Timothy is one of the important grasses cultivated in Hokkaido, northern island of Japan. This crop was first introduced into Hokkaido from the United States in 1870's. Afterthere, many ecotypes well adapted to their climatic conditions in Hokkaido have been derived from those introduced materials. A series of experiment were carried out to investigate for the inter-populational variations for the various characters in timothy in relation to ecological conditions at their habitats. In this report, a few characteristics of germination at different temperatures are presented. The seeds collected from twenty locations in Hokkaido and of three cultivars were used for germination tests. Five constant temperatures from 10℃ to 30℃ were used to determine the germination responses of the natural populations and the cultivars. Germination tests had two replicates, and 50 seeds per petridish were placed on filter paper moistened with deionized water. Germination counts were taken daily during 10 days. Germination characteristics were described with FGP, GD and GU. FGP, GD and GU stand for final germination percentage, mean days to germination and germination uniformity, respectively. The results obtained are summarized as follows: 1) The characteristics of germination at five temperatures were closely correlated with each other except for GU at 10℃. FGP was negatively correlated with both GD and GU, and GD was positively correlated with GU (Table 2). 2) Principal component analysis was applied on the data of three germination characteristics under five different temperatures. The scores on the first principal component devided the 20 natural populations into two groups (Figure 2). The first group consisted of four populations collected in the west side to Hidaka mountains, and the second group consisted of sixteen populations done in the eastern district of Hokkaido (Figure 1). 3) For the first group, germinability was maximum at 20℃ and low at 10℃ and 30℃. Compared with the first group, the second group showed the higher FGP and the faster and more synchronous germination (Figure 3). 4) A multiple regression analysis was applied to find to what extent climatic conditions were associated with inter-populational differentiation in germination characteristics. It was shown that most of the variation observed among natural populations was explained by monthly mean temperature and monthly precipitation during winter season (Table 5). 5) The cultivars germinated quickly and synchronously, and had similar characteristics to the second group of the natural populations.

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Winter hardiness in seedling of 24 cocksfoot varieties from contrasting climatic regions were compard in the field of the Hokkaido National Agricultural Experiment Station at Sapporo. Also, an attempt made to obtain "Winter Hardiness Index" based on plant survival together with seeding vigour, number of panicles and heading rate. Winter hardiness of the varieties developed at Sapporo were quite similar to the varieties from north Europe, Canade where winter temperatures are lower than Sapporo. Excluding these northern varieties, winter hardiness was highly correlated with the mean January temperature in the place of origin. Accordingly, it was concluded that field test is a valuable mean for evaluating potential winter hardiness of plants from warmer climatic regions than the experimental site but not for the plants from colder regions.

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The object of the experiment was to develop or to adapt practical laboratory techniques for testing cold tolerance in cocksfoot varieties. This experiment was done at Sapporo, Hokkaido, with the modified freezing methods developed by LORENZETTI et al. (1971), using 24 varieties from various climatic regions. plant survival was compared under three levels of temperatures ; -14, -12 and -10℃, at a set duration of 16 hours. Results: None of plants survived after -14℃ freezing. About half of plants of Scandinavian and Canadian varieties, contrasting to less than 30% of plants of Japanese varieties survived with -12℃ treatment. With -10℃ freezing treatment percentage plant survival changed greatly among varieties from Hokkaido showing values between about 30 and 50%. Hence, in selecting for hardier plants suited for severe climatic regions -12℃ freezing should be recomeded. Also, -10℃ freezing could be suitable for detecting varietal differences in cold tolerance and for eliminating tender plants. Using the techniques above-mentioned with -10℃ freezing temperature, attempts were made to detect variation in cold tolerance among varieties from different regions. Coinciding with winter temperatures of original places, the varieties from Finland, Norway and Canada showed significantly greater plant survial than the others including Japanese varieties.

