QTL analysis for blast resistance in rice (Oryza sativa L.)
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Date
2018
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MPKV,RAHURI
Abstract
The present investigation entitled "QTL analysis for blast resistance in rice ( Oryza sativa
L.)" was carried out with the objective to identify marker(s) linked to blast resistance in rice.
Rice (Oryza sativa L.) is one of the staple foods in the world, belonging to the family Poaceae.
One of the !imitating factors in the production of rice is the attack of fungal pathogen
Magnaporthe oryzae, causes blast disease which is one of the most destructive diseases affecting
rice production worldwide and can cause heavy economic losses in a susceptible cultivar.
The mapping population used in this study was the derived from cross of two local
genotypes EK 70 (highly susceptible to blast) and RDN-98-2-3-5-14 (resistant to blast). The F9
generation of the RIL mapping population was developed using modified single seed descent
method. Two hundred and four RILs along with parents were used.
Bulk segregant analysis method was employed to identify molecular markers associated
with blast resistance in rice. Among the 32 SSR markers used, 11 were polymorphic among the
parents, whereas five markers viz., RM8225, RM204, AP5659-5, RM247 and RM208 were
polymorphic between susceptible and resistant parent and respective bulks indicating their
possible association with blast resistance in rice.
The phenotypic and genotypic data obtained were used for the identification of single
marker analysis. The chi-square (X2) analysis showed that three markers RM8225, AP5659-5,
RM247 showed expected segregation ratio 1:1 and RM204 gave skewing in favor of EK70 and
RM206 in favor of RDN98-2-3-5-14. Two markers NMSMPi9-l and RM21 showed highly
distorted segregation towards the resistant parent RDN98-2-3-5-14.
Simple regression analysis with phenotypic data indicated that the marker RM8225, RM204, NMSMPi9-l, RM247, and RM208 were significantly linked with the blast resistant
genes in present population. Marker RM8225 was earlier reported to be linked with blast
resistant gene piz on chromosome 6; marker RM 204 was earlier identified in the same
population at F2 generation; NMSMPi9-1 was reported to be linked with Pi9 on chromosome 6;
RM247 was reported linked with pi-ta on chromosome 12 and RM208 was reported linked with
Pib on chromosome 2.
These markers can be used for the marker-assisted selection programme for the
introgression of these genes in desired background involving these parental genotypes.