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Ibaraki, Japan

Matsumoto Y.,Plant Biotechnology Institute | Matsumoto Y.,Tokyo University of Agriculture and Technology | Ogawara T.,Horticultural Institute | Miyagi M.,Plant Biotechnology Institute | And 2 more authors.
Journal of the Japanese Society for Horticultural Science

Fusarium wilt of melon (Cucumis melo L.), caused by Fusarium oxysporum f. sp. melonis, is regarded as a severe disease worldwide. Many resources that are resistant to races 0, 1, and 2 have been reported; nevertheless, no resource of high resistance to either race 1,2w or 1,2y has been reported, although partial resistance has been found. Wild Cucumis species have been reported as genetic resources which have resistance to some diseases and pests of melon. This study identified novel sources of high resistance to race 1,2y in wild Cucumis species. In all, we tested 76 accessions belonging to 11 wild species of the genus Cucumis. After artificial inoculation, the disease severity in each plant was evaluated using a 0-3 disease severity scale (0 = no symptoms, 1 = beginning of yellowing symptom on leaves, 2 = leaves strongly affected, 3 = plant death). The disease index (DI) was calculated as DI = summation of (disease severity × number of plants in that disease severity) × 100/(3 × total number of plants). Accessions showing high resistance (DI = 0) were 34 among six species: C. africanus, C. anguria, C. metuliferus, C. prophetarum, C. subsericeus, and C. zeyheri. By contrast, most accessions in C. dipsaceus, C. meeusei, C. pustulatus, and C. sagittatus exhibited high susceptibility (DI = 80-100). Among these four species, no accession showed high resistance. This is the first report of genetic resources having high resistance to race 1,2y. To introduce this high resistance of race 1,2y to melon, we should investigate methods to overcome reproductive barriers to interspecific crosses between melon and wild Cucumis species. JSHS © 2011. Source

Okubo H.,Kyushu University | Hiramatsu M.,Kyushu University | Masuda J.-I.,Kyushu University | Masuda J.-I.,Horticultural Institute | And 2 more authors.
Floriculture and Ornamental Biotechnology

Lilium brownii var. colchesteri has been widely cultivated for long time by its perfect flower shape with its colour arrangement and fragrance. However, it did not receive enough attention in recent lily research programs, and information on the history and culture is lacking. An overall research project on this species including breeding, flowering control, propagation, virus-free bulb production, flower pigment and scent along with the surveys of old literature and arts to clarify the introduction history of the species into Europe and Japan, has been conducted. The major results are: 1) L. brownii var. colchesterii was probably introduced in about 1600 from Korea to Fukuoka, 2) there was confusion of the species nomenclature of this species in Europe at the time of introduction, 3) all individuals of our present collection in Japan and Korea are clones, 4) F1 hybrids of L. formosanum × L. brownii var. colchesteri obtained through cut-style pollination and ovary slice culture methods showed the early flowering traits of L. formosanum, but the flower shape and colour were similar to those of the pollen parent, 5) F2 seedlings were obtained from self-pollination of F, through ovary-slice culture, 6) control of flowering was successful by temperature treatments, 7) an in vitro propagation procedure was established, 8) virus-free bulblets were obtained by a combination of meristem tip culture and chemotherapy, and 9) pigments that characterize the flower colour were identified. ©2012 Global Science Books. Source

Mishima M.,Kyushu University | Sato S.,Horticultural Institute | Tsuda K.,2845 3 Oshita | Yukawa J.,Kyushu University
Annals of the Entomological Society of America

Hartigiola faggalli (Monzen), a cecidomyiid species that induces leaf galls on Fagus crenata Blume (Fagales: Fagaceae), was studied to assess the degree of sexual isolation between known intraspecific populations derived from two different gall types. "Upper-type galls" form on the lateral veins of upper leaf surfaces, whereas "lower-type galls" develop between the lateral veins of lower leaf surfaces. The two populations were distinguished based on slight differences in theirDNAsequences. They coexisted in F. crenata forests. Emergence, swarming, mating, and oviposition occurred sequentially each day and almost simultaneously in both populations. Thus, they were not isolated from each other in time or space. However, 85% of 134 swarming males flew to females of the same population when responding to female sex pheromone. About 92% of 251 mating pairs were homogenic, and IPSI indicated a significantly homogenic mating. The female sex pheromone and male sensitivity to the pheromone seemed to differ between the two populations. After mating, females of each population oviposited their eggs only on either the upper or lower surfaces of fresh leaves. The strongly assortative mating combined with differences in pheromones and gall morphology indicates that the two populations are almost completely reproductively isolated and that they have diversified into the stage of sibling species. © 2014 Entomological Society of America. Source

Khastini R.O.,Sultan Ageng Tirtayasa University | Ogawara T.,Horticultural Institute | Sato Y.,Center for Conservation and Restoration Techniques National Research Institute for Cultural Properties | Narisawa K.,Ibaraki University
European Journal of Plant Pathology

Two soil-borne fungal endophytes almost completely suppressed the effects of a post-inoculated and virulent strain of Fusarium oxysporum f. sp. melonis when inoculated to axenically reared melon seedlings in Petri dishes. They were identified as Cadophora sp. on the basis of ITS 1-5.8S rDNA-ITS 2 sequences and morphological characters and obtained from the roots of Chinese cabbage grown as bait plants in a mixed soil made up of samples from different forest soils from Alberta and British Columbia, Canada. Hyphae of Cadophora sp. grew along the surface of the root and colonized root cells of the cortex and reduced the ingress of the Fusarium pathogen into adjacent cells. Melon seedlings pre-inoculated with Cadophora sp. were also grown in soil amended with the different N sources, nitrate or the amino acids leucine and valine, and glucose (final C:N ratio = 10:1). After 4 weeks, these seedlings were transplanted into the field and disease symptoms were assessed. Only the endophyte-inoculated seedlings treated with valine could effectively inhibit the development of Fusarium wilt in two plots and reduced disease symptom development by 43 and 62 %. © 2014 KNPV. Source

Harada T.,Horticultural Institute | Harada T.,Okayama University | Komagata T.,Horticultural Institute
Japan Agricultural Research Quarterly

During arching cultivation of roses in autumn and winter, long-day treatment using fluorescent lamps placed above the base of the plants slightly increased the number of cut flowers and also tended to increase the cut flower length in the first year. To further investigate these effects, the light condition of assimilation shoots was modified by supplemental lighting using white light-emitting diodes (LEDs) placed above the assimilation shoots. Supplemental lighting at two different levels of photosynthetic photon flux density (PPFD), 100 and 250 μmol m-2 s-1, increased the number of cut flowers from the middle portion of the assimilation shoots, and the total number and weight of cut flowers according to the light intensity. Irradiation at 250 μmol m-2 s-1 PPFD also increased the number of cut flowers over 80 cm long and the length, weight and stem diameter of cut flowers over 60 cm long. Long-day treatment using fluorescent lamps did not affect the number of cut flowers in the second year. These results indicate that long-day treatment using fluorescent lamps can effectively increase the yield of cut rose flowers in some years, while supplemental lighting using white LEDs for assimilation shoots is a method of increasing it more strongly. Source

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