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In 19 ecotypes of tall fescue mainly originated from European countries and two cultivars, Hokuryo and Kentucky 31, heading behavior and some agronomic characters at heading time were investigated, and the relationship between these characters and adaptation of ecotypes in the place of origin was analyzed. Populations from Tunisia and France emerged heads frequently in the year of sowing. Particularly, those from Tunisia continued to emerge even in the condition of short days in fall, but showed low winter hardiness and were injured by severe winter damage. Based on data concerning nine characters, principal component analysis was applied. In scatter diagram of first and second component, populations examined were classified into six groups. First factor obtained by principal component analysis seemed to show plant type associated with earliness and seed size, and second one seasonal growth pattern. Concerning the first component, a kind of clinal pattern was found. Populations from France had shorter culm, heavier tiller, earlier and larger seeds. As latitude and altitude are higher, populations had longer culm, heavier tiller, later and smaller seeds. As a result, populations located higher than 1000m in European-Alpes had the longest culm, the heaviest tiller, the latest in earliness and the smallest seeds among populations examined. Populations originated from high altitude in Switzerland and Italy were more productive in 1st crop but less in aftermath. On the other hand, populations from France, although less productive in 1st crop, had a tendency to grow uniformly throughout the year.

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In order to assess the use of plant growth retardants for seed production of Italian ryegrass, four chemicals including chlormequat (CCC), daminozide (SADH), ancymidol and dikegulac, were applied at two growth stages (early, stage 5 of the Feekes-Large scale for cereals and late, stage 6-7) with low and high levels. Significant growth reduction of plant height was shown by dikegulac only. Number of ears was increased by the early applications of CCC and remarkably by the high levels of dikegulac. Higher seed weight and seed number per ear were produced by the early applications of CCC and by all the treatments of ancymidol, especially by the latter. But the high levels of dikegulac reduced remarkably both characters. Number of spikelets per ear and weight of 1000 seeds were reduced considerably by the early and the late applications of dikegulac, respectively. The effect of growth retardants on the number of seeds per spikelet was almost the same as the number of seeds per ear. Growth retardants affected the seed yield through the effects on the seed yield components as described above. Thus, the seed yield was increased by the early applications of CCC and ancymidol and was decreased greatly by all the treatments of dikegulac. The marked effect of SADH was not recognized on the seed yield and seed yield components. Judging from this experiment, CCC and ancymidol could be expected to promote seed yield, but further research would be required for practical use.

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The effect of defoliation on the seed crops of Italian ryegrass, Waseaoba and Waseyutaka as early varieties and Yamaaoba and Nasuhikari as late varieties was investigated by cuttings on 8 December, 1 March (just over the wintering) 19 March (before the beginning of the stem elongation) and 9 April (after the beginning of the stem elongation). Varietal differences were recognized in the response of seed yield and yield components to the defoliations, indicating the more sensitivity in early varieties than in late ones. December cutting was likely to increase the seed yields in early varieties due to the increase in the number of ears, and early March cutting did not decrease the seed yield in spite of the decrease in the seed weight per ear but due to the marked increase in the number of ears. But cutting after this time depressed the seed yield of early varieties. The reduction of the seed yield was remarkable in cutting on 19 March more than on 9 April which produced higher number of ears deprssing the apical dominance. The seed yield of a late cultivar, Yamaaoba, at all cuttings was decreased but in another late cultivar, Nasuhikari little offect of defoliation was given on seed yield and yield components, thus it was recognized to be qualified for the dual purposes of seed and forage production. April cutting of all the cultivars delayed markedly heading and flowering time and also occurrence of lodging.

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A field experiment was conducted in Miyagi, Japan, to clarify the influence of seeding time and the effect of magnesia lime fertilizer application on the performance of orchardgrassalfalfa mixture. Broadcasting method and alternate row seeding (5cm width with 20cm interrow space) method were combined with seeding times of mid-August and early September. Magnesia lime fertilizer application were 30kg per are and none. These plots were replicated two times. The results are as follows. In the broadcasting plots, interaction of the seeding time and the magnesia lime fertilization was recognized and the yield component of alfalfa was higher in the magnesia lime fertilization plots of mid-August seeding. However, in the alternate row seeding plots, the effects of seeding time and magnesia lime fertilization were not-significant since severe individual competition resulted small and weak hills of alfalfa. Therefore, it was concluded that the broadcasting was more suitable than alternate row seeding for successful stand establishment and maintenance of higher yield of alfalfa in the orchardgrass-alfalfa mixture. Furthemore, application of more than 30kg per are of magnesia lime at the seeding time of mid-August a little earlier than the optimum seeding time of orchardgrass, is favorable in the mountain districts of Tohoku.

