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圃場の乾湿がコムギ品種ハルユタカおよびダイチノミノリの粒重に及ぼす影響を検討するため, 畦立て処理により高畦区 (35cm高) と低畦区 (5cm高) とを設けて, 収量性, 乾物生産特性, 群落構造ならびに稈の可溶性炭水化物含有率と窒素含有率を調査した. 子実収量は, 両品種とも高畦区が低畦区よりも高かったものの, 千粒重は両品種とも畦立て処理間に差がみられなかった. 個体群成長速度は, 両品種, 両処理区とも開花期後が開花期前より低くなり, とくにハルユタカの高畦区では開花期後に著しく低くなった. これは, 開花期後ではハルユタカで平均緑色面積指数 (GAI) が高畦区で低畦区の2倍以上と高かったにも関わらず, 純同化率 (NAR) が高畦区でほぼ0と極めて低かったためであった. 稈の可溶性炭水化物含有率も, 乳熟期のハルユタカでは高畦区の値が低畦区の2分の1と低く, さらに開花期の値に比べても低かった. 葉身の窒素含有率および群落条件での光合成速度は, ハルユタカでは上位2葉とも高畦区が低畦区よりも高かったものの, いずれもダイチノミノリに比べて著しく低かった. このように高畦処理は, 両品種とも生育初期から個体群の乾物生産を高めたものの, とくにハルユタカでは過繁茂を招き, 開花後の同化量が著しく低下したことで, 子実収量こそ増加したものの粒重は増加しなかった.

A wheat cultivar, "Haruyutaka", bred in Hokkaido, was planted and examined at nine cultivation conditions of the four seasons, 1995/1996 to 1998/1999, in Yamaguchi, Japan, for the purpose of introducing a new genotype into this area. Another wheat cultivar, "Daichinominori", bred in Kyushu, a part of western Japan in the same area as Yamaguchi, was compared with Haruyutaka. The Haruyutaka cultivar had lower grain yields than Daichinominori did for almost all conditions because it always had a lower harvest index and a smaller 1, 000 grain weight. Haruyutaka's culm had a higher content of water soluble carbohydrate at anthesis than at the milk-ripe stage. This suggested that Haruyutaka had accumulated no reserve material in culm during the former grain-filling period. Showing a larger total dry weight, Haruyutaka increased its grain weight, harvest index, and grain yield as it increased its sink capacity. Daichinominori increased its harvest index as it increased its source ability during the grain-filling period. Haruyutaka seemed to achieve a higher grain yield, a higher harvest index, and a heavier 1, 000 grain yield as a result of photosynthesis activity that was not high, but of a quick remobilization of reserve material in culm to grain under the environment of western Japan.

Research was conducted to define the characteristics of rutin, protein, and oil contents of common buckwheat in the Kyushu area with the use of local and breeding varieties containing various origins and ecotypes. The analysis of variance showed that the differences among varieties and years were significant at the 1% level for the rutin, protein, and oil contents. The range of the varietal differences of rutin content was larger than protein and oil content. Except for protein content, environmental variation was bigger than the genetic one. There were many high rutin content varieties in Nepal, but varietal characteristics depending on origin were not found in other origins. It was indicated that a high temperature was advantageous for rutin accumulation during maturing. There was an inverse significant correlation between grain yield and rutin content and a significant correlation between protein content and oil content. But it was unclear that a relationship existed between flour to grain ratio, 1, 000 grain weight, and these contents.

A wheat cultivar "Haruyutaka" bred in Hokkaido has a small harvest index, grain weight and yield when it grows in Yamaguchi, Japan. Ethephon, a growth regulator, applied to the surface of wheat canopy is expected to shorten the wheat culm and translocate the resulting surplus assimilate to the grain resulting in the increase of harvest index, grain weight and yield. In this study, we planted two wheat cultivars, Haruyutaka and Daichinominori (bred in Kyushu), at two sowing densities, 400 and 100 seeds m-2 in Yamaguchi, and sprayed 100 ppm ethephon on the canopy once every three days from flag leaf stage to anthesis with the intention of improving the harvest index Ethephon shortened the culms of both cultivars, but gave no effect on harvest index, grain weight or yield. Culm length was reduced not by shortening the culm elongation period but by reducing the culm elongation rate. The shortening of the culm by ethephon treatment resulted in the accumulation of surplus assimilate in the culm, and increased the percentage of water-soluble carbohydrate (WSC) in the culm. However, the WSC was not used for grain growth, because it remained in the culm until maturity.

Developmental process of spike in winter type wheat Iwainodaichi sown early and its relationships with spike traits such as spikelet number, floret number, grain number, mean grain weight and grain weight per spike were compared with those in Iwainodaichi sown later and spring type wheat Chikugoizumi. Spikelet number per spike of Iwainodaichi was larger than that of Chikugoizumi, probably due to the longer duration from sowing to terminal spikelet formation, which determines the number of spikelets. Floret number per spikelet of Iwainodaichi tended to be smaller than that of Chikugoizumi perhaps due to the shorter duration from terminal spikelet formation to anthesis, which determines the number of florets. As a result, floret number per spike of Iwainodaichi was larger than that of Chikugoizumi. Grain number per spike of Iwainodaichi was larger in the plants sown in 1998 but smaller in the plants sown in 1999 than that of Chikugoizumi, since the ripening ratio of Iwainodaichi was smaller than that of Chikugoizumi sown in 1999. Grain number per spike was also smaller the earlier the sowing. Spike traits of Iwainodaichi sown early were different from those of Chikugoizumi and those of Iwainodaichi sown later, and some of those traits were related to the developmental process of spike. Grain weight per spike of Iwainodaichi sown early, however, was not different from that of Chikugoizumi or from that of Iwainodaichi sown later, since some of those spike traits were negatively correlated.

