Quantitative Trait loci (QTL) Identification for Resistance to Mal de Rio Cuarto Virus (MRCV) in Maize Based on Segregate Population

Abstract

Mal de Río Cuarto virus (MRCV) is one of the most devastating pathogens in maize (Zea mays L.) causing serious yield loss in susceptible cultivars in Argentina. An effective solution to control the virus is to use resistant genes to improve the behavior of susceptible genotypes. The goals of this work are to identify simple sequence repeats (SSR) linked to quantitative trait loci (QTL), for resistance to MRCV, and to validate QTL found in previous research with different genetic backgrounds. Two hundred and eight F 2:3 families derived from a cross between a susceptible inbred line, B73, and a resistant inbred line, LP116, were evaluated across three environments in the disease-endemic region. Disease incidence (INC), disease severity (SEV) and disease severity index (DSI) were employed to evaluate F 2:3 families. Based on this segregant population, ninety-eight simple sequence repeat (SSR) markers selected from 173 markers were used. The means of all measured traits followed near-normal distribution; therefore these traits may be considered as quantitatively inherited characters. For INC, SEV and DSI all estimates showed a moderate heritability ranging from 0,33 to 0,72. Some quantitative trait loci (QTL), each explaining around 10% of phenotypic variance were found on chromosome 1, 6, 8 and 10. The identification of QTL conferring resistance to MRCV may contribute to breeding programs seeking to protect the crop through improved genetic resistance.

Genome‐wide association study of resistance to Mal de Río Cuarto disease in maize

“…On chromosome 6, Redinbaugh et al (2018) reported overlapping of loci conferring resistance to different viruses at 157 Mb. In a very close position, we identified a significant common genomic region for both traits and Rossi et al (2015) reported a QTL for SEV of MRC identified in a F 2:3 population. On Chromosome 8, where the marker S8_168828138 was statistically associated with INC, Bonamico et al (2012) and Luan et al (2012) identified QTL for resistance to Mal de Río Cuarto virus and Rice black-streaked virus, respectively, in the same position (168 Mb).…”

“…The significant genotypic variation observed in both traits reflected the high quality of the phenotypic data, which allowed us to identify genomic regions with substantive power. Therefore, the heritability across environments for both traits was higher than that reported in biparental populations (Bonamico et al, 2012;Rossi et al, 2015). A precise and reliable phenotypic evaluation is one of the main prerequisites for GWAS (Yu, Holland, McMullen, & Buckler, 2008).…”

“…Resistance to MRC behaves as a quantitative trait; several molecular markers have been identified associated with resistance loci in biparental populations (linkage analysis) evaluated in the endemic area (Di Renzo et al., 2004; Rossi, Borghi, Di Renzo, & Bonamico, 2015). Linkage analysis typically results in a relative low mapping resolution because of the limited number of recombination events that occur during the construction of mapping populations, whereas in genome‐wide association studies (GWAS) or association mapping, historical and evolutionary recombination events can help to obtain a higher‐resolution mapping (Zhu, Gore, Buckler, & Yu, 2008).…”

Identification of QTLs for resistance to maize rough dwarf disease using two connected RIL populations in maize

“…A major resistance QTL has been consistently mapped in the region of bin 8.03 on chromosome 8 in different mapping populations [16, 17]. Additionally, a major QTL for MRCV resistance at the same position on chromosome 8 was identified by Di Renzo et al [14], Bonamico et al [23] and Rossi et al [25]. In our study, qZD-MRDD8-1 in RIL-ZD was located in a similar region on chromosome 8 across two years.…”

Genome-Wide Association Implicates Candidate Genes Conferring Resistance to Maize Rough Dwarf Disease in Maize

“…Using the F 2:3 derived-lines from a cross between Mo17 (susceptible) and BLS14 (resistant), Di et al [ 22 ] detected two QTL for resistance to MRCV, which located on chromosome bins 1.03 and 8.03/4, respectively. A very recent research reported four QTL for resistance to MRCV, which located on chromosomes 1, 6, 8 and 10, respectively [ 23 ]. More QTL mapping studies on the resistance to MRDD were conducted in China.…”