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In this study, the authors, in order to make clear the population structure of kudzu vines, examined the stem length proportion of the overwintering stems by the number of vascular bundle rings and the numeric proportion of rooted nodes to non-rooted nodes in these stems, and obtained the following results: The total length of whole overwintering stems in a 200m^2 plot of the natural population of kudzu vines was 149, 542.5cm, and these overwintering stems consisted of one-ring to seven-ring stems (One-ring and seven-ring indicate the numbers of vascular bundle rings in the stems). The stem-length proportions of one-ring to seven-ring stems were 48.33, 37.03, 11.72, 2.14, 0.69, 0.03 and 0.06%, respectively. The stem lengths per 1m^2 were 361.4, 276.9, 87.7, 16.0, 5.2, 0.2 and 0.4cm following the order of the one-to seven-ring stems (Table 1). The smaller stem-length proportion of stems with more than four rings would be attributed to the deaths of these stems caused by physiological deterioration, injury due to the larvae of insects such as Endoclyta sp., and diseases due to Synchytrium minutima, Fusarium sp., and so on. The numeric proportion of the rooted node was a minimum of 7.12% in the one-ring stem. This proportion increased to a maximum of 54.82% in the four-ring stem with an increasing number of rings in the stem (Table 2). These results would indicate that elder stems have more of a chance to come in contact with the soil surface and to produce the nodal root. The rooted nodes have a root system of R-I or R-II in the one-ring, R-I to R-III in the two-ring and R-I to R-IV in the three to the five-ring stems (R-I, R-II, indicate the ranks of the root systems based on the number of vascular bundle rings at the base of the root. For detailed explanation, see previous paper II). This fact suggests that on occasion the vascular bundle rings are formed earlier in the base of the root than in the internode of the stems.

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The effects of NH_4-N, NO_3-N, and NH_4NO_3-N on seedling growth, nodule formation, symbiotic N_2-fixation, and mineral-N assimilation of Desmodium intortum cv. Greenleaf were investigated under controlled conditions. The rate of mineral-N application influenced the DM yield but the form of mineral-N did not. As N rates increased, total nodule number and weight were positively affected with NH_4-N but not with NO_3-N. Weight per nodule increased with higher rates of NO_3-N but not with NH_4-N application. Plant N from symbiotic N_2-fixation increased linearly with NH_4-N, and decreased with NO_3-N application. N originating from mineral-N increased linearly with increasing rates of N application in the following order ; NO_3-N>NH_4NO_3-N>NH_4-N. The data reveal that NH_4-N is a better source of N for starter N.

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Leaf photosynthesis of Italian ryegrass, Lolium multiflorum LAM., and orchardgrass, Dactylis glomerata L., were measured to estimate seasonal variations, changes following the ageing processes of the leaf, responses to light intensities of various leaf positions, and effects of low temperature on photosynthesis in early spring. The results obtained were summarized as follows: 1) In Italian ryegrass, leaf photosynthetic rates were higher at the seedling stage in late autumn and at the growing stage in next spring. In winter season, leaf photosynthetic rates were significantly correlated with the mean daily air temperature during ten days preceding the measurements. Dark respiration rates of leaves were somewhat higher in winter compared with those in other seasons. In orchardgrass, leaf photosynthetic rates were highest in spring, and followed by those in autumn. In sprig time, leaf photosynthetic rates were significantly correlated with the mean daily air temperature during ten days preceding the measurements. 2) The leaf photosynthetic rates in winter reached the highest level three to five weeks after the full expansion of the leaf and then showed the tendency of gradual decline with the ageing. On the other hand, in spring or early summer, leaf photosynthetic rates reached to the highest level one to two weeks after the expansion and had rapid declining tendency, thereafter. 3) The photosynthetic rates of upper leaves were higher than those of lower ones at high light intensities (60 and 20klux), but were not different at low light intensity of seven klux except for the case of Italian ryegrass measured in May. 4) Leaf photosynthetic activities of both Italian ryegrass and orchardgrass suffered from serious damage by -4℃/48h treatment and were killed by -6℃/48h treatment. By means of one week exposing to 10℃ as pretreatment, leaf photosynthetic activities recovered almost completely at two or three days after -2℃/48h treatment. In the case of 15℃ pretreatment, on the other hand, the recovery of leaf photosynthetic activities was still limited to about 20 to 50 percent at one week after treatment. The 2℃/48h treatment did not affect leaf photosynthetic activities.

