A screening technique for resistance to Fusarium root for of common bean

Resistance to Fusarium root rot (FRR) in common bean is documented as a quantitative trait and as
such is greatly influenced by several environmental factors. A reproducible disease screening
technique that considers the selection environment is therefore important in selecting resistant lines. A
study was conducted to evaluate soil composition and irrigation frequency on the severity of FRR,
using a predominant pathogenic isolate from SW Uganda at the International Centre for Tropical
Agriculture (CIAT) in Uganda. Five soil compositions (i) 80% lake sand:20% forest soil, ii) 50% lake
sand:50% forest soil, iii) 80% swamp soil:20% forest soil, iv) 50% swamp soil:50% forest soil and v)
forest soil alone), and five irrigation frequency levels (once a week, twice a week, three times a week,
four times a week, and daily) were evaluated on six common bean varieties with varying levels of
resistance to FRR. Forest soil and 50% swamp soil: 50% forest soil (soil composition); daily irrigation
and irrigation once a week (irrigation frequency) differentiated test varieties most distinctly, according
to their reaction to FRR. In conclusion, a combination of forest soil and daily watering using a
pathogenic isolate FSP-3 provided adequate FRR disease levels for disease evaluation and
differentiation of bean varieties and was adopted for genetic studies on FRR resistance in beans.