The nutritive values of dried fibrous residues prepared from oat and Italian ryegrass in the early heading stage were determined using sheep. As the control, a sun-cured hay prepared from Italian ryegrass at the heading stage was used. Each diet was given to the animals without any supplements as to provide 2.0-2.25% dry matter of their body weight per day. The digestibility of crude protein was not significantly different among the 3 diets and lower than those of the other components. Digestibilities of organic matter, nitrogen free extract (NFE) and energy were the highest in the hay and followed by the oat residue and the ryegrass residue in that order. The digestibility of crude fibre of the residues was higher than that of the hay. The amount of nitrogen retained by animals was not significantly different among the 3 dietary treatments. Ruminal ammonia concentration was the highest in sheep fed the oat residue and the lowest in those fed the ryegrass rasidue. Ruminal propionic acid concentration was significantly high in sheep fed the ryegrass residue. No significant differences were found in the levels of the other volatile fatty acid concentrations among the 3 dietary treatments. Haematocrit value, blood glucose level and blood urea level were the highest and plasma total protein level was the lowest in sheep fed the oat residue and these values were significantly different from those obtained on the hay. The sheep fed on the ryegrass residue was similar in haematocrit value and blood glucose level to those fed on the hay and in blood urea nitrogen level and plasma total protein level to those fed on the oat residue. From these results obtained in the present study, it can be concluded that the value of the dried fibrous residue used in this study as roughage for sheep was quite similar to that of sun-cured hay prepared from Italian ryegrass harvested at heading stage.

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To make clear the geographical variation in the morphology and phenology of Imperata cylindrica (L.) BEADV. in Japan, 402 clones, one clone from one population, were collected from Hokkaido and southwards to Okinawa Prefecture. Dry matter production of 52 clones out of 402 clones were examined in 1985. Five ramets of each clone were used in this experiment. Latitudinal cline was found in the plant size and phenology of this species. The clones from northern parts of Japan were smaller in plant size, emerged later, and their heading time and death time of aerial parts were earlier than those from southern parts. The clones were clearly divided into two varieties based on the presence or absence of hairs on node of culm. Glabrous clones, var. genuina, were confined to Hokkaido, northern parts of Tohoku District and highlands of Central Japan, and they headed exceptionally early. On the other hand, hairy clones, var. koenigii, were distributed in the southern parts of Tohoku District and southwards. This variety was divided into two types based on the phenology. Clones from the Amami Ohshima Islands and southwards were evergreen and headed intermittently in May to October in the Kii-Ohshima Island. Whereas, clones from the southern parts of Tohoku to Kyushu District became dormant in winter and headed once a year, in May. Such differentiation is attributed to the differences in the climatic factors, especially temperature.

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To compare the morphological characters and pollen fertility of the clones from inland populations with those from foredune ones of Imperata cylindrica var. koenigii, 33 clones from 17 inland and 16 foredune populations in the Kii Peninsula were studied and five ramets from one clone per one population were planted in about 6000cm^3 pots filled with clay loam on June, 1984. Plant length, dry matter weight of each organ, length and diameter of rhizome, number of shoots and rhizomes were measured in mid-November. A series of pot experiments was practiced at the Subtropical Plant Institute of Kyoto University in the Kii-Ohshima Island, located at the southern extremity of the Kii Peninsula. The seed set percentage of each population was investigated in the original habitat in mid-June, 1984. Under cultivated condition, the significant differences between inland and foredune populations were detected in the plant size and morphology. The clones from inland populations were significantly longer in plant length, larger in the diameter of rhizome, heavier in leaf, rhizome and total dry matter weight than those of foredune populations. Foredune populations had smaller anther and longer glume than those of inland populations. The seed set percentage of inland populations in original habitat indicated 4.3 to 73.3%, though those of foredune populations were less than 3.6%, because of the male sterility. These genetic differences may be the results of the selection such as cutting, competition with the other species, or salt spray from the sea.

