We examined the effects of water management on seedling establishment and yield of lodging-tolerant rice cultivar, ‘Moeminori’. The non-coated seeds were directly seeded using a puddling seeder. Field experiments were conducted in a paddy field in the Tohoku Agricultural Research Center (NARC), in Akita Prefecture, Japan, from 2013 to 2017. We tested four water management systems: flooding, flooding-drainage (7-day flooding, followed by 5- to 7-day drainage), short-term drainage (7- to 8-day drainage), and long-term drainage (12- to 13-day drainage). Seedling establishment was better with the long-term drainage treatment than the flooding and flooding-drainage treatments. Differences in growth, yield, and grain quality between the treatments were negligible. Lodging was higher with the flooding treatment than the short-term drainage treatment. On-farm trials were conducted at two sites in Akita Prefecture from 2014 to 2016. We tested two water management systems: flooding-drainage (8-day flooding, followed by 3- to 12-day drainage) and drainage (8 to 15 days). Seedling establishment tended to be better for the drainage treatment, when the seeding depth was the same. Differences in growth, yield, and grain quality between the treatments were negligible. This method was as practical as direct seeding of iron-coated seeds, which is conventionally used for seedling establishment. Drainage for about 12 days was therefore appropriate for this cultivation method.
The β-glucan content in grain is higher in the waxy cultivar of naked barley than in the non-waxy cultivar. Topdressing with nitrogen fertilizer at a later growth stage may increase the β-glucan content in grain. We examined the β-glucan content in the waxy cultivar“Kirarimochi” in comparison with that in the non-waxy cultivar“Toyonokaze” and examined the effect of additional nitrogen fertilization on the β-glucan in the grain throughout the grain filling period. The nitrogen topdressing treatments were : (1) nitrogen fertilizer applied at sowing and tillering stages (control), (2) topdressing at the spike formation stage in addition to the control fertilization, (3) topdressing at the spike formation and anthesis stages in addition to the control fertilization. Waxy cultivar “Kirarimochi” had a higher β-glucan content in grain than the non-waxy cultivar “Toyonokaze”.The additional nitrogen topdressing at later growth stages increased grain yield and spike number compared with the control in both cultivars. When determined at 42 days after anthesis, the β-glucan content was higher in “Kirarimochi” than in“Toyonokaze” and was increased by additional topdressing at later growth stages in “Kirarimochi”. However, at 28 days after anthesis, there was no significant difference in the β-glucan contents between the two cultivars under any of the three treatments. The maturity period was delayed by additional topdressing at later growth stages.
‘Setodure’ is the first durum wheat cultivar registered in Japan. High protein content is important for good food processing, as in the wheat for bread. Therefore, fertilizer management is important to obtain a high grain protein content in ‘Setodure’. In 2016/2017 and 2017/2018 cropping seasons, we investigated the effects of nitrogen topdressing on the yield and quality of ‘Setodure’ in Hiroshima prefecture. The effects of topdressing timing, nitrogen rates at anthesis and intensive topdressing at panicle formation and flag leaf stages were examined. There was no significant difference in the effects of topdressing at the flag leaf, heading and anthesis stages. The grain protein content of topdressing at the anthesis stage was significantly higher than that at the flag leaf stage. Next, there was no significant difference in the yield with different nitrogen application rates at anthesis. The grain protein content increased significantly with the increase in nitrogen application rate at anthesis. The increase of nitrogen application by the intensive topdressing at the panicle formation and flag leaf stages increased the yield significantly. In this topdressing, the protein content also increased significantly with increase of nitrogen application rate at the flag leaf stage. Low protein grains reduced the semolina extraction yield and increased the flour yield based on semolina, and the sensory evaluation of spaghetti clearly revealed poorer texture.
Rice cultivars with short panicles are in demand for whole-crop ensilage because they yield fewer spikelets, which are hard for cattle to digest. However, methods for efficient seed production need to be developed. Factors that are effective for seed production have been elucidated in “Tachisuzuka”, but they may not be effective in ‘Tachiayaka’. Here, to elucidate the factors that affect spikelet number per panicle in “Tachiayaka”, we examined the effects of crop management. Comparison of the samples transplanted at various periods and harvested at different altitudes or latitudes revealed negative correlations between spikelet number per panicle and average of daily minimum air temperature from 30 days to 11 days before heading. Plants grown in cold water from 29 days to 10 days before heading had significantly more spikelets per panicle than plants grown in warm water. These results showed that spikelet number per panicle in “Tachiayaka” was greater at lower temperatures during young panicle development.
