Abstract
Key messageGenome-wide association analysis in tropical and subtropical maize germplasm revealedthatMLND resistance is influenced by multiple genomic regions with small to medium effects.The maize lethal necrosis disease (MLND) caused by synergistic interaction of Maize chlorotic mottle virus and Sugarcane mosaic virus, and has emerged as a serious threat to maize production in eastern Africa since 2011. Our objective was to gain insights into the genetic architecture underlying the resistance to MLND by genome-wide association study (GWAS) and genomic selection. We used two association mapping (AM) panels comprising a total of 615 diverse tropical/subtropical maize inbred lines. All the lines were evaluated against MLND under artificial inoculation. Both the panels were genotyped using genotyping-by-sequencing. Phenotypic variation for MLND resistance was significant and heritability was moderately high in both the panels. Few promising lines with high resistance to MLND were identified to be used as potential donors. GWAS revealed 24 SNPs that were significantly associated (P < 3 × 10−5) with MLND resistance. These SNPs are located within or adjacent to 20 putative candidate genes that are associated with plant disease resistance. Ridge regression best linear unbiased prediction with five-fold cross-validation revealed higher prediction accuracy for IMAS-AM panel (0.56) over DTMA-AM (0.36) panel. The prediction accuracy for both within and across panels is promising; inclusion of MLND resistance associated SNPs into the prediction model further improved the accuracy. Overall, the study revealed that resistance to MLND is controlled by multiple loci with small to medium effects and the SNPs identified by GWAS can be used as potential candidates in MLND resistance breeding program.Electronic supplementary materialThe online version of this article (doi:10.1007/s00122-015-2559-0) contains supplementary material, which is available to authorized users.
Highlights
Maize lethal necrosis disease (MLND) has emerged as a devastating disease in eastern Africa since 2011 (Wangai et al 2012)
MLND in eastern Africa was found to result from synergistic interaction between Maize chlorotic mottle virus (MCMV) and Sugarcane mosaic virus (SCMV)
The objectives of the study were (1) to evaluate the diverse array of tropical and subtropical maize lines for their responses to MLND under artificial inoculation; (2) to identify genomic regions, SNPs, and putative candidate genes associated with MLND resistance; and (3) to assess the potential of genome-wide selection (GS) for MLND resistance in maize
Summary
Maize lethal necrosis disease (MLND) has emerged as a devastating disease in eastern Africa since 2011 (Wangai et al 2012). MLND in eastern Africa was found to result from synergistic interaction between Maize chlorotic mottle virus (MCMV) and Sugarcane mosaic virus (SCMV). Each of these viruses individually can cause disease, the synergistic interactions are more pronounced. Wangai et al (2012) first reported the MLND and MCMV in Kenya since the MLND has been reported in Uganda, Tanzania, Democratic Republic of the Congo, South Sudan and Ethiopia, seriously threatening maize production and the livelihoods of smallholder farmers in eastern Africa (Adams et al 2013, 2014) MCMV was first identified in Peru in 1973 (Castillo and Hebert 1974) and has been subsequently reported in the USA, parts of Latin America, and China (Niblett and Clafin 1978; Uyemoto et al 1980; Xie et al 2011). Wangai et al (2012) first reported the MLND and MCMV in Kenya since the MLND has been reported in Uganda, Tanzania, Democratic Republic of the Congo, South Sudan and Ethiopia, seriously threatening maize production and the livelihoods of smallholder farmers in eastern Africa (Adams et al 2013, 2014)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
