Identification of Two Major Rice Sheath Blight Resistance QTLs, qSB1-1HJX74 and qSB11HJX74, in Field Trials Using Chromosome Segment Substitution Lines

Yajun Zhu; Shimin Zuo; Zongxiang Chen; Xingguang Chen; Gang Li; Yafang Zhang; Guiquan Zhang; Xuebiao Pan

doi:10.1094/PDIS-10-13-1095-RE

Identification of Two Major Rice Sheath Blight Resistance QTLs, qSB1-1^HJX74 and qSB11^HJX74, in Field Trials Using Chromosome Segment Substitution Lines

Plant Dis. 2014 Aug;98(8):1112-1121. doi: 10.1094/PDIS-10-13-1095-RE.

Authors

Yajun Zhu¹, Shimin Zuo¹, Zongxiang Chen¹, Xingguang Chen¹, Gang Li¹, Yafang Zhang¹, Guiquan Zhang², Xuebiao Pan¹

Affiliations

¹ The Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, The Key Laboratory of Plant Functional Genomics of the Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou 225009, China.
² The State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou, China.

PMID: 30708790
DOI: 10.1094/PDIS-10-13-1095-RE

Abstract

Sheath blight (SB) is among the most destructive rice (Oryza sativa) diseases worldwide. SB resistance (SBR) is controlled by quantitative trait loci (QTL). Only a few SB resistance QTLs were confirmed previously in field trials that were independent of morphological traits, a crucial factor in plant breeding. Here, we employed 63 chromosome segment substitution lines (CSSLs) to identify SBR QTLs derived from 'HJX74'. Importantly, these CSSLs all carried the same genetic background as 'HJX74', except in the substituted segment introgressed from susceptible 'Amol3(sona)'. In contrast to most reports that mapped SBR QTLs under complex genetic backgrounds, this approach allowed many CSSLs to consistently retain the agronomic traits of 'HJX74' with moderate resistance, giving the needed high reproducibility in SBR scoring. We have identified five SBR QTLs in field tests. Two of them, qSB11^HJX74 and qSB1-1^HJX74, conferred the greatest reduction in SB ratings by approximately 0.9 to 1.2 on a 0 to 9 scale. qSB11^HJX74 exhibited nearly perfect recessive heredity, whereas qSB1-1^HJX74 showed dominant heredity. Using a secondary F₂ population and overlapping substitution segment lines, we further mapped qSB11^HJX74 and qSB1-1^HJX74 to regions of approximately 430 and 930 kb, respectively. The results will accelerate the rice breeding process for resistance to SB disease.