Genetic characterization of angular leaf spot resistance in selected common bean landraces from Tanzania
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Date
2015
Journal Title
Journal ISSN
Volume Title
Publisher
African Journal of Biotechnology
Abstract
Angular leaf spot disease (ALS) caused by Pseudocercospora griseola is one of the most important
bean diseases in Tanzania. The bean landraces Beti-10, Nanka, Nanavala and Nkanamna used in this
study have been identified as resistant to ALS but the nature of inheritance and mechanisms of
resistance against ALS in those potential sources has not been elucidated. This information is crucial
and a necessary first step for a successful breeding programme. The objective of this work was to
study the inheritance of ALS resistance in those landraces and to identify the mechanisms of genetic
resistance using Simple Sequence Repeat (SSR) markers. Crosses were made between resistant bean
landraces and a susceptible bean cv Kablanketi. The parents, F1, F2 and backcrosses derived plants
were used for inheritance studies and for molecular marker screening using 30 SSR markers. Results
indicate that, a single dominant gene control resistance against ALS in each of the four landraces; also
the SSR marker Pv-ag004 was found to be polymorphic between Beti-10 and Kablanketi and linked to
the disease resistance. The resistance were validated by checking the F2 population of the cross
between Kablanketi × Beti-10. Therefore, since marker Pv-ag004 is polymorphic and linked to ALS
resistance, the Beti-10 landrace might be a potential source of ALS resistance. However, a detailed
study with more markers need to be done on these landraces with a view to opening the possibilities of
identifying new markers linked to ALS resistance and mapping of genes associated with resistance to
ALS.
Description
Journal Article
Keywords
Phaseolus vulgaris, Inheritance, ALS, SSR, Pseudocercospora griseola