To explore the possibility of breeding of strains with high digestibility, variability of orchardgrass cultivars was investigated for in vitro dry matter digestibility (IVDMD) in two different experiments. Twenty-four cultivars or strains were evaluated by the one-step cellulase method (J. Japan. Grassl. Sci. 23: 177-182) at each of four harvest times in 1976 and 1977. Significant varietal differences were observed at all four harvest times in 1976 and two times in 1977 (Table 3). Hokkai-9, Potomac, Hokkai-1, Latar et al. indicated significantly higher IVDMD compared with S143, Tammisto, and Saborto through at all harvest times (Tables 1 and 2). Significant positive correlation coefficients were observed between IVDMD's in 1976 and 1977 at each harvest time. There was little year-to-year variation among cultivars (Table 4). IVDMD's of eleven cultivars were determined using the TILLEY-TERRY method (J. Brit. Grassl. Soc. 18: 104-111) at seven harvest times in 1969. Hera had significantly higher IVDMD compared with S143 at all harvest times. The range among cultivars was larger in summer (6.8 to 9.6%) than in spring and fall (3.1 to 7.8%), (Table 5). Discussion suggests orchardgrass breeder should put more importance on digestibility of aftermath growing under conditions of high temperature and low humidity.

View full abstract

Selecting for digestibility by the observation of some plant characters is easier than chemical analysis if those characters are associated with digestibility. This experiment was intended to investigate the relationship between in vitro digestibility and some morphological and physiological traits in hay of space-planted orchardgrass. Characteristics were investigated for leaf color, leaf width, leafiness, growth habit, leaf flexibility, date of ear emergence, spring vigor and in vitro digestibility (Table 1). Digestibility of individual plant was analysed at heading stage by the one-step cellulase method (J. Japan. Grassld. Sci. 23, 177-182, 1977). Significant difference was observed when digestibility of eight varieties were compared with the mean (n=91-97 plants). Variety difference between the highest (Okamidori) and the lowest (Kitamidori) was 3.6%. Range of digestibility for 758 plants was 20.0% (Table 2). In the relationship between in vitro digestibility and plant characters, the trends differe in different varieties. Higher digestibility plants showed lighter leaf color in Okamidori, greater leaf width in Okamidori and Pennlate, and prostrate form in Akimidori, Chinook, Tammisto and Tenderbite. Plants showing earier ear emergence indicated high digestibility in Chinook and Pennlate but low digestibility in Akimidori and Tammisto (Table 4). Using 758 plants, greater leaf width, later ear emergence and prostrate form were correlated positively with high digestibility (Table 4).

View full abstract

This experiment was carried out in order to know the relationship between yield and yield components and the interactions among yield components in 12 varieties of orchardgrass grown under individual plant basis. The results are summarized as follows: 1. Dry weight of a plant indicated significant correlation with the dry weight of a tiller, but not correlated with the number of tillers per plant. There was highly negative significant correlation between the dry weight of a tiller and the number of tillers per plant. The dry weight of a tiller indicated highly significant correlation with (stem thickness)^2×plant height. But the weight of a tiller was influenced by the plant height more than the stem thickness. 2. The tiller number type and the tiller weight type which were classified by the plant type index (dry weight of a plant/(number of tillers per plant)^2) corresponded very well with the distinction of pasture type and the hey type. The plant type index may be a very useful method to classify the grass varieties. 3. The dry weight of a plant in the tiller weight type varieties had highly significant correlation with both of the weight of a tiller and the number of tillers per plant. But in tne tiller number type varieties, it was positively correlated with the number of tillers per plant, but negatively correlated with the dry weight of a tiller. 4. In the tiller weight type, the heading tiller contributed to the yield more than the vegetative tiller. On the contrary, the vegetative tiller did more than the heading tiller in the tiller number type. 5. From the facts described above, we may conclude that the stemmy type is advantageous in the varieties of tiller weight type, and the leafy type is advantageous in the varieties of tiller number type for dry matter production under the individual plant basis.

