A Comparison of Different Stomatal Density Phenotypes of Hordeum vulgare under Varied Watering Regimes Reveals Superior Genotypes with Enhanced Drought Tolerance

Brittany Clare Robertson; Yong Han; Chengdao Li

doi:10.3390/plants12152840

A Comparison of Different Stomatal Density Phenotypes of Hordeum vulgare under Varied Watering Regimes Reveals Superior Genotypes with Enhanced Drought Tolerance

Plants (Basel). 2023 Aug 1;12(15):2840. doi: 10.3390/plants12152840.

Authors

Brittany Clare Robertson^{1

2}, Yong Han^{1

2

3}, Chengdao Li^{1

2

3}

Affiliations

¹ Western Crop Genetics Alliance, College of Science, Health, Engineering and Education, Murdoch University, 90 South Street, Murdoch, WA 6150, Australia.
² Western Australian State Agricultural Biotechnology Centre, Murdoch University, 90 South Street, Murdoch, WA 6150, Australia.
³ Department of Primary Industries and Regional Development, 3-Baron-Hay Court, South Perth, WA 6151, Australia.

Abstract

Enhancing the water-use efficiency (WUE) of barley cultivars may safeguard yield deficits during periods of low rainfall. Reduced stomatal density is linked to enhanced WUE, leading to improved drought resistance across plant genera. In this study, 10 barley varieties exhibiting a range of stomatal density phenotypes were grown under differing soil water contents to determine whether stomatal density influences the capacity of genotypes to resist low water availability. The low-stomatal-density genotype Hindmarsh showed the least impact on biomass production during early development, with a 37.13% decrease in dry biomass during drought treatment. Low-stomatal-density genotypes additionally outcompeted high-stomatal-density genotypes under water-deprivation conditions during the reproductive phase of development, exhibiting 19.35% greater wilting resistance and generating 54.62% more heads relative to high-stomatal-density genotypes (p < 0.05). Finally, a correlation analysis revealed a strong negative linear relationship between stomatal density and the traits of head number (r = -0.71) and the number of days until wilting symptoms (r = -0.67) (p < 0.05). The combined results indicate that low-stomatal-density genotypes show promising attributes for high WUE, revealing novel barley varieties that may be useful to future breed improvement for drought tolerance.

Keywords: barley; drought tolerance; stomata; water-use efficiency; yield.

Grants and funding

B.C.R completed this research whilst being supported by a research training program (RTP) scholarship provided by the commonwealth government of Australia. B.C.R. was additionally supported by a Grains Research and Development Corporation (GRDC) research scholarship funded by the GRDC (grant number: GRS).