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Usami T.,Chiba University | Kanto T.,Hyogo Prefectural Technology Center for Agriculture | Inderbitzin P.,University of California at Davis | Itoh M.,Chiba University | And 5 more authors.
Journal of General Plant Pathology | Year: 2011

In January 2002, Verticillium wilt of lettuce (Lactuca sativa L.) caused by Verticillium tricorpus occurred in upland paddy fields in Hyogo Prefecture for the first time in Japan. This fungal species was first isolated from lettuce in California, USA. In the present study, the genetic relationships between the American and Japanese isolates of V. tricorpus from lettuce were analyzed to determine whether the pathogen could have migrated to Japan from the USA, the major lettuce-seed supplier for Japan. Nucleotide sequences of the rDNA internal transcribed spacer regions, as well as the genes coding for translation elongation factor 1-alpha and RNA polymerase II were compared among American and Japanese V. tricorpus isolates from lettuce. The Japanese isolates of V. tricorpus were distinct from the American. Random amplified polymorphic DNA analyses also supported this conclusion. These results demonstrated that Verticillium wilt on lettuce caused by V. tricorpus in Japan was not related to the isolates causing the disease in California. © 2010 The Author(s).

Ueyama H.,Japan National Agriculture and Food Research Organization | Kato M.,Hyogo Prefectural Technology Center for Agriculture | Kawamukai H.,University of Hyogo | Ikegami M.,Hyogo Prefectural Technology Center for Agriculture | Fujimoto H.,Hyogo Prefectural Technology Center for Agriculture
Journal of Agricultural Meteorology | Year: 2015

Degradation of the quality of Yamadanishiki sake rice has become more evident in the last 15 years, which is partly attributable to high temperature damage to the rice during heading. In response, an information system has been developed to determine the suitable planting period for this rice variety. A key input to this system is daily mean air temperature data at fine spatial resolution, and here an estimation method to calculate such data on a 50–m grid is presented. This database contains daily mean air temperature for 244 days in target regions from April through November over 15 years (1996– 2010). The database is obtained by applying a method whose essence is to convert air temperature to potential temperature and build estimation models of the potential temperature difference between an estimation site and existing observation site. The potential temperature differences are partitioned into two components: a “standard site component (Tssc)” and “estimation site component (Tesc).” Estimation models for Tssc and Tesc are developed using a radiative cooling scale, i.e., the difference of potential temperature between an upper level and ground level. Daily air temperature at each output grid was estimated to have a root mean square error of 0.5℃. Our method is able to acquire precise daily air temperature for past, present and future at the existing observation site, without newly costs for installation and maintenance of regular observing instruments. © 2015, Society of Agricultural Meteorology of Japan. All rights reserved.

Ashida K.,Japan National Agriculture and Food Research Organization | Araki E.,Japan National Agriculture and Food Research Organization | Maruyama-Funatsuki W.,Japan National Agriculture and Food Research Organization | Fujimoto H.,Hyogo Prefectural Technology Center for Agriculture | Ikegami M.,Hyogo Prefectural Technology Center for Agriculture
Journal of Cereal Science | Year: 2013

The starch and protein properties of rice grain are important factors for sake brewing and these properties are reported to be influenced by temperatures during grain ripening. Amylose content, nitrogen content, protein composition, pasting properties measured by a Rapid Visco Analyser (RVA), and their relationship to temperatures during ripening were investigated in a rice cultivar, Yamadanishiki, which was grown under various conditions in the same experimental field. The average temperature after heading was significantly correlated with amylose content and RVA properties, but not with nitrogen content. Under high temperatures during ripening, a decrease in prolamin, which accumulated in type I protein body (PB-I), and an increase in glutelin, which deposits in type II PB (PB-II), were recognized. The ratio of PB-II/PB-I and RVA pasting temperatures were distinctly increased as the temperature became higher. High temperatures during grain ripening would lead to difficulties in digesting steamed rice grains by Aspergillus oryzae, together with ease in digesting rice protein. The average temperature of 11-20 days after heading showed a higher correlation coefficient than that of 1-10 or 21-30 days, implying that temperatures during the middle stage of grain development would be important in determining the rice component that relates to brewing properties. © 2012 Elsevier Ltd.

