Quantitative trait loci mapping for resistance to maize streak virus in F2:3 population of tropical maize

A L Garcia-Oliveira,M Gedil,V Azuh,O O Jacob,A Menkir,P Lava Kumar

doi:10.1007/s42976-020-00020-5

Abstract

Maize streak virus (MSV) continues to be a major biotic constraint for maize production throughout Africa. Concerning the quantitative nature of inheritance of resistance to MSV disease (MSVD), we sought to identify new loci for MSV resistance in maize using F2:3 population. The mapping population was artificially inoculated with viruliferous leafhoppers under screenhouse and evaluated for MSVD resistance. Using 948 DArT markers, we identified 18 quantitative trait loci (QTLs) associated with different components of MSVD resistance accounting for 3.1–21.4% of the phenotypic variance, suggesting that a total of eleven genomic regions covering chromosomes 1, 2, 3, 4, 5 and 7 are probably required for MSVD resistance. Two new genomic regions on chromosome 4 revealed the occurrence of co-localized QTLs for different parameters associated with MSVD resistance. Moreover, the consistent appearance of QTL on chromosome 7 for MSVD resistance is illustrating the need for fine-mapping of this locus. In conclusion, these QTLs could provide additional source for breeders to develop MSV resistance.

Highlights

Amongst the maize virus diseases, Maize streak virus (MSV, genus Mastrevirus) still is a persistent concern that continues to cause significant yield loss in maize production areas across sub-Saharan Africa (SSA)
At 3WAI, MSV Disease (MSVD) severity in the mapping population was at peak with the mean value of 4.8 at five-point scale (Fig. S2)
The differences in reaction to MSVD severity was much more pronounced between both parents at 4WAI (Table 1; Fig. S2)

Summary

Introduction

Amongst the maize virus diseases, Maize streak virus (MSV, genus Mastrevirus) still is a persistent concern that continues to cause significant yield loss in maize production areas across sub-Saharan Africa (SSA). MSVD incidence and severity depend on the virus inoculum sources, vector population and dynamics, stage of infection, surrounding agro-ecology and plant resistance to the disease (Bosque-Pérez 2000). Its incidence can lead up to 100% yield losses in susceptible maize cultivars if MSV outbreak occurs in the presence of drought or irregular early rains (Danson et al 2006). The unpredictable vector survival and migratory patterns makes breeding for MSVD resistance, as well as its management under field conditions, extremely difficult (Danson et al 2006)

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Conclusion