Breeding Drought Tolerant Bean Varieties In Eastern Africa
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Date
2011Author
Kimani, P.M.
Beebe, S.
Type
PresentationLanguage
enMetadata
Show full item recordAbstract
Development of drought resistant varieties is one of the most important strategies for coping with
frequent droughts in bean production areas in eastern Africa. Drought resistant bean varieties are
particularly important for small holder farmers who have few other alternative and practical
options of reducing adverse impacts of drought stress. The objective of this study was to evaluate
bean germplasm for tolerance under moderate to severe drought stress field conditions. Thirty six
small seeded advanced bean lines were evaluated in a 6 x 6 lattice design in drought stressed
and non-stressed treatments at Thika for three years. Grain yield was used as the primary
selection criterion. Significant (P>0.05) environment x stress levels, genotype x stress level,
genotype x environment interactions were detected. Drought intensity (DII) was highest during
the short rain season (DII = 0.5810) and lowest during the long rain season (DII= 0.3918). Yield
reduction due to drought was highest during the first short rain season (58%) but remained at
40% during subsequent long and short rainy seasons. SEA 23, RAB 608, SEA 16 and RAB 618
were the best yielding lines under stress and non-stress environments. These four lines
consistently out yielded all the checks. Yield advantage of the best nine lines varied from 18 to
66.7% under drought stress conditions compared to the drought susceptible and tolerant checks.
SEA 16 showed the lowest drought susceptibility index (DSI). Results of this study indicate
new possibilities of stabilizing bean yields in drought prone environments. Selected lines can be
utilized in breeding drought tolerant bean cultivars.