As barnyardgrass (Echinochloa Crus-galli BEAUV. var. caudata KITAGAWA) is essentially a wild grass, it is presupposed that the grass will easily escape to be a weed on the following rotated paddy field. To control the weed, two experiments in pot and field were carried out. The results obtained were as follows: 1. Although barnyardgrass cultivated on rotated upland field was cut with short interval to prevent the heading, it produced small ears in autumn on the regrowth tillers with only three to four leaves after cutting. So the short interval cutting gave no effect on decreasing the amount of seeds left on the field. 2. The sprouting of barnyardgrass seeds was significantly affected by the method of rice culture. Especially, the transplanting culture after puddling was effective to prevent markedly the sprouting of seeds as compared with the direct seeding culture on upland condition. Late planting was useful to control the weed in comparison with early planting. Both deep tilling and plowing up in land preparation had also significant effects on weed control in comparison with shallow tilling and rotary tilling, respectively. By combining all these effective factors, only 0.1% of all barnyardgrass seeds sprouted from soil without the application of herbicides. 3. In ordinary season transplanting rice culture, barnyardgrass sprouted without any harmful influence on rice plants in the case when herbicides were applied. 4. Barnyardgrass was difficult to control in direct seeding culture of paddy rice on upland condition. Consequently, it is necessary to harvest barnyardgrass before its seed maturation and to till the grassland in the previous autumn.

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In order to contribute to the establishment of the stable highyielding cultivation of barnyardgrass (Echinochloa Crus-galli BEAUV. var. caudata KITAGAWA) as a forage crop, an experiment was conducted to know the relation between the growth state at cutting time and the regrowth after cutting. The results were summarized as follows: 1) The weight of dry matter on the process of regrowth increased following "S shape growth curve". The rate of dry matter production in the initial stage of regrowth was slower than that before defoliation. The bigger the state of growth at cutting time, the larger was the decreasing tendency of that rate. 2) Dry weight and total available carbohydrate content of the stubble did not correlate with "regrowth indexes", such as the ratio of regrowth tillers in whole defoliated tillers, plant height, tiller number and dry matter production in the initial stage of regrowth. But a close positive correlation was found between the total nitrogen percent of the stubble and those indexes. 3) In this experiment, barnyardgrass grew to about 140cm in height and to about 80kg/a of dry matter yield without lodging, and continued to regrow without wilting after defoliation. Since the regrowth with the low ratio of regrowth tillers was consisted of new tillering after defoliation, that caused to delay the regrowth. The regrowth after cutting used to be delayed in the case of the over-growth (i.e., higher than 70cm in height or heavier than 30kg/a in the dry matter yield). 4) In order to raise the high yield during a season, it was discussed in this paper that the cutting interval and time should be decided in a consideration to rise "average productivity" dry matter yield regrowth/duration) during whole growing season, avoiding to delay the regrowth as less as possible.

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Several mixture sowing treatment of two forage crops were made by using barnyard millet, African millet, Rhodesgrass and coloured guinea grass. The results are summarized as follows ; 1. Yields of monoculture were higher in the following order ; African millet, Rhodes-grass, barnyard millet and coloured guinea grass. 2. Yields of mixed culture were intermediate between yields of each component species under mono culture. 3. Each forage crop showed its own seasonal growth pattern. However, the seasonal growth fluctuations were made even when they were mixed. 4. In this experiment, the main factors leading to the competition between two species were considered to be in the early growth, the hight of grass and the regrowth.

