Seasonal variations in the incidence of pine wilt and infestation by its vector, Monochamus alternatus, near the northern limit of the disease in Japan     

Kazumasa Ohta  Kazuhiko Hoshizaki  Katsunori Nakamura  Akihiko Nagaki  Yoichi Ozawa  Aoi Nikkeshi  Akifumi Makita  Kazumi Kobayashi  Osamu Nakakita 《Journal of Forest Research》2012,17(4):360-368

During the last few decades, pine wilt disease has spread to cool-climate regions in Japan and, more recently, the potential risk of it spreading into the European midwest has also become a concern. In a coastal pine stand (84.7?ha) in Akita, near the northern limit of pine wilt disease in Japan, we investigated seasonal variations in the incidence of damage caused by the disease to trees and oviposition by the disease’s insect vector, Monochamus alternatus, during a two-year period. Foliage discoloration occurred throughout each year, and its seasonal variation showed a bimodal pattern in Pinus thunbergii (a higher peak in May–June and a smaller peak in October) and a clear peak in June in P. densiflora, which differed from the patterns in seasonal variation seen for warm-climate regions. Oviposition scars by M. alternatus were found in 40–45% of the trees damaged each year. The percentage of trees that had oviposition scars was higher in P. thunbergii than in P. densiflora. This appeared to reflect the difference in seasonal discoloration pattern between the two species. Analysis of the oviposition risk showed that trees that exhibited discoloration starting between July and October had a significantly higher risk or significantly higher oviposition scar densities, particularly for those that became discolored between August and September (2.5–14.6-fold higher risk than during other months). Oviposition scar densities per damaged tree were similar within the period of higher oviposition risk. Considering both oviposition risks and scar densities, we concluded that trees with discoloration that become apparent between July and October are important targets for preventing the spread of pine wilt disease in Akita.  相似文献   

Semen Collection and Polymerase Chain Reaction‐Based Sex Determination of Black‐Headed and Straw‐Necked Ibis     

K Kaneko  E Uematsu  Y Takahashi  B Tong  S Takino  Y Wajiki  T Kimura  H Yamashiro  Y Kaneko  H Iwaisaki  T Sugiyama  T Yamada  S Yamagishi 《Reproduction in domestic animals》2013,48(6):1001-1005

This study aimed to develop a polymerase chain reaction (PCR)‐based sexing and effective semen collection methods for black‐headed and straw‐necked ibis species. However, most birds are not sexually dimorphic, that is, the sexes appear similar. Therefore, the gender should be determined before semen collection. DNA was extracted from the blood samples of 11 black‐headed and 4 straw‐necked ibis. The sex was determined after PCR amplification of the EE0.6 region of W‐chromosome. The PCR products were separated using gel electrophoresis. A single band indicated the presence of the EE0.6 region and that the individual was a female, while no band indicated that the individual was a male. Further, the single bands from seven specimens were amplified. Semen collection was performed by massage or a combination of massage with electro‐ejaculation and was attempted during all four seasons. The semen was successfully collected in March from male straw‐necked ibis using the massage method. Limited motility, viability and concentration of straw‐necked ibis sperm were observed. The sperm length was 180 μm and that of the nucleus was 30 μm with acrosome located at the tip of the nucleus. Thus, the PCR‐based sexing proved to be an accurate molecular sexing method for black‐headed and straw‐necked ibis. Furthermore, we successfully collected semen and observed the stained sperm nucleus and acrosome of the straw‐necked ibis sperm. We propose that the use of this PCR methodology can be applied as a routine method for sex determination and semen collection in ibis species for future ecological research. However, considering our limited success, further studies on semen collection method are required.  相似文献   

A novel strip meniscometry method for measuring aqueous tear volume in dogs: Clinical correlations with the Schirmer tear and phenol red thread tests     

Keiichi Miyasaka  Yoshiyuki Kazama  Hiroko Iwashita  Shinsuke Wakaiki  Akihiko Saito 《Veterinary ophthalmology》2019,22(6):864-871

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Seed abortion of ‘Tosa-Buntan’ pummelo pollinated with soft-X-irradiated pollens     

