Characterization and Evaluation of Pumpkin (Cucurbita Moschata Duch.).

Abstract

Pumpkin is an emerging important indigenous vegetable in Kenya. However, its potential remains unexploited. This study collected, characterized and evaluated pumpkin germplasm accessions in Kakamega and Nyeri Counties. The 155 accessions collected consisted of 70 and 85 from Kakamega and Nyeri Counties, respectively. Morphological characterization and evaluation was done on-farm in completely randomized design, replicated three times. Morphological characterization and evaluation data were subjected to analysis of variance using the SAS program. Means were separated at P=0.05. Molecular characterization was done by extracting DNA, and polymerase chain reaction was done on 139 accessions using SSR and ISSR primers. Molecular characterization data were scored and phylogenetic analyses conducted using DarWin software. Significant variation (P<0.05) resulted among 146 accessions morphologically. Fruit length to width ratio and fruit weight ranged from 0.7-2.1 cm and 0.5-19.25 kg/accession, respectively. Predominant mature fruit skin colour ranged from green to orange; secondary fruit skin colour from speckled to striped; fruit surface from smooth to warty; and internal flesh colour from white to yellow. Main colour of inner flesh and of outer flesh ranged from yellow to pink-red. Molecular characterization revealed that accessions were varied with amplifications on different loci ranging from 100-500bp for SSR with band ranges of 1 to 4. ISSR primers were more polymorphic with accessions amplified between 200-2000 bp with band ranges of 2 to 7. A total of 526 alleles were identified with 5 SSR primer pairs and 509 alleles with 7 ISSR primers. The Unweighted Pair Group Method of Arithmetic Mean based on Euclidean genetic distance with 1000 bootstraps constructed the dendrograms. There is great variation in pumpkins in Kenya. Cultivars are interbreeding a lot. Conservation of naturalized germplasm needs to be expedited to save it from further distortion and extinction.