| dc.description.abstract | A total of 123 pigeonpea landraces from farmers' fields in four pigeonpea growing regions (low
altitude Coastal , Eastern and Southern plains and Northern highlands) of Tanzania were
characterized for 16 qualitative and 14 quantitative traits and their response to variability across
three pigeonpea production environments in Tanzania (Ilonga) and Kenya (Kampi ya Mawe and
Kabete). The trials were grown in 2002/2003 rainy season at Ilonga and during 2004/2005 rainy
season at both Kampi ya Mawe and Kabete using a 12x12 lattice in three replications, single rows
of 4m length with inter-row and intra-row spacings of l.5m and O.5m respectively. Data on
qualitative traits were recorded on each plant in the plot except for seed traits which were
recorded on a sample from a whole plot. Data on quantitative traits were taken on 5 randomly
selected plants in each plot except pod length, pod width and number of seeds per pod which
were recorded on 10 pods selected randomly from 5 plants also randomly chosen. Days to 50%
flowering, days to maturity and pod and grain yield were taken on plot basis.
Significant polymorphism in the qualitative traits was recorded in base flower colour, pod colour,
flowering pattern, streak pattern, second seed colour, seed colour pattern, and seed shape. There
was relatively low diversity in qualitative traits within the accessions and between collection
regions. Collections from Northern HigWands exhibited low diversity in qualitative traits
(especially physical grain traits) relative to the other 3 regions an indication of selection response
to market preferences. High significant differences (P<O.05) were recorded in agronomic traits
among accessions and in GxE interaction. Medium and long duration genotypes were adapted to
warmer (Kampi ya Mawe and Ilonga) and cooler higWand areas (Kabete) respectively. High
heritabilities were recorded for days to flower, days to maturity, plant heights, raceme number
and 100 seed mass an indication of possibility of improvement through selection. Grain yield had
positive significant correlations with pods per plant, pod yield, racemes per plant and both
primary and secondary branches per plant, traits that were also correlated with plant heights.
Principal component analysis separated the variability in the accessions based on days to flower,
days to maturity, plant heights, number of primary and secondary branches and number of
racemes per plant with Highland collections showing a strong positive loading for these traits on
PCl. Cluster analysis separated the accessions into 6 clusters based on the same traits. There was
close clustering within and between materials from Coastal Zone, Eastern Plains and Southern
Plains with Northern materials distinctly separated and with wide dispersion within. Overall
though, two major diversity groups were evident with Coastal, Eastern and Southern materials in
one diversity cluster and Northern Highlands materials in another cluster. The diversity grouping
in this study has helped establish the possible heterotic groups which may be used in intercrossing
to maximize hybrid vigor and generate varieties adapted to different pigeonpea growing
environments with consumer acceptability. And as much as this grouping based on reproductive
and morphological traits ~ form the basis of forming a core collection of this germplasm
representing the variability groups identified, there is need to extend collection and
characterization to all other pigeonpea areas in Tanzania to capture the actual diversity and
especially now that new improved pigeonpea types are getting adopted by farmers. | en |
