Quantitative Trait Locus Analysis for Deep-Sowing Germination Ability in the Maize IBM Syn10 DH Population.

Hongjun Liu,Sisi Liu,Thomas Lübberstedt,Shupeng Xie,Michael Lee,Changsheng Li,Jiechen Wang,Songlin Hu,Lin Zhang,Guangwu Zhao,Yongzhong Zhang,Xing Zeng,Jianhua Wang

doi:10.3389/fpls.2017.00813

Abstract

Deep-sowing is an effective measure to ensure seeds absorbing water from deep soil layer and emerging normally in arid and semiarid regions. However, existing varieties demonstrate poor germination ability in deep soil layer and some key quantitative trait loci (QTL) or genes related to deep-sowing germination ability remain to be identified and analyzed. In this study, a high-resolution genetic map based on 280 lines of the intermated B73 × Mo17 (IBM) Syn10 doubled haploid (DH) population which comprised 6618 bin markers was used for the QTL analysis of deep-sowing germination related traits. The results showed significant differences in germination related traits under deep-sowing condition (12.5 cm) and standard-germination condition (2 cm) between two parental lines. In total, 8, 11, 13, 15, and 18 QTL for germination rate, seedling length, mesocotyl length, plumule length, and coleoptile length were detected for the two sowing conditions, respectively. These QTL explained 2.51–7.8% of the phenotypic variance with LOD scores ranging from 2.52 to 7.13. Additionally, 32 overlapping QTL formed 11 QTL clusters on all chromosomes except for chromosome 8, indicating the minor effect genes have a pleiotropic role in regulating various traits. Furthermore, we identified six candidate genes related to deep-sowing germination ability, which were co-located in the cluster regions. The results provide a basis for molecular marker assisted breeding and functional study in deep-sowing germination ability of maize.

Highlights

Maize (Zea mays L.) is the largest agricultural crop in the world based on acreage and yield
The objectives of this study were: (i) identifying quantitative trait loci (QTL) controlling deepsowing germination ability in the maize intermated B73 × Mo17 (IBM) Syn10 population; (ii) exploring QTL that are co-localized in the same regions between different phenotypic traits under two sowing conditions; and (iii) mining candidate genes related to deep-sowing germination ability
The results of this study provide a basis for further fine mapping, molecular marker assisted breeding and functional study in deep-sowing germination ability of maize

Summary

Introduction

Maize (Zea mays L.) is the largest agricultural crop in the world based on acreage and yield (http:// faostat.fao.org/). As two-third of the maize cultivation area is located in arid and semiarid regions, seedlings often experience severe drought stress (Iuchi et al, 2001; Tommasini et al, 2008; Christov et al, 2014). To overcome this issue, deep-sowing strategy, an effective measure to ensure that seeds. Maize Deep-Sowing Germination Ability absorb water from deeper soil layers to germinate normally, has been applied (Zhao et al, 2010). Existing varieties show poor germination ability when sown into deeper soil layers (Zhao and Wang, 2008). It is critical to understand and explore how key quantitative trait loci (QTL) or genes are related to deep-sowing germination ability for more efficient breeding of varieties adapted to these (semi-) arid regions

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