CHARACTERIZATION OF TRAIT SPECIFIC RIL TO MAP QTL AND IDENTIFY SUPERIOR TRAIT INTROGRESSED LINES IN RICE (Oryza sativa L.)
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Date
02-07-14
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University of Agricultural Sciences GKVK, Bangalore
Abstract
With the receding water availability, saving water from rice cultivation while
sustaining productivity is essential. This necessitates development of rice cultivars
suitable for semi-irrigated aerobic cultivation. Introgressing water acquisition and its
efficient use for biomass production have been demonstrated to have great significance in
improving productivity.
Towards identifying superior trait introgressed lines, a mapping population
comprising of 230 recombinant inbred lines developed by crossing Thanu (high WUE)
and IET 15963 (high root) was phenotyped for variability in WUE based Δ13C, yield and
spikelet associated traits under aerobic condition. The population was genotyped with 82
polymorphic SSR markers reported to be linked with yield under drought and other
related traits. A genetic linkage map was constructed with a total of 115 which included
62 markers from a previous study. QTLs for important traits like yield under drought,
WUE, roots and traits associated with spikelet fertility were discovered. The combined
approach of previous association mapping and present linkage mapping lead to the
identification of two common markers viz., RM180 and RM307 linked with Δ13C and
root length, respectively. These markers can significantly enhance breeding efficiency
while introgressing complex traits.
Several transgressive segregants with improved root traits and WUE were
identified. Graphical genotyping of these introgression lines with 115 markers revealed
the integration of trait donor genomes. The performance of these selected transgressive
segregants was significantly superior compared with the parental lines as evidenced by a
grametric experiment. The investigation provided a proof of concept that introgression of
root and WUE traits is essential for sustaining rice productivity while saving substantial
amounts of water by growing them under semi-irrigated aerobic conditions.
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Keywords
irrigation, vegetative propagation, rice, planting, yields, biological phenomena, weather hazards, genetics, selection, introgression