The effect of the selection for leaf color in early generations on the grain-protein content and some other brewing characteristics in late generation was investigated in the crosses of Ooseto with Yamadanishiki and Ooseto with Matuyamamii. The leaf color (SPAD) values at heading time in the F2 population showed a normal distribution. The broad-sense heritabilities of leaf color estimated from F2 variance were 0.517 in the cross of Ooseto with Yamadanishiki and 0.397 in the cross of Ooseto with Matuyamamii. The selection for leaf color at heading time toward dark color (H group) and light color (L group) was continued from the F2 generation to F5 generation. In F6 lines, the mean value of the protein content of the H group was significantly higher than that of the L group. Plant length was longer and 1000 grain weight was lighter in the H group than in the L group. Days from transplanting to heading was shorter and the percentage of white core rice was higher in the H group. There was a significant correlation between the leaf color and the protein content. However, some lines in the H group had a higher protein content than the others at the same level of leaf color. The F5-F6 parent-offspring correlation of the leaf color was significant. From those results, it is considered that the leaf color at heading time in early generation can be used as a criterion for the selection for protein content.

This study was undertaken to estimate the optimum time to harvest the grains of winter wheat with high amylogram viscosity. In 1996 and 1997, three characteristics;kernel weight, grain moisture content and falling number of two cultivars, Chihoku-komugi and Hokushin, were determined during the ripening stage. The samples were taken from five different field locations in Hokkaido. In both years, the time of maximum grain weight (Tmax), which indicates physiological maturity, varied with the weather conditions during the ripening stage. Grain moisture content decreased gradually to 40% at a similar rate in all cases, but the rate of decrease below 40%, decrement in moisture content varied with the field location and year (weather conditions). In 1996, grain viscosity started to increase late and slowly, the maximum falling number being less than 300 sec in many locations. In 1997, the viscosity started to increase earlier 32 to 34 days after heading. Hokushin had a higher falling number and kept the viscosity value of over 300 sec for a longer period than Chihoku-komugi. It was concluded that in order to avoid low amylogram viscosity, we have to harvest the grains when the falling number is over 300 sec. This is because at this stage, Tmax had already been reached.

By categorizing the water selected ripened paddy grains into groups with different specific gravity, we observed several characteristics of the paddy grain and brown rice in four cultivars. It was found that the grains of cultivars with heavier grain were intensively distributed in higher specific gravity, whereas those of cultivar with lighter grain were sparsely distributed around lower specific gravity. The coefficient of variation (CV) of the character in brown rice was always higher than that of the respective character in paddy grain. These results suggested that after the size of the hull was determined at flowering, the brown rice still had a wider variation. The brown rice volume was primarily determined by its thickness, and the influences of its length and width varied among cultivars. With the increases of brown rice volume, all characters of the paddy grain volume, the specific gravity of paddy grain, the paddy grain weight, and the brown rice-paddy grain ratio increased. These were found to be consistent in the four cultivars. The hull weight and the paddy grain weight showed positive correlation in two cultivars, but not in the others. It was concluded that the specific gravity closely related with the paddy grain weight, which was mainly determined by its brown rice volume. The brown rice volume was primarily subject to its thickness. The hull's role in regulating the growth of brown rice might be different among cultivars.

The effects of high temperature(32°C/23°C max/min;27.5°C, daily mean temperature), which is common in August in Fukuyama city, Japan, on the grain weight and the grain quality of rice plants were examined. Air temperature was controlled artificially in growth chambers. The grain weight at 32°C/23°C was lower than at 28°C/19°C as a control in all primary branches at a panicle. The proportion of normal grains relative to all grains was smaller at 32°C/23°C. Moreover, the grain weight and the proportion of normal grains relative to all grains at 35°C/26°C were smaller than those at 32°C/23°C. The decrease in grain weight at high temperature accompanies the decrease in grain thickness. The proportion of imperfectly ripened grains relative to all grains at 32°C/23°C was higher than that at 28°C/19°C, and the proportion of nonfertilized grains at 35°C/26°C was higher than that at 32°C/23°C. The cultivars for which the ratio of grain weight at 35°C/26°C to that at 28°C/19°C was lower than 90% were Moritawase, Arborio as a large grain, and Akenohoshi, which tended to have a bad ripening performance. In contrast, the cultivars with a ratio higher than 95% were Koganemasari, Lakhi Jhota as a small grain, and Hoshiyutaka, known as a good ripened cultivar.

In this study, the influences of environmental conditions on the protein content of grain at different positions within a rice panicle were studied. The protein content of basal spikelets (BS) was higher than that of terminal spikelets (TS) and that of spikelets in the middle position on a panicle (SM) under all the environmental conditions studied. BS, TS, and SM produced in the lodging plot had the highest protein content, and BS, TS, and SM produced in the non nitrogen fertilizer plot had the lowest. BS showed a larger variation in the protein content (4.1%) than TS (2.2%) and SM (3.2%) did. Among BS, SM, and TS, there was an inversely proportional relationship between the protein content and the crude grain weight, and a proportional relationship between the amount of protein in a grain and the crude grain weight. Therefore, the high protein content of spikelets with low grain weight could be due to the deficiency of starch accumulation in rice endosperm as shown by the decrease in the amount of protein. It was concluded that variations in the protein content within a rice panicle were caused by the diffrerences in the crude grain weight, which was closely related to the flowering order of spikelets.

In this study we examined the relationship between the culm and ear length of productive tillers and the palatability and physicochemical properties of rice. The diameter of the stem, 1000 grain weight, and the culm and ear length for lower nodal productive tillers were large, high, and long, respectively. The overall eating-quality, taste, and stickiness of cooked rice of productive tillers with long culms and ears were superior to those of productive tillers with short culms and ears. Grains on the productive tillers with long culms and ears showed lower protein content, higher amylose content, higher maximum viscosity and breakdown values, and lower H/-H and H/A3 ratio than those on the productive tillers with short culms and ears. Among productive tillers were inversely proportional relationships between 1000 grain weight and protein content, the H/-H ratio, and the H/A3 ratio, and proportinal relationships between 1000 grain weight and amylose content, maximum viscosity, and breakdown values. It was concluded that the variations in physicochemical procerties and differences in palatability among productive tillers were caused by differences in the extent of the grain filling, which was closely related to the culm and ear length. To produce rice with a high and stable palatability, a cultivation technique that secures lower nodal position tillers and tillers of an earlier order is recommended along with the production of higher 1000 grain weight.