View full abstract

This experiment was carried out in order to classify 12 varieties of orchardgrass grown under individual plant basis by the principal component analysis. Out of 42 characters measured, 11 characters were selected. They were number of tillers per plant, weight of a tiller, tiller angle, stem thickness, plant height, panicle length, 2nd internode length, 3rd leaf breadth, 3rd leaf length×3rd leaf breadth and 3rd leaf length/3rd leaf breadth ordered downward from the flag leaf. The results are summarized as follows: 1) 84% of the total variation of 11 characters were accounted for by 1st, 2nd and 3rd principal components. The 1st principal component is mainly concerned with plant type and plant size. It is assumed that the 1st principal component is almost the same as the plant type index defined in the previous paper (J. Japan. Grassl. Sci., 24, 102-107). In fact, the 1st principal component indicated highly significant correlation with the plant type index (r=0.925). The variety with the large 1st principal component should have the big and elect tillers. Similarly, the 2nd principal component appeared to indicate the size of photosynthetic and non-photosynthetic organs, and the 3rd principal component appeared to correspond to the size of panicle. 2) The classification of 12 varieties was made using these 3 principal components. The result of classification seemed to be short of clearity on this purpose. It was concluded that the classification of grass variety with the plant type index reported in the preceding paper should have a practical meaning. The principal component analysis might be useful in the case of classification of varieties including large numbers of unknown materials.

View full abstract

From the results of a parental, back, and sib crosses, stem rust resistance was dominant, and was inherited hexasomically in a manner of random chromosome segregation. Uredia formation was inhibited equally well in simplex and duplex plants. Weaker dosage effects of the resistance gene compared with that observed in orchardgrass, were referred to higher ploidy level of the host plant.

View full abstract

The experiment reported here was conducted to investigate the growth and yield of corn on a upland field converted from paddy field of ill-drained clayey soil during 1971-1975. The converted upland field was transposed from paddy field in autum of 1970 and the work of under drainage was constructed in April 1971. The results obtained in this experiment were as follows ; 1. In the first year of the experiment on converted upland field, it was found that seedlings of corn plant were some-times suffered from severe wilting due to the violent fluctuation in soil moisture. It was observed that lower growth increment and lower yield were obtained from each plot, particularly in the plot where nitrogen was not applied, plants showed marked reduction of growth and dry matter production. 2. The wilting of corn plants were decreased with a lapse of year, therefore, the growth increment and the yield of corn also increased continuously during five years of experimental period after conversion. 3. It was found that the crop growth and yield were poor in the first year of conversion, thereafter, increased growth and yield seemed to be due to the improvement of soil physical conditions. The authors concluded that it took rather long term and gradual processes to improve upland field converted from paddy field of ill-drained clayey soil.

View full abstract

To show the cause of lower grassland productivity at the early stage of tropical legume/grass mixture system, yields of dry matter and nitrogen and the magnitude of mixture effect on increasing dry matter production were investigated for two years with the mixed stand of Desmodium intortum cv. Greenleaf (De) and Setaria anceps cv. Kazungula (Ks) and the pure stands of De and Ks. Results obtained are as follows: 1) Dry matter yields in the mixed stand were higher in the second year than in the first year. 2) Nitrogen contents in De increased after the second harvest while those in Ks increased with later harvests. Nitrogen yields were, in the decreasing order, the pure stand of De, followed by the mixed stand and the pure stand of Ks. 3) Mixture effect significantly increased in the second year, especially in Ks component. These results were discussed in relation to nitrogen transfer from the legume to the grass. It was concluded that lower grassland productivity at the early stage of the sward establishment was due to longer periods required for the begining of active nitrogen fixation by the legume and of nitrogen transfer from legumes to the grass. Application of starter nitrogen was suggested for a means of increasing grassland productivity at the early stage of the grassland establishment.

