Thirty one cultivars and three synthetics of tall fescue were compared on the row seeding and the space planting for heading habit, herbage yield and seasonal yield distribution. Space planting of entries was performed in November 1982, and row seeding was performed in September 1983. Vigor in spring and fall, summer depression, winter burn and head emergence date of space planted entries were investigated after the summer of 1983, and herbage dry matter yield and plant height were investigated in 1985 and 1986. Herbage dry matter yield in each harvest was correlated significantly to head emergence date in all of the entries. The absolute value of the correlation coefficient was greatest when all entries were evaluated. The correlation coefficients of entries evaluated within the same maturity group were generally non-significant. In early spring and fall, vigor observed in space planting was closely correlated to herbage dry matter yield in row seeding. The entries were classified into six groups by cluster analysis on the basis of 20 characters related to seasonal growth. Clusters I and II a consisted of very early or early maturing entries. Cluster I consisted of five entries bred in Japan and four ones bred in France or U. K. They had high performance throughout the growing season than the entries in cluster II a. Clusters II b, III, IV, V and VI consisted of medium or late maturing entries. The herbage dry matter yields of "Clarine" belonged to cluster II b, and "Hokuryo" belonged to cluster III, were higher than those of the other medium or late maturing entries. "Maris Jebel" and "Maris Kasba", bred from populations collected from North Africa, belonged to the cluster V. These cultivars showed little burn in winter and good growth in early spring.

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This study was undertaken to clarify the relationship between heat treatment and changes in the amino acid composition of rumenbypassed protein by comparing the amino acid contents of feed protein between before and after ruminal exposures. Second cutting Italian ryegrass (Lolium multiflorum LAM.) dried at 40℃, 80℃ and 120℃ and ensiled at 20℃ and 60℃ was prepared, and described as dried materials and ensiled materials, respectively. Rumen-fistulated sheep were used to collect samples after 2 hr. and 6 hr. ruminal exposures by in situ nylon bag technique. 1. The Pro and Val contents of 40℃-, 80℃- and 120℃-dried materials significantly decreased after ruminal exposure. In case of ensiled materials after ruminal exposure, there were two types of amino acids, one was "decrease" and the other was "increase". The former was Pro and Val of 20℃- and 60℃-ensiled materials, the latter was Phe, Arg, Met, Leu, Ileu, Ala, Gly, Glu and His of 20℃-ensiled materials, Phe, Arg, Met, Leu, Ileu , His and Lys of 60℃-ensiled materials. 2. In materials dried and ensiled, the amino acid pattern similarities between materials before and after ruminal exposures showed low value, but those between materials after 2 hr. and 6 hr. ruminaI exposures showed high value. 3. Therefore, though the relationship between heat treatment and changes in the amino acid composition of the rumen-bypassed protein was not clarified, the difference in amino acid compositions of materials between before and after ruminal exposures was recognized. And it was suggested that the amino acid composition was different between feed protein and rumen-bypassed protein.

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To determine the nutritive value of whole-plant silage and stover, we ensiled and compared 4 sorgo types (S), 2 dual purpose type (DP), 6 grain types (G), 1 sorghum-sudangrass hybrid type (SS) and 2 hybrid maize (M) at the adequate harvesting stages. The digestion trials in vivo were carried out with 4 goats. Neutral and acid detergent fiber contents in whole plant of S, DP and M decreased in that order, differences being over 10%, respectively. Silages of S tended to have low dry matter concentration (DM), high pH, low amounts of lactic acid and total volatile fatty acids and high volatile basic nitrogen concentration (VBN) in total nitrogen. The digestibilities of dry matter, organic matter and nitrogen free extract and the contents of digestible organic matter and TDN in whole plant of S, DP and M increased in that order, with differences over 10%, respectively, except for "Sugar Graze" which had a higher digestibility among sorgo type sorghum. Digestible dry matter concentration (DDM) of stover silage was lowest in DP hybrid "Suzuho" ensiled at dough stage, and was highest in hybrid maize at yellow ripe stage, and their difference was about 18%. The DDM of G inbred line "F_6-3 A-5", which had brownmidrib-18 (bmr-18) and bloomless (bm) genes, ensiled at dough stage was 61.8% as much as that of hybrid maize. It is considered that the TDN concentration for the dual purpose sorghum can be obtained by improving the digestibility of stover. For the sorgo type and sorghum-sudangrass hybrid type, it should be expected to improve ensiling characteristics as well as digestibility.

