Genomic influence on somatic embryogenesis in the Triticeae

Somatic embryogenesis is generally accepted to be under genetic control. The influence of genome interactions is not well understood given the difficulties of obtaining the appropriate vegetal material. Synthetic alloploids in which genomes from two species are fused together are suitable subject material to analyse this factor. In the Triticeae tribe amphiploids can be easily synthesised, which provides the opportunity to carry on this type of study. Crossing three autotetraploids, Hordeum chilense (HHHH), Triticum tauschii (DDDD) and Secale cereale (RRRR), we obtained three tetraploid amphiploids, ×Tritordeum (HHDD), ×Triticale (DDRR) and ×Hordecale (HHRR). Somatic embryogenesis from immature inflorescence and flag leaves were scored on parents and amphiploids. Immature inflorescences had a higher embryogenic response than the flag leaves. The amphiploids showed higher regeneration ability than their parents. The best genomic combination was the tetraploid triticale DDRR for every inflorescence and flag leaf size tested, followed by HHDD and HHRR. Heterosis was found to be the main genetic factor affecting the in vitro culture response although there are clear differences among the three amphiploids tested. Received: 11 February 1998 / Revision received: 8 April 1998 / Accepted: 22 November 1998