Tsuneo Ogata  Tomoya Takeichi  Kazunori Matsunaga  Kojiro Hasegawa  Shinzo Yamane  Keita Sugiyama 《Scientia Horticulturae》2008

Cross-pollination was performed with soft-X-irradiated hyuga-natsu pollens (1000 Gy) for ‘Tosa-Buntan’ pummelo (Citrus grandis (L.) Osbeck). This resulted in the transformation of large and complete seeds into small and empty ones (practically seedless). Although fruit set, fruit retention, total soluble solids content (TSS) and titratable acidity of the juice were not affected, decrement in the fruit size was observed. Two weeks after the pollination, endosperm cell division with free nuclei began in both the non-irradiated and irradiated pollen treatment conditions. Seven weeks after pollination, endosperm division with the cell wall occurred in the non-irradiated pollen treatment conditions; however, the endosperm development ceased in most ovules that underwent the irradiated pollen treatment, and the ovules remained in their free nuclear stage. The delayed degeneration of the ovules, following successful fertilization and commencement of endosperm cell division, allow these seedless fruits to be categorized as pseudo-parthenocarpic.  相似文献   

Effect of high temperature stress on the reproductive growth of strawberry cvs. ‘Nyoho’ and ‘Toyonoka’     

N.A. Ledesma  M. NakataN. Sugiyama 《Scientia Horticulturae》2008

High temperatures are known to reduce fruit size and fruit weight in strawberry, but cultivar differences in the response to high temperature stress during the reproductive stage up to the second inflorescence have not been sufficiently reported. We examined the effect of two day/night temperature regimes on fruit set and fruit growth in two cultivars, ‘Nyoho’ and ‘Toyonoka’. A high day/night temperature of 30/25 °C reduced the number of inflorescences, flowers, and fruits in both cultivars compared with plants grown at 23/18 °C. The percentage of fruit set in ‘Nyoho’ was not significantly different between the two temperature treatments, while that in ‘Toyonoka’ was much lower at 30/25 °C than at 23/18 °C. Days to ripening was shorter at 30/25 °C than at 23/18 °C, and no cultivar differences were observed. Fresh weight of primary, secondary, and tertiary fruits was greater at 23/18 °C than at 30/25 °C in both cultivars, and no cultivar differences were observed, except in tertiary fruits. The diameter of fruits from all positions was also reduced at 30/25 °C in both cultivars. Relative growth rates of fruits showed two peaks in both cultivars and in both temperature treatments. Both peaks appeared earlier at 30/25 °C than at 23/18 °C. Percentage of fruit set at 30/25 °C in the second inflorescence was also significantly lower in ‘Toyonoka’ than in ‘Nyoho’. These results indicate that high temperature stress negatively affects the reproductive process in strawberry and that plant response to high temperature stress is cultivar-related in such responses.  相似文献   

Profiling gibberellin (GA₃)-responsive genes in mature mandarin fruit using a citrus 22K oligoarray     

Hiroshi Fujii  Takehiko Shimada  Aiko Sugiyama  Tomoko Endo  Fumie Nishikawa  Michiharu Nakano  Yoshinori Ikoma  Tokuro Shimizu  Mitsuo Omura 《Scientia Horticulturae》2008

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Relationship between inbreeding coefficients and plant height of 1-year-old seedlings in crosses among Japanese pear (Pyrus pyrifolia Nakai) cultivars/selections     

Akihiko Sato  Yutaka SawamuraNorio Takada  Toshio Hirabayashi 《Scientia Horticulturae》2008

Plant height, a vigor trait, in 1-year-old seedlings made from Japanese pear (Pyrus pyrifolia) cultivars/selections was measured using 994 individuals from 29 families. The family mean of plant height was negatively correlated (r = −0.72**) to the inbreeding coefficients (F). The regression of the family mean (Fm) on the F value (Fm = 130 − 104F) showed that inbreeding depressions were 8%, 20%, and 40% for F = 0.1, 0.25, and 0.5, respectively. According to the regression, the family mean at F = 0 was estimated at 130 cm. These results showed that the vigor was greatly influenced by inbreeding in Japanese pear. Within-family variances, the genetic segregation of offspring in a family, differed according to family. The proportions of offspring with plant height above 130 cm (estimated Fm for F = 0) were extremely low, i.e., 0–17% for 0.5 ≤ F < 0.60 and 0–8% for F = 0.75.  相似文献   