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The kernel texture of corn is said to affect its chemical composition, digestibility and nutritive value. To find out what these effects are, we carried out in situ digestion trials with steers and analyzed the varietal differences in chemical composition and dry matter disappearance among 19 maize genotypes with different kernel texture: dent, flint, waxy, sweet, pop, high oil and high amylose corn. Nitrogen cell wall free extract (NCWFE) in dry matter ranged from 66.5% to 80.0%. Starch content of sweet corn ranged from 20.6% to 30.3%, and that of other grain types ranged from 60.0% to 74.2%. Ether extract reached up to 10.6% in high oil corn, but other varieties show less variation (from 2.8% to 6.5%). The 12-hr dry matter disappearance in rumen fluid averaged 51.4% ; the varietal difference being mainly caused by kernel texture. The means were 80.6%, 61.1% and 50% in sweet, waxy and the other varieties, respectively. However, the corrected dry matter disappearances (CDMD), which were calculated by subtracting the water soluble fraction content (%) at zero incubation time from the percentage of 12-hr dry matter disappearance, were 47.0%, 39.7%, 38.5% and 30.5% in waxy, dent, flint and sweet types, respectively. CDMD had positive correlation with total NCWFE and the starch in NCWFE, and had negative correlation with crude protein. Though no difference was detected between the content of starch among dent flint and waxy, the CDMD of waxy was higher by about 8% than that of dent and flint. These results indicate that varietal differences in chemical composition and digestibility are mainly dependent upon kernel texture and endosperm type and suggest that waxy corn starch is highly susceptible to digestion in the rumen.

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An experiment was conducted to investigate the effects of three factors on the establishment of orchardgrass (Dactylis glomerate L.) by direct drilling into Kentucky bluegrass (Poa pratensis L.) sod at Kuju Agricultural Research Center of Kyushu University from August, 1986 to April, 1987. The factors were seeding time (Aug. 1, Sep. 1 and Oct. 1), nitrogenous fertilization (5 kgN/10 a of fast-release fertilizer, 5 kgN/10 a and 10 kgN/10 a of slow-release fertilizer) and post-sowing trimming frequency (none, once and twice). The seeds were sown in a groove of 6 cm depth and 8 cm width in the Kentucky bluegrass sod which had been established in a wooden box (37 × 58 × 23 cm). The results obtained were as follows : 1. Owing to the significantly higher seedling density two months after seeding, October seeding showed the highest stem density in the next spring (April 25) comparing with the other seeding times, although its overwintering rate of stems (the percentage of the number of stems on Feb. 25 to that on Nov. 30) was low. 2. The dressing of 5 kgN of slow-release fertilizer in August seeding was effective for more stems in spring. The treatment of 10 kgN of slow-release fertilizer application showed the highest overwintering rate of stems and stem density in the next spring in September seeding. With the low rate of application (5 kgN) of slow-release fertilizer, the increasing effects on the overwintering rate of stems and the stem density in the next spring were observed in October seeding. 3. In August seeding, post-sowing trimming significantly increased the relative light intensity in the sod, which increased the tillering in spring and the stem density in the next spring. The results suggested that October seeding with the application of slow release fertilizer of 5 kgN/10 a was the most effective for the establishment of orchardgrass by direct drilling into Kentucky bluegrass sward.

