Molecular marker analysis for QTL identification in Indian mustard (Brassica juncea L. Czern & Coss.) for salinity tolerance
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Date
2017
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CCSHAU
Abstract
Salinity tolerance is quantitative and complex phenomenon controlled by numerous interacting quantitative trait
loci (QTLs). To find out genomic regions associated with terminal salinity tolerance a study entitled Molecular
marker analysis for QTL identification in Indian mustard (Brassica juncea L. Czern & Coss.) for salinity
tolerance was conducted with the objective to identify QTLs for salinity tolerance in RH 30 × CS 52 derived F2
and F2:3 populations of Brassica juncea (RH 30-Salinity sensitive and CS 52-Salinity tolerant) and to evaluate both
generations for yield attributes such as plant height (cm), physiological maturity, main shoot length (cm), number
of primary branches/plant, number of secondary branches/plant, number of siliquae/plant, number of seeds/siliqua,
1000-seed weight (g), seed yield/plant (g) and biological yield/plant (g); physiological traits such as relative water
content (%), osmotic potential (-MPa), proline content (µmol/g) and membrane injury (%) under field and salinity
treatments i.e. control, 6 dS/m and 8 dS/m. Out of 358 SSR markers 42 were found polymorphic and 153 were
monomorphic. Linkage map was prepared using 41 SSR markers covering 8 linkage groups and 1 marker did not
map to any of the linkage groups. A total of 91 alleles were identified in the CS 52 and RH 30 genotypes. The total
length of the genetic linkage map was 2298.5 cM and PIC ranged from 0.427-0.730. Composite interval mapping
revealed a total of 23 QTLs were identified for yield attributes and physiological traits in F2 population. Five QTLs
identified for salinity tolerance on two linkage groups 4 and 8 under field and salinity treatments. QTLs identified
in the present study firstly needs to be validated in other populations and then fine mapping of these salinity related
QTLs have to be carried with them in marker assisted selection and breeding for salinity tolerant genotype in
Brassica juncea.
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