To increase the crude protein content of wheat in the Kyushu district, the amounts of basal fertilizer and top dressing were decreased to 72% of standard and the remaining 28% fertilizer was applied at the booting stage. The relation between two dressing methods, conventional and with one more topdressing being added at booting stage, was examined in 16 cultivars, varying widely in crude protein content, over a perid of two years. The mature stage with top dressing at booting stage was delayed about 0.5 day. It increased 1, 000-grain weight and liter weight. Positive correlations were found between the 1, 000-grain weight and the brightness (R554), and between liter weight and flour yield. The influence on grain weight was different for each cultiver throughout the two years. In the second year (1994), the glassiness was more increased in the plot with top dressing at booting stage than in the control plot, but no relation to the decrease in grain and flour qualities was found. The crude protein content of grain and flour increased significantly, and crude protein weight (grain weight × crude protein content) increased in many cultivars in the second year. On the other hand, the ash content of flour decreased significantly. The influence on the whiteness (R445) and brightness of flour was different in cultivars. But brightness was negatively correlated with protein content in the second year. No difference was observed between high and low protein content cultivars as a result of the change of crude protein and ash contents by two dressing methods. Therefore the top dressing at booting stage was effective for an increase of crude protein content in wheat in the Kyushu district.

To clarify the high yielding characteristics of new rice varieties recently bred in the cold region of Japan, we examined their yielding ability, yield component and harvest index in 1996 (24 varieties) and 1997 (21 varieties) in comparison with those of four popular varieties refistered after 1970 in the Tohoku region. The grain yield of these varieties was 716∼845 g/m2 in 1996 and 696∼799 g/m2 in 1997, and the difference among the rice varieties was 100∼130 g/m2 in both years. Twenty varieties of the new rice varieties recorded more than 750 n/m2 grain yield in 1996 and 15 varieties in 1997. Compared with popular varieties, the new rice varieties were classified into four groups:1) the varieties having a larger sink due to larger number of spikelets per m2, including Ouu 316 and Ouu 339, 2) the varieties having a larger sink due to a heavier grain weight and similar number of spikelets per m2, including Fukuhibiki, Akita 59 and Manamusume, 3) the varieties having a similar sink size due to a heavier grain weight but smaller number of spikelets per m2, including Okiniiri and Iwanan 6 and 4) the varieties having a similar sink showing a similar number of spikelets per m2 and similar grain weight, including Hananomai and Jyoudeki. These results suggest that in order to breed high yielding rice varieties in the cold region of Japan, we must enlarge the sink capacity by either increasing the number of spikelets per m2 or incresing the grain weight maintaining a similar number of spikelets per m2.

Agricultural damage was caused by heavy rainfall during typhoon 9709 in the northern part of Yamaguchi Prefecture and the western part of Shimane Prefecture.In Mutsumi village, the amount of precipitation measured by five automatic weather stations from July 26 to 28 was 582∼782m, and the amount of precipitation on July 27 was 429∼547mm.We had more rainfall in Mutsumi village than registered at the observation station(AMeDAS)of the meteorological agency.A farm pond in collapsed four places due to the heavy rainfall at Mutsumi village.At the Asou farm pond, rice plants were buried by earth and sand because of bank collapse.The relationships between accumulation depth of earth and sand and top dry weight and grain weight were approximated by a second-order equation.In this case, the accumulation depth of earth and sand was 50cm and top dry weight was zero.In this case of a depth of 35cm, grain weight was zero.

Field experiments were carried out in 1994, 1995, and 1996 to study the effects of chitin on the growth and yield of rice. The results of experiments in 1994 and 1996 showed that chitin as a basal dressing increased the grain weight, and no difference was noted in the grain weight between chitin 500 gm-2 applied plot and the fertilizer plot. In 1995, since rice leaves in the chitin 500 gm applied plot and the fertilizer plot were infested by Cnapharocrosis medinalis GUENEE, no difference in grain weight was noted between all chitin-applied plots and the fertilizer plot. Positive correlations were observed between the number of spikelets per m2 and the grain weight. The percentage of ripened grains was about 90% in the nonfertilizer and all chitin-applied plots, whereas the fertilizer plot was low. This result may be considered as follows. In the fertilizer plot, LAI at the whole growth stage was high, and light extinction coefficient(K)was increased after heading time. As a result, CGR was decreased. On the other hand, the maximum LAI in the chitin 500 gm-2 plot was about 4.5, light extinction coefficient after heading time was low, and CGR was high. As in the results, grain weight in the chitin 500 gm-2 plot was at the same level as the fertilizer plot.

To clarify the high yielding characteristics of new rice varieties bred recently in the Tohoku region of Japan, their growth and yield characteristics and dry matter production were examined in 1994 and 1995, as compared with those of Hitomebore and Kiyonishiki, popular cultivars in the region. The grain yields of the cultivars and strains used were in a relatively high level, ranging from 650 to 815 g m-2. The sequence of grain yield was Fukuhibiki > Ouu 316, Kiyonishiki > Ouu 327 > Hitomebore. High grain yields in Fukuhibiki and Ouu 316 of the panicle weight type with short culm were mainly due to the large number of spikelets m-2, which was mainly determined by the large number of spikelets per panicle. Fukuhibiki was also characterized by a large grain weight and a high percentage of ripened grains. The percentage of ripened grains was mainly governed by the ripened grains on the secondary rachis branch, which closely related to sink size. The high percentage of ripened grains of Fukuhibiki was due to the high percentage of ripened grains on the secondary rachis branch. The grain yield in Ouu 327 of the big grain type was mainly due to a fairly high percentage of ripened grains and markedly large grain weight, although this strain had a small number of panicles and spikelets m-2. As compared with Hitomebore, Fukuhibiki and Ouu 316 with low plant length showed large weights of total dry matter and extremely large weights of dry panicles, which contributed to their large harvest indices. The results suggest that high yielding Fukuhibiki and Ouu 316 possess the excellent characteristics of dry matter production and distribution.