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The aim of this paper is to show the morphology of macropores in the root zones under the permanent meadow. The structure of macropores was studied by examining the physical conditions of the soil, the morphology of macropores by X-ray and contrast media, and the root system. Soil samples were collected from the root zone shallower than 55 cm in a meadow composed mainly of orchardgrass seeded fourteen years ago. The samples were classified by surface soil layer (0-10 cm), sub-surface soil layer (10-35 cm), and subsoil layer. Each layer was composed of volcanic sandy soil. The physical condition of the surface soil layer was dense and solid, the micropores and the effective pores were small, and the permeability was low. Because of the low density of the soil, the macropores and the effective pores increased in the sub-surface soil layer, but the subsoil layer was higher in permeability. The macropores of the above soils were mainly tubular root pores formed by the grass roots. In the surface soil layer, the pores developed irregularly in the horizontal and the slanting directions along the crack rather than in a vertical direction because of the dense soil. In the sub-surface soil layer thicker pores developed in a vertical direction at a constant distance, but the thinner pores clearly developed in the horizonal direction from these thick ones. In the subsoil layer, the pore morphology was not formed by the grass root, but instead originated from previously planted grasses. Most of these radiographic images were formed by the contrast media. They permeated into pores as follows in the surface soil layer and the sub-surface soil layer, the pores formed between the grass root and the soil but in the subsoil layer, the pores were formed by the root system of the previously planted grasses. The diameter of the radiographic pore ranged between 0.37 and 0.85 mm, but it was larger in the lower layers. In contrast, the diameter of the grass roots was larger in the shallower layer, and ranged from 0.30 to 0.19 mm. Since the pore morphology showed a good correspondence with the soil's physical conditions, it is concluded that the morphology of the micropore of the root system in the drainage zone of the permanent meadow forms mostly by tubular root pore which originates from the grass roots.

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This study was undertaken to obtain some information on the relation of the pasture utilization during autumn and winter to the next spring regrowth of tropical grasses in the lowlands of southern Kyushu. Changes of plant photosynthetic ability (daily maximum rate of net CO_2 absorption on a fine day, Pa) in dallisgrass (Dg) , bahiagrass (Bg) and Rhodesgrass (Rg) grown under different intensities of defoliation from late Nov. in 1987 to next early Feb., were examined during overwintering (Expt 1). In this experiment, defoliations were done intermittently so as to keep no green leaves or to keep about a half of green unfolded leaf. In the another experiment, changes of Pa, tiller numbers (Tn) and shoot dry matter (Dw) during overwintering were compared among Dg grown under different duration of defoliation (Expt 2). In this experiment, all green leaves were removed intermittently until Jan. 23 in 1989 from Oct. 8, Nov. 1 or Dec. 20 in 1988. In Dg and Bg, Pa before late Dec. was higher in the plant with less intensity or shorter duration of defoliation, and there was a relation that the higher the Pa before late Dec., the higher was the Pa in next spring (Expt 1 and 2). This relation was not found in Rg which is less cold tolerant than the other two species (Expt 1). In Dg, the plants with a higher Pa before late Dec. had a larger Dw at this time and also had a higher rate of increase in Tn, Dw and Pa in next spring. However, the spring regrowth of the plant defoliated from Dec. 20 was nearly the same as that of the plant grown without defoliation (Expt 2). Thus, the photosynthesis before late Dec. is effective on spring regrowth and utilization of pasture in late Dec. has no deteriorative effect on the regrowth in next spring in such a species as Dg or Bg which is comparatively cold tolerant among tropical grasses.

