Phenotypic evaluation and genetic analysis of seedling emergence in a global collection of wheat genotypes (Triticum aestivum L.) under limited water availability

Authors

Michael G. Francki, Department of Primary Industries and Regional Development, Western AustraliaFollow
Grantley Stainer, Department of Primary Industries and Regional Development, Western AustraliaFollow
Esther Walker, Department of Primary Industries and Regional Development, Western AustraliaFollow
Gregory J. Rebetzke, Commonwealth Scientific and Industrial Research Organisation
Katia T. Stefanova, Department of Primary Industries and Regional Development, Western Australia
Robert J. French, Department of Primary Industries and Regional Development, Western AustraliaFollow

Document Type

Article

Publication Date

12-24-2021

Journal Title

Frontiers in Plant Science

ISSN

1664-462X

Keywords

emergence, germination, dormancy, QTL, environment, genotype-by-environment interactions, genes

Disciplines

Agronomy and Crop Sciences | Plant Breeding and Genetics

Abstract

The challenge in establishing an early-sown wheat crop in southern Australia is the need for consistently high seedling emergence when sowing deep in subsoil moisture ( > 10 cm) or into dry top-soil (4 cm). However, the latter is strongly reliant on a minimum soil water availability to ensure successful seedling emergence. This study aimed to: (1) evaluate 233 Australian and selected international wheat genotypes for consistently high seedling emergence under limited soil water availability when sown in 4 cm of top-soil in field and glasshouse (GH) studies; (2) ascertain genetic loci associated with phenotypic variation using a genome-wide association study (GWAS); and (3) compare across loci for traits controlling coleoptile characteristics, germination, dormancy, and pre-harvest sprouting. Despite significant (P < 0.001) environment and genotype-by-environment interactions within and between field and GH experiments, eight genotypes that included five cultivars, two landraces, and one inbred line had consistently high seedling emergence (mean value > 85%) across nine environments. Moreover, 21 environment-specific quantitative trait loci (QTL) were detected in GWAS analysis on chromosomes 1B, 1D, 2B, 3A, 3B, 4A, 4B, 5B, 5D, and 7D, indicating complex genetic inheritance controlling seedling emergence. We aligned QTL for known traits and individual genes onto the reference genome of wheat and identified 16 QTL for seedling emergence in linkage disequilibrium with coleoptile length, width, and cross-sectional area, pre-harvest sprouting and dormancy, germination, seed longevity, and anthocyanin development. Therefore, it appears that seedling emergence is controlled by multifaceted networks of interrelated genes and traits regulated by different environmental cues.

Recommended Citation

Francki MG, Stainer GS, Walker E, Rebetzke GJ, Stefanova KT and French RJ (2021) Phenotypic Evaluation and Genetic Analysis of Seedling Emergence in a Global Collection of Wheat Genotypes (Triticum aestivum L.) Under Limited Water Availability. Front. Plant Sci. 12:796176. doi: 10.3389/fpls.2021.796176