Mapping of drought tolerant QTLS in upland Rice variety Banglami
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Date
2021
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Abstract
The study entitled ‘Mapping of drought tolerant QTLs in upland rice variety
Banglami’ was taken up to identify the drought tolerant QTLs in Banglami, a local
medium duration upland low yielding landrace of Assam which is drought tolerant. For
this a mapping population was developed by crossing Banglami with Ranjit, an elite
long duration high yielding photosensitive and drought susceptible variety of Assam.
QTL mapping was done in this population with the use of SSR markers by Verma et
al. (2017a) and Sharma et al. (2017) and several QTLs were mapped. But with the
demand of latest technology which needs QTLs within narrow confidence intervals so
that they can be used precisely in any breeding programme without much problem of
linkage drag, the present work done became demanding as Genotyping by sequencing
(GBS) technology was used to find out SNP markers which will now flank the mapped
QTLs. For this, the mapping population was evaluated for 2 consecutive seasons for
several yield and agronomic traits under both reproductive stage drought stress and
control condition. The phenotypic data collected was associated with genotypic data to
form a high density/saturated linkage map. 4646 polymorphic informative SNPs were
assigned to 12 linkage groups (LGs) covering a total of 1306.424 cM of the rice genome
at an average marker distance of 0.32 cM.
A total of 65 QTLs were mapped which explained a PVE of 1.95- 13.80% with
LOD scores ranging from 2.5- 31.6, out of which 30 QTLs were mapped from stress
data, whereas 35 QTLs were mapped from non stress data. Out of these only 5 QTLs
were major QTLs and 2 QTLs were found to be stable across environments. 3 QTLs
were mapped for the trait grain yield per plant (GYP). 10 QTL clusters were identified
among which cluster no. 10 on chromosome no. 12 had a congregation of 8 QTLs
together within a region of 29 cM and can be considered as a QTL hotspot. Six genes
within the QTL regions were found to be differentially expressed under stress condition.
The genes were Calcium-transporting ATPase 9, Phosphoinositide binding protein,
Histone demethylase JARID1C, Nuclear-pore anchor and OsWAK3 - OsWAK
receptor-like cytoplasmic kinase and Cytochrome P450.
Overall results from the present study sets a good achievement within the
science of molecular breeding and can give a strong scientific background for the future
researchers, the outcomes of which can help them to develop drought tolerant rice
varieties.