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Characteristics of flowering, and pod and seed developments of phasey bean, Macroptilium lathyroides L. URB., were investigated under the field condition. Sowing was done on May 15 in rows 60 cm apart. The number of mature plants was 25 plants per 1 m row length. Flowers were distinguished by five days interval by painting a color on a calyx. Plants were cut and pods were harvested on Aug. 3, 8, 13 and 19. On each harvest, pods were assorted according to the flowering dates. Flowering first occurred on July 18 (65 days after seeding) and increased in number from July 29 till Aug. 4 with the peak on Aug. 1. The proportion of the number of pods originated in this vigorous flowering stage (full-bloom stage) in the total pods at each harvest date was 56-68%. Above 90% of seed germination was attained on the 9th day after flowering and seed weight reached the average ripe seed weight (7.86 g of thousand kernel weight) on the 12th day after flowering. Meanwhile, pod color turned black on the 10th day after flowering, which was a sign of near ripe seed. The pods began to shatter on the 16-17th day after flowering. The total seed yield, germinable seed yield and the yield of seeds in a black pod were the highest in Aug. 19 harvest. The proposed timing of seed harvest for phasey bean was as follows : Harvesting seed should be done after black coloring of all the pods originated in full-bloom stage (the 10th day after the end of full-bloom stage) and before the initiation of shattering of the pods (the 16th day after flowering) originated on the peak date of anthesis (Aug. 1). Consequently the optimum period for the conventional seed harvest by the cutting of plants or peduncles at one time was found to be Aug. 14-17 in this experimental condition.

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To clarify the differences in salt tolerance between the common (C-) and fore-dune (F-) type of Imperata cylindrica var. koenigii, three clones of C-type collected from mountainous regions, the other three C-type clones from coastal plains, and three clones of F-type from fore-dunes of Kii Peninsula were used in the experiment. The concentration of NaCl treated was 0.0, 1.5 and 3.0%. Each treatment had five ramets derived from each clone. In each treatment, 200 ml of NaCl solution was poured into each pot at intervals of two weeks from August 4 to November 10, 1987. On November 24, 1987, the ramets were dug up and their plant length, number of shoots and rhizomes, rhizome length and dry matter weight of each organ were measured. The plant length and total dry matter weight of each clone were decreased with the increase of NaCl concentration. Total dry matter weight of F-type clones was smaller than that of C-type clones in control, but the reverse was observed under NaCl treatment. The decrease of total dry matter weight by NaCl treatment of F-type was smaller than C-type. As for number of shoots, the different clones reacted to increasing NaCl concentration in different ways. The root dry matter production of eight clones except F-type clone No. 8 was reduced by NaCl treatment, but that of clone No. 8 was not. The differences between C- and F-type clones in the response to NaCl treatment were especially clear in rhizome production. The decrease of rhizome weight and length by NaCl treatment was smaller in F-type than C-type. F-type of I. cylindrica var. koenigii is probably well adapted to the habitat where plants have been exposed to salt spray.

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A model which describes changes in dry matter digestibility (DMD) of grasses on grazing grassland was invented. The model was simulated under several grazing systems on the improved grassland in the Kanto district in Japan. The results of simulation showed as follows 1. increase in number of cattle increased the DMD, 2. and decreased the amount of plant production. 3. The maximum plant production was obtained under the condition of four heads of cattle per hectare, 4. but the maximum animal production under the condition of six heads of cattle. 5. The results of simulation show that the grassland management option to obtain the maximum plant production does not alway give the maximun animal production.

