, consisting of characterised using environmental data obtained about 450 annual and perennial species (Alis- through use of geographic information systems. cioni et al. 2003). The diversity in the genus Three drought-tolerant species, P. antidotale, has led to a confusing taxonomy and the delim- P. turgidum and P. phragmitoides, were very itation of the genus is not entirely clear. Current different agro-morphologically from the other names in use to describe Panicum maximum are species. Of these drought-tolerant species, Urochloa maxima (Jacq.) R. Webster (ITIS 2006) P. phragmitoides appeared to have the best agro- and Megathyrsus maximus (Jacq.) B.K. Simon morphological attributes for use as forage in dry & S.W.L. Jacobs (Simon and Jacobs 2003). areas. P. maximum, P. coloratum and P. infestum As the confusion surrounding the placement of appeared more similar, and were not entirely sep- P. maxi mum in the genus has not yet been settled, arated using cluster analysis. The accessions of this paper uses Panicum sensu lato as the defi ni- these 3 species could be divided into 5 different tion for the genus, following the defi nition used clusters with similar characteristics. The majority in the world grass species database of the Royal of the P. maximum accessions belonged to 2 Botanical Gardens at Kew (Clayton et al. 2006). clusters, mainly differing in the size and robust- The International Livestock Research Insti- ness of the plants. A strong correlation was found tute (ILRI) conserves in its genebank a collec- between characters describing the robustness of tion of Panicum accessions mainly collected in Africa. Additional cultivars of major importance the P. maximum plant and the annual precipita- were acquired from commercial sources and tion at the collection site. Promising P. maximum some promising accessions were obtained from accessions for use in cut-and-carry systems were a breeding program by the Institut français de identifi ed. recherche scientifi que pour le développement en coopération (ORSTOM) in Ivory Coast (Noirot et al. 1986). P. maximum has the largest number Correspondence: Mark van de Wouw, Maijweg 10, 5211 AA ‘s-Hertogenbosch, The Netherlands. of accessions in the Panicum collection held Email: [email protected] at ILRI. 003_08_03_VanDeWouw_etal.indd3_08_03_VanDeWouw_etal.indd 4400 225/2/085/2/08 110:35:370:35:37 AAMM Characterisation of Panicum accessions 41 For a germplasm collection to be useful, it for future uses (Table 2), and were observed should be properly characterised and described on the regrowth, on primary culms with newly and the information made widely available, so fully exserted infl orescences. The infl orescence that accessions can be selected for specifi c uses characters were observed on culms from which and environments. With a multi-species collec- 10–30% of the spikelets had shed. All leaf obser- tion, it is also important that similar species are vations were taken on the second leaf below the compared for their forage potential and agro- fl ag leaf. Wherever possible, observations were morphological characteristics to give a better made on 10 different plants per accession as sug- indication of the agronomic potential of lesser- gested by van de Wouw et al. (1999b). Spikelet known species. observations were made on 10 randomly sampled In the current study, a wide range of morpho- spikelets from the harvest of the full plot. To logical, agronomic and environmental characters avoid overemphasis on the size of different plant were examined for 6 perennial Panicum species. parts, only one measurement each of leaf, spikelet The emphasis was on P. maximum, which is the and infl orescence was used as an actual measure- most widely used of the Panic grasses. P. anti- ment. The other characters were used as ratios dotale, a native grass of India, is the only non- to indicate the shape of the observed plant parts. African Panic grass in this study. Some accessions For those accessions, in which clearly 2 different of P. coloratum and accessions from some lesser- genotypes could be distinguished, with differ- known forage species, such as P. turgidum Forsk., ences beyond those expected for natural variation P. phragmitoides Stapf and P. infestum Anderss within a popu lation, observations were carried ex Peters were also included. Little published out