Open Access
ARTICLE
Pseudogamous Apomixis in Maize and Sorghum in Diploid-Tetraploid Crosses
Marina Tsvetova1, Lev Elkonin1,*, Yulia Italianskaya1
1 Agricultural Research Institute of South-East Region, Department of Biotechnology, Saratov, 410010, Russia.
* Corresponding Author: Lev Elkonin. Email: .
Phyton-International Journal of Experimental Botany 2019, 88(4), 389-401. https://doi.org/10.32604/phyton.2019.07485
Abstract
Apomictic seed development is a complex process including
formation of unreduced embryo sac, parthenogenetic embryo development from
the egg cell, and endosperm formation either autonomously, or due to
fertilization of polar nuclei by the sperm (under pseudogamous form of
apomixis). In the latter case, an obstacle to the normal endosperm development is
disturbance of maternal (m) -to-paternal (p) genomic ratio 2m: 1p that occurs in
the cases of pollination of unreduced embryo sac with haploid sperms. Usage of
tetraploid pollinators can overcome this problem because in such crosses
maternal-to-paternal genomic ratio is 4m: 2p that provides formation of kernels
with plump endosperm. Using tetraploid lines as pollen parents we observed
formation of plump kernels on the ears and panicles of diploid maize and
sorghum accessions. These kernels had hybrid endosperm and diploid maternaltype
embryo or hybrid embryo with different ploidy level (2n, 3n, 4n). The
frequencies of plump kernels on the ear ranged from 0.2-0.3% to 5.7-6.2%
counting from the number of ovaries. Maternal-type plants were found in two
maize lines, their frequency varying from 10.7 to 37.5% of the progeny plants. In
CMS-lines of sorghum pollinated with tetraploid sorghum accessions, the
frequency of plump kernels ranged from 0.6 to 14.0% counting from the number
of ovaries; the frequency of maternal-type plants varied from 33.0 up to 96.1%.
The hybrid nature of endosperm of the kernels that gave rise to maternal-type
plants has been proved by marker gene expression and by SDS-electrophoresis
of endosperm proteins. These data testify to variable modes of seed formation
under diploid × tetraploid crosses in maize and sorghum both by amphi- and by
apomixis. Therefore, usage of tetraploid pollinators might be a promising
approach for isolation of apomixis in maize and sorghum accessions.
Keywords
Cite This Article
Tsvetova, M., Elkonin, L., Italianskaya, Y. (2019). Pseudogamous Apomixis in Maize and Sorghum in Diploid-Tetraploid Crosses.
Phyton-International Journal of Experimental Botany, 88(4), 389–401.