Two edamame (green soybean) cultivars, “Natsudoritambaguro 1” and “Natsudoritamabaguro 2”, were bred in 2009 as new early black soybean in Kyoto prefecture and are called, "Kyo Natsuzukin" (commercial name). In order to develop cropping types for stable production of these cultivars, the flowering characteristics under different photoperiods, and the suitable sowing time outdoors and in plastic greenhouses were examined. The critical day length was detected in “Murasakizukin 2”, and “Shintambaguro”, but “Natsudoritambaguro 1” and “Natsudoritambaguro 2” flowerd independent of day length. By changing the sowing time from April 15 to May 24 in the transplanting culture of “Kyo Natsuzukin” under outdoor conditions, the harvesting time also changed from July 20 to Aug. 23. The sowing time suitable to obtain a target yield (400 g m^–2 fresh weight pods with over 10 mm thickness), was from early to late May, with harvesting from early to late August. Although sowing in April allowed harvesting in middle to late in July, it reduced the pod number and yield compared with those in May and April sowing. To combine the earlier harvesting and stable yield in the unheated plastic greenhouse, later than late-May sowing and later than early-April transplanting, and harvesting in middle to late June may be necessary because vegetative growth was poor and pod number and yield were small in the culture sown on March 1. A close relation was found between the amount of vegetative growth and the pod yield in “Kyo Natsuzukin” cultivars used in this study.

In order to elucidate the optimum harvesting time of the early black seeded soybean “Tambaguro” for new edamame (green soybean) “Kyo Natsuzukin” (commercial name), we examined the thickness and appearance of pods, and the chemical components of boiled seeds during the seed growth using two cultivars, “Natsudoritambaguro 1” and “Natsudoritambaguro 2”, in Kyoto prefecture in 2010–2013. The average pod thickness in both cultivars reached 11 mm at 51–52 days after flowering in 2010, a high-temperature year, and reached 12 mm at 56–57 days after flowering in 2011, an average-temperature year, but did not increase thereafter. Assuming that the early limit of the harvesting period is the time when the percentage of thinner pods less than 10 mm thick, which is the standard thickness for shipment in Kyoto, reached less than 30%of total pods. This time corresponds to the time when the accumulated temperature after flowering reached 1400 degrees Celsius in both cultivars. Throughout the harvesting period in both cultivars, the color of seed coat changed from light to deep purple, but the content of free sugars and amino acids reached the maximum before the time when the color of whole hilum became pinkish. At this time, the pod thickness reached 10–11 mm, which is slightly thicker than the shipment standard in Kyoto. Therefore the optimum harvesting time judged from the chemical property is earlier than that judged from the pods appearance.

Abnormally early ripening, locally called “Kareure”, induces early senescence of leaves and poor grain filling. The objectives of this study were to find the cause of Kareure. Kareure occurred in trial fields in 2001/12 and 2012/13 where mineral or nitrogen fertilizers or both were additionally applied. Thousand grain weight in the trail fields was 15% and 30% lower in 2011/12 and 2012/13, respectively, than in fields where plants ripened normally (control). The mineral fertilizers rich in silicate, calcium and iron did not influence the thousand grain weight. In 2012/13, omitting of the top-dressed nitrogen made the symptoms worse and increase of top-dressed nitrogen after heading did not influence the symptoms. However, increase of basal nitrogen reduced the symptoms in 2012/13. Excision of spikes significantly alleviated early fall in greenness and relative water content of flag leaves. Cultivars that have been evaluated as susceptible to Kareure in other regions were also susceptible in this region. We discussed the possibility that Kareure might be induced by nitrogen deficiency that might also induce early decline of water uptake and senescence during grain filling.

Yielding abilities of elite high yield varieties “Fukuhibiki” and “Bekoaoba”, a new high yield variety “Iwaidawara”, and a new high yield line “Ouu418” were examined, using the data of the performance test for breeding. These varieties, which were for feed, showed higher yield, compared with the varieties for staple food under the condition of standard nitrogen application. The varietal difference in yield was enlarged by high nitrogen application (HN). The yield did not significantly vary with variety or line by HN. By contrast, “Bekoaoba” and “Ouu418”, which had a short culm and strong lodging resistance, had slightly higher yield by extremely HN. However, the increase in yield was only 2%, suggesting that it was difficul to increase the yield by extremely HN. Yielding abilities of 10 varieties and lines including other new lines for feed and 6 varieties for staple food were compared. All 10 varieties and lines had the smaller number of panicles per area and the larger sink size per panicle (=the number of spikelet per panicle × single grain weight). However, we found no lines showing significantly higher yield, compared with the high yield varieties “Fukuhibiki” and “Bekoaoba”. We concluded that breeding for extremely high yield was difficult and that breeding for varieties with a stable high yield and that allow large scale - low cost cultivation was more important.

As the population of rice farmers decreases in Japan, the management scale of rice cultivation is expected to enlarge and the large-scale rice farmers in the Tohoku region need to continue transplanting late. In the present study, we examined the effects of late transplanting on yield, grain quality, eating quality, and the adaptability of varieties to late transplanting. Late transplanting in mid-June delayed heading for 18 days, decreased the number of panicles per area and the percentage of ripened grain, increased the thousand grain weight slightly, and did not affect the number of spikelets per panicle, compared with conventional transplanting in mid-May. As a result, late transplanting decreased grain yield by 15%. On the other hand, late transplanting improved appearance grain quality slightly and did not affect eating quality. These results suggest that late transplanting could be introduced into the rice cultivation system in the Tohoku region if it is effective from the perspective of management. Among nine varieties in the late transplanting, the percentage of ripening grain decreased and the weight of immature grain increased, as the heading became later. These results suggest that the use of extremely early varieties would effectively minimize the yield decline in late transplanting.

