Retracted: Verification of single nucleotide polymorphism (SNP) markers associated with maize (Zea mays. L) streak virus resistance in early generation maize lines

Maize streak virus (MSV) is a devastating viral disease of maize in sub-Saharan Africa. The disease may cause up to 100% yield loss in susceptible crops. The use of molecular markers can facilitate the development of varieties resistant to the virus. The objective of this study is to assess the usefulness of Single Nucleotide Polymorphism (SNP) markers linked to MSV resistance in selecting for resistance at early generations of inbred line development in maize. A total of 160 maize lines were genotyped with three SNP markers that are linked to MSV resistance. These lines were tested for their reaction to MSV through artificial inoculation using viruliferous Cicadulina triangular at the three leaf stage; maize streak virus symptom was scored from 7 days after inoculation for six weeks at weekly interval on a scale of 1 to 5. MSV titer on the upper and lower leaves was determined using Direct Antigen Coating Enzyme linked Immunosorbent Assay (DAC-ELISA). One hundred and forty-two (142) of the 160 maize lines had the favourable marker allele for MSV resistance while 18 maize lines did not have the allele. Differences among the 160 maize lines for MSV symptom on upper leaves at six week after inoculation were significant (P< 0.01). Favourable allele of the SNP markers was significantly associated with MSV symptom score at 6 week after inoculation and MSV titer status. The percentage of maize lines with desirable marker allele with resistance based on symptoms score and ELISA were 97.9 and 93%, respectively. The three SNP markers showed high efficiency in the identification of MSV resistant maize lines and therefore have potential for use in marker-assisted selection. The SNP markers were not effective in detecting MSV resistance in few genotypes, indicating a need to develop other markers for resistance.   Key words: ELISA, genotyping, inoculation, maize streak virus, SNPs.   See: Notice of Retraction