Grain-filling rate improves physical grain quality in barley under heat stress conditions during the grain-filling period

Authors

Hamid Shirdelmoghanloo, Department of Primary Industries and Regional Development, Western AustraliaFollow
Kefei Chen, Curtin University of Technology
Blakely Paynter, Department of Primary Industries and Regional Development, Western AustraliaFollow
Tefera Angessa, Department of Primary Industries and Regional Development, Western AustraliaFollow
Sharon Westcott, Department of Agriculture and Food, WAFollow
Hammad Aziz Khan, Department of Primary Industries and Regional Development, Western AustraliaFollow
Camilla Beate Hill, Murdoch University
Chengdao Li, Department of Primary Industries and Regional Development, Western AustraliaFollow

Document Type

Article

Publication Date

5-13-2022

Journal Title

Frontiers in Plant Science

ISSN

1664-462X

Keywords

grain weight, plumpness, heat stress, grain-filling, stay-green, water-soluble carbohydrates, barley

Disciplines

Agricultural Science | Agronomy and Crop Sciences

Abstract

Heat stress is a primary constraint to Australia's barley production. In addition to impacting grain yield, it adversely affects physical grain quality (weight and plumpness) and market value. The incidence of heat stress during grain filling is rising with global warming. However, breeding for new superior heat-tolerant genotypes has been challenging due to the narrow window of sensitivity, the unpredictable nature of heat stress, and its frequent co-occurrence with drought stress. Greater scientific knowledge regarding traits and mechanisms associated with heat tolerance would help develop more efficient selection methods. Our objective was to assess 157 barley varieties of contrasting genetic backgrounds for various developmental, agro-morphological, and physiological traits to examine the effects of heat stress on physical grain quality. Delayed sowing (i.e., July and August) increased the likelihood of daytime temperatures above 30°C during grain-filling. Supplementary irrigation of field trials ensured a reduced impact of drought stress. Heat tolerance appeared to be the primary factor determining grain plumpness. A wide variation was observed for heat tolerance, particularly among the Australian varieties. Genotypic variation was also observed for grain weight, plumpness, grain growth components, stay-green and stem water-soluble carbohydrates (WSC) content, and mobilisation under normal and delayed sown conditions. Compared to normal sowing, delayed sowing reduced duration of developmental phases, plant height, leaf size, head length, head weight, grain number, plumpness, grain width and thickness, stem WSC content, green leaf area retention, and harvest index (HI), and increased screenings, grain length, grain-filling rate (GFR), WSC mobilisation efficiency (WSCME), and grain protein content. Overall, genotypes with heavier and plumper grains under high temperatures had higher GFR, longer grain-filling duration, longer green leaf area retention, higher WSCME, taller stature, smaller leaf size, greater HI, higher grain weight/plumpness potentials, and earlier flowering. GFR played a significant role in determining barley grain weight and plumpness under heat-stress conditions. Enhancing GFR may provide a new avenue for improving heat tolerance in barley.

Recommended Citation

Shirdelmoghanloo H, Chen K, Paynter BH, Angessa TT, Westcott S, Khan HA, Hill CB and Li C (2022) Grain-Filling Rate Improves Physical Grain Quality in Barley Under Heat Stress Conditions During the Grain-Filling Period. Front. Plant Sci. 13:858652. doi: 10.3389/fpls.2022.858652