REGENERATION OF GERMAN SPRING WHEAT-VARIETIES FROM EMBRYOGENIC SCUTELLAR CALLUS

In order to get suitable material for transformation attempts, 18 from 20 spring wheat cultivars released in Germany in the year 1995 were a ssayed for their regeneration capabilities. From 1200 isolated immatur e embryos per cultivar embryogenic scutellar callus was induced, and t herefrom plants were regenerated. Strong variety-specific differences could be detected in the percentages of embryos (scutella), which prod uced embryogenic callus (21.6-96.1%), of the scutellum surface areas s howing embryogenic callus (7.5-67.5%), of regenerating scutellar calli (under optimal conditions 19.4-95.4%), and concerning the numbers of regenerant plantlets obtained per original embryo (under optimal condi tions 1-19). For all varieties, there was a close parallelism between the parameters just mentioned. There were no differences in rooting an d in ex vitro culture of regenerant planes: all of them could be grown to normal, fertile plants. The best regenerating varieties were <Comb >, followed by <Hanno>, <Naxos>, <Tinos>, and <Thasos>. Except <Tinos> , they were used for biolistic transformation experiments.