PubMed | Maruwa Biochemical CO., Kyoto University, Hyogo Prefectural Technology Center for Agriculture and Panasonic
Type: Journal Article | Journal: Journal of economic entomology | Year: 2016

Development of spider mite management technology other than chemical control is desired because of the serious development of acaricide resistance worldwide. Recent studies have evidenced the lethal effects of ultraviolet-B (UVB) radiation on spider mites. To develop the technology on how to use UVB irradiation for spider mite control, we tested whether UVB lamp-light reflection sheet (LRS) combinations suppressed the population size of Tetranychus urticae Koch on strawberry in a greenhouse from December to May (2012-2013, 2013-2014) in Japan. We designed four combinations of UVB lamps and LRSs: 1) neither UVB lamps nor LRSs (UV-LRS-); 2) a UVB lamp without an LRS (UV+LRS-; 2012-2013 only); 3) a UVB lamp and a mulch-type LRS (UV+LRSm); and 4) a UVB lamp and a wing-type LRS (UV+LRSw). The number of adult females peaked at 438.0 and 222.0 per plant in UV-LRS- of 2012-2013 and 2013-2014, respectively, and peaked at 191.6 females in UV+LRS- of 2012-2013. In contrast, the peak abundance was 20.9-98.0 females in UV+LRSm, and fewer than 15 females were noted in UV+LRSw over either experimental period. UVB irradiance on lower leaf surfaces was higher in UV+LRSm and UV+LRSw than UV-LRS- and UV+LRS-, and the mite densities were significantly correlated with UVB irradiance on lower leaf surfaces. Consequently, we conclude that the combinations of UVB lamp-LRS have an excellent capacity to control T. urticae on greenhouse strawberry, and that the LRS was an essential component in this technological approach.

Tanikawa T.,Japan Forestry and Forest Products Research Institute | Hirano Y.,Nagoya University | Dannoura M.,Kyoto University | Yamase K.,Hyogo Prefectural Technology Center for Agriculture | And 5 more authors.
Plant and Soil | Year: 2013

Aim: Ground-penetrating radar (GPR) has been applied to detect coarse tree roots. The horizontal angle of a root crossing a scanning line is a factor that affects both root detection and waveform parameter values. The purpose of this study was to quantitatively evaluate the influence of root orientation (x, degree) on two major waveform parameters, amplitude area (A, dB × ns) and time interval between zero crossings (T, ns). Methods: We scanned four diameter classes of dowels in a sandy bed as simulated roots using a 900 MHz antenna from multiple angles to clarify the relationships between the parameters and x. Results: Angle x strongly affected reflection images and A values. The variation in A(x) fitted a sinusoidal waveform, whereas T was independent of x. The value of A scanning at 90° was estimated by A values of arbitrary x in two orthogonal transects. The sum of T in all reflected waveforms showed a significant linear correlation with dowel diameter. Conclusions: We clarified that root orientation dramatically affected root detection and A values. The sum of T of all reflected waveforms was a suitable parameter for estimating root diameter. Applying grid transects can overcome the effects of root orientation. © 2013 Springer Science+Business Media Dordrecht.

Hirano Y.,Nagoya University | Hirano Y.,Japan Forestry and Forest Products Research Institute | Yamamoto R.,Kobe University | Dannoura M.,Kobe University | And 8 more authors.
Plant and Soil | Year: 2012

Aims: Tree roots in forest soils can be detected using nondestructive ground-penetrating radar (GPR). However, few studies have investigated root detection frequency; i. e., how many and which roots are identified in a radar profile out of the total quantity of roots present in a forest stand. The objective of this study was to quantify root detection frequency and uncertainty, including relationships between root detection and radar parameters using 1.5 GHz GPR in a Pinus thunbergii forest on sandy soils. Methods: We compared the vertical distribution of 829 excavated roots with distributions identified visually in radar profiles using GPR on 17 transects. Results: The detection frequency for number of roots less than 1.0 cm in diameter was only 6.6 %, but 54 % of roots that were larger than 1.0 cm were detected. Roots larger than 2.0 cm were identified with less frequency by GPR at deeper depths (20-30 cm) than were shallower roots. Conclusion: Our study indicates that GPR methods estimate root biomass to be 68 % of the excavated root biomass and that the detection frequency for number of roots in radar profiles using GPR is related to root biomass, although there is uncertainty in the attenuation of radar waves with depth, soil water condition and root orientation. © 2012 Springer Science+Business Media B.V.