Cultivar difference on dry matter production and grain production in two-rowed barley (Hordeum distichum L. emend, LAMARK) of warm regions in Japan were investigated from 1987 to 1989. Fifteen Japanese cultivars and nineteen foreign cultivars in 1987/1988, and four Japanese cultivars and eleven foreign cultivars in 1988/1989 were grown under field conditions. The full heading stage of Japanese cultivars except New Golden and Kanto Nijyo 19 in 1987/1988 was in the early of April, but the foreign cultivars except WI-2727 was in the late of April. The top dry weight of Japanese cultivars was 615-1001 g m-2, and that of the foreign cultivars was 744∼1088 g m-2. The top dry weight of late maturing cultivars in the full heading stage was higher than that of early and middle maturing cultivars. The LAI of Japanese cultivars was 3∼4, and Nishinochikara was 4.97, higher than the early maturing cultivars. The maturing stage of Japanese cultivars except New Golden, Daisen Gold and Kanto Nijyo 19 was in the middle of May. The grain weight were 408∼544 g m-2. The harvest index (HI) of breeding cultivars in Japan in recent years was 41∼42 and that of Hakei 86-107 was 46.1.

Changes in the number and size of spikes, grains, endosperm cells and starch granules was examined in relation to the limited assimilates caused by shading treatments. Spring wheat canopy (Triticum aestivum L. cv. Haruyutaka) was covered with a 95% shading cloth so as to cause failure in the assimilation at the initial, early and late grain filling phases; initial shading, from two days before anthesis until seven days after anthesis; early shading, from seven days until 14 days after anthesis; and late shading, from 14 days until 21 days after anthesis. The grain yield decreased (11% as compared to no shading) due to a decrease in the number of grains (17%), especially decreasing (62%) at the third floret position in the initial shading, while a decrease of one grain weight at all floret positions resulted in 20% and 16% decreases in the grain yield in early and late shadings, respectively. The reduction of grain weight was not due to a decrease in the number of endosperm cells, but to a decrease in the size of large starch granules. Differences in the effects of shading on changes in sink characters could be explained in terms of the physiological process of grain formation.

The effects of salty wind on the brown rice weight and quality of rice were investigated using a wind tunnel. Two varieties, cv. Hinohikari, cv. Yumehikari, were grown in 1/2000a Wagner's pots containing paddy field soil. The brown rice weight of a plot (non-salty water and non-water sprinkling) was 36.2 g/plant, D and H plots (weak wing treatment; 7.1±1.6 m/s, strong wind treatment; 14.4±4.3 m/s) with salty water treatment were 11.0 g/plant, 15.0 g/plant, respectively and under the condition of 60l/40 min water sprinkling treatment after salty water treatment were 21.7∼22.1 g/plant. The effects of salty water, water sprinkling, wind speed and treatment time on brown rice weight and 1000 grain weight were analyzed by the type I quantification method. According to the result of analysis of salty water treatment of brown rice weight, category scores were 6.47 and -9.71, and the partial correlation was 0.949. On the other hand, with water sprinkling treatment on brown rice weight, category scores were -1.87 and 2.81, and the partial correlation was 0.655. However, the partial correlation of wind speed or treatment time with brown rice weight was low.

The relationships between grain size and quality in wheat were investigated with Koyukikomugi from 1989 to 1991. In 1990/1991 experiment, Koyukikomugi was harvested at maturity by combine, and grains were dried in a layer type dryer until about 11% moisture content was achieved. The grain samples were separated into nine size classes using a sieve every 0.2 mm for seed size from above 3.0 mm to below 1.6 mm in diameter. The grains and 60% extraction flour by Buhler experimental mill in each grain size were analyzed for crude protein and ash content. The dough characteristics were assessed using Brabender machines. The 1, 000 grain weight was increased with an increase in seed size, while the crude protin content of grain and 60% flour in 1990/1991 were constant. The ash content was the highest in 2.4 mm-sized seeds in the 1989/1990 and in 2.6 mm-sized seeds in 1990/ 1991. The milling yield was increased with an increase in seed size and the differences among seed sizes were statistically significant at the 1% level. The values of the whiteness (R455) and brightness (R554) of flour color were higher in the flour made from larger grain, but the values of the grain with yellowish pigmentation (log R554/R455) were the inversely related to them. The farinogram characteristics and amirogram MV showed no significant differences among seed sizes. The area and resistance (R) of extensogram characteristics had also statistically significant differences, while the differences in extensibility (E) and R/E were not significant among seed sizes. It is concluded that the grains with larger seed size were superior with regard to flour yield and flour color but were slightly inferior with regard to Bartender characteristics.

The effect of shading at different growing stage on wheat was examined to confirm the stage when the spike number and the character of spike were determined. Spike number decreased by shading to full heading date. T3 showed a marked decrease in the spike number compared with M, T1 or T2. Spikelet number decreased to floret differentiation stage of tillers by shading. Since floret differentiation stage was delayed in T3 than in comparison with that in M, T1 or T2, spikelet number of T3 decreased later than M, T1 or T2 by shading. Sterile spikelet number of tillers decreased to full heading date by shading. Grain number per spikelet of tillers was affected by shading from two weeks before full heading to ripening stage. Grain weight of tillers was affected by shading at ripening stage.

The relationship between the difference of date of anthesis (Δt) and that of final grain weight (Δw)was studied by observing pairs of spikelets at various positions on the panicle of rice cultivers, 'Nipponbare' and 'Musashikogane'. A high negative correlation was found between the deviation of Δt (Δt-Δtmode ; Δtmode was the most frequently observed Δt) and that of Δw (Δw-Δwmode ; Δwmode is the Δw when Δt = Δtmode), in all pairs of spikelets both on the same (Fig.2) and on different (Fig.3) primary rachis branches. Thus, the results suggest that early flowering spikelets bear larger grains than later flowering spikelets on the corresponding position of primary rachis branch. This fact is probably because early flowering augments nutritional distribution.

