Genetics and mechanisms of Bruchid resistance in selected common bean (Phaseolus vulgaris L.) landraces from Tanzania and Malawi
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Date
2017
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Sokoine University of Agriculture
Abstract
Bean bruchids are the devastating pests of common bean which causes huge losses
during storage. Two landraces Kalubungula and KK25 were identified to be resistant
to bruchid infestation and damage but the mechanism and genetics of resistance were
unknown. The aim of this study was to (i) characterize the storage protein related to
resistance in these landraces (ii) determine genomic region and map QTL’s related to
resistance (iii) phenotype progenies response to bean bruchid infestation.Two
mapping populations KSy and KSw and Nagaga x KK25 recombinant inbred lines
was created in this study. We reported no association between resistance to the
storage proteins in KSw and KSy. Resistance in Nagaga x KK25 recombinant inbred
lines reported to be due to storage proteins Arcelin-5 and Phytohaemagglutinin found
at 25KDa. On determination of genomic region and QTL’s related to bruchid
resistance, a total of 328 novel single nucleotide polymorphisms (SNP’s) were
reported from KSy and 435 SNP’s from KSw assembled in 11 linkage groups of P.
vulgaris. QTL’s associated with bruchid resistance were mapped on linkage group
five (PV05) and linkage group nine (PV09) in KSy and KSw mapping populations
except for seed size and 50% adult bruchid emergence. Seed size QTL’s were
distributed on different linkage groups indicating little or no association between the
resistance and seed size. To evaluate the response of progenies to bruchid infestation,
15 lines out of 53 (28.3%) were resistant in KSy population and 5 lines (10.4%) out
of 48 were resistant in KSw population. Resistant lines identified may be important
sources of bruchid resistance in breeding programs and the QTL’s may be of
importance in marker development for marker assisted selection in common bean.
Description
A DISSERTATION SUBMITTED IN PARTIAL FULFILMENT OF THE
REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN CROP
SCIENCE OF THE SOKOINE UNIVERSITY OF AGRICULTURE.
MOROGORO, TANZANIA. 2017
Keywords
Genetics mechanisms, Bruchid resistance, Common bean, Phaseolus vulgaris L., Tanzania landraces, Malawi landraces