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Two interspecific hybrid plants between tetraploid Trifolium ambiguum M. BIEB. (2n = 4x = 32) and T. repens L. (2n = 32) were produced by the ovule culture technique. The hybrid plants were intermediate between the T. ambiguum and T. repens parents in morphological traits. Their hybridity was confirmed by isozyme analysis. However the field performance of the hybrid plants was very poor in comparison with the parent plants. Moreover, the hybrid plants were highly sterile, and a few back-crossed seeds with T. repens were produced, and only one of them grew into whole plant. The present study suggested the possibility of transfer of valuable traits from T. ambiguum to T. repens.

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Trends of net photosynthetic rates of populations during the period from autumn to next early spring at Miyazaki were investigated for eight tropical grasses, namely, Panicum coloratum var. makarikariense, P. maximum var. trichoglume, P. milioides, P. repens, Pennisetum clandestinum, P. purpureum, and two cultivars of Setaria anceps. The reduction of the photosynthetic ability in population (daily maximum photosynthetic rate on a fine day, Pa) in autumn, due to the lowering of air temperature, occurred earliest in two Pennisetum species and latest in two cultivers of Setaria. Pas of other grasses than P. coloratum were nearly zero during the period from the beginning of January to the end of February. P. coloratum maintained a small amount of green leaves and Pa throughout the winter. During the period before the middle of December, the photosynthesis in the morning was suppressed by the after-effect of low night temperature in all grasses when the air temperature at dawn dropped to below about 10℃. The lower night temperature, the severer suppression, and the suppression was the most in P. purpureum and P. repens, and the least in P. milioides. After the end of February, grasses except for P. maximum, which did not overwinter, showed gradual increases of Pas followng the beginnings of spring regrowth under the increase of air temperature. The time of the beginning and the rate of increase of Pa in spring regrowth were considerably different among grasses. This difference, however, had no correlation with the difference among grasses in the changes of Pas during the preceding periods. On the other hand, a tendency was seen that the recoveries of Pas following the spring regrowth were slower in the grasses in which the morning suppressions of photosynthesis were severer, when the recoveries of Pas were estimated by the relative values of Pas at the end of April to the muximum values of Pas in the previous autumn.

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The first year growth of kudzu plants grown at 40, 80 and 120 cm spacings was compared. Dry weights of the plant tops, roots and litter and leaf area were measured 8 times at three week intervals during the period from July 17 to December 11. Growth parameters were calculated using only plant tops. Plants and litter were harvested at planting (PS) and interplant (IS) sites, using a 20 × 20 cm quadrat. Differences in top and root growth among spacings were small in IS throughout the growing season. In PS, however, there were significant differences in the seasonal trends of these dry weights among spacings. The greatest top and leaf dry weights, 475 g m^<-2> and 329 g m^<-2>, respectively, were obtained at 80 cm spacing. The highest value of maximum LAI was 5.2 at 40 cm spacing and maximum LAI was smaller at the wider spacings. Seasonal trends in RGR, NAR, CGR and RLGR were similar in all spacings of IS. In PS, significant differences existed between 120 cm spacing and the other two spacings in RGR, NAR and CGR. This result was attributed to the difference in stem dry matter accumulation. The highest maximum CGR, 6.2, was obtained at 80 cm spacing, with optimum LAI 2.9 and NAR 2.2.

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The life history of broadleaf dock (Rumex obtusifolius L.), an aggressive weed in parmanent grasslands, was investigated in order to find out the effective method for controlling this weed. Seedlings of broadleaf dock sown in the current spring were cultivated in 1/2000 a wagner pots under individual plant condition. Chronological changes including plant length, leaf number, stem or sprout number, leaf area and dry weight were examined at two-week intervals from June to November in 1987. Above ground parts of all experimental plants were cut on 13 August at fullripe stage, and after that, process of regrowth was examined. As for top growth, it was observed that plant length, leaf number and top dry weight increased in accordance with growth of plant after budding, and reached the maximum values in blooming stage. While, stem or sprout number increased in both periods from budding to ripening stage and regrowth stage. Number of seed production was estimated about 15,000 per plant. The maximum values of leaf area per plant was attained at blooming stage and period before wintering. Individual leaf area at different leaf position increased remarkably after 3rd leaf, especially as high a leaf area value as 100 cm^2 was maintained by the radical leaves such as 6th to 13th leaves. After that position, leaf area decreased rapidly. As for root growth, dry weight and diameter of tap roots increased gradually with the progression of growth, but the dry weight of lateral roots showed variation by growth stage. These results suggest that the top growth of broadleaf dock is changing remarkably with growth stage, but the root growth increase nearly from spring to autumn.

