Selection of elite clones for higher general combining ability (described as GCA, afterward) is a basic procedure in synthetic variety method. In order to clarify the relationships between the characteristics of space-planted and clonally propagated plants and between the characteristics of space-planted or clonally propagated plants and their GCA, about 3, 000 individual plants were established in the experimental field of Hokkaido National Agricultural Experiment Station. Thirty four plants were selected for disease resistance and general agronomic characteristics, and propagated into 10 to 12 propagules in 1971. Eighteen clonal lines were finally selected and polycross seeds of these clonal lines combined with other 17 clonal lines selected separately from the varieties introduced in 1968 were harvested in 1973. The polycross progenies were tested for their yielding performance from 1974 to 1976. Randomized block method with three replications was used. One plot consisted of two rows 2.5m in length and 50cm apart. The results were as follows ; 1. The means of the characteristics of selected individual plants were greater than those of original populations, however, the mean of plant type of selected plants was more prostrate than that of original population. The ranges of the characteristics of clonal plants were greater than those of individual plants. 2. In the characteristics of space-planted individuals, flowering date showed significant correlations with spring vigor and fall vigor. Thickness of stem showed significant correlations with leaf size and plant height. There was high correlation between stem number and plant weight. In the characteristics of clonal plants, upright plant showed larger leaf size and higher plant height than the other plant types. The plant which showed early flowering date in space-planted nursery, showed large leaf size in clonal observation nursery and high polycross seed yield. On the other hand, leafy plant in space-planted nursery showed prostrate plant type and low plant height in clonal observation nursery. 3. Flowering date in the second year and fall vigor in the established year in spaceplanted nursery showed significant correlation with GCA of seedling vigor. Plant type, leaf size and plant height in clonal observation nursery showed significant correlation with GCA of early growth (plant height of 51 days after seeding). Leafiness and plant height in the space-planted nursery showed significant correlations with GCA of plant height. More upright type, higher plant height and larger leaf in the space-planted nursery showed higher GCA of plant height in the progeny test. The plant which has higher plant height in the space-planted nursery showed high GCA of yield. Plant weight in space-planted nursery did not show significant correlation with GCA of yield. The plant which has higher polycross seed yield showed higher GCA of yield. 4. According to principal component analysis, following selection would be effective in winter hardy population. Fall vigor in the established year, flowering date and spring vigor in the second year in the space-planted nursery seem to be characteristics effective for selection towards higher GCA of yield. Furthermore, plant weight in clonal observation nursery, polycross seed yield and weight per seed of polycross seed seem to be characteristics also effective for the selection towards higher GCA of yield.

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Seedlings of Zea mays L. cv. Great Bell were grown in aerated liquid cuture under four treatments ; control, removing root cap from seminal root, additions of 10^<-7>M triiodo-benzoic acid (TIBA) and 5×10^<-6>M cycloheximide (CHM) into culture solution respectively. The seminal roots sampled were dehydrated, embedded in paraffin cake, cut into continuous sections in both longitudinal and transversal directions and stained for mitotic investigation. Mitosis in the mitotic zone of the roots was examined microscopically. Results obtained are as follows ; 1. Mitosis was active between 200 to 800μm from the root apices in both the control and the TIBA treated plants and it was ceased beyond 1200μm. 2. In the decapped roots, whose root caps were removed, mitosis was active between 200 to 1000μm from the root apices and no further cell division occurred beyond 1400μm. This means that the mitotic activities were kept 100 to 200μm further back as compared to those of the control and the TIBA treated plants. 3. Mitotic activities were active in both the stele and the cortex of the decapped and the TIBA treated roots. 4. An asymmetrical distribution of mitotic activities in the mitotic zone in the roots was found especially in the decapped and the TIBA treated roots. From the results mentioned above, it is suggested that the mechanism of the rotation growth of the root is originated in the asymmetrical distribution of mitotic activities in the root and that the root curvature comes from the excessive accumulation of auxin within the root tissues resulting in ethylene formation. It was possible to straighten the root curvature by either removing root cap, TIBA application or applying CHM.