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Copper and zinc concentrations in soils and grasses were examined in the meadows of horse breeding farms. Soils and grasses were collected on the same points. Timothy in the meadows was examined as a representative grass species. The results are as follows : 1. The average value of the total Cu concentration in Residual Regosols, Andosols and Brown Forest Soils is lower than that of Brown Lowland Soils, Gray Lowland Soils and Gley Soils. 2. Soluble Cu was extracted with 0.1 N-HCl from the air-dried soil samples. Soluble Cu concentration was decreased with the increasing phosphate absorption coefficient. The Cu concentration was less than 1 ppm, when the phosphate absorption coefficient was more than 1400. 3. In case of the low soluble Cu soil, when 0.1 N HCl that contains 100 mell of protons (pH 1.07), was added to the soil, proton concentration in the 0.1 N HCl soil extracts was found to be lower than 12-13 me/l (pH 2.3<). At the same time, large amount of Al ion ranging from 40 me/l to 70 me/l was dissolved in the 0.1 N HCl extracts. 4. There was a few soil samples that contained soluble Zn lower than 1.5 ppm. In this case, the proton concentration in the 0.1 N HCl extracts was lower than 1 me/l (pH 3.0<). Thus the sum of Al3+, Ca2+ and Mg2+ ions in the 0.1 N HCl extracts was at high level above 70 me/l. 5. Cu and Zn concentrations in the timothy were a half compared with adequate concentrations in rations for horse. 6. It was found that Cu and Zn concentrations in the timothy have no correlation with the concentration of soluble Cu and Zn in the soils.

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The Aneurolepidium (=Leymus) grassland, in northeast China and Inner Mongolia, has been furnishing forage to animals for many years but its productivity has recently decreased. The objective of this study is to make clear the present situation of vegetation and also find out how its utilization could be harmonized with conservation practices. The vegetation survey was carried out by the line method in the following pastures ; hay-making pasture in which herbage was harvested once a year in August, grazing pasture in which continuous grazing from spring to autumn occurred, and protected pasture which had neither been cut nor grazed for five years. Hay-making had little influence on vegetation, but grazing had a harmful influence; coverage and plant height of Aneurolepidium chinense (=Leymus chinensis) , a dominant species, decreased ; many invaders such as Suaeda glauca, alkali-soil tolerant species, and annuals etc. increased considerably. From these results, it appears that severe defoliation and trampling of grazing animals are the main causes of the degeneration of soil and plants, and that the grazing system should be improved for grassland conservation.

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Surveys on vegetations and management of sown pastures in the west slope of Mt. Fuji were made by the point method in order to analyse the vegetation and diagnose the productivity. Data of frequency of each species were used for analyzing the correlation matrix and the principal components. As a result some species groups were distinguished ; perennial ryegrass-Kentucky bluegrass-white clover group and orchardgrass-tall fescue group, etc. Based upon these informations 43 pastures were classified into five types by the species with maximum value of frequency ; Type A is observed in a grazing pasture that consists much of perennial ryegrass-Kentuckey bluegrass-white clover, containing fairly large numbers of weed species and appeared in relatively old pastures. Types B, C, D, and E are pastures used for cutting. Type B consists much of orchardgrass, tall fescue and sometimes of red clover, and is observed in new pastures containing a small number of weeds. Type C consists much of ryegrass accompanied with orchardgrass or reed canarygrass depending upon years after pasture establishment and contains some extent of weeds. Type D is an old pasture consisting much of reed canarygrass with weed of Rumex obtusifolius L. and none of annual weed. Type E consists much of weed species, annual weed in young pastures and Rumex obtusifolius L. in old patures.

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Effect of fermentative quality of silage on ruminal volatile fatty acid (VFA) composition was studied. Sheep were fed on 19 grass silages, 11 alfalfa silages and a clover silage. High correlation coefficients were obtained between crude protein and digestible crude protein (r=0.975, P<0.01), and between cellular content and digestible cellular content (r=0.979, P<0.01), irrespective of fermentative quality of silage. Sheep fed on poor quality silage of high butyric acid content showed high proportion of butyric acid and low proportion of propionic acid in rumen. Feeding of silage rich in lactic acid resulted in high ruminal proportion of propionic acid. However, in low moisture silage or formic acid treated silage, ruminal proportion of propionic acid was high in spite of low lactic acid content in silage. The higher the cellular content of silage was, the higher ruminal molar percentage of butyric acid at 4 hour after feeding was. Its multiple regression equation between molar percentage of butyric acid (RC 4.mol %), cellular content of silage (CC, % dry matter) and butyric acid in silage (SC 4.% dry matter) was as follows. RC 4=0.1637 × CC + 1.157 × SC 4 + 2.668 (R=0.749, P<0.01). These results showed that butyric acid content of silage was highly related to ruminal VFA composition.

