| Summary: | Manihot esculenta ssp flabellifolia possesses valuable genetic variability for protein and
disease resistance genes that were introgressed into cultivated cassava. FLA 444- 5 with a
protein content of 10.5% (dry weight basis) was hybridised with cassava through controlled
crosses and backcrossed to cassava to obtain the B1P2 family used in this study. The interspecific
hybrids had protein values ranging from 0.77% - 11.25%, which indicated
introgression of the trait.
Application of in vitro seed germination, overcame the bottleneck of seed dormancy and
insufficient planting materials for replicational trials at an early stage of evaluation. High
positive and negative correlations were estimated in the B1P2 backcross family for yield
traits, quality traits, and pests. Moderate to high heritability values were estimated for
commercial roots, roots per plant, harvest index, root weight, fresh root yield, dry root yield,
dry matter content, post harvest physiological deterioration, and protein content. Protein
content and dry matter content were negatively correlated, but not significantly. Location and
year did not show any significant difference in protein yield by genotype. Evaluation of
whitefly in this study showed a high number of genotypes (86.70%) being resistant to
infestation and infection in this Colombian high pressure pest region.
SSR markers (817) were screened in the parental lines and four B1P2 progenies, 402
polymorphic markers were identified; of which 105 were used for map construction. The
genetic map consisted of 29 linkage groups spanning 1249.55 cM with average marker
interval of 16.16 cM. A total of three QTL (protg.7, protg.13 and protg.23) controlling
protein were identified in the three different environments, with one QTL present across all
three environments. The individual effects of alleles at these QTL ranged from 15% to 25%
of the phenotypic variance explained.
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