In vitro embryo rescue and plant regeneration following self-pollination with irradiated pollen in cassava (Manihot esculenta Crantz)
Loading...
Date
2015
Journal Title
Journal ISSN
Volume Title
Publisher
African Journal of Biotechnology
Abstract
Cassava is a highly heterozygous species; hence, current methods used in classical cassava breeding
cannot match the urgent need to high yielding varieties. Recently, progress was made through
androgenesis and gynogenesis as pathways for raising doubled cassava haploid lines to overcome
problems associated with cassava’s inherent reproductive biology, but these efforts were limited (no
candidate cassava plantlets were regenerated). For the first time, this study shows that pollen
irradiation coupled with self-pollination and embryo rescue regenerated 62 candidate cassava plantlets.
Plants of an elite cassava variety, Nase14, served as a mother plant and as the pollen donor for the
irradiation. Irradiation dosages of 50 to 250 Gray studied across five pollination events and 300 or 500
Gray in one pollination event caused a reduction in pollen germination up to 67.0%. By 15 days after
pollination (DAP) with irradiated pollen, up to 89.7% of the pollinated flowers had aborted. By embryo
rescue time (42 DAP), significant differences were observed in number of fruits, seeds and embryos
generated, with the non-irradiated pollen treatments having significantly higher numbers. Sixteen (16)
heterozygous SSR markers in the parent and ploidy analysis showed that none of the regenerated
plants was haploid or homozygous. However, the plantlets resulting from pollination with non-irradiated
pollen had 56.2% homozygous loci, while progeny derived from irradiated treatments had frequencies of
homozygous loci between 28.1 and 55.0%. This is the first time to use irradiated pollen in cassava as a
pathway to generate candidate plantlets as an initial step in double haploid production.
Description
Keywords
Cassava, Doubled haploids, Embryo rescue, Plant regeneration, Pollen germination, Pollen irradiation.
Citation
Buttibwa, M., Kawuki, R. S., Tugume, A. K., Akol, J., Magambo, S., Apio, H., ... & Baguma, Y. (2015). In vitro embryo rescue and plant regeneration following self-pollination with irradiated pollen in cassava (Manihot esculenta Crantz). African Journal of Biotechnology, 14(27), 2191-2201. DOI:10.5897/AJB2015.14577