O.T. BAER, C.E. REANO, G.B. GREGORIO, MG.Q. DIAZ, LJ.A. PABRO, L. TAMBA, N. BALTAZAR, ME.R. FABREAG, A.E. POCSEDIO, S. LACAM, A.G. KUMAR, and T.P. LAUDE
SUMMARY
Bacterial stalk rot (BSR) caused by Dickeya zeae is one of the important diseases of maize that significantly affects maize yield performance. Resistance to D. zeae is influenced by high humidity and temperature. Affected tissues are described as soft, mushy, and emitting a foul odor. Yield losses can reach approximately 98.8% of the grower‟s potential. Quantitative trait locus (QTL) mapping experiments using seven biparental populations were conducted at Syngenta Philippines, Inc., from 2014–2020 to locate consistent QTL and markers involved in BSR resistance. The QTL detected in NMM033, NMM073, NMM089, NMM090, NMM091, NMX003, and NMX001 populations were used to estimate the numbers and positions of consensus QTL with BioMercator V4.2.3 software. Metaanalysis for BSR resistance was conducted by considering all QTL for BSR resistance traits identified in 2014–2020. Among the 49 distinct markers on chromosomes (chrs) 1 to 10, eight most significant loci 1 were detected, i.e., MSRQTL1-1, MSRQTL2-1, MSRQTL3-1, MSRQTL3-2, MSRQTL5-1, MSRQTL5-2, MSRQTL6, and MSRQTL10-1. Meta-QTL were identified in chrs 1, 5, and 10 in four populations; in chr 2 in three populations; and in chrs 3 and 6 in two populations evaluated in this study. The regions identified in chrs 1, 2, 3, 5, 6, and 10 with high QTL colocalization across biparental populations were considered as important QTL for BSR resistance traits. Further implementation through fine-mapping is recommended for marker development. The impact of this discovery would strengthen downstream applications in marker-assisted backcrossing and is not only limited to maize BSR resistance but also to other native traits of different crops.
Keywords: Zea mays L., bacterial stalk rot, Meta-QTL analysis
DOI: http://doi.org/10.54910/sabrao2022.54.1.6