title: Ploidy effect and genetic architecture exploration of stalk traits using DH and its corresponding haploid populations in maize.
abstract: BACKGROUND
  Doubled haploid (DH) lines produced via in vivo haploid induction have become indispensable in maize research and practical breeding, so it is important to understand traits characteristics in DH and its corresponding haploids which derived from each DH lines. In this study, a DH population derived from Zheng58 × Chang7-2 and a haploid population, were developed, genotyped and evaluated to investigate genetic architecture of eight stalk traits, especially rind penetrometer resistance (RPR) and in vitro dry matter digestion (IVDMD), which affecting maize stalk lodging-resistance and feeding values, respectively.
  
  
  RESULTS
  Phenotypic correlation coefficients ranged from 0.38 to 0.69 between the two populations for eight stalk traits. Heritability values of all stalk traits ranged from 0.49 to 0.81 in the DH population, and 0.58 to 0.89 in the haploid population. Quantitative trait loci (QTL) mapping study showed that a total of 47 QTL for all traits accounting for genetic variations ranging from 1.6 to 36.5% were detected in two populations. One or more QTL sharing common region for each trait were detected between two different ploidy populations. Potential candidate genes predicated from the four QTL support intervals for RPR and IVDMD were indirectly or directly involved with cellulose and lignin biosynthesis, which participated in cell wall formation. The increased expression levels of lignin and cellulose synthesis key genes in the haploid situation illustrated that dosage compensation may account for genome dosage effect in our study.
  
  
  CONCLUSIONS
  The current investigation extended understanding about the genetic basis of stalk traits and correlations between DH and its haploid populations, which showed consistence and difference between them in phenotype, QTL characters, and gene expression. The higher heritabilities and partly higher QTL detection power were presented in haploid population than in DH population. All of which described above could lay a preliminary foundation for genetic architecture study with haploid population and may benefit selection in haploid-stage to reduce cost in DH breeding.
authors.affiliation: National Maize Improvement Center of China, China Agricultural University (West Campus), 2# Yuanmingyuan West Road, Beijing, 100193, China. mengyujie25@126.com.
authors.forename: Yujie
authors.initials: Y
authors.lastname: Meng
authors.affiliation: Beijing Key Laboratory of Crop Genetic Improvement, College of Agronomy, China Agricultural University (West Campus), 2# Yuanmingyuan West Road, Beijing, 100193, China. junhuili@cau.edu.cn.
authors.forename: Junhui
authors.initials: J
authors.lastname: Li
authors.affiliation: National Maize Improvement Center of China, China Agricultural University (West Campus), 2# Yuanmingyuan West Road, Beijing, 100193, China. jianjuliu23@163.com.
authors.forename: Jianju
authors.initials: J
authors.lastname: Liu
authors.affiliation: Institute of Plant Breeding, Seed Science, and Population Genetics, University of Hohenheim, 70599, Stuttgart, Germany. huganye@163.com.
authors.forename: Haixiao
authors.initials: H
authors.lastname: Hu
authors.affiliation: National Maize Improvement Center of China, China Agricultural University (West Campus), 2# Yuanmingyuan West Road, Beijing, 100193, China. wellion@cau.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: National Maize Improvement Center of China, China Agricultural University (West Campus), 2# Yuanmingyuan West Road, Beijing, 100193, China. wenxinliu@cau.edu.cn.|Beijing Key Laboratory of Crop Genetic Improvement, College of Agronomy, China Agricultural University (West Campus), 2# Yuanmingyuan West Road, Beijing, 100193, China. wenxinliu@cau.edu.cn.
authors.forename: Wenxin
authors.initials: W
authors.lastname: Liu
authors.affiliation: National Maize Improvement Center of China, China Agricultural University (West Campus), 2# Yuanmingyuan West Road, Beijing, 100193, China. chen368@126.com.|Beijing Key Laboratory of Crop Genetic Improvement, College of Agronomy, China Agricultural University (West Campus), 2# Yuanmingyuan West Road, Beijing, 100193, China. chen368@126.com.
authors.forename: Shaojiang
authors.initials: S
authors.lastname: Chen
mesh_terms: D002482:Cellulose / Q000235:genetics; D015870:Gene Expression; D017343:Genes, Plant; D006238:Haploidy; D008031:Lignin / Q000235:genetics; D018547:Plant Stems; D040641:Quantitative Trait Loci; D019655:Quantitative Trait, Heritable; D003313:Zea mays / Q000033:anatomy & histology / Q000235:genetics*
chemical_list: D002482:Cellulose; D008031:Lignin