Genetic characterization and identification of moleculat markers associated with root traits and WUE through LD based association mapping in rice germplasm accessions (Oryza sativa L.)
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Date
2011-11-18
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University of Agricultural Sciences, Bengaluru
Abstract
The hoisting population and the unfavorable climate change have reported
massive depletion of irrigation water in many parts of the world. Saving water has
become one of the prime areas of research in recent years. Rice is a satple food crops for
more that half of the human commumity. With the receding water availability, saving
water and improving rice productivity under upland conditions is essential. Pyramiding
two or more traits through trait introgression breeding on to single genetic background
would be most conceivable approach to achieve the above objective. Among several
traits, water acquisition and efficient utilization have paramount significance in
improving productivity under water limited conditions. The above being multi-genic in
inheritance, a comprehensive molecular breeding program is therefore essential.
A set of diverse germplasm accessions were extensively phenotyped in two
season’s i.e 2007 and 2008 for root traits and Water Use Efficiency (WUE). WUE was
phenotyped based on carbon isotope discrimination and Root phenotyping was done on a
specially constructed root structure. ANOVA revealed a significant genetic variability
among root traits, WUE and other associated traits. Regressions analysis revealed a
significant consistency between the experiments for most of the physiological traits.
The same set of germplasm accessions was genotyped by locus specific SSR
markers on a capillary based electrophoresis system. Molecular analysis revealed
adequate genetic diversity among the germplasms. Model based population structure
analysis revealed the presence of four distinct sub-populations among the germplasms.
This structure was confirmed by distance based neighbor-joining analysis. Marker-trait
association analysis was carried out using the software TAssEL MLM strategy
considering both population structure and relatedness. Several QTLs were discovered for
root traits, WUE and associated traits. The markers RM223, RM163 and RM 224 have
been identified to be associated with root trait and WUE as well and also as overlapping
markers for several traits.
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mud, processed animal products, livestock