Genetic variability for vascular streaking in cassava

Pages 430-437

Ilona P.C and A.G.O. Dixon


One hundred and twenty five cassava genotypes comprising 110 improved clones and

15 landraces were screened for resistance to vascular streaking (VS) in the roots. Varietal differences were significant and damaged roots were more susceptible to VS than undamaged roots. Sixteen varieties did not show VS symptoms when roots were undamaged until 7 days after harvesting under field conditions.  Vascular streaking in damaged roots was highly related to that of the undamaged roots (r=0.60**). A significant relationship also exists between VS and root moisture loss (r=0.41 *). In addition, there were significant relationships between days to VS and root flesh colour (r=0.38**), root mealiness (r=-0.33*) and dry matter content (r=-0.23*).  It is possible to practice direct, indirect and index selection for resistance to VS using the above mentioned traits.

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