separately for each genotype and the letters information exists on the agronomy and morpho- ‘a’ and ‘b’ were added to the accession number. logical diversity, as well as the forage potential, The correlations between the observed charac- of these last 3 species. ters were calculated using Pearson’s correlation coeffi cient. Characters that showed a high corre- lation coeffi cient (= > 0.7) were reviewed, and if Materials and methods the correlation could be explained by an overlap in measurements, one character was excluded to The study was carried out at the ILRI Zwai seed avoid indirect weighting in the cluster analysis. multiplication site, in the Rift Valley of Ethi- After standardising the variables to a mean of 0 opia (7°54′N, 38°44′E) at an elevation of 1640 m and a variance of 1, principal component analysis above sea level. The site has an annual average was carried out. Hierarchical clusters were rainfall of 600 mm, of which the majority falls formed using the average and complete linkage during July–September. The soil at the Zwai site algorithms of the NTSYS 2.01 program. The fi rst is loamy sand and has been classifi ed as a vitric analysis included all accessions, while a second andosol (King and Birchall 1975). The pH(H2O) analysis excluded outliers, because outliers tend of the soil was 8.1. The plots were fertilised with to distort clustering. The full dataset was explored 200 kg/ha/yr N in the form of 6 split applications using a discriminant analysis in SYSTAT 8.0 of ammonium sulphate. Additionally, 60 kg/ha/yr to fi nd the characters which best described the P in the form of triple superphospate was applied resulting clusters of accessions. once a year. Geographic Information Systems (GIS) tech- Seventy-four accessions were used in the niques were used to extract data on the collection study, 59 being Panicum maximum (Table 1). environment for those accessions with informa- The collection came mostly from Africa, with an tion on the collection site. When coordinates emphasis on countries in east Africa (Figure 1). were not known, they were obtained by refer- Each accession under study was established by ring to maps using the collection site description. root splits in a 2 × 5 m plot, with a spacing of A set of 19 bioclimatic variables (Table 3) at the 50 × 50 cm between individual plants. The plants collection sites was extracted using climatic sur- were irrigated weekly and were cut back to a faces on a 1 km spatial resolution (Hijmans et al. height of 15 cm at the start of the observation, 2005). These bioclimatic variables were derived just before the rainy season. from monthly temperature and rainfall values to Forty-nine characters were selected, based generate biologically more meaningful variables. on expected variation and possible importance Using the same coverage, the altitude of the 003_08_03_VanDeWouw_etal.indd3_08_03_VanDeWouw_etal.indd 4411 225/2/085/2/08 110:35:380:35:38 AAMM 42 Mark van de Wouw, Maria Alexandra Jorge, Jürgen Bierwirth and Jean Hanson 0COLORATUM 0INFESTUM 0MAXIMUM 0PHRAGMITOIDES 0TURGIDUM Figure 1. Collection sites of Panicum accessions used in the characterisation study. Table 1. List of accessions and species used in the characterisation study. ILRI No Species Country of collection Other numbers2 6586 Panicum antidotale 6587 Panicum antidotale 7148 Panicum antidotale CPI56977 6584 Panicum coloratum var. makarikariense 96601 Panicum coloratum Ethiopia CIAT16379 138211 Panicum coloratum Ethiopia CIAT16378 127971 Panicum infestum Kenya CIAT16577 128051 Panicum infestum Kenya CIAT16568 128461 Panicum infestum Kenya CIAT16569 111 Panicum maximum cv. Makueni Kenya 12 Panicum maximum cv. Riversdale 13 Panicum maximum cv. Colonião 144 Panicum maximum cv. Petrie 145 Panicum maximum cv. Hamil 978 Panicum maximum Rwanda 9801 Panicum maximum Rwanda 10091 Panicum maximum Burundi 10351 Panicum maximum Burundi 10471 Panicum maximum Burundi 10481 Panicum maximum Burundi 21181 Panicum maximum Ethiopia 21241 Panicum maximum Ethiopia 21401 Panicum maximum Ethiopia 21441 Panicum maximum Ethiopia 003_08_03_VanDeWouw_etal.indd3_08_03_VanDeWouw_etal.indd 4422 225/2/085/2/08 110:35:390:35:39 AAMM Characterisation of Panicum accessions 43 ILRI No Species Country of collection Other numbers2 6580 Panicum maximum FAO27201 6581 Panicum maximum 6946 Panicum maximum cv.