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Propagated plants of a clone from orchardgrass, var. Frode, were grown at 10°, 17°, 24°, or 30℃ in growth cabinets for 10 days before cutting under the natural daylength in January-February. After cutting at 5cm height, the plants grown under each of these temperature condition were devided into four groups and were grown at 10°, 17°, 24°, or 30℃, respectively. They were harvested 5, 12, and 25 days after cutting. The results are summarized as follows. 1. The temperature during 10 days before cutting influenced the growths of the grasses. When the plants were grown under higher temperature condition, the plant height and the leaf area were increased and the number of tillers was decreased. The dry weight and the carbohydrate content of the stubble increased with fall of the temperature. 2. After cutting, more accelerated regrowth was observed in dry weight and in leaf area when the plants were grown under lower temperature condition before cutting. This trend was remarkable when the temperature after cutting was high. The dry weight and the carbohydrate content of the basal part of the top of the plants grown under low temperature condition before cutting were large at each harvest time. This trend was more pronounced when the temperature after cutting was lowered. 3. When the plants were grown under higher temperature condition after cutting, more accelerated regrowth was observed in dry weight and in leaf area. This trend was more pronounced when the plants were grown under lower temperature condition before cutting. The dry weight and the carbohydrate content of the basal part of the top of the plants grown under low temperature condition before cutting increased with fall of the temperature after cutting.

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In this experiment, the relation between basal coverage and the yield were studied on orchardgrass swards in 1970. Swards were treated with 3 levels of fertilizer application (N.P.K. 1kg/a/year, 2kg/a/year and 4kg/a/year). Each sward were divided into 4 plots which treated with different degrees of basal coverage in early spring of the year, namely 25, 35, 50, 65% of basal coverage in plots of 4kg/a fertilization and 35, 50, 65, 75% of basal coverage in plots of 1kg and 2kg/a fertilization. The results were summarized as follows ; 1) In the sward of low level of fertilizer application, orchardgrass swards continued as same degrees of basal coverage as treated in early spring through the year even though in the plot of high basal coverage. But in the plots of heavy fertilizer application, it was difficult to keep up the high basal coverage and decreased gradually with the cutting were repeated (Fig.1). 2) In the plots of low level of fertilizer application, linear correlation were obtained between basal coverage and fresh yields in each cutting, high yield were obtained in plots of high basal coverage. But in the swards of heavy fertilizer application, the maximum yield was not always obtained with high basal coverage but with middle degree of basal coverage, namely there was the optimum basal coverage for maximum yield (Fig.3). 3) The optimum basal coverage for maximum yield was 35-46% in the sward of 4kg/a fertilization, and 45-56% for 2kg/a fertilization. The optimum coverage was seemed to decrease according with the increase of fertilizer application level. 4) The reason and the mechanism of these results as above mentioned were discussed with the relation between basal coverage and number of stubbles in unit area, basal coverage-stubble size relation and the relation between yield and number of stubbles (Fig.5 and 6).

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The tropical grasses can hardly continue to survive throughout the winter season in northern area of Japan. In southwestern area, however, a few species of the tropical grasses have been introduced and improved because of the useful characteristics and the perennial behaviour. Recently various species of tropical grasses, such as a number of species of panic grass, have been introduced from tropical areas to reduce the seasonal fluctuation of pasture production. However, their winter survival or cold resistance has been little studied. It is essential for the more effective use and the improvement of the tropical grasses to know the specific and varietal differences of the capability of winter survival and cold resistance. This study was undertaken to establish the convenient procedures of testing the winter survival and cold resistance of the introduced tropical grasses and to evaluate the specific and varietal differences of the grasses. The results were as follows: 1) During the winter season at average temperature of 5℃, adult plants of panic grasses were transplanted from the field to the 1/5, 000 are Wagner's pots in the green house and observed their sprout. The sprout declined gradually with the duration remaining in the field. All the varieties which showed vigorous shoot growth in the sprout testing were able to survive in the field and sprout in April. 2) The sprout of the plants transplanted frow the field to the green house proportionally increased as increasing the response to triphenyl tetrazolium chloride (TTC) in the tissues of stem bases. 3) The specific and varietal differences in the resistance of the seedlings to the chilling damage at 5℃ apparently corresponded with the capability of the winter survival of the plants in the field. 4) The appearance of the chilling damage on the seedling was modified by the leaf stage, the duration of exposure to chilling temperature and the growing temperature prior to the chilling treatment. 5) From assessment of the above testing, all the evaluated varieties of switch grass and giant panic grass, and klein grass introduced from U.S.A.-all showed the same capability of winter survival and cold resistance as dallis grass and bahia grass which could survive throughout the winter season in Nasu, Tochigi Pref.. A few varieties of coloured Guinea grass, such as N-780 and Singapore strain, exhibited comparatively high winter survival, whereas these grasses could hardly survive throughout the season. Morocco, Bambatsi and Karahari strain of coloured Guinea grass continued to survive only 2 months under the field condition in this experiment. All the other species, such as Makarikari grass, Kablabla grass and Guinea grass, hardly survived.

