Current citrus breeding programs have three objectives: developing diverse varieties that satisfy assorted commercial needs; improving overall fruit quality; and releasing varieties quickly. However, these objectives may conflict with each other owing to the limited available orchard space, and conventional breeding systems have not progressed rapidly enough to resolve this problem. “Citrus Breeding 2.0” is a novel approach to overcome the trilemma of citrus breeding. “Citrus Breeding 2.0” will increase diversity by referring to parentage, improve the overall fruit quality through composite selection, and minimize the breeding time through genomics-assisted selection. Extended applications of “Citrus Breeding 2.0” are also possible for purposes of rebreeding or improving an existing variety.
Many root-colonizing Pseudomonas spp. exhibiting biocontrol activities produce a wide variety of secondary metabolites with antibiotic activity against plant pathogens in the rhizosphere. Among these metabolites, 2,4-diacetylphloroglucinol (DAPG) is one of the most typical antibiotics in model biocontrol strains of Pseudomonas protegens. We screened DAPG-producing strains among 2,800 fluorescent pseudomonads isolated from the field in Japan. In addition to P. protegens, several other strains close to, but different from, P. protegens have been identified and found to exhibit biocontrol activity. Recent advances in genomic research on these strains revealed that they build up strain-specific genomic repertoires for the biosynthesis of secondary metabolites and niche adaptation. In this mini-review, we introduced our recent genome-based characterization of P. protegens and related strains. Comparative genome analyses in combination with different bioassays have become a powerful tool for the identification of novel biocontrol factors of potentially beneficial strains.
With increases in the scale of feed-crop production in farm management, croplands are dispersed into larger areas and feed-crop production become more expensive. Here I examine how to increase feed production economically through livestock farm management under the condition of cropland dispersion. I constructed farming models reflecting cropland dispersion based on farm surveys and simulated optimized feed production by using the integer programming method. In the first study, I analyzed the effect of dispersion of feed-cropping fields on the management entities of breeding cattle for beef in the Kyushu District of Japan. The simulation results suggested that large-scale beef calf-raising farms would need to use feed-cropping fields ≦1 km from the cattle sheds to achieve increased feed self-sufficiency. Moreover, if a farm has a total of 14 ha of fields at 0.4 ha per field ≦3 km from the cattle shed, it would cover expenses even if calf prices declined to the support price. My second study revealed that feed crop-production costs could be decreased by optimizing feed-crop allocation (grasses and corn) to the fields around the total mixed ration (TMR) center run by Hokkaido dairy farmers. This could be achieved depending on the state of activities of the center that contracts out the harvesting and bunkering operations and on harvesting conditions.
Citrus greening disease, huanglongbing (HLB), is one of the most destructive citrus diseases worldwide. The causal agent, Candidatus Liberibacter asiaticus (Las), is transmitted by the Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae). In Okinawa, in the beginning of 2000, HLB was widespread. Local control and planting of HLB-free trees were considered necessary measures to manage HLB. In 2006, 25 HLB-free trees were planted at an experimental field in Okinawa. Then, insecticides were sprayed in the experimental field according to the spray calendar (during the experimental period: imidacloprid 20%, thiamethoxam 10%, dinotefuran 20%, and clothianidin 16%; each application rate was 0.1 L/m2). In addition, “local control,” that is, insecticide spraying [fenitrothion 50% twice a year from 2006 to 2008, mineral oil 97% once, and methidathion 40% (June-July) once after 2008; each application rate was 0.1 L/m2] and removal of HLB-positive trees in the residential area, were continued. Until 2010, psyllids were very few, and none of the 25 planted trees were infected with HLB in the experimental field. Even in 2011, only 3 of the 25 trees were infected, indicating that the HLB infection rate was low when greening-free trees were initially planted and local control (pest control and removal of infected trees in the residential area) was effective at an early stage of cultivation. This result suggests that even in Japan, local control and planting HLB-free trees are effective in managing HLB.
The role of agricultural investment growth in alleviating climate risks for wheat production systems and markets was examined using a partial equilibrium model, the Wheat Economy Climate Change (WECC) model, which covers the wheat markets of 10 countries and two regions. This study examines how future agricultural investments will affect the world wheat market. The volatility of international wheat prices at baseline is expected to increase in 2014-2016 and until 2040 because of climate change. However, a constant increase in agricultural investments in major producing countries will contribute to international wheat price stability. In particular, agricultural investments in Russia are crucial for stabilizing international wheat prices in mid-long term under future climate change conditions.
Surplus use of agricultural inputs such as fertilizers and pesticides that cause land and water pollution have been a serious problem in China. This study investigated surplus fertilizer use for corn, rice, vegetable, and tomato farming in terms of farm management by the smoothed bootstrap levels. Higher surplus fertilizer use was observed for farmers using manure, although their chemical fertilizer use levels were similar or lower. It was also confirmed that the input value of both purchased and self-made manures was more unstable than that of chemical fertilizers.
In this study, an immunohistochemical (IHC) technique for detecting Newcastle disease (ND) virus (avian avulavirus 1) using paraffin sections of formalin-fixed tissues was developed by production of novel monoclonal antibodies. Mice were immunized with ND virus isolate APMV1/chicken/Japan/Fukuoka-1/2004 (genotype VII), and 14 mouse hybridoma clones producing IgG antibodies against the ND virus were established. Among these antibodies, only three reacted with the viral antigen on the paraffin sections, while one (22C483) exhibited the highest sensitivity in IHC analysis. Results of immunoprecipitation, western blot analysis, and indirect enzyme-linked immunosorbent assay showed that 22C483 reacted with the nucleoprotein of ND virus. Thus, IHC analysis using 22C483, in combination with enzyme digestion treatment for antigen retrieval, can be used for elucidating the pathogenesis of ND.
This study, conducted over a four-year period (January 2013 to December 2016) in Northern and Southern Japan, aimed to compare environmental factors affecting the growth of calves born at the same time of the year in these two geographical regions. Data were collected from calf markets to calculate the daily gain (DG) of each calf based on body weight and age (in days). There were no significant differences in DG between the two regions. In both regions, DG of calves born in winter and spring tended to be lower than that of calves born in summer and fall. In Northern Japan, the mean DG showed a significantly negative correlation with the temperature–humidity index (THI) during the three months after birth. However, there was no significant correlation with THI during the month of birth. By contrast, in Southern Japan, the mean DG showed a significantly positive correlation with THI during the month of birth. However, there was no significant correlation with THI during the three months after birth. These observations suggest potential drawbacks of the current barn structures adapted to the environment of each region and indicate the importance of appropriate rearing management, considering the seasonal changes of each region.