A putative polyploid seedling tree appeared among the polyembryonic mango (Mangifera indica L.) `Gomera-1', widely used as a rootstock in the Canary Islands. Initially detected because of its wider and more coriaceous leaves, further studies showed that fruit from this seedling are considerably larger than normal, although all other fruit characteristics (including polyembryony) were similar to those of standard `Gomera-1' (G-1) fruit. The progeny of this plant has, to date, proved to be morphologically identical to the mother plant. Studies of seedlings from normal G-1 trees growing in the same orchard showed that 10% of the plants had morphological characteristics similar to those of the putative polyploid seedling. Flow cytometry and chromosome count analyses confirmed that G-1 is diploid, whereas the putative polyploid is a stable tetraploid. The study also showed that the morphologically abnormal seedlings from diploid parent trees were spontaneous tetraploids.
Víctor Galán Saúco, María José Grajal Martín, Domingo Fernández Galván, Águeda Coello Torres, José Juárez, and Luis Navarro
Li-ping Chen, Yan-ju Wang, and Man Zhao
In this study, in vitro induction of tetraploid Lychnis senno Siebold et Zucc. and its cytological and morphological characterization were conducted. For polyploid induction, nodal segments with axillary buds from in vitro grown plants were kept for 3 days in MS (Murashige and Skoog, 1962) liquid or solid media added with a series of concentrations of colchicine. Out of total 588 recovered plants, 15 tetraploids and 6 mixoploids determined by flow cytometry analysis were obtained. The tetraploid contained 48 chromosomes, twice the normal diploid number of 24, as observed under light microscope. The tetraploid plants exhibited much larger but less stomata than diploid plants. Moreover, significant differences in stem height and leaf size between the diploid and tetraploid plants were noted. The tetraploid plants were more compact than diploids.
Masaki Yahata, Seiichi Harusaki, Haruki Komatsu, Kayo Takami, Hisato Kunitake, Tsutomu Yabuya, Kensuke Yamashita, and Pichit Toolapong
The morphological characteristics and reproductive potential of a haploid plant obtained from the cross between `Banpeiyu' pummelo (Citrus grandis) and `Ruby Red' grapefruit (C. paradisi Macf.) were investigated. The haploid was confirmed to be derived from female gamete of `Banpeiyu' pummelo by isozyme and random amplified polymorphic DNA (RAPD) analysis. Flow cytometry analysis revealed that the haploidy was maintained in several tissues and organs of this plant. It also had the typical morphology of a haploid, such as small leaves and flowers, and had slightly fertile pollen grains. Furthermore, diploid progenies were obtained from the cross between `Kiyomi' tangor and the haploid. The hybridity of these seedlings was confirmed by assessment of the leaf characteristics and RAPD analysis. These results suggest that this haploid produced fertile unreduced pollen grains (n = 9).
William G. Hembree, Thomas G. Ranney, Brian E. Jackson, and Mark Weathington
completed for selected taxa to confirm ploidy and further calibrate the flow cytometry results following the methods of Lattier et al. (2014) . Root squashes were prepared for selected plants by collecting actively growing root tips and placing them in a
Joseph J. Rothleutner, Mara W. Friddle, and Ryan N. Contreras
were assigned accession numbers. Table 1. Source and collection information for 67 Cotoneaster accessions. Genome sizing. Holoploid (2C) genome sizes were determined by flow cytometry (CyFlow PA; Partec, Münster, Germany) and comparison of mean
Ryan N. Contreras and Kimberly Shearer
greatly beneficial in a developing breeding program. Measuring genome size in plants can be accomplished quickly and effectively using flow cytometry, as demonstrated by a number of genome size surveys of angiosperms ( Jones et al., 2007 ; Lattier et al
Bruce L. Dunn and Jon T. Lindstrom
Frazier, 1968 ). Plants treated with chemical inhibitors must be screened to identify polyploid plants. Flow cytometry is recognized as a quick way to confirm and sort plants based on relative DNA content of nuclei without having to do labor
Akira Sugiura, Takeshi Ohkuma, Young A Choi, Ryutaro Tao, and Mihoko Tamura
To produce nonaploid Japanese persimmon (Diospyros kaki L.f.) by artificial hybridization, we surveyed the natural occurrence of unreduced (2n) pollen among hexaploid cultivars and sorted them from normal reduced (n) pollen. The sorted 2n pollen was crossed with a hexaploid female cultivar and the resultant embryos were rescued by in vitro culture techniques to obtain plantlets. Three out of six male-flower-bearing cultivars (2n = 6x = 90) produced 2n pollen at rates of 4.8% to 15.5% varying with the cultivar, which was estimated by both pollen size and flow cytometry. After sorting giant (2n) from normal pollen grains by using nylon mesh, they were crossed with a hexaploid female cultivar. The seeds obtained from pollination with normal pollen were perfect, but those obtained from pollination with giant pollen were mostly imperfect, with embryo growth being suspended at the globular stage. Although the rate of survival was very low, some embryos at the globular stage were rescued successfully and grown in vitro. Both flow cytometric analysis and chromosome counting proved that the plantlets obtained were nonaploid.
Kimberly A. Pickens, (Max) Z.-M. Cheng, and Stephen A. Kania
@utk.edu . We thank Lori Osburn, Joo-Young Kim, and Diane Trent for their invaluable assistance on this project and Dr. Tom Ranney at North Carolina State University for their help and knowledge with the flow cytometry portion of this article. We also thank Dr
Elisabet Claveria, Jordi Garcia-Mas, and Ramon Dolcet-Sanjuan
de Barcelona, for his help with the flow cytometry determinations. Use of trade names does not imply endorsement of the products named nor criticism of similar ones not named.