Mapping and Validation of Major Quantitative Trait Loci for Resistance to Northern Corn Leaf Blight Along With the Determination of the Relationship Between Resistances to Multiple Foliar Pathogens of Maize (Zea mays L.)

Abstract

Among various foliar diseases affecting maize yields worldwide, northern corn leaf blight (NCLB) is economically important. The genetics of resistance was worked out to be quantitative in nature thereby suggesting the need for the detection of quantitative trait loci (QTL) to initiate effective marker-aided breeding strategies. From the cross CML153 (susceptible) × SKV50 (resistant), 344 F2:3 progenies were derived and screened for their reaction to NCLB during the rainy season of 2013 and 2014. The identification of QTL affecting resistance to NCLB was carried out using the genetic linkage map constructed with 194 polymorphic SNPs and the disease data recorded on F2:3 progeny families. Three QTL for NCLB resistance were detected on chromosomes 2, 5, and 8 with the QTL qNCLB-8-2 explaining the highest phenotypic variation of 16.34% followed by qNCLB-5 with 10.24%. QTL for resistance to sorghum downy mildew (SDM) and southern corn rust (SCR) were also identified from one season phenotypic data, and the co-location of QTL for resistance to three foliar diseases was investigated. QTL present in chromosome bins 8.03, 5.03, 5.04, and 3.04 for resistance to NCLB, SDM, and SCR were co-localized, indicating their usefulness for the pyramiding of quantitative resistance to multiple foliar pathogens. Marker-assisted selection was practiced in the crosses CM212 × SKV50, HKI162 × SKV50, and CML153 × SKV50 employing markers linked to major QTL on chromosomes 8, 2, and 10 for NCLB, SDM, and SCR resistance, respectively. The populations were advanced to F6 stage to derive multiple disease-resistant inbred lines. Out of the 125 lines developed, 77 lines were tested for their combining ability and 39 inbred lines exhibited high general combining ability with an acceptable level of resistance to major diseases.

Prospecting quantitative trait loci for maydis leaf blight (MLB) resistance using a population of teosinte‐introgressed maize (Zea mays ssp. mays) and in silico identification of candidate MLB resistance genes

“…Scoring for MLB response was done once, 35 days after the artificial inoculation following rating scale of 1–9 (Hooda et al, 2018). One time disease scoring of population for mapping foliar disease‐resistant QTLs in maize has also been adopted previously by Zwonitzer et al (2010) and Ranganatha et al (2021). The disease rating was then converted into percent disease index (PDI) by using the formula given below:…”

Distribution, Etiology, Molecular Genetics and Management Perspectives of Northern Corn Leaf Blight of Maize (Zea mays L.)

“…Moderate to high genomic prediction accuracies were observed between 0.58 and 0.83 based on population and continent. Recently, Ranganatha et al [130] evaluated CML153 (susceptible) and SKV50 (resistant) based 344 F 2:3 population for NLCB resistance and identified two major QTLs namely qNCLB-8-2 (phenotypic variation of 16.34%) and qNCLB-5 (phenotypic variation of 10.24%). Nevertheless, numerous QTLs have been identified in different populations by different research groups, but integrating the data of all the QTLs is an efficient approach to identify the consensus or stable regions harbouring multiple QTLs.…”

Identification of candidate gene associated with maize northern leaf blight resistance in a multi-parent population

“…Wang et al ( 2018 ) identified 11 QTLs from cross Ye478 × Qi319, and identified qNCLB7.02 as a consistent major resistant locus across multiple environments, with PVE ranging from 10.11% to 15.29%. Ranganatha et al ( 2020 ) detected five NLB resistant QTLs with PVE ranging from 1.64% to 16.34% in 344 families of an F 2:3 population derived from cross CML153 × SKV50. Ding et al ( 2015 ) conducted GWAS for mean rating, high rating and area under the disease progress curve using single-marker and haplotype-based associations in a population of 999 maize inbred lines, and identified multiple SNPs associated with NLB across all 10 maize chromosomes.…”