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A series of trials has been carried out to determine the level of voluntary intake and digestibility of clipped orchardgrass and alfalfa fed at several growth stages to wethers. The rectilinearity of the relationship between digestible crude protein intake (Y_<DCPI> : g/kg^<0.75>) and crude protein intake (X_<CPI> : g/kg^<0.75>) : Y_<DCPI>=a + b X_<CPI> and the curvilinearity of the relationshipe between crude protein digestibility (Y_<CPD> : %) and crude protein intake (X_<CPI> : g/kg^<0.75>) : Y_<CPD>=b + a/X_<CPI> seem to be the result of certain interrelationships among the potential crude protein digestibility (=b) and excretion of delayed residues flow through gastrointestinal tract (=a). The regression equations are shown below : orchardgrass : YD_<CPI>=-1.2 + 0.82 X_<CPI,> (r=0.99, p < 0.01, n=102) Y_<CPD>=78 - 87/X_<CPI>, (r=-0.94, p <0.01) alfalfa : Y_<DCPI>=-1.8 + 0.88 X_<CPI> (r=0.99, p < 0.01, n=55) Y_<CPD>=88 - 167/X_<CPI>, (r=-0.78, p <0.01) The fill of undigested crude protein (UCPF : g/kg^<0.75>) would equal the crude protein excretion added to (a). The rate of passage (Kp) can be represented by Kp=crude protein excretion/UCPF The rate of digestion (Kd) can be represented by Kd=(crude protein intake - UCPF × Kp)/UCPF Metabolic fecal crude protein excretion (MFCPE : g/kg^<0.75>) can be represented by MFCPE=a + (true digestibility - potential digestibility) × crude protein intake Estimated average values of total amount of crude protein present in the gut (fill), Kp, Kd and true digestibility (TD) are shown below : orchardgrass : fill=7.8 g/kg^<0.75>, Kp=0.69, Kd=1.40, TD=92% alfalfa : fill=10.8 g/kg^<0.75>, Kp=0.69, Kd=2.45, TD=96%

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A series of trials has been carried out to determine the level of voluntary intake and digestibility of clipped orchardgrass and alfalfa fed at several growth stages to wethers. The rectilinearity of the relationship between digestible cell contents intake (Y_<DCCI>: g/kg^<0.75> and cell contents intake (X_<CCI>: g/kg^<0.75>): Y_<DCCI> = a + bX_<CCI> and the curvilinearity of the relationship between cell contents digestibility (Y_<CCD>: %) and cell contents intake (X_<CCI>: g/kg^<0.75>): Y_<CCD> = b + a/X_<CCI> seem to be the result of certain interrelationships among the potential cell contents digestibility (= b) and excretion of delayed residues flow through gastrointestinal tract (= a). The regression equations are shown below: orchardgrass: YD_<CCI> = - 3.5 + 0.79 X_<CCI>, (r = 0.98, p <0.01, n = 102) Y_<CCD> = 75 - 261/X_<CCI> (r = - 0.94, p <0.01) alfalfa: Y_<DCCI> = - 5.3 + 0.86X_<CCI> (r = 0.99, p < 0.01, n = 55) Y_<CCD> = 86 - 516/X_<CCI>, (r = - 0.73, p < 0.01) The fill of undigested cell contents (UCCF: g/kg^<0.75>) would equal the cell contents excretion added to (a). The rate of passage (Kp) can be represented by Kp = cell contents excretion/UCCF The rate of digestion (Kd) can be represented by Kd = (cell contents intake - UCCF × Kp)/UCCF Metabolic fecal cell contents excretion (MFCCE: g/kg^<0.75>) can be represented by MFCCE = a + (true digestibility - potential digestibility) × cell contents intake Estimated average values of total amount of cell contents present in the gut (fill), Kp, Kd and true digestibility (TD) are shown below: orchardgrass: fill = 25.0 g/kg^<0.75>, Kp = 0.72, Kd = 1.28, TD = 99% alfalfa: fill = 34.8 g/kg^<0.75>, Kp = 0.70, Kd = 2.10, TD = 95%

