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Mapping QTLs for grain yield under drought in rice involves phenotyping
and genotyping of large mapping populations. The huge cost incurred in
genotyping could be considered as a bottleneck in the process. Whole
population genotyping (WPG), selective genotyping (SG), and bulk segregant
analysis (BSA) approaches were employed for the identification of major
grain-yield QTLs under drought in rice in the past few years. The
efficiency of different QTL mapping approaches in identifying major-effect
grain-yield QTLs under drought in rice was compared using phenotypic and
genotypic data of two recombinant inbred line populations,
Basmati334/Swarna and N22/MTU1010. All three genotyping approaches were
efficient in identifying consistent-effect QTLs with an additive effect of
10% or more. Comparative analysis revealed that SG and BSA required 63.5%
and 92.1% fewer data points, respectively, than WPG in the N22/MTU1010
F"3":"4 mapping population. The BSA approach successfully detected
consistent-effect drought grain-yield QTLs qDTY"1"."1 and qDTY"8"."1
detected by WPG and SG. Unlike SG, BSA did not lead to an upward estimation
of the additive effect and phenotypic variance. The results clearly
demonstrate that BSA is the most efficient and effort saving genotyping
approach for identifying major grain yield QTLs under drought.
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