Genomic influence on somatic embryogenesis in the Triticeae

Somatic embryogenesis is generally accepted to be under genetic control. Th e influence of genome interactions is not well understood given the difficu lties of obtaining the appropriate vegetal material. Synthetic alloploids i n which genomes from two species are fused together are suitable subject ma terial to analyse this factor. In the Triticeae tribe amphiploids can be ea sily synthesised, which provides the opportunity to carry on this type of s tudy. Crossing three autotetraploids, Hordeum chilense (HHHH), Triticum tau schii (DDDD) and Secale cereale (RRRR), we obtained three tetraploid amphip loids, x Tritordeum (HHDD), x Triticale (DDRR) and x Hordecale (HHRR). Soma tic embryogenesis from immature inflorescence and flag leaves were scored o n 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 affect ing the in vitro culture response although there are clear differences amon g the three amphiploids tested.