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This experiment was conducted to clarify the influence of nitrogen application on the efficiency of solar energy utilization in orchardgrass. The varieties examined were Latar (tiller weight type), Kitamidori (medium type) and S 143 (tiller number type). Nitrogen fertilizer was applied at 4 levels, 0 (N_0), 7.5 (N_1), 15 (N_2) and 30kg N/10a (N_3). The results obtained were summarized as follows: 1. The efficiency of solar energy utilization (Eu) showed the highest value in Latar, and the lowest value in S 143. Eu of both Latar and Kitamidori increased almost linearly with increasing N application up to N_2 level, and that of S 143 increased up to N_3 level (Table 1). 2. With increasing N application the efficiency of intercepting energy (Ei) increased up to N_1 level in both Latar and Kitamidori, and up to N_2 level in S 143. The efficiency of energy conversion (Ec) increased up to N_2 level in 3 varieties. 3. Specific leaf area (SLA) and the leaf dry weight (LbW) increased at higher N levels. C/F ratio (stem dry weight/leaf dry weight) of both Latar and Kitamidori was not affected by N application, but that of S 143 increased at higher N levels (Table 1). 4. Ei was correlated significantly with Eu before heading stage, but not significantly after heading stage. Ec was correlated significantly with Eu during the whole growing season (Fig.1). Relative light intensity at the soil surface in the canopy was associated with LAI in whole varieties. The regression coefficient of relative light intensity on LAI for S 143 was larger than that of Latar and kitamidori (Fig.2). 5. The solar radiation intercepted by the canopy (KS) and the dry matter production (ΔW) have positive correlation (Fig.3). 6. Nitrogen concentration of leaf (LbN%) have positive correlation with Ec. High correlation coefficient was obtained in the relation between Ec and LbN%×PTI (plant type index) (fig.4).

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Relative drought sensitivity was assessed by measuring dry matter yield, top-root ratio, plant and soil water concentration, diffusion resistance and transpiration rate of five tropical pasture legumes ; Macroptilium atropurpureum cv. Siratro, Stylosanthes guyanensis cv. Schfield, Centrocema pubescence, Glycine wightii cv. Cooper, and Desmodium intortum cv. Greenleaf, grown under five different irrigation levels ; the levels equivalent to 2000, 1500, 1000, 750, and 500mm/yr were even divided on daily base. The comparative decrease in dry matter yield at each irrigation level showed that the growth of legumes were fovoured in order of Cooper<Schofield<Siratro<Centro<Greenleaf under water-stressed condition. Top-root ratio, and plant top and soil water concentration changed with decreasing irrigations levels. With changing pattern of these parameters the following three groups of the legumes were made: Group I-Siratro ; Group II-Schofield, Greenleaf and Centro ; and Group III-Cooper. The group I changed gradually its parameter with decreasing levels of irrigation, the group II showed significant change with the level below 750mm and the group III showed a little change in between 2000 and 750mm but greater change in 500mm of irrigation level. Siratro has shown higher diffusion resistance, thereby lower transpiration rates under relatively higher soil water level. Cooper showed sensitive response of increasing diffusion resistanse to decreasing soil water level even at relatively higher water status of the soil. The other three legumes have shown somewhat intermediate patterns of the above two patterns. The results concluded that Siratro either decrease top-root ratio or increase diffusion resistanse with a little change in soil water levels, thus indicated sensitive morpho-physiological adaptation to soil water stress as compared to the other legumes tested.

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To find grass species which show good compatibility with Siratro, and to evaluate the role of Siratro in the mixed croppings for incresing the pasture productivity, dry matter yield, percent legume and legume effect on increasing yield were compared under two clipping intensities using pure and mixed croppings of Siratro (Macroptilium atropurpureum cv. Siratro) and six tropical pasture grasses: Guinea grass (Panicam maximum, Ok-72-1040), Rhodes grass (Chloris gayana cv. Pioneer), Pangola grass (Digitaria decumbens), Bermuda grass (Cynodon dactylon cv. Common), Setaria (Setaria anceps cv. Kazungula), and Monbrasam grass (Digitaria monbrasam). In the established phase of the pasture, annual total dry matter yield of Siratro mixed with Pangola grass, Guinea grass, and Setaria were greater than those with Rhodes grass, Bermuda grass, and Monbrasam grass showing greater mixture effect expressed in the former cases. Percent legume and mixture effect on increasing dry matter yield increased with longer clipping interval as compared to shorter interval, especially, legume component in the mixture recieved significant favourable effect. With shorter clipping interval the mixture effect occured almost in the grass component, being more stressed in the association with a grass species which show greater growth during high temperature periods. With longer clipping interval, however, the legume component received more favourable effect of mixture, especially in the associations with grasses of higher plant height. The results above have shown that Pangola grass, Guinea grass, and Setaria are suitable for mixing with Siratro for increasing mixture effect when grown in Southern part of Sowth-Western islands of Japan.

