Abstract
Thermal stress at the reproductive stage poses a substantial constraint on cereal production worldwide. This study was conducted to assess tolerance to terminal high-temperature stress in 45 wild (Hordeum vulgare ssp. spontaneum) genotypes, 4 cultivars (H. vulgare ssp. vulgare), 98 F3 and 79 BC1F2 families derived from hybridization of the most tolerant wild genotype and a susceptible cultivar ‘Mona’. Results of analysis of variance showed the significant genotypic and high-temperature stress effects on all the traits studied. In contrast to the cultivated genotypes, the wild ones were found less affected by high-temperature stress. The multivariate analysis highlighted the additional high-temperature tolerance components in the tolerant families and wild genotypes. Grain yield strongly correlated (p < 0.01) with stress tolerance, yield stability, and heat tolerance indices. The reduction in the reproduction period caused by high-temperature was much higher in cultivated genotypes than in wild ones. In conclusion, the ingenuous-focused strategies like escape/avoidance are being used primarily to cope with heat stress by cultivars, while adaptive-focused coping strategies such as tolerance are being implemented by wild barley.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
Revised pre-print
Abbreviations
- Car
- carotenoid content
- Chla
- chlorophyll a content
- Chlb
- chlorophyll b content
- Chla+b
- total chlorophyll content
- Chla/b
- ratio of chlorophyll a to chlorophyll b
- DA
- days to anthesis
- DM
- days to maturity
- GW
- 1000-grain weight
- HTI
- heat tolerance index
- NGS
- number of grain per spike
- NT
- number of fertile tillers
- PH
- plant height
- Pro
- proline content
- RGP
- reproductive growth period
- SPL
- spike length
- SSI
- stress susceptibility index
- STI
- stress tolerance index
- TOL
- tolerance index
- Yp
- grain yield under normal conditions
- Ys
- grain yield under high-temperature stress conditions
- YSI
- yield stability index.