8th INTERNATIONAL WHEAT CONFERENCE

quANTITATIVe TRAIT LoCI foR ReSISTANCe To SPoT
BLoTCh CAuSed By BIPoLARIS SoRokINIANA IN WheAT
(T. AeSTIVum L.) LINeS ‘NINg 8201’ ANd ‘ChIRyA 3’
U. Kumar 1 , A. K. Joshi 2 , S. Kumar 3 , R. Chand 4
and M. S. Röder 1
1 Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstr. 3, 06466
Gatersleben, Germany
2 CIMMYT, South Asia Regional Office, P.O. Box 5186, Kathmandu, Nepal
3 Department of Molecular Biology and Genetic Engineering, Sardar Vallabh Bhai Patel
University of Agriculture and Technology, Meerut 250110, India
4 Department of Mycology and Plant Pathology, Institute of Agricultural Sciences, Banaras
Hindu University, Varanasi 221005 India
E-mail address of presenting author: a.k.joshi@cgiar.org
Spot blotch caused by Bipolaris sorokiniana is a destructive disease of wheat in warm and
humid wheat growing regions of the world. To identify quantitative trait loci (QTLs) for
spot blotch resistance, two mapping populations were developed by making the crosses
between common susceptible cultivar ‘Sonalika’ with the resistant breeding lines ‘Ning
8201’ and ‘Chirya 3’. Single seed descent (SSD) derived F 6 , F 7 , F 8 lines of the first cross
‘Ning 8201’ × ‘Sonalika’ were evaluated for resistance to spot blotch in 3 blocks in each
of the 3 years. After screening of 388 pairs of simple sequence repeat (SSR) primers between
the two parents, 119 polymorphic markers were used to genotype the mapping
population. Four QTLs were identified on the chromosomes 2AS, 2BS, 5BL and 7DS and
explained 62.9% of phenotypic variation in a simultaneous fit. The QTL on chromosome
2A was detected only in one year and explained 22.7% of phenotypic variation. In the
second cross (‘Chirya 3’ × ‘Sonalika’), F 7 and F 8 population were evaluated in 3 blocks in
each of the two years. In this population, five QTLs were identified on chromosomes 2BS,
2DS, 3BS, 7BS and 7DS. The QTLs identified in the ‘Chirya 3’ × ‘Sonalika’ population
explained 43.4% of phenotypic variation in a simultaneous fit. The alleles for reduced
disease severity in both the populations were derived from the respective resistant parent.
The QTLs QSb.bhu-2B and QSb.bhu-7D from both populations were placed in the same
deletion bins, 2BS1-0.53-0.75 and 7DS5-0.36-0.61, respectively. The closely linked markers
Xgwm148 to the QTL on chromosome 2B and Xgwm111 to the QTL on chromosome
7D are potentially diagnostic markers for spot blotch resistance.
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