Effects of daminozide on somatic embryogenesis from immature and mature embryos of wheat

The influence of daminozide, an inhibitor of gibberellins biosynthesis, on the somatic embryogenesis in immature and mature embryo derived from tissue cultures of wheat was investigated. Low concentrations of daminozide (0.064-0.127 mM) positively affected the somatic embryogenic capacity of immature embryos (cv. ‘Andros’) cultured on the medium supplemented with either 2,4-dichlorophenoxyacetic acid (2,4-D) or dicamba or para chlorophenoxyacetic acid (p-CPA). The higher concentration of daminozide (0.51-1.02 mM) reduced the regeneration of shoots. The modification of exogenous/endogenous ratio of gibberellins by application of exogenous GA3 did not remove the effect of daminozide. On the contrary, its combination with GA3 inhibited the somatic embryogenesis and resulted in the supression of the development of somatic embryos. The supplement of 0.127 mM daminozide to 2,4-D containing medium increased the embryogenic competence of immature embryos of 11 Russian spring and winter varieties. For ten varieties the number of shoots produced per callus did not differ statistically from the control medium; one variety showed the increase of shoot number. In contrast with immature wheat embryos, mature ones (cv. Tajoznaja) did not response to daminozide supplementation either of the inductive or the different- tiative media. The present observations provide a method to increase the embryogenesis efficiency for wheat commercial varieties which immature embryos display low embryogenic potential.