QTL MAPPING FOR BACTERIAL LEAF BLIGHT, SHEATH BLIGHT, BLAST AND BROWN SPOT TOLERANCE USING RIL POPULATION OF RICE (Oryza sativa L.).
Loading...
Date
2013
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Rice (Oryza sativa L.) is a high economic and staple food of more than half of
the world's human population. Diseases are among the most important limiting factors
that affect rice production, causing annual yield loss conservatively. Due to the
breakdown of resistant cultivars, in the face of high pathogenic variability of the
pathogen population, identified quantitative trait loci (QTLs) can be use for disease
control. Identification and mapping of QTL is a valuable starting point for positional
cloning of genes present in the QTL region of the genome. Once the tightly linked
markers have been identified, the quantitative trait loci (QTLs) can be selected for
breeding programs using marker-assisted selection (MAS) strategy.
Two potential indica genotypes, Danteshwari: a high yielding popular rice
cultivar but resistance to few diseases and Dagad deshi: a tall deep rooted poor yielder
and susceptible to few diseases, along with their derived F14 RILs were used for the
phenotypic evaluation of four diseases such as Bacterial leaf blight, Sheath blight, leaf
Blast and Brown spot tolerance. The analysis indicated that the Sheath blight and
Blast disease index of RILs were continuously distributed as expected for a
quantitative trait but Bacterial blight resistance and Brown spot tolerance for RIL
population showed continuous variation with nearly normal distribution. Among all
122 lines used for screening of four diseases, the line numbers “71” and “77” were
found to be resistant for all four diseases such as BLB, Sheath blight, leaf Blast and
Brown spot. Only eight lines showed resistance against all three diseases.
The Single Marker Analysis tests the association between marker genotypes
and trait values using F-test in QTL cartographer 2.5. There were many RM and
HvSSR markers found significance at 0.01% level with BLB trait on chromosomes 1,
3, 4, 8, 9, 11 and 12. The only marker RM273 on chromosome 4 was found
significant at 0.1% for total lesion area for Sheath blight resistance. Similarly,
markers RM3825 and HvSSR1-87 were found significant at 0.1% and 0.01%
respectively for individual lesion length cover % of sheath length. HvSSR2-12 on
chromosome 2; RM410, RM242 and RM553 on chromosome 9; RM277 and
HvSSR12-51 on chromosome 12 were significant at the 1% level with leaf Blast.
Similarly, the highly associated marker for Brown spot tolerance was HvSSR1-55 on
chromosome 1 significance at 0.1% .
A total of 162 well distributed rice SSR (RM and HvSSR) markers
polymorphic between Danteshwari and Dagad deshi were used to construct a linkage
map. The genotypic data and phenotypic data of field condition of diseases reaction
were analyzed using QTL cartographer 2.5 and QTL IciMapping 3.2.
Description
Keywords
diseases, rice, genes, chromosomes, biological phenomena, genetics, planting, locus, bacteria, phenotypes