Somatic embryogenesis and plant regeneration in diploid Allium fistulosum × A. cepa F₁ hybrid onions

Abstract

Procedures were developed for disinfestation of non-dormant basal plate tissue excised from field grown basal plate tissue of diploid Allium fistulosum × A. cepa F₁ hybrid onions. Contamination levels varied with the season and vegetative development of plant material. Callus initiated from basal plate tissue and immature inflorescences of the F₁ hybrids was maintained on a BDS-based medium containing 0.75 mg/l picloram and 2.0 mg/l BA. When this medium was supplemented with vitamins and glycine, and with proline at 2.5 gm/1, somatic embryos began to form. Their development continued on a BDS-based shoot promotion medium containing 0.03 mg/l picloram and 0.32 mg/l 2iP supplemented with vitamins, glycine and proline. Genotypes differed significantly in the numbers of structures regenerated. Plantlets from somatic embryos were rooted into BDS or half-strength BDS medium without growth substances and were successfully transferred to sterilized potting mix in plastic commercial corsage boxes.