Identification of quantitative trait loci for agronomically important traits and their association with genic-microsatellite markers in sorghum |
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Authors: | G Srinivas K Satish R Madhusudhana R Nagaraja Reddy S Murali Mohan N Seetharama |
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Institution: | (1) National Research Center for Sorghum, Rajendranagar, Hyderabad, 500030, India |
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Abstract: | The identification of quantitative trait loci (QTLs) affecting agronomically important traits enable to understand their underlying
genetic mechanisms and genetic basis of their complex interactions. The aim of the present study was to detect QTLs for 12
agronomic traits related to staygreen, plant early development, grain yield and its components, and some growth characters
by analyzing replicated phenotypic datasets from three crop seasons, using the population of 168 F7 RILs of the cross 296B × IS18551. In addition, we report mapping of a subset of genic-microsatellite markers. A linkage map
was constructed with 152 marker loci comprising 149 microsatellites (100 genomic- and 49 genic-microsatellites) and three
morphological markers. QTL analysis was performed by using MQM approach. Forty-nine QTLs were detected, across environments
or in individual environments, with 1–9 QTLs for each trait. Individual QTL accounted for 5.2–50.4% of phenotypic variance.
Several genomic regions affected multiple traits, suggesting the phenomenon of pleiotropy or tight linkage. Stable QTLs were
identified for studied traits across different environments, and genetic backgrounds by comparing the QTLs in the study with
previously reported QTLs in sorghum. Of the 49 mapped genic-markers, 18 were detected associating either closely or exactly
as the QTL positions of agronomic traits. EST marker Dsenhsbm19, coding for a key regulator (EIL-1) of ethylene biosynthesis,
was identified co-located with the QTLs for plant early development and staygreen trait, a probable candidate gene for these
traits. Similarly, such exact co-locations between EST markers and QTLs were observed in four other instances. Collectively,
the QTLs/markers identified in the study are likely candidates for improving the sorghum performance through MAS and map-based
gene isolations. |
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