We conducted this work to get the informations about the shape and quality of rice kernel in the improved indica varieties, comparing with the japonica varieties. The results obtained are as follows: 1. In all varieties, a high positive correlation (r=0.9065) was found between the hull weight and the length × width of the kernel. 2. In all varieties, there was no correlation between the hull weight and the thickness of the kernel, but the varieties, which had bigger hulls, had a greater thickness in the kernel in the japonica varieties. On the other hand, the varieties which had bigger hulls and whose kernel's length × width were over 16 mm2, had a smaller thickness in the kernel in the improved indica varieties. 3. Varietal differences of the increase in the grain weight were observed. Among the early varieties, the increase in the grain weight stopped more rapidly in Chosaeng Tongil which belongs to the improved indica variety than in Gohyakumangoku and Reimei which belong to the japonica variety. 4. White belly kernels occured more in the very early varieties and the improved indica varieties except SML 680 2/1 which is long slender kernel. At the heading stage, they had a much smaller leaf area per spikelet than the other japonica varieties. 5. In the japonica varieties, Gohyakumangoku Llnd Jinheung had a much bigger hull than the other japonica varieties (almost the same with IR-8, Chosaeng Tongil, SML 680 2/1, Namking 11, which belong to the improved indica variety.) and their grain weight were much larger than the improved indica varieties. But the percentage of the occurrence of white belly kernel was much lower in these than in the improved indica varieties. At the heading stage, they had 1.2 to 2.2 times larger leaf area per spikelet than the improved indica varieties. 6. A long slender kernel variety SML 680 2/1 produced 18.8% of white belly kernel, though the percentage was much smaller than that of the other indica varieties. 7. The opaque part of the white belly kernel was small in the very early varieties which had a small hull, and very large in the improved indica varieties which had a large hull.

Investigations were made on the effect of isoprothiolane (diisopropyl-1, 3-dithiolan-2-ylidene malonate, IPT) on the ripening of rice (Oryza sativa L.) under the low temperature conditions. The similar experiment was repeated 4 times in rice cultivation season every year from 1984 to 1987. Two varieties were used: Nipponbare and Koshihikari. Twenty seeds were directly sown in 1/5, 000a plastic pot (except for 1984.) and grown in a greenhouse. At 9, 12 days before heading or at the heading time, IPT 12% granule (FUJI-ONE(R)) at 200∼800 g/a was applied to rice plants in the pot under a flooded condition. The plants were tansferred to a growth chamber and kept under natural or atrficial day-light at 20/13°C (day/night)to cause cool! weather damage to them. Their panicles were collected at regular intervals. Grains were weighted on each rachis-branch. In 1985, both transpiration rate and color in the flag leaf were measured at 4 weeks after heading. The experimental results accumulated in four experiments in four years show that IPT had a promotive effect on grain weight, particularly the inferior grain weight until about 3 weeks after heading under the low temperature condition. After 6 weeks heading however, its effect decreased. IPT also increased the transpiration rate of the leaf blade at 4 weeks after heading.

This experiment was conducted to evaluate the effect of the amount of irrigation water on growth and grain yield of grain sorghum during drought stress period and to make efficient use of irrigation water under four treatments : 0, 1, 2 and 3 irrigations per week. Twenty millimeters of water was applied at each irrigation time. Irrigation water was applied from July 12 to Augllst 2, when grain sorghum was heading time through milk stage. Leaf water potentials measured by pressure chamber (Daiki Rika K.K.) were affected by the quantity of irrigation water and lowered by less amount of irrigation water. The recovery of leaf water potential by irrigation was 2 to 3 bars and the difference of leaf water potential between well irrigated treatment (3 irrigations per week) and others was enlarged when drought stress was accelerated. Two irrigation treatment never became lower than - 19 bars which is a critical point of grain sorghum when stomata close. Leaf diffusive resistance measured by porometer (Lambda Instruments Corp.) was high in no and one irrigation treatments. However, it was low in two and three irrigation treatments and no difference was recognized between them. Top growth of grain sorghum was slowered and stopped by drought stress and its recovery after drought was small. Stressed top growth was mainly due to slow development of grain head and decay of lower leaves. Grain yields decreased as the amount of irrigation water decreased, but no statistical difference was recognized between well irrigated and two irrigation treatments. Reduced grain yields were attributed to low 1, 000 grain weight. From the results of grain yield and difference between evapotranspirations and the amounts of irrigation water during drought stress period, drought damage will be reduced by irrigation of about 40 millimeters of water a week.

The differences in growth and grain yield of seven wheat varieties cultivated in soils belonging to four different groups were examined under the same fertilizer conditions during two growing seasons, 1982-84. Plant growth was most vigorous in the Gray Lowland Soils (GLS). In the Red Soils (RS) tillering stopped and the leaf color became pale in late January. In the Thick High-humic Andosols (THA) and the Light-colored Andosols (LCA), tillering and leaf emergence rates were lower than in the other soils from the start of the tillering stage. The young spike and culm elongation occurred earlier in RS and later in THA and LCA. Grain yield was 649 g/m2 in GLS and 440-500 g/m2 in the other soils. Lower yield in RS was due to the decline in the spike number and grain weight per spike, whereas in THA and LCA it was due to the decrease in the spike number. These differences in the growth and grain yield of wheat in each soil were mainly associated with the soil fertility and soil temperature patterns. The varieties with the greatest yield was differed with each soil. In the most fertile soil, GLS, the yield of Asakazekomugi was the highest, because of the higher percentage of productive tillers (ca. 50%), large spike number, and less lodging which reduced the loss of grain weight per spike. In THA and LCA, the yield of Norin 64 was the highest, because of the vigorous tillering activity and the larger spike number. In RS the yield difference among varieties was not significant.

The effects of nitrogen supply (1N, 2N) at heading on the pattern of accumulation of dry matter and nitrogen in the caryopses at different positions on panicle were investigated to clarify the positional differences of caryopsis growth. The photosynthetic activities and the nitrogen contents of leaf blades were also taken into account. Caryopsis position on panicle was selected as shown in Fig. 1. Results are summarized as follows; 1. The superior caryopsis (I) at the upper position on panicle, in the control, accumulated the dry matter and nitrogen rapidly and in a short duration at the first half of ripening period. On the other hand, the inferior caryopsis (VI) at lower position on panicle accumulated these materials slowly and over a long duration at the second half of ripening period. 2. Nitrogen supply at heading increased markedly the rate of accumulation of dry matter and nitrogen in all caryopses, but had little influences on the duration of the accumulation and on the time of the rapid accumulation in ripening period, as compared with the control. 3. Nitrogen content of all caryopses at maturity was clearly increased as the quantlty of nitrogcn supplied increased. Grain weight also increased but not so much as the nitrogen content. The ratios of increase of both grain weight and nitrogen content by the nitrogen supply were very remarkable in the inferior caryopsis (VI) which was ill-ripened ln the control. 4. The increase of grain weight and grain nitrogen content by the nitrogen supply at heading was caused by the rise of accumulating rate of these materials in caryopsis throughout the ripening period. 5. Nitrogen supply at heading maintained the photosynthetic activities and the nitrogen contents of leaf blades at relatively high level during ripening period. Nitrogen contents of leaf blades in each plot began to decrease abruptly at 10 days after heading and reached the lowest level at 25 days after heading relatively. 6. It was suggested that the occurrence of the early increased rate of accumulation of translocated substantes might be need for the improvement of ripening of inferior caryopsis and the factors controlling the accumulation rate of inferior caryopsis might involve not only the supplylng ability of source organs but also the function of inferior caryopsis for sink organ.

