Discovery of genomic regions associated with resistance to late wilt disease caused by Harpophora maydis (Samra, Sabet and Hing) in maize (Zea mays L.).

N C Sunitha,E Gangappa,S Ramesh,H B Hemareddy,Dharanendra Swamy,R P Veeresh Gowda,Sunil Biradar

doi:10.1007/s13353-021-00672-x

N C Sunitha, E Gangappa + Show 5 more

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https://doi.org/10.1007/s13353-021-00672-x

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Abstract

Late wilt disease (LWD) caused by Harpophora maydis (Samra, Sabet and Hing) is emerging as major production constraint in maize across the world. As a prelude to develop maize hybrid resistance to LWD, genetic basis of resistance was investigated. Two F2:3 mapping populations (derived from CV156670 × 414-33 (P-1) and CV156670 × CV143587 (P-2)) were challenged with LWD at two locations (Kallinayakanahalli and Muppadighatta) during 2017 post-rainy season. A wider range of LWD scores was observed at both locations in both the populations. LWD response was influenced by significant genotype × location interaction. Six and 56 F2:3 progeny families showed resistance level better than resistant parent. A total of 150 and 199 polymorphic single nucleotide polymorphism markers were used to genotype P-1 and P-2, respectively. Inclusive composite interval mapping was performed to detect significant Quantitative Trait Loci (QTL), QTL × QTL, QTL × location interaction effects. Three major and four minor QTL controlling LWD resistance were detected on chromosome-1. The position and effect of the QTL varied with the location. Significant di-QTL interactions involving QTL (with significant and/or non-significant effects) located within and between all the ten chromosomes were detected. Five of the seven detected QTL showed significant QTL × location interaction. Though two major QTL (q-lw-1.5 and q-lw-1.6) with lower Q×L interaction effects could be considered as stable, their phenotypic variance is not large enough to deploy them inMarker Assisted Selection(MAS). However, these QTL are of paramount importance in accumulating positive alleles for LWD resistance breeding.

Highlights

Maize productivity in India is constrained by several prevalent and emerging insect pests and diseases
Five of the seven detected Quantitative Trait Locus/Loci (QTL) in our study showed significant QTL × location interaction
Though two major QTL (q-lw-1.5 and q-lw-1.6) with lower QTL × location (Q×L) interaction effects could be considered as stable, their phenotypic variance is not large enough to deploy them in MAS

Summary

Introduction

Maize productivity in India is constrained by several prevalent and emerging insect pests and diseases. Stalk rot caused exclusively by seed-borne and soil-borne pathogen H. maydis causes premature wilting symptoms at postflowering stage, a condition known as Late Wilt Disease (LWD). LWD has been reported in about 10 countries, with significant economic losses in Egypt (Sabet et al 1961), India (Payak et al 1970), Spain and Portugal (Molinero-Ruiz et al 2010) and Israel (Drori et al 2013). 3.5 to 38.4% loss of grain yield attributable to soil inoculation by H. maydis has been reported based on an empirical study using a limited number of genotypes in Egypt (El-Naggarr et al 2015). We have reported 5.8 to 44.2% grain yield losses attributable to LWD by creating artificial epiphytotic condition through injecting H. maydis inoculum into the stem internode (Sunitha et al 2020) in India

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