Nucellar embryo culture of <i>Citrus sinensis</i> L. and <i>Citrus limon</i> L.

Abstract

Nucellar tissue cultures of polyembryonic Citrus sinensis cultivar Valencia Late and Citrus limon cultivar Rough Lemon produced somatic embryos within 60 days of culture on Murashige and Skoog (MS) basal medium supplemented with 0.4 g l-1 of filter-sterilised casein hydrolysate or 10% coconut water. Embryos that were separated and subcultured in MS media containing casein hydrolysate or coconut water but without hormones, first developed roots within 4 to 8 months and then shoots within 6 to 9 months of in vitro culture. Plantlets were transplanted to soil from 7 to 9 months after initiation. Callus-like tissue consisting of pseudobulbils was observed after 4 to 5 months from the time of initiation. Pseudobulbils developed into visible embryos with multiple cotyledons when subcultured into MS media containing casein hydrolysate or 10% coconut water after 19 to 27 days of in vitro culture. These embryos produced plantlets in which roots developed after 6 to 10 months and shoots formed after 8 to 11 months from the time of initiation.



Key Words: Citrus, nucellar embryo culture, somatic embryogenesis


(African Crop Science Journal: 2000, 8(2): 109-116)