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There are grazing lands of ca. 44,000 ha, of which ca. 28,700 ha are steep mountainous lands (the gradient is more than 15 degrees) in Aso area. Additionally, there is much precipitation (ca. 2,600 mm/yr), and the annual range of temperature is wide in the area. Therefore, in order to promote the utilization and conservation of steep grasslands, a mixed community system pasture with native and introduced grasses was introduced and studied. In grazing in this system, energy efficiency from global solar radiation to consumed digestible herbage and changes in vegetation were compared with improved or native pastures. The energy of available herbage was 4.66 Mcal/m^2 and the energy of consumed digestible herbage was 3.94 Mcal/m^2 on the mixed community system in 1987, and the system had a high energy efficiency (Eu %) throughout the year. It is suggested that the mixed community system is useful for stabilizing annual plant production and conserving the steep grasslands in Aso area.

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Orchardgrass (cv, kitamidori), tall fescue (cv, hokuryo) and timothy (cv, senpoku) were cut at the first week and 2nd week after the date of first heading from 1979 to 1981. Tillers of each species were classified into three groups, booting, heading and vegetative tillers. Distribution ratio of classified tillers and in vitro dry matter digestibility (IVD) of those tillers were determined. IVD of field grasses (a mixture of different growth stage tillers), the distribution ratio of classified tillers and IVD of those tillers varied with the year. Annual variations in IVD of the field grasses were influenced by the differences in distribution ratio of tillers and changes in ambient temperature. Only heading tillers of the above species in a fixed area were cut at 3-day intervals during the heading period in 1982. Relationship between the number of days from May 1 till cutting (X1) and 3-day daily mean ambient temperature before cutting (X2 ; ℃) to variation of IVD (Y ; %) of heading tillers were investigated by multiple regression analysis. Significant relationships between variables were as follows : regarding three species in a lump, later heading tillers were lower in IVD than earlier ones, viz., partial correlation coefficients (PCC) of X1 and of X2 were - 0.977 and - 0.541, and standard partial regression coefficients (SRC) of X1 and of X2 were - 0.966 and - 0.135, respectively. In the case of timothy, changes in IVD of heading tillers were associated with both X1 and X2, viz., PCC of X1 and of X2 were - 0.994 and - 0.991, and SRC of X1 and of X2 were - 0.887 and - 0.727, respectively. Relationship between IVD and chemical components of heading tillers (Exp. in 1982) were as follows : cell wall constituents (CWC), acid detergent fiber and acid detergent lignin contents of orchardgrass increased with the decrease in IVD. No such relationship was observed in the case of tall fescue and timothy, and CWC contents of those species were not correlated with IVD.

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Four Japanese orchardgrass cultivars were evaluated in dry matter (DM) yield, DM intake and animal gain, and compared with a perennial ryegrass (Lalium perenne L.) and a tall fescue (Festuca arundinacea SCHREB.) cultivars. Sheep were rotationally grazed on swards sown as monoculture, and were weighed every 7 or 14 days. Animal gain of each cultivar was estimated in TDN kg units using the NRC standard because the weight and the number of grazed sheep differed in each plot. Significant differences were obtained in DM yield, TDN percentage, TDN yield and animal gain between orchardgrass cultivars. Cv.Okamidori was significantly higher in TDN % but lower in DM yield, TDN yield, and animal gain than the other three cultivars. As means of TDN % over three years, cv.Okarnidori was higher by 2.4 to 3.1 units than the other cultivars. Although the difference contributed to higher intake, that created only the slight increase in animal gain. Compared with orchardgrass cultivars, cv.Yatugane perennial ryegrass showed higher DM yield and TDN yield, and cv.Hokuryo tall fescue was lower in TDN and intake.