View full abstract

The effect of temperature on mineral N absorption and symbiotic N fixation by Desmodium intortum cv. Greenleaf (De) was studied using ^<15>N. To study this effect, three different temperature conditions of 20℃, 25℃ and 30℃ were imposed on the seedling of De inoculated and applicated with starter N. Plants were harvested 8 times at 5 day intervals commencing in 8 days after the germination. Items studied were DM yield, leaf area, nodule number, nodule weight, total N and the proportions of N originated from N fertilizer and symbiotically fixed N. Results obtained were as follows: 1) DM yield was higher in order of 30℃>25℃>20℃ with wider difference between 25℃ and 20℃. 2) Better nodulation was seen at higher temperature. White nodule increased at lower temperature. Nodule weight per leaf area showed similar trend to nodule number. Nodule number per root weight was higher at 30℃, followed by 25℃ and 20℃ without any significant difference between 25℃ and 20℃. 3) N content was higher at higher temperature and wider differences between tem-temperatures were recognized in the plant top. Total N yield and the portion of N originated from nodule was higher at higher temperature. The N originated from nodule out-yielded that from fertilizer at 25℃ and 30℃, but not at 20℃. The N fixed per nodule weight at 25℃ and 30℃ doubled that at 20℃. 4) The basic mechanism in which starter N affects the seedling growth of De and N fixation might be identical at all temperature conditions to those described in the previous paper. However, N fixation played a more significant role at higher temperature, and N absorption at lower temperature.

View full abstract

1. The significance of seed volume weight in selecting good germinating seeds of green panic was investigated. 2. There were close correlations between seed volume weight on one hand and weight per 1000 seeds, ratio of "actual seed volume" to seed volume and the seed thickness measured under pressure of dial gauge on the other hand. "Actual seed volume" was measured using an apparatus for measurement of actual soil volume. Hence it was thought that these four seed characters were related equally to germination percentage. Actually the correlation coefficients were similar between these four seed characters and the germination percentage (r=0.81-0.85). 3. "Specific gravity" (seed weight/actual seed volume) and the seed thickness measured without pressure had no relation to germination percentage. 4. It was thought that in presuming germination percentage of green panic seeds, seed volume weight was most suitable criterion because of its relation to germination percentage and its easiness of measurement. 5. Seed lots with volume weight over 240mg/cc showed germination percentage more than 35%, and seed lots of 200-230mg/cc germinated at rates about 20%. Seeds of 200mg/cc or less germinated at rates less than 10%.

View full abstract

The method for measuring the volume weight of a small amount seed of green panic by a measuring cylinder was investigated. Practical methods for putting seed into a measuring cylinder and for measuring its volume were detailed. Seed volume is to be measured immediately after putting seed into a measuring cylinder, because when the bottom of the measuring cylinder is knocked the obtained value of volume weight vary with volume of seed measured. Capacity of the measuring cylinder should be over volume of seed measured and should be minimum. Satisfactory correct volume weight of green panic seed in practical use is given by one measurement for seed of 100-500cc, by average of two measurements for 50-100cc, and by average of three measurements for 4-50cc.

View full abstract

The changes in sucrose and fructosan hydrolyzing activities (SHA and FHA) associated with the insoluble fraction in the haplocorm of timothy were examined during the regrowth after cutting. SHA increased during the first 2 days, followed by decrease till 4th day and thereafter kept almost constant, while FHA was not altered by cutting. Some properties of these enzymes were also tested. The optimal pHs for SHA and FHA were 4.5 and 6.0, respectively, the pH activity curve of FHA being broad within the range of pH 5.0-7.0. SHA was most active at around 30℃. β-Fructofuranosidase, α-glucosidase, β-glucosidase and cellulase were bound to the insoluble fraction. The release of SHA from the insoluble fraction was partially attained by treatment with papain, but not by 1M NaCl, 0.25M borate buffer, cellulase, bromelin and pronase. SHA remained in the insoluble fraction was increased only by treatment with cellulase.

