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Nukui S.,Niigata University | Kitamura S.,Niigata University | Kitamura S.,Kaneko Seeds Co. | Hioki T.,Niigata University | And 6 more authors.
Breeding Science | Year: 2011

Fertile plants undergoing male gametogenesis can be treated with nitrous oxide (N 2O) gas to obtain 2n male gametes. N 2O treatment is also expected to restore the fertility of interspecific hybrids through meiotic restitution or mitotic amphidiploidization. However, this technique has few applications to date, and it is unknown how N 2O treatment restores fertility in sterile hybrids. To establish optimal N 2O treatment conditions and determine its cytological mechanism of action, we treated various sized floral buds with N 2O gas at different anther developmental stages from fertile and sterile hybrid lilies. N 2O treatment using the optimal 1- 4 mm floral buds induced mitotic polyploidization of male archesporial cells to produce 2n pollen in fertile hybrid lilies. In sterile hybrid lilies, N 2O treatment doubled the chromosome number in male archesporial cells followed by homologous chromosome pairing and normal meiosis in pollen mother cells (PMC), resulting in restoration of pollen fertility. Backcrossing the resultant fertile pollen to Lilium × formolongi produced many triploid BC1 plants. Thus N 2O treatment at the archesporial cell proliferating stage effectively overcame pollen sterility in hybrid lilies, resulting in fertile, 2n pollen grains that could produce progeny. The procedure presented here will promote interspecific or interploidy hybridization of lilies. Source

Watanabe S.-I.,Japan National Agriculture and Food Research Organization | Inoue K.,Nagasaki Agricultural and Forestry Technical Development Center | Emoto S.,Forestry and Fisheries Research Center | Ishibashi Y.,Saga Prefectural Agriculture Research Center | And 2 more authors.
Japan Agricultural Research Quarterly | Year: 2014

Kyushu island, in southern Japan, is one of the main producers of green asparagus (Asparagus officinalis L.) in Japan, accommodating protected mother-fern culture in plastic greenhouses (PMC) as a conventional crop. In PMC, since few spears are produced from November to January, we attempted to produce spears during this period by prolonging the harvest of PMC to November and introducing "Fusekomi" forcing culture (FFC), in which rootstocks grown outdoors are transplanted into heated and/or thermal-retained culture beds in a plastic greenhouse in late autumn or early winter and spears are generally harvested for the following two or three months. In PMC, a combination of a foliage spray of Benzyladenine solution with thermal retention treatment in autumn prolonged the harvest period to the end of November without any significant decrease in yield the following spring. In FFC, rootstocks grown in the lowlands showed inferior spear productivity when transplanted into a greenhouse in late November, probably due to insufficient exposure to low temperature for breaking dormancy. In contrast, rootstocks grown in the highlands showed superior in productivity because they would be sufficiently exposed to low temperature for breaking dormancy by the time of transplanting. In lowlands, heating of greenhouses was unnecessary for FFC throughout the harvest period due to the mild winter climate. These results suggested that profitable year-round production of green asparagus without heating could be realized in Kyushu by combining PMC and FFC cropping types. Source

Kishimoto N.,Japan National Institute of Agrobiological Science | Nagai J.-I.,Kagoshima Prefectural Institute for Agricultural Development KIAD | Kinoshita T.,Saga Prefectural Agriculture Research Center | Ueno K.,Kumage Branch | And 2 more authors.
PLoS ONE | Year: 2013

Transcriptional gene silencing (TGS)-a phenomenon observed in endogenous genes/transgenes in eukaryotes-is a huge hindrance to transgenic technology and occurs mainly when the genes involved share sequence homology in their promoter regions. TGS depends on chromosomal position, suggesting the existence of genomic elements that suppress TGS. However, no systematic approach to identify such DNA elements has yet been reported. Here, we developed a successful novel screening strategy to identify such elements (anti-silencing regions-ASRs), based on their ability to protect a flanked transgene from TGS. A silenced transgenic tobacco plant in which a subsequently introduced transgene undergoes obligatory promoter-homology dependent TGS in trans allowed the ability of DNA elements to prevent TGS to be used as the screening criterion. We also identified ASRs in a genomic library from a different plant species (Lotus japonicus: a perennial legume); the ASRs include portions of Ty1/copia retrotransposon-like and pararetrovirus-like sequences; the retrotransposon-like sequences also showed interspecies anti-TGS activity in a TGS-induction system in Arabidopsis. Anti-TGS elements could provide effective tools to reduce TGS and ensure proper regulation of transgene expression. Furthermore, the screening strategy described here will also facilitate the efficient identification of new classes of anti-TGS elements. © 2013 Kishimoto et al. Source

Sanada-Morimura S.,Kyushu Okinawa Agricultural Research Center | Otuka A.,Kyushu Okinawa Agricultural Research Center | Matsumura M.,Kyushu Okinawa Agricultural Research Center | Etoh T.,Saga Prefectural Agriculture Research Center | And 3 more authors.
PLoS ONE | Year: 2015

Overseas migration of the small brown planthopper, Laodelphax striatellus (Fallén), occurs during the winter wheat harvest season in East Asia. Knowing the take-off time of emigrating L. striatellus is crucial for predicting such migrations with a simulation technique because winds, carriers of migratory insects, change continuously. Several methods were used in China and Japan from late May to early June 2012 and again in 2013 to identify the precise timing of take-off. These methods included: a tow net trap mounted to a pole at 10 m above the ground, a helicopter-towed net trap, and a canopy trap (which also had video monitoring) set over wheat plants. Laodelphax striatellus emigrated from wheat fields mainly in the early evening, before dusk. The insects also emigrated during the daytime but rarely emigrated at dawn, showing a pattern that is unlike the bimodal emigration at dusk and dawn of two other rice planthoppers, the brown planthopper, Nilaparvata lugens (Stål), and the white-backed planthopper, Sogatella furcifera (Horváth). There was no significant difference in the temporal pattern of take-off behavior between females and males of Japanese L. striatellus populations. © 2015 Sanada-Morimura et al. Source

Watanabe Y.,Kagoshima University | Watanabe Y.,Saga University | Kuchi-ishi N.,Saga University | Nakashima T.,Saga Prefectural Agriculture Research Center | And 7 more authors.
Journal of the Japanese Society for Horticultural Science | Year: 2011

An aseptic bioassay utilizing female and male donor materials was performed in order to assess the allelopathic activities of cladophylls and root systems in dioecious asparagus. The aseptic sandwich method revealed that the growth of acceptor plants was significantly inhibited by the addition of over 30mg fresh weight of cladophylls. When female and male cladophylls were separately adopted for the sandwich method, there was no sexual difference in the allelopathic activity of both youthful and senescent cladophylls. To detect the allelopathic effects of root systems, the plant box method employing female and male regenerants was used aseptically, and the growth of acceptor plants was seriously inhibited irrespective of sex expression in donor plants. Early in vitro flowering seedlings expressing individual sex were effectively used for the bioassay, and the results indicated that the degree of allelopathic activities was the same as that in regenerants. These results show that allelopathic activity in female and male plants was equivalent, and that the application of materials that can distinguish between the sexes would be useful for assaying the mutual effects of sexuality on allelopathy. The aseptic bioassay system that employed female and male materials presented here could promote the isolation and identification of allelochemicals. JSHS © 2011. Source

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