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Heavily grazed and poorly productive nezasa grassland was fenced to protect from grazing for one, two or three years and nitrogenous fertilizer was applied in four rates, 0, 10, 20, and 30kg N/10 a/yr and forage performances were compared to those of continuous grazing. Dry weight in early autumn, grass height, leaf number per stem and stem number/400 cm^2 in early summer and early autumn were measured. Growth of nezasa grassland which has been yearly cut for hay in autumn was also investigated. Height and leaf size of nezasa in grazed paddock were as short as one third with less leaves by two, with double stem number per unit area as compared to hay paddock. In spelled paddock topdressed with nitrogenous fertilizer, grass height reached to those of hay paddock and leaf number and leaf size recovered to three fourths, but stem density remained as double as those of hay paddock. When paddocks were grazed again after the long spel, leaf siz, leaf number per stem began to decrease again, but they still remained longer or more than those of continuously grazed paddock even after two years since opening. Average dry weight of fertilized grassland was twice compared to that of non fertilized grassland after one year from fertilizing. Although differences were small, larger dry weights were obtained under heavier fertilization after one year from fertilizing. But at the same period, grass height were lower under heavier fertilization suggesting excess application of fertilize. It is not decided however that 20 or 30kg is over supply of nitrogen because grassland with these nitrogen increased their dry weight after two or three years from fertilizing, whereas grassland with 10kg nitrogen stopped increasing it's dry weight after one year from fertilizing.

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Experiments were conducted to study the effect of cutting time upon the nutritive value and voluntary intake of orchardgrass as well as to predict the relations between them. Digestion trials were carried out with wethers over six years to determine the voluntary intake and digestibility of the herbage clipped at several growing stages. The samples consisted of twenty first cuttings and forty three aftermaths. Relationship between the time of cutting in days since April 30 (X) until July 26, and the percentage of digestible dry matter (DDM) was estimated. There was a highly significant correlation not only between growing time and DDM but also voluntary dry matter intake (VI: g/W^<0.75>). The regression equation was DDM=87.3-0.55X (r=-0.96 p<0.01), while VI=94.2-0.76X (r=-0.89 p<0.01). In early summer grasses which were the aftermath grown before August 1st, the relations between DDM and the days of regrowth (X) was shown as DDM=72.5-0.38X (r=-0.73 p<0.01), while between the VI and X VI=86.1-0.68X (r=-0.62 p<0.05). In late summer grasses which were the aftermath grown after August 1st, relations between DDM and the days regrowth (X) were reasonably expressed by quadratic equation DDM=47.0+1.31X-0.022X^2 (R=O.61) while between the VI and X, VI=25.2+3.07X-0.051X^2 (R=0.66). Autumn grasses, which were the last cutting of the year in autumn, showed the much slower rate of fall in digestibility and voluntary intake noted above. DDM may be predicted by the equation DDM=63.0+0.38X-0.0047X^2 (R=0.82), while between the VI and X, VI=81.0-0.33X (r=-0.83 p<O.01), whose X is the days of regrowth.

