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Genetic and molecular marker analysis for heat tolerance in wheat (Triticum aestivum L.em.Thell)

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Title Genetic and molecular marker analysis for heat tolerance in wheat (Triticum aestivum L.em.Thell)
 
Creator Bhusal, Nabin
 
Contributor Sarial, A.K.
 
Subject Heat tolerance, RILs, Phenotyping, Genotyping, QTL, Wheat
 
Description Genetics of heat tolerance is quantitative and a complex phenomenon controlled by expression of
numerous interacting quantitative trait loci (QTLs). To find out genomic regions associated with terminal
heat tolerance a study entitled “Genetics and molecular marker analysis for heat tolerance in wheat
(Triticum aestivum L. em. Thell)” was conducted. A mapping population of F8:9 of 251 recombinant inbred
lines (RILs) of wheat derived from a cross between HD2808 (tolerant) x HUW510 (susceptible) was
genotyped and phenotyped along with their parents under normal and stress (terminal heat) conditions
during 2013-14 and 2014-15 Rabi season in a RBD. Data were recorded for various morpho-physiological
traits including grain yield, 1000-grain weight, grain filling duration, grain filling rate, grain numbers/main
spike, grain weight/main spike and harvest index. HSI of each trait was used to find out the effect of heat
stress. Analysis of variance revealed significant differences for all traits studied over sowing conditions
and years. DNA was isolated following CTAB method for genotyping. Total 380 SSR markers
representing approximately 18 on each chromosome were used to detect parental polymorphism. Parental
polymorphism was obtained 21.5%. Linkage map was constructed using 52 polymorphic primers
representing 8 linkage groups. Composite interval mapping over conditions and years identified 86 QTLs
with maximum 36 QTLs under timely sown (non stress), 31 QTLs under late sown (heat stress) and 19 for
HSI of traits. Favorable alleles for QTLs associated with heat tolerance were associated with HD2808.
QTLs were detected for all morpho-physiological traits studied except for effective number of tillers.
Maximum QTLs were detected for days to heading (9). Grain yield related trait for which parents
genetically differed under heat stress like, grain weight/main spike and grain number/spike had (8) QTLs
each while, 1000-grain weight (7). Of these, three QTLs were found consistent and stable over the
conditions and years. They were located between gwm448 and wmc296 markers, with a marker gwm122
embedded onto QTL region. 1000-grain weight recorded maximum (30.1%) phenotypic variance, was
flanked with markers gwm448 at 6.35 cM and wmc296 at 8.6 cM distance followed by grain number
(201.1%) at 5.7 and 9.7 cM and grain weight (19.8%) flanked at 4.5 and 7.4 cM. These markers could be
utilized for marker assisted selection for screening germplasm and breeding for heat tolerant cultivars.
 
Date 2016-11-25T09:18:38Z
2016-11-25T09:18:38Z
2016
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/87464
 
Language en
 
Format application/pdf
 
Publisher CCSHAU