The experiment was performed to find out the effect of irregular disposition of drill-seeded rice plants upon yield in direct sowing culture. Row of 1 m length was divided into ten equal sections (10 cm row) and number of plants in them was varied. Co-efficient of variation (cv) of number of plants in 10 cm row was used as the index of irregular disposition and five plots of cv 0 %, 30 %, 60 %, 100 %, and 150 %, were established. 1. The more irregular disposition of plants was, the more decrease in grain weight (per unit area) was. It's degree was more remarkable in Fujiminori (early maturing and panicle type variety) than in Manryo (medium maturing and medium tiller type variety). 2. Decrease of grain weight was caused by that of number of panicles (per unit area). In Fujiminori, number of panicles decreased according as irregularity in disposition of plants increased. grain weight per panicle being remained unchanged. Therefore grain weight decreased in proportion to increase in irregularity of plant disposition. In Manryo, however, grain weight per panicle increased though number of panicles decreased. Accordingly decrease of grain weight compared with the plot of cv 0 % was not observed in plots of cv 30∼100 %. 3. In Fujiminori, decrease of grain weight with irregular disposition of plants was more marked in the case of low seeding density than in that of high one. In Manryo, however, the difference of the effect of irregular disposition on grain weight caused by different spacing densities was not clear.

Generally in indicas, compared with japonicas the carbohydrates concent in plant is less at heading time, number of spikelets per panicle is more, ripening period is short, therefore, competiton for absorbing carbohydrates among kernels on panicle is very severe and inferior kernels become sterile, abortive and opaque easily. By top dressiag in indicas carbohydrates content at heading stage decreases and number of spikelets per panicle, especially on secondry branches increases, then the competition among kernels becomes more severe causing the inferior kernels stop their growth and bdcome sterile, abortive and opaque kernels. More over grain weight of normal kernel is also decreased. In japonicas, carbohydrates content scarcely decreases and increase in number of flowers per panicle is small, which causes the ripening slightly deteriorate, and on the other hand the grain weight shows a slight increase. As a result in two varieties of japonica, grain yield per panicle is increased. Grain yield of Dular remains unchanged, where as, a slight decrease and rather decrease is obtained in case of Bluebonent and Te-Tep respectively. Karalath, which is thought a most unadaptable variety to heavy manuring decreases to 84%. Moreover, by heavy manuring, increase of panicles per plant is conslderable in japonicas, but it is small in indicas, so heavy manuring obviously causes increase of the yields in japo-nicas and scarcely increases rather decreases in indica varieties. In the light of these points it could be recommended that increase of yields can be obtained with the additional nitrogen fertilizer, when depending upon the nitrogen application the number of panicles per plant is increased and the flowers per panicle, particulary the flowers of secondary branches are kept almost constant. In varieties having such characteristics, the ripening does not deteriorate and high yields of good quality are expected. (Kinmaze and Towada) Besides this, with high nitrogen when panicle increases in size, branches in(:rease in number but the number of flowers on secondary branches does not increase or increase nominally the ripening is not severely worsened. This characteristic is also suitable for heavy manuring. This trend is observed in Bluebonnet.

Process of grain production of rice plant in Chugoku district was analized using the same data as shown in the preceding report. The results obtained were as follows: Close relation was observed between the ripening of grains (the yield per 1, 000 spikelet) and the number of spikelets per unit area, but it differed by locality, namely, the relation was negative in Okayama but positive in Tottori, and in Hiroshima the relation was positive when the number of spikelets per tsubo was less than 75 thousand and negative when much more than it, and in other localities clear relation was not seen. The yield per 1000 spikelet had close relation with the 1, 000 grain weight, and the 1, 000 grain weight had been influenced by air temperature in ripening stage, and these relations were marked in late varieties and also at San-in district. In general, sequential correlations were found to exist among the following factors which contribute toward the yield of rice grown in Chugoku district: grain yield ∝ number of spikelets ∝ number of panicles ∝ number of tillers ∝ number of secondary tillers.

It is generally accepted as impossible to produce seed of Chinese matgrass under the natural conditions in Japan where the temperatures in autumn are too low. Studies were made in order to find out the possibility of seed production of Chinese matgrass by speeding up its flowering date at high temperature in summer (evading cool climate in autumn), through due photoperiodic treatment by making the best use of the responses of Chinese matgrass to photoperiodism. Effects of photoperiodic treatment on the heading date, stem growth, seed setting, and viability of seed obtained were examined. The test results can be summarized as follows: (1) Long-day (24hours) treatment promoted stem elongation. In case where long-day treatment was started in June, the promoting effect was greatest, but no heading was found in the case of long-day treatment plot. (2) Short-day (8 hours) treatment inhibited stem elongation. The inhibiting effect was remarkable in case where short-day treatment started in June was continued lasting for long days. The earlier the short-day treatment was started, the more in the number of stems per hill. Short-day treatment hastened the heading date, but the later in the start of short-day treatment, the less in the number of days from the start of treatment to the flowering date, and the more in the number of spikelets on the stems. (3) It was, after all, clarified that the seeds produced from the spikelets bearing flowers during the period ranging from mid-July to late August and collected in late September had germinating ability. Particularly, excellent seeds were produced from the spikelets bearing flowers during the period from late July to early August. For producing such excellent seeds, the short-day treatment started in early July is deemed most effective. (4) Seeds of excellent quality were 1.4 to 2.2mm in length, 0.3 to 0.5mm in width, 0.2 to 0.3mm in thickness, and about 120 mg in 1, 000 grain weight.