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Chemical composition of the first and second cutting grasses of fall panicum cultivated in the paddy or upland fields were analyzed and the grasses were ensiled in experimental silos. The relations between the chemical composition of the ensiled grass and the quality of its silages ensiled with or without the treatments were investigated. Six components in fall panicum were similar to soiling corn harvested before heading stage for the first cutting and heading stage for the second cutting. There were no remarkable differences in the components except crude protein between the paddy and upland condition. Contents of calcium and phosphorus were generaly lower than the pasturage and high level crude silicic acid were not contained in the grasses. The WSC contents in dry matter were low as approximately 5% in the first cutting and high as approximately 10% in the second cutting and ratios of WSC to crude protein were under 0.5 in the first cutting and above 0.8 in the second cutting. NO_3-N contents were considerably high at upland field condition and low at paddy field condition. The quality of the first cut silages was remarkably poor. Addition of glucose at the rate of 1% of the material grass considerably improved the quality but the grass contained low NO_3-N required the addition of 2% glucose for the improvement. The elevation of Flieg's evaluation was not contributed with the addition of 0.1% NO_3-N on material dry matter and acetic, butyric and total acid contents decreased in the silages of low nitrate materials, and butyric acid increased in those of high nitrate. Wilting at about 80% moisture was not enough to improve the quality of silages and the addition of 1% glucose were required for good quality. Silages ensiled the second cutting grass were good quality without the treatments. From these results it was deduced that the silage making from the first cutting of fall panicum requiered the treatments such as the sugar addition or wilting.

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In order to determine the cutting dates to cut grass at an any given digestibility, changes in in vitro dry matter digestibility (IVDMD), crude protein (CP) content and dry matter (DM) yield with advancing primary growth were investigated by the regression analysis on the growing day. The species tested comprised timothy (4cv.), orchardgrass (3cv.), tall fescue (3cv.), meadow fescue (1cv.), read canarygrass (1cv.), alfalfa (3cv.), red clover (3cv.) and ladino clover (1cv.). Changes in IVDMD, CP content and DM yield with advancing primary growth were well fitted by the linear regression, the asymptotic regression and the quadratic regression, respectively. After the investigation on change in IVDMD, the cultivars of timothy and tall fescue were divided into two groups, which one was early-heading cultivar group and the other was late-heading cultivar group. The cultivars of orchardgrass, alfalfa and red clover were lumbed together respectively. The regression equations of IVDMD, CP content and DM yield were calculated each group. There were considerable differences in changes in IVDMD, CP content and DM yield between groups with advancing growth. IVDMD and CP content of grasses decreased rapidly while those of legumes decreased slowly. Reed canarygrass decreased in IVDMD most rapidly at 0.63% per day, and the other grasses decreased at 0.4-0.5%. Alfalfa and red clover decreased in IVDMD at 0.32%, 0.36% respectively. Ladino clover decreased in IVDMD most slowly at 0.17%. Early-heading cultivars tended to be more digestible and to have higher CP content than late-heading cultivars, but to be less in DM yield at 50% heading stage. There was a tendency for early-heading cultivars to reach at a given IVDMD earlier than late-heading cultivars. At a given IVDMD, early-heading cultivars tended to have higher CP content than late-heading cultivars, but to be less in DM yield. At 70% IVDMD the cutting dates ranged from 13th-14th June for early tall fescue, orchardgrass and reed canarygrass, to 24th-28th June for late timothy, alfalfa and red clover.

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The simultaneous determination of volatile fatty acids and lactic acid by gas-liquid chromatography was studied to improve the conventional method in rapidity and simplicity to evaluate the quality of silage by analyzing the organic acid contents. The column used was made of glass (1.5m) and filled with telephtalic acid (solid support) coated with PEGPE-3, 000 at 3%. Aqueous extract of silage to which diethylen glycol had been added as an internal reference substance was directly introduced into the gas-liquid chromatograph. The column temperature was programmed from 100℃ to 180℃. The volatile fatty acids and the free lactic acid were separated well in a shorter time. The elution was done in the order of acetic acid, propionic acid, isobutyric acid, butyric acid, isovaleric acid, valeric acid, isocaproic acid, caproic acid, diethylene glycol and lactic acid. Present method is superior to the conventional ones in rapidity and simplicity of the operation, therefore it is more useful for evaluating the quality of silage.

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Neutral detergent fiber (NDF) and acid detergent fiber (ADF) of orchardgrass, and filter paper were chemically esterified with ferulic acid (FA) and p-coumaric acid (PCA). The degradability of the fibers by commercial cellulase decreased linearly with the content of the esterified phenolic acids ; the regression coefiicients were -6.7% NDF/percent FA, -4.0% NDF/ percent PCA, -13.1% ADF/percent FA or PCA, and -9.4% filter paper/percent FA or PCA. Acid-soluble lignin is suggested also to inhibit enzymatic degradation, since NDF had higher content of acetyl bromide lignin and the degradability of NDF was less than that of ADF.

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