A questionnaire survey was conducted in Yamanashi Prefecture in the course of adapting a wearable robotic suit, which was originally developed for assisting human care (Yonetake and Toyama, 2005), to agriculture. Among various farm operations, farmers had a heavy workload when grape berry thinning followed by cluster shaping and pruning, and 58% of farmers hoped to buy a wearable agri-robot suit that may support their arms, legs, and back. Using the main Ovako Working Posture Analysis System (OWAS), physical workload was evaluated during pruning and berry thinning in vineyards on a slope and flatland; pruning was a heavier workload than berry thinning irrespective of the farm topography and, for both operations, working on the slope was a heavier workload. According to the second OWAS working posture percentages for the relative proportions of the postures of different body parts, workers have to maintain a static posture by raising the arms at or above shoulder level for more than 70% of the total working time in berry thinning. The arm posture in berry thinning was classified as AC3 and corrective measures are necessary as soon as possible. In the OWAS analysis system, although pruning was evaluated to have a higher level of physical stress than berry thinning, farmers felt that it is a lighter workload because it involves various postures, such as walking and sitting, whereas in berry thinning the farmer has to maintain the same posture by raising the arms and farmers especially felt arm fatigue while berry thinning. These results suggested that a mechanical support system is necessary to reduce the workload of grape farmers. Thus, in Japanese grape production, a wearable agri-robot suit focused on a support system for the back, arms and legs with free and rapid movement of the wearer might be an alternative solution to reduce the workload of grape farmers.

This study was conducted to clarify the ecophysiological traits of high-yielding 'Benihoppe' with focus on its dry matter production, plant growth analysis, and leaf photosynthetic rate in comparison with those of 'Toyonoka' and 'Sachinoka'. Total dry matter of 'Benihoppe' was higher than that of 'Toyonoka', while no difference was found between their harvest indices. In 'Benihoppe', the crop growth rate (CGR) and leaf area index (LAI) were higher than those of 'Toyonoka' and 'Sachinoka'. The large LAI of 'Benihoppe' was attributed to its ability to bear larger leaves than other cultivars, while 'Benihoppe' demonstrated a superior net assimilation rate (NAR) to that of 'Toyonoka'. NAR is affected by leaf photosynthetic activity; however, no difference was observed between the leaf photosynthetic rates of 'Benihoppe' and 'Toyonoka'. Petioles in 'Benihoppe' that supported large leaves were longer and upright, and NAR might be affected by their trait, which allow solar radiation to penetrate the plant canopy. Thus, the outstanding CGR in 'Benihoppe' may be a result of the large LAI and upright petioles which allow solar radiation to penetrate the plant canopy.

Rapid propagation of Honey orange (Citrus tangerina) was achieved by induction of shoots from epicotyl and cotyledonary node explants and rooting of cotyledonary node derived shoots. Significant explant differences were observed in the induction of direct shoots. Cotyledonary node explant is the most efficient in regeneration frequency followed by epicotyl explant. Cotyledonary node explants cultured on Murashige and Skoog (MS) medium supplemented with 8.88 µM N6-benzyladenine (BA) and 0.54 µM α-naphthaleneacetic acid (NAA) developed more than five shoots per explant. The isolated shoots transferred onto the MS medium supplemented with 5.4 µM NAA rooted 100% within 30 days.

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