Incorporation of resistance to angular leaf spot and bean common mosaic necrosis virus diseases into adapted common bean (Phaseolus vulgaris L.) genotype in Tanzania
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Date
2012-07-03
Journal Title
Journal ISSN
Volume Title
Publisher
African Journal of Biotechnology
Abstract
Angular leaf spot (ALS) caused by the fungus Pseudocercospora griseola and Bean common mosaic
and necrosis virus (BCMV/BCMNV) are important diseases of common bean in Tanzania that can cause
severe yield reduction when uncontrolled. This study was conducted to incorporate resistant genes for
ALS and BCMV/BCMNV diseases into adapted, market class and farmers and consumers preferred
bean genotype using marker assisted selection. The parents Mexico 54 and UBR(25)95 donor of Phg-2
and I/bc-3 genes for ALS and BCMV/BCMNV, respectively were used for the recipient being Kablanketi.
In selection, SCAR markers SNO2, ROC11 and SW13 linked to Phg-2, bc-3 and I gene, respectively were
used. A parallel backcrossing (modified double cross) procedure was used. The F1, F2 and backcrosses
from single crosses were characterized. The Chi square values for ALS were 0.081 (P<0.776) and 0.017
(P<0.896) and for BCMNV were 1.609 (P<0.205) and 1.2 (P<0.273) for molecular and phenotypic
screening, respectively. The resistance to ALS and BCMNV was found to be monogenic and the genes
involved are dominant and recessive, respectively. The heritability of ALS was found to be high (0.772)
implying that selection for ALS can be done early in segregating populations. High correlation values, r
= 0.741 and 0.624 for ALS and BCMNV, were obtained between phenotypic and molecular data,
indicating high reliability for markers. In selection, it was possible to select lines with multiple disease
resistances. This work signified the use of MAS for multiple gene screening.
Description
Research paper
Keywords
Common bean, Pseudocercospora griseola, marker assisted selection, genotype, inheritance.