ELECTRIC FIELDS FOSTER EMBRYOGENESIS AND ANDROGENIC PLANT REGENERATION IN ASPARAGUS OFFICINALIS

Androgenesis has been used for several years in Asparagus officinalis to produce homozygous genotypes, including anther-derived super male plants, as used to create the male hybrid 'Andréas'. However, only a limited number of clones can be regenerated to fertile plants by this method; besides, after testing a very large range of anther donor genotypes, we obtained androgenetic plants from on average 60% of them. Parallel to work with anthers, we have studied isolated microspore culture of some asparagus genotypes. The results obtained showed the positive effect of electric pulses with low voltage (250 and 500 V/cm) on embryogenesis induction and microcallus proliferation. This methodology has been extended to a wide range of genotypes and to intact anthers. The electrical parameters permitted a significant improvement of androgenic response, inducing it in recalcitrant genotypes and leading to the formation of embryos, calluses, and whole plants. These plants will be tested for homozygosity and as parents in breeding schemes in future.