Viability assessment of in vitro produced synthetic seeds of cucumber

Abstract

Friable, embryogenic calli of F1 cucumber (Cucumis sativus) cultivar, Royal, were induced from the hypocotyl pieces cultured on solidified MS-basal media supplemented with 2,4-dichlorophenoxy acetic acid (2,4-D) and benzyl amino purine (BAP). Embryogenic calli were transferred to liquid Murashige and Skoog (MS)-basal  media supplemented with 5 ƒÊM naphthaleneacetic acid (NAA) and 1 µM BAP. The mature somatic embryos  were encapsulated in sodium alginate mixture in synthetic seeds. The encapsulation mixture containing 3%  sodium alginate, 100 mM calcium chloride and one-fourth volume of the cell suspension nutrient mixture  containing 5x10^-4 somatic embryos per ml was found the best. Synthetic seeds remain viable up to 14 weeks  when stored at 4°C. Germination efficiency of synthetic seeds was decreased to 57% after 10 weeks of  storage followed by rapid decrease in survival rate to 0% after 15 weeks. Genetic diversity between mother  plants and in vitro produced synthetic seeds showed resemblance as assessed by amplified fragment length polymorphism (AFLP) markers.

Key words: Artificial seed, Cucumis sativus, encapsulation, somatic embryogenesis, sodium-calcium alginate.