Evolution of wild barley at “Evolution Canyon”: adaptation, speciation, pre-agricultural collection, and barley improvement

Abstract

The present paper reviews the state of cultivated barley, Hordeum vulgare, in Old World agriculture and its domestication through its progenitor, wild barley, Hordeum spontaneum. It focuses on the adaptation, incipient sympatric speciation, and domestication of H. spontaneum in the “Evolution Canyon” model. The “Evolution Canyon,” at lower Nahal Oren, Mount Carmel, Israel, reveals evolution in action at a microsite caused by interslope microclimatic divergence across life from viruses and bacteria through fungi, plants, and animals including mammals. The interslope adaptive complexes of H. spontaneum at “Evolution Canyon” include genetic diversity, drought resistance by dehydrin I, rhizosphere bacteria, and Eibi I gene promoter. Isa defense locus and vitamin E components also diverge between the opposite tropical and temperate abutting slopes. A highly likely pre-agricultural collection site of H. spontaneum is described on the Natufian cemetery of the Oren and Um Usba caves in “Evolution Canyon”. Finally, the paper briefly reviews the remarkable interslope incipient sympatric speciation of H. spontaneum at “Evolution Canyon”, as is true for other organisms such as bacteria, Drosophila, and spiny mice, Acomys. Sympatric ecological speciation is still controversial and “Evolution Canyon” provides an appropriate site to explore it in H. spontaneum and other organisms across life.

Keywords:

• Hordeum spontaneum
• ecological incipient speciation
• microclimatic natural selection

Acknowledgments

This paper is dedicated to my good friend Daniel Zohary, a great explorer of life and domestication of plants in the Old World. I thank the Ancell-Teicher Research Foundation of Genetics and Molecular Evolution for continuous financial support throughout this study. I also thank all my colleagues and students who collaborated with me in the “Evolution Canyon” Research Program across life starting in 1991.