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Effects of paraquat application, and seed-bed preparation by surface cultivation were investigated in order to sod-seed red clover (Trifolium pratense L.) into timothy (Phleum pratense L.) -dominant swards. The following results were obtained : 1) Suppression of timothy by paraquat application was related to its dose, amount of timothy canopy at the application time and duration from harvest to spraying. Moreover, it was suggested that the effect of paraquat application on timothy varied greatly with weather condition ; under drought and high temperature, timothy almost died by spraying 19 to 95 g/10 a (active ingredient) of paraquat and was suppressed even by 9 g/10 a. Consequently, it was considered that using paraquat as a method of temporary suppression of timothy at sod-seeding was very risky for practical use. 2) The partial treatment of sward surface using slot seeder (John Deere Powr-till Seeder) or the overall treatment of sward surface by disk harrow, if it was followed by compaction, offered good seed-bed for sod-seeding red clover. However, the emergence and establishment of sod-seeded red clover was poor in non-treatment sward, especially under the drought condition.

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Field trial and in situ digestion trials with brown midrib-3 maize hybrids were carried out to determine the effect of brown midrib-3 (bm_3) gene on agronomic traits and nutritive value of stover in Chushin dist., Nagano, Central Japan. In 1987, comparisons were made between isogenic materials, normal (1/2 of plants) and bm_3 (1/2 of plants) from two triple hybrids developed with inbred lines. The seed parents were yellow dent hybrids (S_4 lines homozygous for the normal allele × S_6 line homozygous for the bm_3 allele) derived from an American hybrid and an American synthetic variety. The pollen parent was a white flint inbredline (S_1 line homozygous for the bm_3 allele) derived from a Yugoslavian local variety. The bm_3 (homozygous for the bm_3 allele) and normal (heterozygous) stands were grown at the rate of 625 plants/a in a split-plot design with two replicates by thinning after appearance of brown pigment on the midrib. Vigor in early growth and maturity were similar in both phenotypes : bm_3 type (homozygote for bm_3) and the normal type (heterozygote). The effect of heterozygosis for bm_3 on stalk length, ear height, lodging resistance at silage harvest appeared to vary according to the genetic background of seed parents. Dry matter yields of bm_3 type were 10-20% lower than the normal type. In comparison with the nomal type, the number of ear per unit area in brn3 type decreased but the proportion of grain in whole-crop dry matter of bm_3 type were not decreased. Whole-crop dry matter concentration and the proportions of organic cellular content, organic cell wall content (OCW), NDF, ADF and silica in stover did not differ significantly. In comparison with the content of low digestible fraction in OCW (Ob) and the ADL concentration in stover for bm_3 homozygote were 6% and 2% lower, and the in vitro digestibility of OCW and content of estimated digestible organic matter were 10% and 4% higher on the averages, respectively. 24-hr in situ disappearance of dry matter in whole-crop harvested at silking stage was also 4% higher for homozygote than for heterozygote when used steers. It is concluded that the gain of digestible organic matter content in stover and whole crop of bm_3 hybrids through heightened cell wall digestibility is about 4%, but the dry matter yield loses 15-20%. These results indicate that the combining ability and dry matter productivity of parental lines are important for breeding bm_3 hybrids.

