Earliness per se×temperature interaction: consequences on leaf, spikelet, and floret development in wheat.

Simon Griffiths,Gustavo A Slafer,Paula Prieto,Helga Ochagavía,Zoe Wilson

doi:10.1093/jxb/erz568

Simon Griffiths, Gustavo A Slafer + Show 3 more

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https://doi.org/10.1093/jxb/erz568

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Abstract

Wheat adaptation can be fine-tuned by earliness per se (Eps) genes. Although the effects of Eps genes are often assumed to act independently of the environment, previous studies have shown that they exhibit temperature sensitivity. The number of leaves and phyllochron are considered determinants of flowering time and the numerical components of yield include spikelets per spike and fertile floret number within spikelets. We studied the dynamics of leaf, spikelet, and floret development in near isogenic lines with either late or early alleles of Eps-D1 under seven temperature regimes. Leaf appearance dynamics were modulated by temperature, and Eps alleles had a greater effect on the period from flag leaf to heading than phyllochron. In addition, the effects of the Eps alleles on spikelets per spike were minor, and more related to spikelet plastochron than the duration of the early reproductive phase. However, fertile floret number was affected by the interaction between Eps alleles and temperature. So, at 9 °C, Eps-early alleles had more fertile florets than Eps-late alleles, at intermediate temperatures there was no significant difference, and at 18 °C (the highest temperature) the effect was reversed, with lines carrying the late allele producing more fertile florets. These effects were mediated through changes in floret survival; there were no clear effects on the maximum number of floret primordia.

Highlights

Adaptation to a wide range of environmental conditions is critical for wheat which is grown in most arable lands of the world and all of which are experiencing further change in growing conditions as a consequence of climate change (Asseng et al, 2015; HernandezOchoa et al, 2019; Leng and Hall, 2019)
We studied the dynamics of leaf, spikelet, and floret development in near isogenic lines with either late or early alleles of earliness per se (Eps)-D1 under seven temperature regimes
Flowering due to the action of early alleles of Eps genes was reported in Triticum aestivum by Zikhali et al (2015) due to a deletion of the chromosomal region including ELF3 corresponding to the earliness per se locus Eps-D1

Summary

Introduction

Adaptation to a wide range of environmental conditions is critical for wheat which is grown in most arable lands of the world and all of which are experiencing further change in growing conditions as a consequence of climate change (Asseng et al, 2015; HernandezOchoa et al, 2019; Leng and Hall, 2019). Major genetic factors controlling adaptability involve photoperiod and vernalization sensitivity (Ppd and Vrn) and earliness per se (Eps) genes. The latter, normally with smaller effects, are quite relevant in regions where the crop has been already reasonably well adapted as they allow for fine-tuning adaptation (Slafer, 2012; Gomez et al, 2014; Zikhali and Griffiths, 2015). Flowering due to the action of early alleles of Eps genes was reported in Triticum aestivum by Zikhali et al (2015) due to a deletion of the chromosomal region including ELF3 corresponding to the earliness per se locus Eps-D1. Wheat organs as affected by Eps alleles×temperature | 1957

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