Rice Genomics and Genetics 2015, Vol.6, No.6, 1-5
1
Research Report Open Access
Linkage Mapping of Quantitative Trait Loci for Traits Promoting Aerobic
Adaptation on Chromosome 8 in
Indica
Rice (
Oryza sativa
L.)
Kharb A.
1
, Sandhu N.
2
, Jain S.
1
, Jain R. K.
1
1. Department of Molecular Biology, Biotechnology and Bioinformatics, College of Basic Sciences and Humanities, CCS Haryana Agricultural University,
Hisar, 125004, India
2. Division of Plant Breeding, Genetics, and Biotechnology, International Rice Research Institute, Manila, Philippines
Corresponding author email:
Rice Genomics and Genetics, 2015, Vol.6, No.6 doi: 10.5376/rgg.2015.06.0006
Received: 29 May, 2015
Accepted: 03 Aug., 2015
Published: 20 Aug., 2015
Copyright
©
2015
Kharb et al., This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article:
Kharb A., Sandhu N., Jain S., and Jain R. K., 2015, Linkage Mapping of Quantitative Trait Loci for Traits Promoting Aerobic Adaptation on Chromosome 8 in
indica Rice (
Oryza sativa
L.), Rice Genomics and Genetics, Vol.6, No.6 1
-
5 (doi:
10.5376/rgg.2015.06.0006
)
Abstract
Identification of major effect QTLs for traits promoting aerobic adaptation using molecular markers can greatly enhance
the efficacy of breeding programs to develop high yielding, direct seeded, water efficient rice varieties. The Filial (F
2
) population
derived from HKR47, high-yielding low-land
indica
rice variety, and MAS26, aerobic
adapted
rice variety,
was developed and
analyzed for the identification of larger and consistent effect QTLs for yield, yield attributing and root traits under aerobic cultivation
conditions. The population displa
y
ed large variation for all the physio-morphological traits including grain yield per plant and root
traits. Phenotypic correlation analysis revealed that grain yield per plant showed positive correlation with root length (r
2
=0.279),
fresh root weight (r
2
=0.232) and dry root weight (r=0.269). A total of 803 SSR markers, distributed on 12 rice chromosomes, were
analyzed for parental polymorphism survey; of these 125 (about 16%) displayed polymorphism. NTSYS-pc UPGMA tree cluster
analysis and two-dimensional PCA scaling showed scattering of the F
2
population between the two distinct parental genotypes; the
population was inclined towards MAS26. Composite interval mapping (CIM) analysis revealed a total of six QTLs (qTN
8.1,
qTN
8.2,
qTN
8.3,
qTGW
8.1,
qYPP
8.1
and qRL
8.1
) on chromosome 8 (within a region of 24.9 cM) which individually explained 13.7%
~
27.3% of
the phenotypic variation. Chromosome 8 also possesses QTL for aroma and kernel elongation demonstrating that it might be difficult
to introgress these QTL promoting aerobic adaptation in Basmati rice.
Keywords
Aerobic rice; Linkage mapping; Microsatellite marker; QTL; Root; Yield
Water scarcity has critical impact on world’s food
self-sufficiency and security. Almost one-fifth of the
world's population, live in areas of physical scarcity
of water and almost one quarter of the world's
population, face economic water shortage (where
countries lack the necessary infrastructure to take
water from rivers and aquifers). Water use has been
growing at more than twice the rate of population
increase in the last century (FAO, 2007,
w -
.fao.org/nr/water/docs/escarcity.pdf). According to
the International Water Management Institute (IWMI),
agriculture, which accounts for about 70% of global
water withdrawals, is constantly competing with
domestic, industrial and environmental uses for a
scarce water supply (Sentilinger, 2013,
terproject.org/ water-scarcity-and-agriculture). Indian
agriculture totally depends on monsoon and the
agriculture sector in India uses 85% of the country’s
available water. Less than 3% of the world’s water is
fresh and even of this 3% over 2.5% frozen, locked
up as glaciers and only 0.5% fresh water is available
to man for various purposes. In such a scenario, if
we continue to apply current water management
practices, by 2050, the global agricultural sector will
need to double the amount of water to feed the world.
According to the UN Convention to Combat
Desertification (UNCCD), with the existing climate
change scenario, almost half the world's population
will be living in areas of high water scarcity by 2030
(UN, 2014,
carcity.shtml).
Rice, world’s most important food crop that feeds
over half of the global population, is the biggest
consumer of fresh water diverted for irrigation.
Globally rice is grown over an area of about 164.7
