Genetic Variability and Inter-Relationship among some Nigerian Pumpkin Accessions (Cucurbita spp.)

摘要

Ten Nigerian pumpkin accessions were evaluated during the 2007 and 2008 planting seasons to estimate the magnitude of genetic variability and the character association among some yield characters. The results revealed wide genetic variability among the accessions. The genotypic and heritabilty estimates were high in days to 50% emergence, days to 50% flowering, fruit diameter and number of seeds/fruit in both planting seasons. However, genotypic and heritability estimates were low in number of male and female flowers at both planting seasons. At both plantings, the number of seeds/fruit had a significant (P < 0.01) positive correlation with the number of male flowers/plant and fruit diameter. A significant positive correlation was also obtained between the number of female flowers and the number of fruits/plant in both planting seasons, an indication that both traits increased or decreased simultaneously. Thus, increasing the number of female flowers would favour fruiting in pumpkin. In both planting seasons, path analysis revealed that days to 50% flowering had the highest positive direct effect on fruit weight and also, had a high direct contribution to the fruit yield. The significant positive correlation between the weight of harvested fruitsand fruit diameter in the 2007 planting season was due to the combination of the direct and indirect effects of fruit diameter to fruit yield. In 2008 planting, the number of female flowers recorded high positive direct effects on the weight of fruits/plant but its influence was nulified by the high negative indirect effects (-0.46) of number of fruits/plant. The results indicated that days to flowering, fruit diameter and number of seeds/fruit can be used as selection criteria to increase fruit yield in Nigerian pumpkins.