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It has been found that a number of temperate forage crops require light on their seed germination. The germination of light-sensitive seeds has been shown to be controlled by reversible phytochrome reaction, in which the photoconversion of the pigment are independent of temperature. However, the germination of such seeds is also apparently dependent on temperature. It is therefore assumed that the mechanism of light-sensitive seed germination is made up of both photoreaction and thermoreaction. The present experiment was carried out to evaluate the interaction of light and temperature eflects on germination of the seeds stored at 10℃ and room temperature of Rumex obtusifolius L. which has been regarded as being temperate herbaceous plant with a typical light-sensitive seed. The results obtained were as follows ; 1) The seeds of Rumex obtusifolius L. could not germinate under continuous dark condition at any constant temperature. 2) Immediately after harvest of mature seeds, the light-dependent germination occurred within a limited temperature range, that is 18℃-20℃. But, with the lapse of the period of dry seed storage at room temperature, the range of germination temperature gradually widened above 20℃. 3) The temperature range permissible for light-dependent germination was increasingly widened by the dry storage at room temperature, but scarecely by the storage at 10℃. The light requirement for germination, however, was not influenced by the dry storage at any temperature. 4) Difference in widening of the temperature range was shown among three seed lots which were collected from different habitats. 5) The time course pattern of the germination under continuous light condition at about 20℃ was invariable during the dry storage of seeds at both 10℃ and room temperature. On the contrary, the time course of the germination at the temperature range higher than 20℃ was hastened corresponding with widening of the temperature range permissible for light-dependent germination as shown in Figure 2.

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Previously, we reported that the seeds of Rumex obtusifolius L. gradually became able to germinate under continuous light condition at increasingly higher temperatures above 18-20℃ during the after ripening following harvest of the mature seeds. However, little information has been obtained about the above-mentioned change in germination capacity during the seed development, except that the viability of the seeds was acquired about tenth day from flowering. The present investigation was undertaken to make clear the changes in dry weight, % moisture content and others during seed development of Rumex obtusifolius L., and to evaluate the effect of stage of development at harvesting on the germination capacity under light condition at various temperatures. The results obtained were as follows ; 1) No germination occurred under continuous dark condition regardless of temperature in any stage of seed development at harvesting. 2) In the development of the seeds, three developmental phases could be recognized as follows ; The first phase lasted for about 15 days after flowering. During this period, dry weight increased rapidly, reaching 50% of the weight of the mature seed at the end of the phase, and moisture content remained constant in the range above 70%. The seeds harvested during this stage were not viable. The second phase lasted for 15 to 30 days. During this period, dry weight continued to increase, reaching a maximum at the end of the phase, when moisture content was yet above 50%. The seeds harvested 15 days after flowering gave 10% germination under the light condition at 18℃ and 23℃, and the germination percentage at both temperatures rapidly increased with the seed development, and then full germination capacity was reached by the thirtieth day. The third phase lasted for 30 to 40 days. During this period, a drop in % germination at 23℃ occurred, indicating the narrowing of the temperature range permissible for light-dependent germination. While dry weight remained approximately constant, moisture content fell rapidly from about 50% to equilibrium (10-15%), so that the color in the perianth changed from green to brown. 3) Difference in the time of flowering among the panicles in the same plant was observed. The dry weight of the seeds in the late-flowering panicle compared with the early-flowering one rapidly increased during the seed development. In the same manner, moisture content of the seeds in the late-flowering panicle began to fall at earlier time than that of the seeds in the early-flowering one. The acquirement of seed viability and the narrowing of the temperature range for germination of the seeds in early-flowering panicle largely delayed in comparison with the late-flowering one. 4) Difference in dry weight, % moisture content and germination capacity changes during development among the seeds in different branches within the same principle was scarcely observed, though the time of flowering varied among the branches within the same principle.