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YAMAMOTO, S., T. KONDO and Y. MIND (1980) Extraction of total nonstructural carbohydrates from forage plants containing starch by α-amylase. J. Japan. Grassl. Sci. 26, 305-310. The extraction of total nonstructural carbohydrates (TNC) from forage plants containing starch was tried using α-and β-amylases. Materials tested were corn ear, alfalfa root, Rhodesgrass leaf sheath and corn starch. Non-structural carbohydrates (NC) were extracted more effectively by α-amylase (Bacillus subtilis origin) than by β-amylase (seed of Glycine hispida origin) treatment. A trace of xylose was detected only in the extract of Rhodesgrass by α-amylase treatment. The all residues treated with α-amylase retained a trace amount of NC. Alpha-amylase treatment was considered to be effectual for the extraction of TNC from forage plants.

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Italian ryegrass containing large amounts of nitrate was ensiled in laboratory siols with calcium carbonate (CaCO_3), glucose and urea. Effect of these additives on the disappearance of nitrate was investigated. In Expt. I, Italian ryegrass was ensiled with 3% glucose, 0.6% urea, 0.6% CaCO_3 and 0.6% CaCO_3+3% glucose, and in Expt. II it was ensiled with 3% glucose, 0.6% CaCO_3, 0.6% CaCO_3+3% glucose, 0.8% CaCO_3+3% glucose and 1.0% CaCO_3+3% glucose. The silos were kept at 28℃ in the temperature control room and opened at intervals of 3, 7, 15 and 50 days after ensiling. The results obtained were as follows: 1. In the silages added with CaCO_3 and urea alone the nitrate contents considerably decreased with advancing period of ensiling, and from 97.9 to 100% of nitrate disappeared at 50 days after ensiling. These silages were characterized by a low lactic acid and a high NH_3-N content and a high pH value. 2. In the silages added with CaCO_3+glucose and glucose alone at ensiling, the contents of nitrate decreased for the first 3 days after ensiling, but they changed little after this period. These silages were characterized by a high lactic acid and a low NH_3-N content and a low pH value. 3. Nitrate disappeared to a large extent in rather the poor quality silage and in a good quality silage the disappearance of nitrate was depressed. The silages added with CaCO_3+glucose at ensiling were good in quality and the rate of nitrate disappearance from these silages were slightly higher than that from silage added with glucose alone at ensiling, though the rates of nitrate disappearance from the formers were lower than 41%.

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Changes in estrogenic activity of ladino clover, red clover, and alfalfa due to fermentation in the silo were studied. The first crops of ladino clover, red clover and alfalfa were harvested at flowering stage and chopped into approximately one cm length. These chopped legumes were ensiled in the laboratory silos with and without formic acid. Formic acid was added at ensiling at the rate of 0.6% of the fresh material. A portion of the chopped legumes were wilted before being ensilied. Two silos were prepared for each treatment and kept in an incubator of 15℃ and 30℃, respectively. After a 30 day ensilage period, the contents were taken out and analyzed. Estrogenic activity of each silage was estimated by uterine weight responses of mice. Ovariectomized immature mice (23 days of age) were fed the diet containing 30% freeze dried silage for 6 days and then killed. In both cases of ladino clover and red clover, there was no significant difference between estrogenic activity of fresh material and that of silages preserved by different methods. Whereas, the estrogenic activity of unwilted alfalfa silage was significantly greater than that of fresh material, wilted and formic acid silages. The estrogenic activity of formic acid alfalfa silage was quite similar to that of fresh material. The estrogenic activity of wilted and unwilted alfalfa silages stored at 30℃ were higher than at 15℃. Estimated activity per 100g dry matter of the fresh material and wilted, unwilted and formic acid silages stored at 15℃ were equivalent to 1.42, 1.44, 1.81 and 1.56μg of diethylstilbestrol (DES), and those of alfalfa silages stored st 30℃ were 1.92, 2.67 and 1.39μg of DES, respectively.

