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Genetic diversity in the storage protein hordein encoded by two loci, Hor1 and Hor2, was analyzed electrophoretically in seeds from 123 individual plants of wild barley, Hordeum spontaneum, the progenitor of cultivated barley. The test was conducted in two topographically different 100 meter transects in Israel, each equally divided into basalt and terra rossa soil types. Altogether 15 Hor1 and 16 Hor2 phenotypes were detected; 7 phenotypes in Hor1 and 5 in Hor2 were common. Significant differentiation of both Hor1 and Hor2 phenotypes and their associations was found with soil type and topography. Likewise, significant correlations were found between hordein phenotypes and allozyme types detected in a previous study. Our results suggest that at least part of the hordein polymorphisms in wild barley is adaptive and selected by soil and topographic differences over very short distances.

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Genetic variability within and between populations of the wild progenitor of barley was studied electrophoretically. Thirty enzyme loci were assayed in 437 individuals representing 11 populations of H. spontaneum in Turkey. The results indicated that: (a) H. spontaneum in Turkey is genetically rich in allozyme variation, but because of predominant self-pollination the variation is maintained as different homozygotes in the population; (b) genetic differentiation of populations includes clinal, regional, and local patterns, sometimes displaying sharp geographic differentiation over short distances; (c) overall indices of allozymic diversity and some allele frequencies of wild barley are significantly correlated with the environment and are predictable ecologically, chiefly by combinations of temperature and humidity variables; (d) a high percentage of alleles (66~ occur in local areas or are distributed sporadically rather than widespread; (e) Wright Fixation index was very high, F= 0.995; (f) genetic distance was high (D= 0.11, ranking from 0.031 to 0.288) between populations, and (g) average relative genetic differentiation was high among populations (Gst=0.47, ranging from 0.02 to 0.66).The spatial patterns and environmental correlates and predictors of genetic variation of H. spontaneum in Turkey, indicated that genetic variation in wild barley populations is not only common, but also at least partly, adaptive. Therefore, a much fuller exploitation of these genetic resources by breeding is warranted.

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