Association between QTLs and morphological traits toward sheath blight resistance in rice (<i>Oryza sativa</i> L.)

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, and qSB-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.

Mapping QTL for Root and Shoot Morphological Traits in a Durum Wheat × T. dicoccumSegregating Population at Seedling Stage

“…The components that represented the original variables (traits) were also extracted. Only those with eigenvalues ≥ 3.0 were considered as having a major contribution to the total variation [ 56 ]. The first and second principal component axis scores were plotted to aid the visualization of the genotype differences.…”

Understanding sheath blight resistance in rice: the road behind and the road ahead

“…They recommended not to target these ShB QTLs for utilization, as some of the PH‐QTLs are mistaken as ShB QTLs and have pleiotropic effects. Moreover, plant compactness and leaf angle are the two other morphological characters that were found to be significantly correlated with sheath blight resistance in previous studies (Han et al , ; Hossain et al ., ). Plant compactness may influence the microclimate (change in relative humidity and temperature) of the canopy, which significantly influences pathogen growth and sheath blight incidence.…”

Strategies to Manage Rice Sheath Blight: Lessons from Interactions between Rice and Rhizoctonia solani

“…For instance, four QTLs for RSB resistance have been identified in F 8 recombinant inbred lines of two rice varieties from the United States, which are allelic to the QTLs for plant height and heading date (Goad et al 2020 ). The flag leaf angle, length and plant compactness are also tightly linked with the RSB resistance QTLs, qRlh11 , qSBR11-3 , qSBR11-1 , qSBR9-1 , qShB3-2 and qSB-9 (Hossain et al 2016 ). The reason for the correlation between morphological traits and resistance may be related to canopy microenvironment.…”