Development of synthetic seeds involving androgenic and pro-embryos in elite indica rice

Abstract

Synthetic seeds were produced from anther-derived mass-multiplied embryos and pro-embryos of rice (Oryza sativa L.) var. IR 72. A high dose (4-6 mg L⁻¹) of BAP was found to produce a large number of dormant embryos, pro-embryos and embryo-like structures in about 45 d. These were encapsulated in sodium alginate (2.5% w/v) matrix. Germination and plantlet regeneration capacity of the encapsulated seeds were tested by culturing them on MS fortified with different combinations and concentrations of BAP, Kn and NAA. The result indicated that BAP in combination with lower concentrations of NAA increased germination of beaded embryos over control (MS without hormones). High percent of germination (55-87.5%) was observed when MS was supplemented with BAP and lower concentration of NAA; whereas, addition of Kn in MS reduced the germination percentage. The germination of unbeaded pro-embryos was 92.5% on MS basal medium. The reduced rate of germination of artificial seeds may be attributed to the damage incurred while separating the embryos from clusters and/or owing to adverse effects of chemicals used for encapsulation. Moderate germination (40.0%) was seen on sterile sand. Synthetic seeds may be used for in vitro propagation as well as genetic transformation experiments, especially involving biolistics.