Caryopsis Dormancy Patterns of Wild Barley(Hordeum spontaneum)and Its Association with Agronomic Traits and Ecogeographical Parameters

Patterns in caryopsis dormancy and its agronomic and ecogeographical associations were investigated in 16 wild barley(Hordeum spontaneum) ecotypes from different habitats in Israel.The results showed that heat treatment(40℃) could break dormancy of caryopses.Germination percentages under breaking dormancy treatments were significantly different among the 16 ecotypes.Dormancy-break patterns were fitted by logistic growth curves:all eight xeric ecotypes showed an S-shaped curve,whereas all eight mesic ecotypes displayed a reverse L-shaped curve.For depth of dormancy,as reflected by the time to maximum germination percentage,the lowest(15.6 days) was for the ecotype 37-N from the north slop of Evolution Canyon(mesic),whereas it was the highest(103.1 days) for 32-6 from Ein-Zukim(near Dead Sea)(xeric).In addition,nine of 11 Spearman’s Rho Correlations between dormancy depth and agronomic traits of 16 H.spontaneum ecotypes were significant.Dormancy depth showed closest correlation with kernel weight.Nine of 15 correlations between dormancy depth and ecogeographical factors were significant.Caryopses dormancy was mainly influenced by their original location,as well as temperature and local water conditions.Therefore,natural selection adapted wild barley to a dry and warm environment by increasing dormancy.The results of dormancy in wild barley will be subjected to genetic analyses and should be helpful for improving modern barley cultivars.