| dc.description.abstract | Pumpkin is one of the most morphologically variable genera in the entire plant kingdom. In
Kenya, its genetic diversity is undocumented and distribution is haphazard. An expedition
was done in Kakamega and Nyeri regions in 2012 using purposive sampling and IPGRI
descriptors that led to collection of 155 accessions planted and replicated three times in
the Chuka University experimentation farm. The character ranges were green to orange
for mature fruit rind, speckled to striped secondary fruit rind, smooth to warty fruit surface,
and white to yellow internal flesh, and yellow to pink-red inner flesh and outer flesh. Sex
type was monoecious, with most flowers being male and flowering early; only 9
accessions had female flowers appearing early. Most accessions had globular fruits and
second fruit cycle. All the accessions had fruit vein tracks and peduncles that abscised
when overripe. Deep fruit ribbing was in 40, while small blossom scars were in 69
accessions. Shannon diversity index based on qualitative traits ranged 0.49 to 1.79, with
average of 0.97. Fruit shape and seed coat surface displayed high and low indices,
respectively. Nyeri accessions had the highest diversity index. CATPCA, factor and cluster
analysis determined relationships of the accessions based on the dissimilarity of
qualitative characters. CATPCA and factor analysis reduced the dimensionality of the
characters to 13 PCs and factors, respectively. CATPCA captured 78.3% and factor
analysis 72.1% of the total variation. The two methods jointly identified second fruiting
cycle, central leaf lobes, leaf pubescence type, leaf glossiness, and plant growth habit,
leaf and flower colour contributing most to divergence of the accessions. The
communalities were mostly high except for few characters exhibiting high specificity.
Configuration by scatter Bi-plot along the first two PC axes grouped 124 accessions into
variegated and green-leafed. Cluster analysis identified four groups with 59, 40, 24 and 1
accessions in clusters one, two, three and four, respectively. The green-leafed accessions
were grouped in cluster three and four, and the variegated into cluster one and two. The
characters with high discrimination can be useful in identifying variation that can be used
for direct selection and in assisting breeders in the identification of pumpkin germplasm
with desirable traits for inclusion in breeding and improvement programmes. | en_US |
