Seedling and field assessment of wheat (Triticum aestivum L.) dwarfing genes and their influence on root traits in multiple genetic backgrounds

Abstract

Deployment of the Rht-B1b and Rht-D1b dwarfing genes helped facilitate the Green Revolution to increase wheat yields globally. Much is known of the influence of these genes on plant height and agronomic performance but not of their effects on root architecture. We assessed 29 Near-Isogenic Lines (NILs) representing 11 Green Revolution and alternative dwarfing genes across multiple genetic backgrounds for root architecture characteristics in controlled and field environments. Genetic background did not influence plant height but had a small and significant (p<0.05) effect on root architecture. All dwarfing gene NILs were significantly (p<0.01) shorter compared to tall controls. The Green Revolution Rht-B1b and Rht-D1b sometimes had longer seedling roots but were not different to their respective tall controls for root depth in the field. The Rht8, Rht12 and Rht18 dwarfing gene NILs produced long seminal roots in seedling pouches, and greater maximum rooting depth (MRD) and root penetration rate (RPR) in the field. Genotypic increases in MRD and RPR were strongly correlated with increased harvest index and grain yield particularly in dry environments. Careful root phenotyping highlights the potential of novel dwarfing genes for wheat genetic improvement under water-limited conditions.

Long coleoptile genotype and soil texture interactions determine establishment success and early growth parameters of wheat sown at depth

“…Soil texture also effects wheat root characteristics such as rooting angle and rooting depth (Wasson et al 2012, Rich et al 2020. Ingvordsen et al (2022) found that dwarfing genes (including Rht18) produced longer seminal roots in seedling pouches, and greater maximum rooting depth (MRD) and root penetration rate (RPR) in the field, compared to the control. Combined, the increased MRD and RPR was associated with increased grain yield under water stress (Ingvordsen et al 2022).…”

“…Ingvordsen et al (2022) found that dwarfing genes (including Rht18) produced longer seminal roots in seedling pouches, and greater maximum rooting depth (MRD) and root penetration rate (RPR) in the field, compared to the control. Combined, the increased MRD and RPR was associated with increased grain yield under water stress (Ingvordsen et al 2022). Therefore, in addition to improved establishment opportunities of LC, the addition of Rht18 to wheat genotypes may result in deeper root systems that access deep profile late-season water in waterlimited environments (Lilley and Kirkegaard 2011).…”

Meiotic instability and irregular chromosome pairing underpin heat‐induced infertility in bread wheat carrying the Rht‐B1b or Rht‐D1b Green Revolution genes

“…The yield benefits of gibberellin‐insensitive semidwarfs rely on optimal growth conditions (Rebetzke et al ., 2014; Jatayev et al ., 2020; Ingvordsen et al ., 2022). Warm temperatures reduce wheat productivity by affecting almost all aspects of reproductive development.…”

Identification and validation of a locus for wheat maximum root length independent of parental reproductive environment

“…The wheat SHORT ROOT LENGTH 1 as an ethylene responsive factor transcription factor, controlled root length in an auxin-dependent pathway ( Zhuang et al, 2021 ). Dwarf genes ( Rht8 , Rht12 , and Rht18 ) in wheat have been reported to affect MRL in the field ( Ingvordsen et al, 2022 ). Moreover, 33 QTL for four wheat root traits including seven for MRL were detected using hydroponic culture and soil-filled pot methods ( Zheng et al, 2019 ).…”