Abstract
Maize rough dwarf disease (MRDD) is a significant viral disease caused by rice black-streaked dwarf virus (RBSDV) in China, which results in 30% yield losses in affected summer maize-growing areas. In this study, two connected recombinant inbred line (RIL) populations were constructed to elucidate the genetic basis of resistance during two crop seasons. Ten quantitative trait loci (QTLs) for resistance to MRDD were detected in the two RILs. Individual QTLs accounted for 4.97–23.37% of the phenotypic variance explained (PVE). The resistance QTL (qZD-MRDD8-1) with the largest effect was located in chromosome bin 8.03, representing 16.27–23.37% of the PVE across two environments. Interestingly, one pair of common significant QTLs was located in the similar region on chromosome 4 in both populations, accounting for 7.11–9.01% of the PVE in Zheng58×D863F (RIL-ZD) and 9.43–13.06% in Zheng58×ZS301 (RIL-ZZ). A total of five QTLs for MRDD resistance trait showed significant QTL-by-Environment interactions (QEI). Two candidate genes associated with resistance (GDSL-lipase and RPP13-like gene) which were higher expressed in resistant inbred line D863F than in susceptible inbred line Zheng58, were located in the physical intervals of the major QTLs on chromosomes 4 and 8, respectively. The identified QTLs will be studied further for application in marker-assisted breeding in maize genetic improvement of MRDD resistance.
Highlights
Maize (Zea mays L.) is an important food crop worldwide and is a major global source of protein and carbohydrates for humans and livestock
Among the three parental lines, D863F was most resistant to maize rough dwarf disease (MRDD) (2016 disease severity index (DSI): 2.82%, 2017 DSI: 4.20%), followed by ZS301 (2016 DSI: 23.55%, 2017 DSI: 18.75%) and Zheng58 (2016 DSI: 90.25%, 2017 DSI: 93.96%)
Screening and evaluation of MRDD resistance in maize germplasm is necessary for breeding resistant maize hybrids
Summary
Maize (Zea mays L.) is an important food crop worldwide and is a major global source of protein and carbohydrates for humans and livestock. Maize is the natural host of several viruses, some of which cause diseases that affect yield and quality in some maize production zones [1, 2]. In China, maize rough dwarf disease (MRDD) was first discovered in Xinjiang and Gansu in 1954, and spread to other provinces [3, 4]. The main symptoms of MRDD include internode shortening, malformed tassels and significant delays in vegetative growth [5,6,7]. Four virus species in the genus Fijivirus, Mal de Rıo Cuarto virus (MRCV), maize rough.
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