“Setokirara”, a wheat cultivar for bread making, tends to have a low grain protein content in spite of its high yield. In this study, we examined the effect of applying nitrogen fertilizer after anthesis on the grain protein content and the nitrogen accumulation in plant organs. The nitrogen fertilizer was applied by two methods: spreading soil surface with ammonium sulfate and foliar spraying with urea in solution. Furthermore the foliar spraying was performed by three methods: (1)spraying the full amount at anthesis, (2) spraying half the amount at anthesis and the other half one week after anthesis and (3) spraying the full amount at one week after anthesis. The grain yield was not increased by any method of nitrogen topdressing. The grain protein content was increased by all methods of topdressing, but there were no differences between ammonium sulfate and urea, or with the time of applying urea. Nitrogen from foliar spraying of urea was temporarily accumulated in vegetative organs, leaf + chaff + culm, and then translocated to grains. Nitrogen from ammonium sulfate applied to the soil surface was also accumulated in vegetative organs in one season, but was accumulated directly in grain not through vegetative organs in another season. Both nitrogen content and SPAD value of leaves were increased by nitrogen topdressing, but dry matter weight was not increased. Nitrogen application increased chlorophyll accumulation in leaves, but surplus chlorophyll did not appear to increase dry matter production.

The drying condition after harvesting is one of the most important factors that determine the quality of peanut seeds. In this study, we investigated the effects of temperature, humidity and presence or absence of leaves and stems during pod drying on eating quality of peanut seeds. The presence or absence of leaves and stems during pod drying had no discernible effect on either sucrose or starch contents of seeds. The increase in the sucrose content and decrease in the starch content of seeds during drying became slower with the decrease in the moisture content of seeds. These results show that gradual drying of pods until the moisture content of seeds becomes less than 20% would be necessary to improve the taste and flavor of seeds. It was also suggested that there was no significant effect of remaining leaves and stems during the drying process on the taste and flavor of seeds.

Soybeans with a large interval between central and lateral blooming are considered to be tolerant to cold weather (CW) during the flowering stage. We introduced the lateral blooming (LB) trait into Hokkaido soybeans, and evaluated their CW tolerance. We conducted two crosses between an indeterminate CW tolerant Canadian variety Labrador with the LB trait and determinate Hokkaido varieties without the LB trait. Then we selected determinate lines with and without the LB trait. The selected lines were exposed to the low temperature of 18ºC day/13ºC night for four weeks from the beginning of flowering. The CW tolerance index (CTI) concerning the pod number and seed yield was significantly higher in the lines with the LB trait (LB lines) than in the lines without the LB trait. Similar results were observed at the test field for cold tolerance in a cooler region where the two lines were selected. The CTIs concerning the pod number and seed yield in the two selected lines were significantly higher than those in Toyomusume, and also tended to be higher than or equal to those in Hayahikari. The two lines mentioned above had a larger number of LB nodes than in Toyomusume, and longer total flowering period (about 15 days) than in Toyomusume and Hayahikari (about 10 days). Thus, the introduction of the LB trait into soybeans was suggested to improve CW tolerance in Hokkaido.

Stabilization and increase in soybean yield in three croppings (rice-wheat-soybean) in two years are important issues in cultivation on upland fields converted from paddy fields with poor drainage in mountainous areas. This study investigated the effects of improved drainage cultivation with a chisel plough on the soil physics and the growth and yield of soybean in local fields and fields in the research center in 2016 and 2017. The penetration resistance value in the plot of cultivation with a chisel plough (chisel plot) at a depth of 13 cm to 20 cm was lower than that of cultivation without a chisel plough (the plot without chisel), because the subsoil layer was soft. Decrease in the value of the soil matric potential at 15 cm depth in the chisel plot tended to be greater than that in the plot without chisel, especially in the wet soil. After using a chisel plough before sowing wheat, these effects such as superior soil drainage characteristics were succeeded to the next soybean cropping. Compared with the plot without chisel, soybean in the chisel plot had a higher establishment ratio, larger number of ripening pods and a higher yield. These results suggest that cultivation with a chisel plough would bring about superior soil drainage characteristics, an improved establishment ratio and higher yield of soybean in upland fields converted from paddy fields with poor drainage in mountainous areas.