Nineteen rice varieties in the Tohoku region of Japan were classified into five groups; varieties bred before 1950 (Group 1), varieties bred after 1950 until 1980 (Group 2), varieties bred after 1980 and currently in cultivation (Group 3), more recent varieties bred for staple food by Tohoku Agricultural Research Center (TARC) (Group 4) and recent varieties bred for feed by TARC (Group 5). Their agronomical traits were comparatively examined in the field condition with low nitrogen application. The culm was long in Group 1, intermediate in Groups 2 and 3 and short in Groups 4 and 5. By contrast, grain yield did not vary significantly with the group. These results indicate that the historical increase in grain yield in rice varieties in the Tohoku region was attributed to the spreading of varieties in Groups 2 and 3 which had intermediate length of culm and lodging resistance resulting from the increase in nitrogen application. Among the 19 varieties, the number of panicles per area was negatively related with the width of the leaf blade, the diameter of internode, the number of spikelets per panicle and thousand grain weight. On the other hand, the culm length was not clearly related with other traits. These results indicate that the historical changes in the traits are not attributed to the decrease of culm length. The grain quality (appearance quality of brown rice) and eating quality of varieties in Groups 1 and 2 ranged from inferior to superior, and those of varieties in Groups 3 and 4 were superior. We discuss about the future direction of rice breeding in the Tohoku region of Japan considering these results.

We investigated the effect of Glu-B1 (b, i), Glu-B3 (g, i) and Wx-B1 (a, b) alleles on the bread-making quality using eight types of near isogenic lines. The lines carrying both Glu-B1i and Glu-B3g showed the highest sodium dodecyl sulfate (SDS) sedimentation value, the longest mixing time during bread-making, and the highest specific loaf volume. The lines carrying Glu-B3g showed more elastic bread crumbs compared with those carrying Glu-B3i. The lines carrying Wx-B1b showed softer, less elastic and later staling bread crumbs compared with those carrying Wx-B1a. The lines carrying both Wx-B1b and Glu-B1b had the lowest specific loaf volume. These results suggest that the introduction of Wx-B1b was effective in softening and delaying the staling of the bread crumbs during storage. Wx-B1a and Glu-B3g were effective in adding elasticity to the crumbs. Moreover, the presence of both Glu-B1i and Glu-B3g was effective in improving the dough properties and specific loaf volume.

Seeds of Linum usitatissimum L. variety Lirina were drill-sown with row spacing of 30 cm in 2014, 2015 and 2016. Thinning after emergence to about 1, 2, and 4 cm spacing within a row resulted in planting densities of 250～330 m^–2 (H), 150 ～160 m^–2 (M), 75～85 m^–2 (L), respectively. Planting density had no effect on the number of capsules per unit area (m^–2), although the number was smaller in L than in H in 2016. Three yield components which contributed to determining the number of capsules per unit area, namely, the number of stems (=main stem and basal branches) per plant, the number of inflorescence branches per stem, and the number of capsules per inflorescence branch, increased as plant density decreased. On the other hand, the number of seeds per capsule, single seed weight, and yield were not affected by planting density. These results indicate that the linseed plant maintains the number of capsules per unit area and yield through three compensatory growth processes, that is the development of basal branches, inflorescence branches, and flowers.

The food-service industry demands inexpensive and palatable rice. The cultivar “Yamadawara” produces high yields of palatable rice, thereby satisfying this demand. To clarify the requirements for high yields (above 800 g m^–2) of brown rice in “Yamadawara”, we examined the effects of nitrogen application on yield in different growth seasons. Increasing nitrogen application levels led to a significantly higher yield in 2016 but had no significant effect in 2015. Nitrogen application led to significantly higher spikelet number per area in both years. Therefore, the difference in yield response with the year was attributed to spikelet maturation. Solar irradiation during the first part of the maturation period (until 20 days after heading) had a significant positive correlation with yield. However, the mean temperature during the same period had a significant negative correlation with appearance quality. Based on these results, we concluded that the requirements for obtaining a yield above 800 g m^–2 in “Yamadawara” were (1) heading between 9 and 15 August in Fukuyama, and (2) application of nitrogen fertilizer sufficient to produce 41,000–45,000 spikelets m^–2.

Aconite(Aconitum japonicum Thunberg) is a perennial Ranunculaceae species, which contains aconitine alkaloids especially in its tuberous root, and is used as a medicinal crop. The ingredient content is important as a material for Chinese medicine. In this study, we analyzed the relationship between the size of the tuberous root and the percentage ingredient contents. The percentage total alkaloid content of the tuberous root decreased with the increase in dry weight of the tuberous root and stayed constant at a dry weight exceeding 35g. In the field experiments, total alkaloid, mesaconitine, hypaconitine and aconitine contents were determined in the tuberous roots according to size: large (>30 mm), medium (>20 mm) and small (<20 mm). The tuberous root size showed a significantly negative correlation with the percentage ingredient content of the tuberous root. Thus, it is concluded that the cultivation technology to produce a larger tuberous root is effective to control the percentage ingredient content. However, cultivation conditions and their interaction with tuberous root size also had significant effects on the percentage ingredient content. In the tuberous root, we found that the percentage aconitine alkaloid content was high in both apical and basal parts, especially in the apical part with buds. This may be why the percentage content of ingredients is lower in larger tuberous roots. When the ingredient content needs to be analyzed for a large number of samples with different genotypes or under different cultivation conditions, each tuberous root should be divided longitudinally so each sample has both apical and basal parts.