• Horticultural Science & Technology
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• v.31 no.4
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• pp.483-489
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• 2013

The abnormal seedlings, a common physiological anomalies, emerged during embryo rescue severely restricted grape breeding. To enhance the efficiency of the seedless grape breeding by reducing the production of abnormal seedlings in the course of embryo rescue, we investigated the effects of genotype, media type, embryo style, pre-chilling on the deformity rate of the abnormal seedlings during embryo rescue. The abnormal seedlings were firstly classified into seven categories based on their morphology. Our results indicated that the emergence of abnormal seedlings was highly dependent on the female parent genotype. Polyembryony was advantageous to diminish the number of abnormal plantlets and the germination rate of embryo was 100%. We also found that pre-chilling treatment could reduce the number of abnormal plantlets and promote the embryo germination. The abnormal plantlets were reduced significantly by the addition of $ZnSO_4$ $10{\mu}mol{\cdot}L^{-1}$ or mashed-banana $500mg{\cdot}L^{-1}$ to either embryo development or germination media. Transferring the abnormal seedlings onto the suitable fresh media in 4 weeks after embryo germination provided an effective way to transform them into normal seedlings.

• Horticultural Science & Technology
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• v.29 no.6
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• pp.617-622
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• 2011

The study was conducted to determine the efficiency in producing spontaneous polyploids in some mandarin hybrids with different seed embryony. Seed formation by open pollination, frequency of spontaneous polyploids, and plant growth characteristics were evaluated in four mandarin hybrids with polyembryony such as 'Amakusa', 'Haruka', 'Hayaka', and 'Seminole' and two with monoembryony such as 'Benibae' and 'Harehime'. The mean number of the developed seeds per fruit was 10.0 and frequency of small seeds was 25.1%. Polyploids were selected from plants germinated in vitro by a flow cytometry and confirmed by chromosome analysis. One triploid was produced from 'Harehime', one tetraploid, 'Amakusa', and one tetrapoid, 'Benibae'. There were little differences in leaf shape, thickness, petiole length, and internode length between diploids and polyploids such as tri- or tetraploid. However, polyploids had larger stomata and lower density of stomata in abaxial epidermis than diploids. SPAS indicating chlorophyll content and photosynthetic rate were significantly affected by ploidy level. The results indicated that spontaneous polyploids might be produced by open pollination in some mandarin hybrids and monoembryony had higher frequency in polyploid occurrence than polyembryony.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.9
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• pp.1229-1233
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• 2006

To find the candidate genes concerned with ovulation rate of sheep, Differential Display Reverse Transcription Polymerase Chain Reaction was employed to find the differently expressed cDNA controlling ovulation in the Small Tail Han sheep of polyembryony and in Tan sheep of single birth. Twenty-four primer pairs of three anchored primers and eight arbitrary primers were assembled to amplify the specialized bands from these sheep. Positive cross tests were applied to optimize the ascertainable PCR conditions in which different special bands can be identified by silver strain in one PCR tube. After eliminating the false positive PCR products by Northern hybridization, 24 differential display bands were acquired from the ovary in the Small Tail Han sheep. These EST bands were sequenced and 18 different ESTs were found in which five ESTs had several copies and 13 ESTs had only one copy. Comparing these ESTs with homologous sequences by BLAST in the GenBank, there were six ESTs with known open reading frame (ORF) and function, three ESTs with known ORF and no function, and 9 ESTs without homologous sequence. These ESTs partly represent several genes such as NOS2, tensin, TCRA, CDKN1A, ESR1 and ACTB which express especially in Small Tail Han sheep.

• Journal of Plant Biotechnology
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• v.43 no.3
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• pp.261-271
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• 2016

Citrus is an economically important fruit crop widely growing worldwide. However, citrus production largely depends on natural hybrid selection and bud sport mutation. Unique botanical features including long juvenility, polyembryony, and QTL that controls major agronomic traits can hinder the development of superior variety by conventional breeding. Diverse factors including drastic changes of citrus production environment due to global warming and changes in market trends require systematic molecular breeding program for early selection of elite candidates with target traits, sustainable production of high quality fruits, cultivar diversification, and cost-effective breeding. Since the construction of the first genetic linkage map using isozymes, citrus scientists have constructed linkage maps using various DNA-based markers and developed molecular markers related to biotic and abiotic stresses, polyembryony, fruit coloration, seedlessness, male sterility, acidless, morphology, fruit quality, seed number, yield, early fruit setting traits, and QTL mapping on genetic maps. Genes closely related to CTV resistance and flesh color have been cloned. SSR markers for identifying zygotic and nucellar individuals will contribute to cost-effective breeding. The two high quality citrus reference genomes recently released are being efficiently used for genomics-based molecular breeding such as construction of reference linkage/physical maps and comparative genome mapping. In the near future, the development of DNA molecular markers tightly linked to various agronomic traits and the cloning of useful and/or variant genes will be accelerated through comparative genome analysis using citrus core collection and genome-wide approaches such as genotyping-by-sequencing and genome wide association study.

• Horticultural Science & Technology
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• v.33 no.4
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• pp.598-604
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• 2015

This study was carried out to develop molecular techniques to allow the selection of zygotic seedlings in the early stage of the plant development. We identified 37 pollen-specific molecular markers from RAPD analysis and successfully used them for identification of the zygotic seedlings from various hybrid crosses. Three Satsuma mandarin cultivars ('Morita unshiu', 'Nangan 20' and 'Miyagawawase') were used as mother parents and seven cultivars ('Ponkan', 'Lee', 'Kinokuni', 'Shiranuhi', 'Tamnaneunbong', 'Shinyegam', and 'Sunburst' mandarins) served as pollen parents. PCR analysis showed that 2 primers could identify zygotic hybrid seedlings. Among them, an UBC-27 primer was used to identify the zygotic seedlings from hybrid crosses of "'Nangan 20' ${\times}$ 'Kinokuni'" mandarin, "'Nangan 20 ${\times}$ Ponkan'" mandarin and "'Miyagawawase ${\times}$ Sunburst'" tangerine. In total 29 out of 40 seedlings (73%), 9 out of 47 seedlings (19%), and 13 out of 45 (29%) were identified as zygotic seedlings, respectively. These results can show that the pollen-specific markers selected in this study can be used effectively for early identification of zygotic seedlings from Citrus hybrid crosses.

• Journal of Life Science
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• v.21 no.4
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• pp.502-508
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• 2011

The purpose of this study was to evaluate the methods of identifying zygotic seedlings of crosses between 'Morita unshiu' (Citrus. unshiu Marc.) and 'Ponkan' (C. reticulata Blanco). In order to investigate the frequency and position of zygotic seedlings and to determine the efficiency of zygotic seedling identification, random amplified polymorphic DNA (RAPD) and sequence-related amplified polymorphism (SRAP) were performed using UBC (9, 27, 229, 230, and 254) primers and F4/R27, F7/R14, F12/R10, and F44/R62 primer sets, respectively. A total of 37 putative zygotic seedlings out of 55 individuals were selected by RAPD and SRAP. The F7/R14 primer pair showed a screening ability of 45.5% (25/55), whereas the primer UBC27 revealed the highest efficiency of zygotic seedling identification (50.9%, 28/55). When both UBC27 and F7/R14 were properly used for selection of hybridized seedlings of 'Morita unshiu' (C. unshiu Marc.) and 'Ponkan' (C. reticulata Blanco), screening efficiency was increased to 60% (33/55) for putative zygotic seedlings. Thus, it is possible to select putative hybrid zygotic seedlings in an accurate and effective manner by RAPD and SRAP.