title: Association between QTLs and morphological traits toward sheath blight resistance in rice (Oryza sativaL.).
abstract: Sheath blight is considered the most significant disease of rice and causes enormous yield losses over the world. Breeding for resistant varieties is the only viable option to combat the disease efficiently. Seventeen diverged rice genotypes along with 17 QTL-linked SSR markers were evaluated under greenhouse conditions. Pearson's correlation showed only the flag leaf angle had a significant correlation with sheath blight resistance under greenhouse screening. Multivariate analysis based on UPGMA clustering and principal component analysis (PCA) indicated that the flag leaf angle, flag leaf length, and plant compactness were significantly associated with the following SSR marker alleles: RM209 (116,130), RM202 (176), RM224 (126), RM257 (156), RM426 (175), and RM6971 (196), which are linked to the SB QTLs:QRlh11,qSBR11-3,qSBR11-1,qSBR9-1,qShB3-2, andqSB-9. A Mantel test suggested a weak relationship between the observed phenotypes and allelic variation patterns, implying the independent nature of morphological and molecular variations. Teqing and Tetep were found to be the most resistant cultivars. IR65482-4-136-2-2, MR219-4, and MR264 showed improved resistance potentials. These results suggest that the morphological traits and QTLs which have been found to associate with sheath blight resistance are a good choice to enhance resistance through pyramiding either 2 QTLs or QTLs and traits in susceptible rice cultivars.
authors: School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia , Bangi, Selangor 43600 , Malaysia.
authors: Md Kamal
authors: MK
authors: Hossain
authors: Plant Breeding, Genetics and Biotechnology Division, International Rice Research Institute , Manila 7777 , Philippines.
authors: Kshirod Kumar
authors: KK
authors: Jena
authors: School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia , Bangi, Selangor 43600 , Malaysia.
authors: Md Atiqur Rahman
authors: MA
authors: Bhuiyan
authors: School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia , Bangi, Selangor 43600 , Malaysia.
authors: Ratnam
authors: R
authors: Wickneswari
keywords: QTLs; SSR markers; association; morphological traits; resistance; sheath blight