View full abstract

Orchardgrasses of two clonal lines (Cl79, Cl637) were planted in Wagner pots after first cutting, and were grown at the controlled temperatures of 15/10, 20/15, 25/20 and 30/25℃ (day/night), and outdoors, respectively. After 40 days, they were harvested and analysed for nonstructural carbohydrate composition by means of liquid chromatography. The contents (%DM) of monosaccharides declined with increasing temperature, their ranges being 1.4-0.5% for glucose and 1.8-0.2% for fructose. The effects of temperature on sucrose contents (3.7-6.5%) were not consistent, but the percentages of sucrose in total nonstructural carbohydrates were high and constant at and above 20/15°. Fructosan contents were higher at low temperatures, though maximum value was only 0.7%. Starch contents ranged from 0.4-1.6%, showing minimum values at 20/15°. Total nonstructural carbohydrate levels were lowest at 25/20°(Cl79) and at 20/15°. (Cl637), the higher levels at higher temperatures were due to the increases in sucrose and starch. Sugar contents of the plants grown outdoors were within the ranges with the plants in the controlled environments, except for sucrose of Cl637 and starch of Cl79.

View full abstract

Changes in population density and distribution of stubbles were studied in each sward of perennial ryegrass, timothy, tall fescue and redtop. The swards were treated with three levels of fertilizer application (light-, medium- and heavy-fertilization) and two levels of cutting frequency (three and five cuttings per year). Population densities were surveyed at each cutting for two years and the pattern of spatial distribution of stubbles in swards were investigated at the last cutting in the autumn of the second year, as the distribution of stubbles in swards was considered to show whether the individual plant might die out or survive through out the process of changes in population density. 1) The population density decreased faster in the first year than that of the second year in all swards. The rates of decrease were larger under the treatments of heavy fertilization with less frequent cuttings. The decreases were also larger in swards of tall fescue and perennial ryegrass than those of timothy and redtop (Fig.1). 2) The plant weight, however, were larger in such swards as the rates of decrease were notable than those of lower rates of decrease. And a functional relation was obtained in each cutting between plant weight and population density notwithstanding the differences of the species and the treatments (Fig.5). 3) In order to know the spatial distribution of stubbles, size of a stubble (diameter of stubbles), distance from a stubble to an adjacent stubble and size of the adjacent stubble were measured. High correlation was obtained between stubble size and the distance between two neighbouring stubbles. In other words, small sizes of stubbles were situated adjoining in a short distance with one another, and large ones were situated at a distance (Fig.3). And in swards where various sizes of stubbles were dispersed, large size of stubbles were dispersed at a distance, and comparatively small size of stubbles were adjoined to the large ones (Fig.4). 4) These inclinations on the distribution of stubbles seemed to show that the competition among individual plant had exerted marked influence upon the changes in population density.

View full abstract

The dispersion characteristics of heifer excreta on pasture were investigated and described quantitatively. Dispersion patterns were examined by fitting the theoretical distributions to the observed excretal frequency distributions and by MORISITA's I_δ-index. The results obtained were as follows: 1) Most of the excretal clumps of 2-8a were formed by the effect of grazing equipments, e.g., watering place and salt racks. Excretal dispersion including these clumps were more aggregated, and when these clumps were removed they became less aggregated. 2) Frequency distributions of excreta per quadrat were described by the Poisson or the negative binomial models after the significant clumps caused by grazing equipments were removed. 3) When significant clumps caused by grazing equipments were removed, applicable conditions of the two kinds of models were divided into three parts by the relationship between the quadrat size and the mean density of dung and urine as shown in Fig.4, and the 'common k' of the negative binomial model estimated on dung was 4.40 (confidence limits: 4.00-4.88).

View full abstract

In order to clarify the relationships between milk yield and seasonal fluctuations in grass growth, this investigation was carried out deal with pasturing cows parturition in spring and summer. The milk yield of summer parturition cows was about 20 per cent lowered as compared with that of spring parturition cows, even eliminate high temperature in summer. Under the condition of independent of temperature for milk yield, i.e. below 27℃, it was recognized significant possitive correlation between milk yield and grass standing crop in pasture. Consequently, the highest milk yield showed when the peak of grass growth, i.e. spring flush, corresponded to the peak of lactation curve. On the other hand, the more deviate these two peaks each other, the lower the milk yield. From these results, it became clear that animal output of dairy pasture within arable land was more depended on pasture output than that of permanent pasture without arable land.

View full abstract