Photosynthesis and transpiration are important factors for improving crop yield. We examined the leaf and canopy transpiration rates of GP2, a heading gene mutant of hd3a, a rice orthologue of Flowering Locus T (FT) which promotes stomatal aperture in Arabidopsis FT in comparison with those of its wild type Gimbozu. Measurements were conducted with LI-6400 in 2012 and 2013. In addition, we measured and canopy surface temperature with a thermography camera at the experimental field in Kyoto University in 2013. The ratio of canopy transpiration between GP2 and its wild type Gimbozu was quantitatively analyzed using micro-weather data and canopy temperature. The photosynthesis measurements showed that GP2 had lower stomatal conductance (gs) than its wild type Gimbozu. Furthermore, the canopy temperature was higher and transpiration rate was lower in GP2 than in Gimbozu in the afternoon toward the end of July. These results indicated that Hd3a controls the transpiration in rice. Although there was no significant difference in the plant biomass and yield between GP2 and Gimbozu, these findings contribute to our understanding of water use efficiency in rice production.
We tried to develop a cultivation method to obtain many seeds with a high germination rate in black-seeded soybean "Tambaguro" for Edamame (green soybean) cv. “Murasakizukin 3” in Kyoto prefecture. When “Murasakizukin 3” was sown at a later date, the winnowed grain yield was lowered, but the yield was increased due to the decrease of seed coat cracking, and the germination rate was high. From the results of this study, the best sowing time to obtain a stable high percentage of germination was after July 5–10 in Kyoto Prefecture. When the planting density was in the range of 3.1 to 6.3 hills m–2, the winnowed grain yield increased with the increase in the planting density. When white-surface black-underside double multi was laid, the winnowed grain yield increased further, due to the increase in the hundred winnowed grain weight. This was considered to be due to the retention of soil moisture. However, the effect of foliar application of Ca and urea during the ripening period for the percentage of germination and yield was not clear.
Efficient cultivation management of raising seedlings is required in transplanting rice cultivation. However, in Akita prefecture, the techniques for raising seedlings to stabilize production is labor-intensive. We seeded 180 g of seeds (dry weight) in a nursery box, and raised them in a vinyl house without warming (180 g seedlings hereafter). For comparison, we seeded 100 g of seeds, which is the conventional seeding density by the same method (100 g seedlings hereafter). We used two rice varieties ‘Akitakomachi’ and ‘Menkoina’. The characteristics of these seedlings and their growth after transplanting were compared. The leaf number of the 180 g seedlings was over 4, but was 0.3–0.8 less than that of the 100 g seedlings. The number of nursery boxes used for transplanting the 180 g seedlings was 64–77%％of that used for transplanting the 100 g seedlings. After transplanting, tillering from the lower nodes of the 180 g seedlings increased as compared with the 100 g seedlings. In cultivation of the 180 g seedlings, second tillering occurred frequently, the number of tillers in the highest tillering period increased, and number of panicles also increased. The growth stage from the young panicle formation stage to the maturity stage was delayed by 0-3 days as compared with the 100 g seedlings. The leaf color of the 180 g seedlings during the ripening period remained high. The yield of the 180 g seedlings was higher than that of the 100 g seedlings and the quality of brown rice was the same. These results demonstrate the usefulness of the high density (180 g seedlings) labor-saving and stable production method for transplanting rice cultivation.
Glassy grains in barley tend to increase with nitrogen topdressing at a later growth stage. A characteristic of waxy barley varieties is that their glassy grain rate is less likely to be increased by topdressing. The yields of these varieties is expected to be raised by using a higher top to basal nitrogen dressing ratio or high nitrogen topdressing while maintaining a low glassy grain rate. We cultured the waxy barley variety ‘Haneumamochi’ and its non-waxy original version ‘Fiber Snow’ in Niigata Prefecture using a higher top to basal nitrogen dressing ratio and compared their yield and quality. We tested three types of dressings: ‘normal topdressing,’ which has a higher rate of basal to topdressed nitrogen, ‘high topdressing ratio,’ which has reduced basal nitrogen and higher topdressed nitrogen, and ‘increased topdressing,’ which has a higher topdressed nitrogen ratio than ‘high topdressing ratio.’ The yield from ‘high topdressing ratio’ was higher than for ‘normal topdressing.’ It appears that in the ‘high topdressing ratio’ plants, the number of spikelets increased as a result of higher nitrogen concentration in the plants in winter, which is the early spikelet differentiation period. The number of grains per head also increased as a result of a decrease in sterility of the lower spikelets due to topdressing during the flag leaf emergence stage. The glassy grain rate of ‘Haneumamochi’ was clearly lower than that of ‘Fiber Snow.’