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Gene flow between species of different ploidy levels is important in plant evolution and breeding. A cytological study was conducted on a natural population with individuals belonging to the diploid L. purpurea Gay (2n = 10) and to the tetraploid L. coquimbensis F. Phil (2n = 18) species, as well as intermediate phenotypes of apparent hybrid origin. The genus Leucocoryne is endemic to Chile and it exhibits heterogeneity, presumably genetic, for shape, size, and color of its flowers. The objective of the study was to determine if there is gene flow between species having different ploidy levels. From the karyotypic analyses of the seeds, only parental types having 2n = 10 and 2n = 18 individuals were observed. However, from the bulb analyses, 2n = 10, 2n = 18, 2n = 14, and 2n = 22 individuals were encountered. The karyotypes of the 2n = 14 and 2n = 22 individuals suggest the occurrence of natural interespecific hybridization between species with different ploidy levels in nature. Models which may account for the origin of these genotypes are proposed.

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. Determination of ploidy. Flow cytometry was used to determine the ploidy level of the endosperm-derived E. alatus ‘Compactus’ plants. Ploidy determination was based on the total DNA content per nucleus measured with a CyFlow Ploidy Analyser (Partec GmbH

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The majority of edible bananas (Musa L.) are triploid (2n = 3x = 33) cultivars known as dessert, plantain, or cooking bananas with predominant AAA, AAB, and ABB genomes, justifying the aim of breeding programs to develop improved hybrids of the different utilization classes in the triploid background. This usually involves crossing 3x landraces to 2x accessions that are donors of resistance genes, selecting 4x and 2x primary hybrids from the 3x-2x progenies, and crossing 4x-2x hybrids to produce secondary 3x hybrids. Ploidy and genome segregation routinely occurs during this process and constitutes a major hindrance for selection because this is not easily detectable at the morphological level. This study was carried out to assess the potential of early screening for discriminating ploidy and genome classes in 4x (AAAB)-2x (AA) breeding populations, based on flow cytometry and genome-specific RAPD analysis. Results indicate that progenies of 4x-2x crosses produced predominantly 3x progenies (94.1%). RAPD analysis identified seven genomic classes, dominated by AAA and AAB configurations segregating 1:1 (χ2 = 0.21, P = 0.05). Plant size and bunch weight increased with ploidy level, justifying ploidy-based grouping of progenies for homogenous field evaluation. Similarly, genome-based grouping within ploidy classes is recommended to allow proper evaluation of progenies according to targeted postharvest utilization. Thus, ploidy analysis by flow cytometry and genome determination by RAPD open prospects for enhancing breeding efficiency in the development of triploid bananas or plantains.

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Broccoli (Brassica oleracea L. Italica group) breeders routinely use anther or microspore culture to produce dihaploid (diploid), homozygous lines. During the culture process, polyploidization occurs and diploid regenerants can result. However, polyploidization may not occur at all, or it may involve a tripling or quadrupling of the chromosome complement. Thus, regenerated populations must be screened to identify the diploids that are the regenerants most likely to set seed and serve as inbred lines. DNA flow cytometry has proven a useful procedure for determining ploidy of anther derived regenerants. This study was undertaken to evaluate the effect of leaf age and sampling procedures on ploidy determination via flow cytometry. Anther-derived plants were analyzed at a four- to five-leaf stage (transplant stage) and at time of heading (mature plant stage). In addition, leaves were sampled on a given date and stability of the flow cytometry preparations was evaluated over 7 days. Lastly, the stability of ploidy readings of leaves stored at 4°C was examined over a 7-day period. In only one case out of 123 comparative assays did leaf age affect ploidy determination. For that exception, a haploid at transplant stage was a diploid at the mature plant stage. Flow cytometry preparations and also leaves stored at 4°C gave consistent ploidy determinations up to four days after preparations were made or tissue was refrigerated, respectively. These results indicate that broccoli breeders can make flow cytometry preparations on site and send them offsite for flow cytometry analysis. Alternatively, leaves could be refrigerated, sent offsite, and then prepared and analyzed at another location.

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was measured for each nucleus using a Partec PA-1 ploidy analyzer (Partec GmbH). For each sample, at least 5000 nuclei were analyzed, revealing a single peak with a cv <5.0% for all but two samples. Twelve samples were processed twice, and data were

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value of this new ploidy level and this new chromosome number, UF-15-414 and its known parents and grandparents, and ‘White Wing’ and two of its known progeny cultivars were characterized at the individual, cellular, and molecular levels. Specifically

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(Juglandaceae) ( Manos and Stone, 2001 ) ( Table 1 ). Species differ in not only morphology and habitat, but also in ploidy (i.e., 2 n = 32 vs. 64) with Apocarya section species being diploid (100% of species) and Carya section species being either diploid (40

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studies with geographic location of origin, ploidy level, and taxonomic group designation. Randomly selected sets of eight plants of A. mitschurinii ‘Viking’ were moved into the greenhouse on 9, 16, 24, and 28 Dec 2014 and 5 and 21 Jan 2015 and

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in pollen germination and pollen tube growth Am J Bot. 50 859 865 https://doi.org/10.2307/2439772 Czarnecki, DM II Hershberger, AJ Robacker, CD Clark, DG Deng, Z. 2014 Ploidy levels and pollen stainability of Lantana camara

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among Citrus hybrids obtained from different crosses with ‘Satsuma’ mandarin. Ploidy and Cytoplasmic Male Sterility Another approach for eliciting seedlessness involves the coupling of parthenocarpy with male sterility. Sterility can

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