The phenotypic variation in caryopsis dormancy and seedling salt tolerance was investigated in 16 wild barley ecotypes in Israel. Depth of dormancy, as reflected by the time to maximum germination percentage, ranged from 15 to 103 days under dormancy-break treatment. Lower dormancy was characteristic of the mesic ecotypes, whereas deeper dormancy was characteristic of the xeric ecotypes. Dormancy-break patterns were revealed by growth curves: the xeric ecotype showed an S-shaped curve, whereas the mesic ecotype displayed a reverse L-shaped curve. Seedling salt tolerance was assessed by the ratio of root or coleoptile length in a seedling grown in 100 or 200 mM NaCl solution to that of a seedling grown in water. The root- and coleoptile-length ratios of mesic ecotypes were much higher than that of the xeric ecotypes, except that there was no observable difference in coleoptile-length ratio at 100 mM NaCl. The mesic ecotype was more tolerant to salt than the xeric ecotype at the young seedling stage, and seedling salt tolerance was negatively correlated with caryopsis dormancy depth. Thus evolutionary background environments have had a strong effect on the intensity of caryopsis dormancy in wild barley. Through natural selection, wild barley has adapted to dry and hot environments by increasing dormancy but not young seedling salt tolerance.
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Acknowledgements This work was supported by the German-Israeli Project Cooperation (grant DIP-B-4.3), the Israel Discount Bank Chair of Evolutionary Biology, the Ancell-Teicher Research Foundation for Molecular Genetics and Evolution, and the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry. The authors thank Mr. Fei Yang for his help in data analysis and comments, and the English editorial comments by Ms. Camille Vainstein of Faculty of Agriculture, Hebrew University of Jerusalem.
- Dormancy pattern
- Growth curve
- Hordeum spontaneum
- Mesic and xeric ecotype
- Root- and coleoptile-length ratio
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Agronomy and Crop Science
- Plant Science