ECOLOGICAL CORRELATES OF RAPD DNA DIVERSITY OF WILD BARLEY, HORDEUM-SPONTANEUM, IN THE FERTILE CRESCENT

Genetic variability in RAPDs(Randomly Amplified Polymorphic DNA) was s tudied in 104 genotypes of wild barley, Hordeum spontaneum from 21 pop ulations sampled in Israel, Turkey and Iran, seven population from eac h country. The band (= loci) frequencies were calculated for each popu lation and correlated with ecogeographical variables. In general, high RAPD genetic diversity indices were associated with stressful environ ments, either with hot or cold steppes and deserts. Interpopulational genetic distances showed no association with the geographic distance b etween the populations' provenance. Significant Spearman rank correlat ions between RAPD band frequencies and ecogeographical parameters of p rovenance occured. Frequencies of RAPD bands were significantly correl ated with the principal component factors of allozymes. The correlatio n data indirectly suggest that natural selection appears to be the maj or determinant of both RAPD and allozyme diversities both being correl ated with environmental stress.