Genetic Study on Post-Harvest Root Deterioration in Cassava

Abstract

Post-harvest root deterioration (vascular streaking) of cassava (Manihot esculenta Crantz) clones (accessions and breeding lines) was evaluated with harvests from different ages, seasons and locations to assess the effect of environmental factors on cassava genotypes. Vascular streaking was sensitive to any of these environmental factors. Genotype x location interaction was highly significant suggesting that final cultivar selection should be carried out in each location. Genetic analysis carried out in one location suggested that inheritance of vascular streaking was, at least partly, controlled by additive factors and quantitative rather than qualitative. Narrow sense heritability of 0.64 was obtained. Vascular streaking was highly significantly correlated with root dry matter content in all the trials conducted during seven years. Since free recombination between resistance to vascular streaking and high root dry matter content may not be possible, the most acceptable balance between these two traits should be defined according to the use of product and edafo-climatic condition of production area prior to selection program.