This study identified and mapped QTL associated with physiological resistance to Fusarium Root Rot (FRR) disease, in addition to root architecture traits previously reported as positively correlated with FRR resistance, in a black bean Recombinant Inbred Line (RIL) population. The parents of this population were the resistant landrace ‘Puebla 152’ and the cultivar ‘Zorro’ that had no previously known resistance to FRR. One QTL associated with FRR resistance and four QTL associated with root architecture traits were detected. Total root weight and shallow root weight were associated with the same QTL on Pv09. A QTL associated with root length was detected on Pv01, and was found to be independent of the fin determinacy locus. The QTL associated with FRR resistance, along with another associated with deep root weight and total plant biomass were detected 260 kbp apart on Pv05. None of the detected QTL accounted for more than 13% of phenotypic variation, indicative of the fact that FRR resistance and root traits are governed by several genes of minor influence. Puebla 152 was the source of all the beneficial alleles governing the QTL detected, a confirmation that the cultivar is a good source of physiological root rot resistance along with root architecture traits that may be valuable in breeding for root rot avoidance in common bean.Additionally, two field surveys were conducted in the common bean-growing areas of Uganda to update the available information on the extent and severity of bean diseases. Root rots, caused by Sclerotium and Fusarium species, along with insect damage by the bean beetle (Callosobruchus maculatus) were found to be the most significant biotic constraints in the areas surveyed.
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