Differentiation in competitive ability and cold tolerance between diploid and tetraploid cultivars in Lolium perenne   总被引：4，自引：0，他引：4  

Shuichi Sugiyama 《Euphytica》1998,103(1):55-59

In a diploid grass, perennial ryegrass (Lolium perenne L.), many autotetraploid cultivars have been released and widely used in many cool temperate countries. In this study, competitive ability and cold tolerance, which seem to be important factors in determining geographical distribution and persistency of this species, were compared between six diploid and five autotetraploid cultivars. The tetraploid cultivars had significantly higher competitive ability and lower cold tolerance than the diploid cultivars. Furthermore, there was no overlap in the two traits between them. These results suggest that chromosome doubling has a larger effect on competitive ability and cold tolerance than does the genetic difference between the populations within a single ploidy level. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Identification of coumarins from lemon fruit (Citrus limon) as inhibitors of in vitro tumor promotion and superoxide and nitric oxide generation.   总被引：1，自引：0，他引：1  

Y Miyake  A Murakami  Y Sugiyama  M Isobe  K Koshimizu  H Ohigashi 《Journal of agricultural and food chemistry》1999,47(8):3151-3157

Three coumarins were isolated as siginificant inhibitors of tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced Epstein-Barr virus (EBV) activation in Raji cells from the peel of lemon fruit. They were identified as 8-geranyloxypsolaren (LE-1), 5-geranyloxypsolaren (bergamottin, LE-2), and 5-geranyloxy-7-methoxycoumarin (LE-3), respectively, by spectroscopic analysis. Three isolates had no potential O(2)-scavenging and markedly suppressed TPA-induced superoxide (O(2)(-)) generation in differentiated human promyelocytic HL-60 cells. Furthermore, LE-1 and LE-3 reduced both lypopolysaccharide (LPS) and interferon-gamma (IFN-gamma)-induced nitric oxide (NO) generation in mouse macrophage RAW 264.7 cells. Similarly, they were found to be NO generation inhibitors rather than scavengers by measuring the extracellular L-citrulline levels. The occurrence of these coumarins in a lemon fruit was abundant in the flavedo of the peel based on quantitative analysis using high-performance liquid chromatography (HPLC). The present study suggests that the coumarins in lemon fruit are promising chemopreventive agents by inhibiting radical generation.  相似文献   

Identification of quantitative trait loci for powdery mildew resistance in highly resistant cucumber (Cucumis sativus L.) using ddRAD-seq analysis     

Koichiro Shimomura  Mitsuhiro Sugiyama  Yoichi Kawazu  Yosuke Yoshioka 《Breeding Science》2021,71(3):326

Powdery mildew, caused by Podosphaera xanthii (syn. Sphaerotheca fuliginea ex Fr. Poll.), is one of the most economically important foliar diseases in cucumber (Cucumis sativus L.). Cucumber parental line ‘Kyuri Chukanbohon Nou 5 Go’, developed from weedy cucumber line CS-PMR1, is highly resistant to powdery mildew and is promising breeding material. We performed quantitative trait locus (QTL) analysis using double-digest restriction-site-associated DNA sequencing (ddRAD-Seq) in a population from a cross between ‘Kyuri Chukanbohon Nou 5 Go’ and the Japanese native cultivar ‘Kaga-aonaga-fushinari’, which is susceptible to powdery mildew. The resistance of the population and its parents was evaluated using leaf disc assays and image analysis. We detected one major QTL on Chr. 5 that was effective at both 20°C and 25°C and one minor QTL on Chr. 1 effective at 20°C. We detected two additional QTLs in subpopulation: one on Chr. 3 effective at 20°C and one on Chr. 5 effective at both 20°C and 25°C in a position different from the major QTL. The resistance alleles at all four QTLs were contributed by ‘Kyuri Chukanbohon Nou 5 Go’. The results of this study can be used to develop practical DNA markers tightly linked to genes for powdery mildew resistance.  相似文献