The relationships between the growth habit of so-called summer vers. autumn soy beans (reported by T.Nagata in 1948) and other characteristics, which were investigated parallel, found as follows ; (1) The interrelation between the growth habit of summer vers. autumn soybeans and the earliness of flowering of the tested varieties was so closer that correlation coefficient showed as in r=0.85. Therefore, the summer type found as the earier, the autumn types the later, the intermediate types the medium late varieties. (2) 4 types were observed in the changes of flowering days (from germination to flowering) according to the differrent periods of seeding. These types were called as "the Ecological types of flowering". (fig 1) The autumn types belonged to the type I and type III, namely their flowering days were remarkably shortened when they were sown in both July and August. The type II and type IV, namely those not remarkably shortened even when they were sown in July and thereafter, were recognized mostly in the summer types. In the intermediate types, there were found all these 4 types existed. (3) It was found that the first flower was born at the heigher nodes in the autumn types and at the lower in summer typer. And the correlation coefficient calculated between these characteristics was r=+0.86. The changes in order according to the different seeding times was found as same as in that of flowering days. (4) The closer relationships between the growth habit of summer vers. autumn types and the stem length, number of blanches, grain weight per plant, and the weight of a plant were observed. Therefore, the autumn types produced comparatively more yields than the summer types. The pseudo summer types (SIp) was long as in stem length, but it had a small number of branches. (5) There was found no closer relationships between the growth habit of summer vers. autumn soy beans and the morphological characteristics, namely the forms and colour in various parts of the plant. Therefore, differences. in summer vers. autumn types were defined purely as physiological and ecological.

1. The author calculated the main yielding factor of soy bean at all prefectural agricultural experiment stations Japan, the total sum of variety investigated by him amounts to 4500. But he argues here onlyon the main yielding factor. 2. The stem length is min. 20, max. 140, mean 65, σ 21 cm. 3. The per tan yield is min. 0.0, max. 3.0, mean 1.17, σ 0.556 koku. 4. The author made the calorie calculation to compare yielding efficiencies of soy bean and paddy rice and sweet potato each other, and the results are as follows: soy bean 680000±310000 Cal., paddy rice 1570000±320000 Cal. and sweet potato 2920000±10400O Cal. 5. But the soy bean must be considered as protein resource, and the comparison of per tan protein yields are as follows : soy bean 57±27 kg. paddy rice 47±10 kg. and sweet potato 26±9kg. 6. The author also argued about the test weight and a hundred grain weight of soy bean.

To determine the method for discriminating the stage of yield forecast, the author examined what character of rice may be utilized as an index of the discrimination. The obtained results are as follows. 1) Close relation between the rate of moisture content of ear and grain weight on the ripening stage was found, irrespective of places, years and varieties. Therefore, the ripening process of ear can be discriminated by the former. 2) Furthermore, close relation was found between the rate of moisture content of ear and percentage of milky grains. Therefore, the former can be discriminated by the latter. It was found high correlation between grain yield and fresh weight of ear at the stage when percentage of milky grains bigins to decrease. Frome these results, the stage when percentage of milky grains became 10±3%, seems to be a suitable stag for forecasting yield.

In order to know whether application of red colored hill soil to rice fields has good effects not only in the case of ordinary transplanting but in the case of early transplanting culture, and moreover to find the optimum quantity of nitrogenous fertilizers in the latter case, some experiments were carried out by the authors, the results obtained being as follows: [I] Effects of red colored hill soil put in, (a) A larger number of ears was obtained. (b) Good harvests were obtained. (c) The elongation of lower internodes were controlled. (d) Total nitrogen content in the plant decreased. (e) In consequence of the results (c) and (d), the plant became lodging resistant. The tendency above rnentioned was distinctly noticed especially in early transplanting. [II] Effects on early transplanted rice crop, (a) Decrease in a thousand grain weight of rice often liable to application of abundant nitrogenous fertilizers was checked by hill soil duplication. (b) A larger number of ears was obtained. [III] Effects on three kinds of ill-drained paddy fields which consist of mack, sandy soil and heavy clay, respectively, showed a similar tendency as above mentioned in all cases. From those facts there were elucidated good effects of red colored hill soil put in early transplanted rice fields under ill-drained condition. Crop damages frequently caused by heavy fertilizing may be thus controlled to some extent.

In the previous experiment, it was shown that the late transplanting resulted in the remarkable decrease of yields.. with the aim to analyze the reduction of yield caused by the late transplanting, we have compared the growth and yield of rice crop under two different treatment; one sown densely (18 × 18cm) and other sown sparsely (24.2 × 24.2cm) on the seed bed, both transplanted later than usual. The seedlings in sparsely sown plot produced their tillers regularly; they have more than thirty tillers already at the time of transplanting, and howed high yield. But in the other plot the tillering is inhibited; no one tiller at the time of transplanting, and showed low yield, about half of that in the usual cultme. After the seedling were transplanted, the tillering has continued to some extent in former plot, but the many new tillers appeared at the higher nodes of the stem in letter plot. The high yield obtained in the sparsely sown plot may be explained by the following five reasons: (1) Seedlings were grown for longer time under favourable condition because the seed bed was more fertile than the paddy field and also it was rsurrounded by shelter-hedge. (2) As rice plants had good enough space to grow until the time of transplanting (5thof July) they could produce many healthy tillers from the lower nodes of their stem; 30 or more tillers were growing at the time of transplanting. (3) consequently the larger number of tillers and ears were produced. (4) As tillers from the lower part of the stem appeared early, the date of heading was also early, resulting heavy grain weight. (5) As far as the result of this experiment was concerned, the rice crop sown sparsely seemed to be able to produce higher yield, even when it transplanted later than usual culture method. But this trend might not be always observed because the different result would be obtained under different weather. The low yield of densely sown plot may be explained by the following fact; (1) tillering was inhibited seriously because of the narrow space given, and after they were transplanted. Appeared the tillers from the upper part of the stem as well as the tillers of higher order. (2) The number of tillers and stems were fewer than those of other plots.(3) As the tillering was delayed, date of heading was also delayed, and the light grains were produced.

