Fine Mapping of qFSR3.1 for Fusarium Stalk Rot Resistance in Maize (Zea Mays L.)
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Date
2020
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Abstract
Post flowering stalk rots are one the most destructive fungal diseases of maize caused by a
number of pathogens out of which, Fusarium verticillioides causing fusarium stalk rot (FSR)
is most prevalent pathogen in north-west India causing yield losses from 10-42 percent in
severe cases up to 100 percent. The disease is difficult to control by chemical methods, due to
its soil borne nature. Exploiting genes and quantitative trait loci (QTLs) related to FSR is
helpful for improving resistance. In the previous study at Punjab Agricultural University,
Ludhiana, a major QTL on chromosome 3 flanked by two markers viz. umc2118-bnlg1647
conferring resistance to FSR in maize was identified with a genetic distance of 20 cM.
Therefore, the present study was undertaken to fine the previously identified major QTL with
more markers to narrow down the region. A total of 190 RILs from a cross between LM5
(resistant parent) and CM140 (susceptible parent) were evaluated for FSR disease reaction
along with both the parents at tasseling stage and the data was recorded after maturity. The
disease reaction data fits normal distribution which clearly indicates that the inheritance of
FSR is under the control of quantitative loci. The data recorded for incubation time revealed
that spring season favours FSR development more than Kharif. Parental polymorphism was
surveyed using 180 SSRs and 36 SSRs of them were polymorphic. A linkage map of 268.4
cM was constructed with 26 polymorphic SSRs by genotyping 190 RILs. Both genotypic and
mean value of phenotypic data was analysed using QTL cartographer and the distance was
narrowed down to 6 cM from 20 cM with the newly linked markers PAUS_7 and PAUS_10.
Further these linked markers were applied on backcross population (BC1F1) generated from
highly resistant (line no.7) and highly susceptible (line no.126) RILs of the population under
investigation. These linked markers were used for selection of heterozygous plants in BC1F1
population. Further saturating the region identified in our study may provide useful
information of genes underlying FSR and the linked markers can be used in marker assisted
breeding programmes (MAS).
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Citation
Saini, Sandeep (2020). Fine Mapping of qFSR3.1 for Fusarium Stalk Rot Resistance in Maize (Zea Mays L.) (Unpublished M.Sc. thesis). Punjab Agricultural University, Ludhiana, Punjab, India.