II.42 Esterase isozymes in a Middle East Collection of Hordeum Spontaneum.
George Fedak and Tibor Rajhathy. Research Branch, Canada Department of Agriculture, Ottawa, Ontario, Canada.
A recent cereal species collecting expedition sponsored by the Canada Dept. of Agriculture, to the Middle East countries brought back 40 samples of H. spontaneum, collected from wild habitats and cultivated fields in Iraq, Syria, Lebanon and Turkey. Prior to planting for seed increase the plumule tissue excised from several seeds of each sample was analyzed for esterase isozymes. The analysis was carried out on starch gels according to Scandalios (1969).
A total of five basic patterns with extensive variation within each was observed in the 40 samples analyzed. No peculiar geographical distribution of zymo types was observed, however samples collected in close proximity were inclined to have similar patterns. In comparing the H. spontaneum esterase zymotypes with those previously observed in Canadian cultures, only a small number of similarities were found. The total number of band positions observed at the A, B, C and D loci in Canadian cultivars, however, is only a fraction of the total observed at the same positions in a world wide collection of cultivars (Allard et al., 1969; Kahler & Allard, 1970). There were not likely any bands in the A and C zones of H. spontaneum that weren't previously detected in cultivated barley by Allard et al. (1969). Preliminary results indicate that positions were found in the B zone that haven't previously been found in cultivated barley. In addition, positions were observed in the E & F zones that weren't detected by us in cultivated material using the same techniques.
It is expected that a considerable degree of polymorphism will be found among the H. spontaneum collections when larger seed samples are examined. In current studies, only 2 or 4 seeds of each collection were analyzed and in many instances more than one pattern was observed. Illucidation of this phenomenon must await the propagation of the introduced seed.
From this limited amount of information on isozyme patterns it is premature to speculate that H. spontaneum was a possible progenitor of H. vulgare but several observations indicate that similar isozyme patterns exist in both species. It can be concluded from the above studies that different land races of H. spontaneum possess qualitatively different isozyme systems.
References:
Allard, R. W., Kahler, A. L. and Weir, B. S. 1969. Barley Genetics II (in press).
Kahler, A. L. and Allard, R. W. 1970. Crop Sci. 10:444-448.
Scandalios, J. G. 1969. Biochemical Genetics 3:37-79.