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To examine the use of near infrared reflectance spectroscopy (NIRS) in screening for mineral concentrations, 72 orchardgrass samples from hay-managed field were analyzed in both NIRS and chemical analysis. One half of the samples was used to develop a calibration equation, while the other half was used as an unknown sample-set. In addition, 42 orchardgrass samples managed with pasture-type harvest and 48 perennial ryegrass samples managed with hay-type harvest were used as unknown sample-sets. Chemical values from each calibration sample were regressed on the corresponding spectral data using a stepwise multiple regression analysis. Three wavelengths were selected for phosphorus (P), potassium (K), calcium (Ca) and magnesium (Mg) to compare the accuracy of NIRS analysis, and only one wavelength was taken for nitrogen (N). Except for Ca, the coefficients of variation (CV) from regression of laboratory values on NIRS spectra were 6.6% or lower, and the coefficients of determination (R^2) were .945 or higher. However, CV and R^2 for Ca were 13.2% and .824, respectively. Judging from the coefficients of determination for unknown sample-set (r^2) and CV of unknown samples, the accuracy of NIRS analysis was at the highest for N, followed by K, P and Mg, and Ca was at the lowest. As the result of comparison between NIRS estimates and chemical values in unknown sample-set of the same population, 8 or more samples in the top 10 of chemical values were selected for N, K, P and Mg by NIRS prediction. These results suggest that NIRS can be used in screening of orchardgrass for these minerals. However, Ca, K/(Ca + Mg) and Ca/P ratios may be a serious limitation to successful prediction compared with the above minerals.

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Three maize cultivars (FFR-915C, JX-77 and G-4578) were grown in the field with water-stressed treatment and control. Leaf water potential, osmotic potential and solute concentration in cell sap were measured on 20th day after the treatment. Degree of leaf rolling was measured on 22nd day after the treatment. Cultivar FFR-915C could maintain high turgor under water stress by lowering the osmotic potential. Sugar and K were the major contributors to the osmotic potential. Degree of leaf rolling was less in cultivar FFR-915C and it could recover from leaf rolling by maintaining high turgor under water deficits. FFR-915C seems to be tolerant to drought than other two cultivars.

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The changes of the population density of tick, Haemaphysalis longicornis Numann, have been investigated at four paddocks in Kawatabi farm of Tohoku University. 1) Tick's density was very different among paddocks. Tick's density in the highest dense paddock was 17.3 times as much as that in the lowest one. 2) Tick's density in native pasture was not necessarily higher than that in sown pasture. 3) The relationship between stocking rate and tick's density showed a curved line with one peak. When stocking rate was low level, tick's density increased with the increase of stocking rate. On the other hand, when stocking rate was high level, it decreased with the increase of stocking rate. These results indicated that tick's density in permanent pasture was mainly affected by stocking rate. Therefore, it is assumed that the grazing cattle are not only the host of ticks but also the suppressing factors for the tick population under certain conditions.

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The purpose of this study was to provide information on forage utilization characteristics of syrian hamsters (Mesocricetus auratus) in comparison with those of mice, rats, chinese hamsters (Cricetulus griseus) and guinea-pigs. Mice, rats, chinese hamsters and sryian hamsters were fed following 4 diets ; dehydrated alfalfa (Medicago sativa L.) without supplement, commercial 17% fibre herbivore diet (D1), 14% fibre herbivore diet (D2) and commercial 7.5% fibre experimental small animal diet (D3). Guinea-pigs were fed only the dehydrated alfalfa and the D1. Digestibilities of apparent dry matter and cell-wall constituent, and dry matter intake were measured in the short-term digestion trials, using animals in two stages of postweaning and mature. Weight gains were measured in the long-term growth trials. There were no differences in weight gain of syrian hamsters between D1 and D3, but mice, rats and chinese hamsters had less weight gainin the high fibre diet than in the low fibre diet. In guinea-pigs, syrian hamsters, chinese hamsters, rats and mice fed high fibre diet (D1) in postweaning stages, apparent dry matter digestibilitles was 73.8, 59.7, 51.5, 54.3 and 48.6%, respectively, and apparent cell-wall digestibilities were 61.6, 29.7, 30.1, 25.1 and 22.3%, respectively. In the alfalfa meal without supplement condition, guinea-pigs as well as mice, rats and chinese hamsters could not survive but syrian hamster grew well. Apparent dry matter and cell-wall digestibility of the alfalfa in postweaning stages of syrian hamsters were 50.2 and 31.1%, respectively. Thus, syrian hamsters had higher dry matter digestibility than mice and rats in high fibre diet, but these differences did not exist in low fibre diet. These results suggest that syrian hamsters have a possibility of use as pilot animal for study on nutrition of hervibora.

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