GENETIC MAPPING OF FUNCTIONAL MARKERS LOCATED IN QTL REGION FOR FUSARIUM WILT RESISTANCE IN CHICKPEA (Cicer arietinum L.)
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Date
2016-02-01
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UNIVERSITY OF AGRICULTURAL SCIENCES
Abstract
Fusarium wilt (FW) is a major disease of chickpea (Cicer arietinum L.) in all the
chickpea growing areas. The present investigation utilized the FW linked QTLs/markers
information to fine map the FW resistance regions. Forty six markers linked to FW
resistance were reported which were physically mapped onto chickpea genome sequence.
Among them, 23 markers were mapped on six chromosomes and six were mapped on
unplaced genomic scaffold. After physical mapping, 16 genomic regions were selected
for identification of genes and microsatellite repeats. Totally 36.85 Mb on chromosomes
and 1.65 Mb on scaffolds were scanned for genes and SSR motifs. Altogether, 1,578
genes and 2,250 genic SSR motifs were identified and primers could be designed for only
941 genic SSR motifs. From among 941 markers 168 markers were selected for primer
synthesis and 161 showed required amplification. Two intraspecific linkage maps of
chickpea were constructed using recombinant inbred lines (RILs) of JG62×WR315 (JW)
and K850×WR315 (KW) using a set of 23 and 22 polymorphic SSR markers respectively
for genotyping after screening 168 markers. Three linkage groups spanning a distance of
144.51 and 100.46 cM with an average markers density of 6.53 and 5.23 cM were
observed for population JW and population KW respectively. The RILs were phenotyped
for wilt resistance over two seasons. Six QTLs (qW60-07-1-1, q60pot-3-3, qW30-08-1-1,
q30pot-3-1, qW30-07-3-1, and qW30-08-3-1) in population JW with phenotypic variance
ranging from 8.56-23.62 per cent and one QTL (qWilt60-07-3-1) in population KW
explaining phenotypic variance of 9.45 per cent were identified. These seven redefined
QTLs were physically mapped to three chromosomes (2, 4 and 6) suggesting that there
are three different loci controlling FW resistance. The QTLs were redefined with a
smaller interval harbouring 75 putative candidate genes for disease resistance.
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