Genetic diversity of drought-responsive genes in populations of the desert forage Dactylis glomerata

Restriction fragment length polymorphisms were used to estimate genetic diversity in six populations of Dactlylis glomerata collected in two different geographical locations in Israel. The objective of this study was to test the hypothesis that drought-responsive genes would have a higher genetic diversity in populations adapted to arid environments. Drought-responsive and non-responsive genes were isolated as cDNAs from leaves of D. glomerata. These cDNAs were used as probes on genomic Southern blots. Populations of D. glomerata collected in the southern arid region of Israel had greater genetic diversity for drought-responsive genes (0.388, repressed; 0.340, induced) than populations of plants collected in the northern Mediterranean region of Israel (0.308, repressed; 0.314, induced). The populations collected in the Mediterranean region had greater genetic diversity for the genes that were non-responsive to drought (0.185 versus 0.086). The gene flow between populations was relatively high, 2.47 for induced, 1.96 for repressed and 3.5 for non-responsive genes. These results suggest that plant conservation analyses should also consider stress responsive genes in estimates of genetic diversity, to select populations for conservation.