Two groups of samples were used as materials. One of the groups consisted of the crops of variety Norin No.1 from eight prefectures, each representing the soft-rice-producing region in Japan, and the other group consisted of the crops of the same variety from eight prefectures representing the hard-rice-producing regions. The water-content was measured by means of the KETT infra-red ray water-content meter of the Sanwa Electric Institute (calibrated with Mr.NAGAHARA's desiccation-method at 135°C), the specific gravity by means of the REISHAUER's pycnometer, and the hardness by means of the hardness meter of the Kiya type. The results obtained are as follows : (1) The water content of soft rice was about 1% higher than that of hard rice. (2) The 1000 grain weight of soft rice was about 1.7 g. higher. (3) The specific gravity of soft rice was a little (0.01) higher. (4) The fracture hardness was 1.0 kg. lower and the breaking hardness, 0.8 kg. lower. (5) The comparison of its correlation coefficients with those of hard rice showed no significance. Then, the water-content was changed between 10 % and 20 % at an interval of 2 %, and the other properties above mentioned corresponding to each level of the water-content were measured. As the results : (6) The 1000 grain weight of soft rice was invariably about 2g. heavier than that of hard rice. (7) The specific gravity of the former was invariably about 0.02 higher. (8) In the hardness of fracture and breaking, there was no difference between the two kinds of rice, either of the properties depending on water-content. (9) The correlation coefficients were found to exsist significantly only (a) between the water-content and the 1000 grain weight ; (b) between the water-content and the fracture hardness ; and (c) between the 1000 grain weight and the fracture hardness. Soft rice was more or less lower than hard rice, in (a) and there was much difference in (b) and (c) between the two sorts of rice. Nearly all the researches on rice quality in the past have left the physical properties of soft and hard rice and their differences dark. But the present research has clarified that at least the 1000 grain weight and the specific gravity of soft rice, whether in a natural state or at a level of water artificially controlled, are higher than those of hard rice. The present author believes that it can be ascribed to the quantitative difference in solid materials, that is, largely in starch, and also in protein, between soft rice and hard rice.

1.In the previous experiment, it was shown that the late transplanting of rice results in a remarkable decrease of yields, particularly when the seeds are sown densely in the nursery, and thinner seeding seems to be able to raise seedlings to produce higher yield, even when they are transplanted later than usual. 2. With the aim to analyze the low yields caused by late transplanting, wa have compared the growth and yield of rice plarnts sown at four different densities in the nursery ; i. e. 541cc, 180cc, 45cc and 18cc of seeds were sown respectively per 3.3m2. Seedlings thus obtained were transplanted under the same density ; 90 hills per 3.3m2 (24.2cm×15.2cm) of paddy field. 3. Yields of the plants transplanted 30 days later when compared with the control are as follows : (i) Plot sown at the density of 541cc per 3.3m2 gives only three quarters of the yield of the control culture. (ii) Sparsely sown plot (180cc, 54cc and 18cc plot) showed nearly the same or even larger yields than that of the control. 4. The high yields obtained in the sparsely sown plots may be explained as follows : (i) As the seedlings had good enough space to grow in the nursery, they could produce many healthy tillers on the lower nodes by the time of transplanting (July 5).(ii) Consequently the larger number of tillers and ears were obtained from lower nodes.(iii) As tillers from the lower node start early in growth, and their heading take place also early, In such a case even the tillers produced from upper nodes on late transplanting, ded not so much delay in heading (iv) The reduction in grain weight, grain numbers per ear, and fertility were compensated by the increased number of stems. 5. The low yield of the 541cc plot may be explained as follows : (i) Many of the main stems died prematurely. (ii) Tillers have appeared from the upper nodes. (iii) As tillering delayed, heading also became late, fertility, decreased and reduced weight of grains resulted. (iv) Although the number of stems or ears were equal to that of usual culture it, could not overcome the seriously decreased weight of each ears, in this case.

The results of experiments carried out from 1950 to 1958 are reported here conclusively. Lowering of rice yield caused by the delayed transplanting, especially when seeding was made very densely on seed-bed, can be explained as follows: 1) Seedlings are grown to too old, 2) shifting of tillering nodes to upwards, and 3) consequently delaying of tillering and heading takes place. Therefore if the sowing is made lately, or sparsely at the normal sowing date on the nursery-bed, and transplanted lately, the yield can be almost as much as those of the standard culture, because these lately transplanted rice plants can carry on rapid growth and heading does not delayed due to the following reasons; 1) As rice plants have good enough space to grow until the time of transplanting, they can produce many healthy tillers from the lower nodes of their stem. 2) Consequently the larger number of tillers and ears are produced. 3) As tillers from the lower part of the stem appears early, the date of heading is also early and which results in heavy grain weight. After late transplanting, the progress of accumulation and translocation of starch, sugars, total carbohydrates or nitrogen compounds in the plants sown lately or sparsely at the normal date of the plots were found practically not different with standard culture plot.

The author measured the weight of each rice grain divided into the two classes : the normal and the inferior, by the texture of grain, harvested from 155 experimental paddy fields distributed in Iwate Prefecture, in 1950, and made a ferquency distribution table (Table 3). Confliction came from the fact that the normal grains contain those which are lighter than the mean weight of the inferiors, and on the other hand, the inferiors contain those which are heavier than the mean weight of the normals, the frequency distributions of both being of wide ranges from 6 mg. to 24 mg. classes. The lower limit of grain weight of the upper 95% range in the normals was 16 mg. and the upper limit of the lower 95% range in the inferiors was 18 mg. About 16 mg. may be established as a limit weight between the normal and inferior rice grains.

(1) The author examined the flowering order of the sesame, dividing the flowers, by there position, in two sorts of the chief flowers and the side flowers. (2) The difference in the days of flower opening between node to node was on average about one day in the chief flowers, advancing from the bottom to the upper part almost straightly. (3) Many aborted were found in the chief flower groups at the bottom of stem, while in the side flowers they located at various positions. (4) The percentage of fruit-setting was rather low at the lower flowers, highest at the middle and suddenly decreased at higher part. (5) The side flowers were observed less than the chief flowers both in the percentages of flower-setting as well as of fruit-setting. (6) The length of pods was short at the bottom, increasing toward the middle part, but gradually lessened from the middle to the high, showing a sudden decrease at the top, while in thickness and breadth they were smaller at the low to the middle parts and then gradually decreased upwards. (7) The grains in a pod were rather few in number at the low part, largest at the middle and a few at the high part. (8) The dried grain weight was heavy at the low part, while lather light at the middle, and the lightest at the high part.