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A series of trials were carried out over a five-year period to determine the ad lib, intake (10-15% refusal level) and digestibility of clipped alfalfa (Saranac) fed at several growth stages (first cutting and aftermath) to wethers. Voluntary intake and nutritive value were kept almost constant throughout the growing seasons. DCP, TDN, DE content and voluntary intake in 1st, 2nd and 3rd cutting were DCP; 14.5, 16.2, 15.9%, TDN; 57.9, 58.6, 60.8%, DE; 2.70, 2.80, 2.79kal/gDM and voluntary intake; 86, 84, 85g/day/W^<0.75>, respectively. The changing amounts of digestible dry matter in alfalfa were related to the amount of digestible cell content and indigestible cell wall, however digestible cell wall was observed to have little relation. There was not significant correlation between voluntary intake and dry matter digestibility. Fecal dry matter excretion (g/day/W^<0.75>) of wethers in their full intake was about 33g, varying a little from 1st to 3rd cutting, 34, 32, 31g, respectively.

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First-cut immature high protein Italian ryegrass hay (CP 27.8% of DM) was fed to four Japanese native castrated male goats at four levels of dry matter intake (0.7, 1.4, 2.1 and 2.8% of body weight) in a 4×4 Latin square design and the effect of level of intake on digestibility and nitrogen balance was studied. Goats fed rations at 2.1 and 2.8% levels of intake gained their weights, whereas those fed at 0.7 and 1.4% levels lost their weights. The level of dry matter intake required for maintenance was estimated to be 2% of body weight from the following linear regression equation. y=-0.27+0.14x(y=kg of daily gain, x=percent of dry matter intake to body weight). The digestibilities of NFE, crude fiber, CW, cellulose and hemi-cellulose of the hay slightly decreased with increasing levels of intake. The digestibilities of dry matter, crude protein, crude fat and ADF, and DCP and TDN contents of the hay were the highest at 1.4% level, and above this level they decreased with increasing levels of intake. The negative nitrogen balance was observed for the groups fed at 0.7 and 1.4% levels of intake, whereas it was positive for the groups fed at 2.1 and 2.8% levels. The ratio of fecal nitrogen to dry matter intake was the highest for the group fed at 0.7% level. This was probably due to the increase in the ratio of metabolic fecal nitrogen to dry matter intake at the extremely low level of food intake and this was thought to be a main factor depressing the digestibility of crude protein at 0.7% level of intake. The regression equations and the coefficients of correlation between the digestibility of crude protein (y_1) or crude fiber (y_2) and the percent of dry matter intake to body weight (x) obtained were as follows: y_1=74.23+9.01x-2.29x^2 r=0.983 y_2=90.34-1.43x r=-0.986 The results of this experiment indicates that even with the high protein hay the level of intake affected on its digestibility though the effect was not so large as with low protein hay.

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This paper was described the difference on the young tree-damage by grazing beef cattle between Japanese red pine and Japanese cedar, and between the tame pasture and the native pasture. Cattle were grazed in 4 experimental plots: Japanese red pine-tame pasture, Japanese red pine-native pasture, Japanese cedar-tame pasture, and Japanese cedar-native pasture. Cattle were grazed at the moderate intensity with the utilization of approximately 65% to the available forage of each pasture, in June (spring) and August (summer). The tree-damage was mainly classified into three categories: the trampling injury, the browsing injury and the dead. The trampling injury was composed of the stem breakage, the sub-branch breakage, the bark removed and the lightly trampling. (1) The trampling injury The trampling injury occurred on two tree species more frequently in the tame pasture than in the native pasture, in two seasons. On Japanese cedar, the percentage of trampling injury was 29% in the tame pasture and 19% in the native pasture on an average of two seasons. This is because of the difference grazing capacity between the tame and the native pasture. The increase of grazing capacity by introducing forage plants caused heavier grazing pressure against young trees. (2) The browsing injury The browsing injury occurred only in Japanese red pine, and did not occure in Japanese cedar at all. The percentage of browsing injury of Japanese red pine varied with the understory vegetation and the season. The browsing injury occurred more frequently in the tame pasture than in the native pasture, and more frequently in spring than in summer. About 69% of all Japanese red pine in the tame pasture were browsed in spring. And the percentage of the others was 3-10%.

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