Fine mapping of QTL (qSLB8.1 and qSLB9.1) for southern corn leaf blight resistance in maize (Zea mays L.)
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Date
2020
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Punjab Agricultural University, Ludhiana
Abstract
Southern corn leaf blight (SLB) caused by Cochliobolus heterostrophus, is a fungal disease of
maize. It is prevalent in warm region and can cause yield losses upto 40 percent. Therefore
the present investigation was undertaken using 192 RILs developed from cross between LM5
(resistant parent) and CM140 (susceptible parent). RILs along with parental lines were
evaluated for SLB disease reaction by inoculating plants at V7-9 stage and data was recorded
three times in an interval of 15 days. Disease reaction data showed normal distribution which
indicates the quantitative nature of inheritance. Days to anthesis (DTA), days to silking (DTS)
and anthesis-silking interval (ASI) were also evaluated and low correlation was observed
between flowering traits with disease data. A total of 100 SSR markers of chromosome 8 and
50 SSR markers of chromosome 9 were developed using MISA. Among 221 markers, 71
showed polymorphism between the parental lines. A linkage map was constructed with
genomic coverage of 56.3 cM for chromosome 8 (within marker interval umc1075 and
bnlg1067) with 20 markers and 9.6 cM for chromosome 9 (within marker interval bnlg1626
and bnlg1091) with 10 markers. QTL analysis was done using QTL cartographer and
previously identified QTL qSLB8.1 has been narrowed down with PAU_63-PAU_116
(qSLB8.1) as new flanking markers from distance of 7 cM/110 Mb to 3 cM/42.4 Mb; and in
qSLB8.2 distance has been narrowed down to 3.9 cM from 5.6 cM by QTL flanked by
markers PAU_95-umc1872 (qSLB8.4). Further, more markers can be designed and identified
flanking markers can be used for marker assisted selection.
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Citation
Simranjit Kaur (2020). Fine mapping of QTL (qSLB8.1 and qSLB9.1) for southern corn leaf blight resistance in maize (Zea mays L.) (Unpublished M.Sc. thesis). Punjab Agricultural University, Ludhiana, Punjab, India.