Submitted to: Theoretical and Applied Genetics
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/14/2004
Publication Date: 12/1/2004
Citation: Jones, M.W., Redinbaugh, M.G., Anderson, R.J., Louie Jr, R. 2004. Identification of loci controlling resistance to maize chlorotic dwarf virus. Theoretical and Applied Genetics. 110:48-57. Interpretive Summary: Maize chlorotic dwarf virus (MCDV) causes significant disease problems in corn in the southeastern part of the U.S. The most effective, economical and environmentally sustainable way to manage the disease caused by MCDV in corn is to develop hybrids resistant to the virus infection. Before resistant hybrids can be developed, virus resistant lines must be identified and the genes and chromosomal regions associated with resistance must be mapped. The identification of a line with strong resistance to MCDV, the availability of a robust screening technique to separate resistant and susceptible plants and the isolation of a virus strain that produced strong symptoms on susceptible plants allowed us to identify chromosomal regions associated with MCDV resistance. Regions of chromosomes 3 and 10 were responsible for most of the virus resistance. These regions were associated with specific markers that will facilitate development of MCDV resistant hybrids by corn breeders.
Technical Abstract: Ineffective screening methods and low levels of disease resistance have hampered genetic analysis of maize (Zea maize L.) resistance to disease caused by maize chlorotic dwarf virus (MCDV). Progeny from a cross between the highly resistant maize inbred Oh1VI and the susceptible inbred Va35 were evaluated for MCDV symptoms after multiple virus inoculations using the viral vector, Graminella nigrifrons. Area under the disease progress curve (AUDPC) scores for veinbanding, leaf twist and tear and whorl chlorosis symptoms in F1 and F2 populations indicate that MCDV resistance was quantitatively inherited. Genotypic and phenotypic anlayses of 314 F2 individuals were performed using Mapmaker/EXP, composite interval mapping (CIM) and analysis of variance. CIM identified two major quantitative trait loci (QTL) on chromosomes three and ten, and two minor QTL on chromosomes four and six. Resistance was additive, with alleles at the loci on chromosomes three and ten contributing equally to resistance. IMPACT STATEMENT: We identified specific molecular markers in the corn genome that are associated with a high degree of resistance to maize chlorotic dwarf virus (MCDV) infection. These markers will let corn breeders use marker assisted selection to develop MCDV-resistant, agronomically desirable hybrid corn. Because the markers associated with MCDV resistance are also associated with resistance to other maize-infecting viruses, scientists will use the information to develop new knowledge about the evolution of disease resistance in corn and to identify strategies for breeding corn with resistance to multiple virus diseases.