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The growth pattern and productive system of napier grass (Pennisetum purpureum SCHUMACH.) and corn (Zea mays L.) plants grown in field were comparatively studied to find the principal factors determining the high productivity of napier grass. 1. At the early growth stage (planting to June) of napier grass, the number of stems highly increased to about 100 stems/m^2 for 23 days after planting, and the leaves and stems elongated horizontally covering the ground. By which the structure of plant population was improved to have a higher light utilization efficiency at the growth stage with relatively low leaf area index (LAI). 2. In summer, the middle growth stage (July to August) of napier grass, the number of stems of napier grass were rapidly decreased by self-thinning to about 25 stems/m^2. However, due to a high rate of leaf expanding at high temperature, the plant population came to have a large leaf area index (LAI=13.3). In addition, the stem elongated rapidly and its elongating angle turned from horizontal to vertical direction. These phenomena caused the improvement of productive structure in napier grass, and the light extinction coefficient (K) in the plant population reduced to K=0.4. Therefore napier grass could preserved a high net assimilation rate (NAR) in this season, and the maximum crop growth rate (CGR) reached 53.3 g/m^2/day , while NAR of corn plants did not increase in this season because the population structure was not improved so much. 3. Even at the late gowth stage (September to November), napier grass hold a relatively high LAI because the plants could compensate for the leaf area reduction with scenescence by the continuous emergency of new leaves. 4. Napier grass changed the population structure adequetely according to the growth environment to create a high efficiency of light utilization and high productivity through the whole growth stages. The final dry matter weight of napier grass was 4.4 kg/m^2, two-fold that of corn plants.

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In order to establish suitable medium conditions for in vitro selection of aluminum (Al)-tolerant cells of alfalfa, the effects of the concentration of phosphate, pH and the concentration of Al in the medium were examined. With low concentrations of phosphate in the MS medium, the growth of cells in suspention culture was greatly suppressed. Addition of phosphate at intervals of two days accelerated proliferation of suspension-cultured cells when 1/8, 1/4 and 1/2 of the standard concentrations of KH_2PO_4 were added in this way. Proliferation of cells in suspension culture in standard MS medium was more rapid than that in MS with 1/10 KH_2PO_4 at all pH values tested. In standard MS, the proliferation of suspension-cultured cells increased with increases in pH from 3.0 to 4.5. In contrast, MS with 1/10 KH_2PO_4 and pH 4.0 gave the highest proliferation rate of suspension-cultured cells. Wet weight of the cells in suspension on the seventh day after culture initiation increased in proportion to the increase in the wet weight of cells added at culture initiation. However, the increase in wet weight per gram of cells added at culture initiation was highest with 0.5 g of cells per 50 ml of liquid medium. The increase in wet weight of suspension-cultured cells up to the fourth day after culture initiation was suppressed with increased concentrations of Al in MS medium with 1/10 KH_2PO_4. There were no differences in packed volume of suspension-cultured cells between the control and cells cultured in 0.05 or 0.1 mM Al_2 (SO_4)_3・18 H_2O on the eighth day after culture initiation. However, proliferation of suspension-cultured cells was suppressed at 0.2, 0.4 and there was no proliferation at 0.8 mM Al_2 (SO_4)_3・18 H_2O. Residual Al in the medium in treatments with initial concentrations of 0.05, 0.1, 0.2 and 0.4 mM Al_2 (SO_4)_3・18 H_2O was almost absent one day after culture initiation. We conclude from the proliferation of suspension-cultured cells, the Al content of cells and residual Al in the medium, that MS medium with Al concentrations of 0.2 mM to 0.4 mM Al_2 (SO_4)_3・18 H_2O will be the most suitable for future attempts to isolate Al-tolerant cells.

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