Hosomi A.,Research Institute of Environment | Miwa Y.,Research Institute of Environment | Mano T.,Hyogo Prefectural Technology Center for Agriculture
Journal of the Japanese Society for Horticultural Science | Year: 2013

Shoot growth and fruit production of 'Masui Dauphine' fig trees (Ficus carica L.) were compared between a novel training method and a control method, with various tree spacing. In the novel training, the shoots were elongated downward from a horizontal limb at 180 cm height, whereas control training had upward growing shoots from a horizontal limb at 40 cm height. Sprouted shoots of the novel training trees leafed a few days earlier than controls. The difference in training did not significantly affect longitudinal growth (the internode length and leaf area) of the shoots but, on the apical portion of the shoots, the shoot diameter and leaf weight per area in novel training were less than in controls. Many lateral shoots sprouted on the shoots of the novel training in autumn. The novel training prevented failure of fruit set, which was observed on the basal portion of control shoots with excess vigour owing to narrow tree spacing. The novel training promoted coloring of fruit on the basal portion of the shoots and depressed it on the apical portion. The size and weight of fruit tended to be reduced on the shoots that underwent novel training. The observed characteristics of novel training may be due to the change of lighting conditions and reduced photosynthetic rate due to downward shoot positioning. © 2013.

Shoji K.,Kobe University | Matsumoto I.,Hyogo Prefectural Technology Center for Agriculture | Kawamura T.,Kobe University
Engineering in Agriculture, Environment and Food | Year: 2011

To enhance the accuracy of an impact-based yield sensor installed inside the grain tank of a combine, we measured the individual impacts of intermittent grain flow accelerated by an auger blade. Non-linear calibration was modeled to relate each impulse received by the sensor to the weight of grain released at a single rotation of the auger blade, taking into account the rotational speed of the auger. The parameters were optimized through pairs of signal recording and grain weight at harvest in situ. The relative error of calibration was less than 2%. The proposed instrumentation and signal processing showed robustness to the flow rate of grain, and the maximum relative error of validation was 3.5%.

Yamasaki M.,Kyoto University | Ito Y.,Hyogo Prefectural Technology Center for Agriculture | Ando M.,Kyoto University
Canadian Journal of Forest Research | Year: 2014

Bark and ambrosia beetles sometimes kill trees by attacking them en masse; however, their attack is not necessarily successful. Less than half of the fagaceous trees attacked by the ambrosia beetle Platypus quercivorus (Murayama) die, and the factors affecting this mortality are still unknown. To examine this issue, the survival of all stems of fagaceous trees attacked by the ambrosia beetle was investigated in a secondary forest from 2008 to 2010. In an area of 93 ha, 2130 stems (1278 genets) of fagaceous trees were attacked by P. quercivorus during the study period, and 813 of these stems died. A generalized additive mixed model was constructed to predict the probability of mortality of the attacked stems. A best-fit model showed that the probability of mortality was higher in Quercus crispula Blume than in Castanea crenata Sieb. & Zucc. A positive correlation was determined between the density of the attacked trees and the probability of mortality, suggesting that mass attack of P. quercivorus occurs not only on individual trees, but also on groups of trees. Assuming that trees attacked earlier in the season have a higher probability of mortality, the observed negative effects of altitude suggest that P. quercivorus initially seeks hosts at lower elevations.

Yamasaki M.,Kyoto University | Ito Y.,Hyogo Prefectural Technology Center for Agriculture | Ando M.,Kyoto University
Agricultural and Forest Entomology | Year: 2014

The ambrosia beetle Platypus quercivorus uses fagaceous tree species as its hosts, and causes Japanese oak wilt by transporting and introducing the pathogenic fungus Raffaelea quercivora into the host tree. To protect fagaceous trees, it is necessary to understand the host selection process used by the beetle in heterogeneous forests. The occurrence of beetle attack on Quercus crispula and Castanea crenata was monitored from 2008 to 2011 in two 1-ha and one 0.5-ha plots established in a secondary forest. The stem and crown densities of each fagaceous tree species were calculated at 11 different spatial scales for each individual tree. Model application and selection were performed to clarify factors affecting the probability of attack by P. quercivorus. As shown in previous studies, a higher probability of attack was predicted for Q. crispula than for C. crenata, and the predicted probability of attack was lower for trees attacked in the previous year. The effect of stem density on the probability of attack was positive at a small (radius 5m) spatial scale and negative at larger (radius 5-17.5m) scales. We interpreted this to indicate that a dense distribution of fagaceous trees in a small area had a higher probability of attack, and that this probability decreased with an increasing density of fagaceous trees in a surrounding concentric area. A positive effect of crown density was detected, suggesting that P. quercivorus has a means of detecting host trees in areas with high crown densities of fagaceous species. © 2013 The Royal Entomological Society.

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