Tropical Grasslands (2006) Volume 40, 45–59

Morphological and agronomic characterisation of Indigofera species using multivariate analysis

ABUBEKER HASSEN1,2, N.F.G. RETHMAN2 AND Z. APOSTOLIDES3

1Oromiya Agricultural Research Institute, Adami Tulu Research Center, Zeway, Ethiopia
2Department of Plant Production and Soil Science, and
3Department of Biochemistry, University of Pretoria, Pretoria, South Africa

Abstract

Knowledge of the existing genetic variation between various morphological and agronomic traits is vital for any collection, conservation and breeding programs. Forty-one Indigofera accessions from 8 different species were studied in a randomised block design with 3 replicates to characterise the accessions, using morphological and/or agronomic data analysed using multivariate methods, to identify a core set of attributes to be used in characterisation of Indigofera germplasm. Morphological data were obtained from 9 plants in each accession while 15 plants were harvested in each accession for dry matter yield determinations. Principal component analyses indicated that the first 2 components accounted for 80.0, 92.5 and 73.9% of the total variability for morpho logical, agronomic and combined data sets, respectively. Cluster analysis, using morpho logical data, revealed 6 main groups, with I. coerulea 9004 being classified in a separate group due to its large stem diameter, leaf and leaflet size (length and width). Five main agronomic groups were highlighted in cluster analysis of the agronomic data. Nine accessions were included in the agronomic groups II and III characterised by tall plants with low leaf percentage. Among the rest, I. vicioides 10486 was classified in a separate group due to its high leaf yield. Clustering of combined morphological and agronomic data revealed 8 main groups. Once again two high yielding groups (IV and V) were identified on the basis of their plant height, stem yield, total dry matter yield and canopy diameter. A character discard resulted in the selection of 8 determinant characteristics, namely: growth habit, days to 50% flowering, extent of branching, leaflet length, leaf yield, plant height or length of the principal stem, leaf percentage and canopy spread measured at the widest point. These can be regarded as the core attributes for Indigofera germplasm characterisation, which can be used for the identifi cation of suitable breeding material for specific purposes.

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