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Previously, we reported that the temperature range for light-dependent germination of Rumex obtusifolius L. seeds was affected by the stage of seed development at harvesting. Especially, in later stage of the seed development in which the moisture content fell rapidly, the narrowing of the temperature range for germination occurred, indicating the establishment of seed dormancy. The present experiment was undertaken to make clear the changes in the germination capacity and the moisture content during air drying period immediately after harvesting at various stages of development and after-ripening of the seeds. The results obtained were as follows; 1) The seeds harvested on the 30th day from flowering were estimated to be at the beginning of the third phase of seed development as shown in the second report of this series. Immediately after harvesting, the moisture content of the seed was 60.7% and the germination occurred under continuous light condition at both 20℃ and 25℃. When the seeds were dried in air at room temperature after harvesting, however, the germination rapidly decreased only at 25℃ as the moisture content decreased. On the contrary, the time course of the germination at 20℃ was hastened corresponding with the length of air drying period. No germination under continuous dark condition regardless of temperature occurred at any stage of air drying period after harvesting. 2) The seeds harvested on the 21st day from flowering were estimated to be at the second phase of the seed development. The seeds showed a high germination percentage at both 20℃ and 25℃ under light condition immediately after harvest. During air drying period following the harvest, the germination at 25℃ under light condition hardly decreased in spite of the decrease of the moisture content. 3) Many of the seeds were hardly detached from the plant after maturing in field condition. The light-dependent germination of the seeds attaching to the plant occurred within a limited temperature range, that was 18℃-23℃, for about one month after maturing. But, with the lapse of the period of after-ripening in field condition, the range of the germination temperature gradually widened above 23℃. 4) Early in the after-ripening, the time course of the germination at 18℃ was hastened and a constant pattern was established. 5) Changes in the germination capacity and the moisture content of the seeds harvested at any stage of after-ripening were scarcely observed during air drying period following the harvest.

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It is well known that synthetic estrogens, such as diethylstilbestrol (DES), have a growth promoting effect for ruminants and a growth depressing effect for mice or rats. The data presented in the previous papers have demonstrated that the growth of intact male and spayed female hamsters were accelerated by oral administration of estrogenic substances in herbage, i.e., genistin and coumestrol, as well as DES. And also, it has been estimated that sex difference of growth rate in the hamster is mainly caused by sex hormones which regulate secretory rates of corticosteroids from adrenals gland and growth hormone from pituitary gland. The present investigations were conducted to see if the estrogenic substances in herbage could be effective for increment of growth hormone and prolactin of the golden hamster (Mesocricetus auratus). The hamsters used for this study were obtained from an inbred colony maintained in our laboratory and were fed ad lib. a pellet diet containing 20 percent crude protein. Six successive experiments were carried out to study the effects of DES and estrogenic substances in herbage on pituitary hormones of young intact male and spayed female hamsters. Analysis of growth hormone and prolactin in the pituitary gland were carried out by a disk-electrophoretic method. In the case of intact male hamsters, DES had a depressing effect on the adrenals weight, whereas genistin and coumestrol had no effect on it. The weight of anterior pituitary and contents of growth hormone and prolactin in the pituitary gland were increased by administrations of DES, genistin and coumestrol. In the case of spayed female hamsters, administrations of DES, genistin and coumestrol increased both contents of growth hormone and prolactin in the pituitary gland, however, these substances did not affect on the weights of adrenals and antrior lobe of pituitary. From this series of experiments, then, it may be concluded that the growth promoting function of DES, genistin and coumestrol for young intact male and spayed female hamsters can be attributable to their increasing effect on the growth hormone in the pituitary gland.

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