In the U.S.A. Corn Belt, there are many superior breeding populations resulting from population improvement. The introduction of these populations to the northern part of Japan, in most cases, has not been successful due to their late maturity. BS 13 (S_2) C_1 introduced from the U.S.A. was selected for early flowering by sibmating over a five-generation period with relatively small population size. Responses to selection for early flowering were 2.0 days/cycle and 1.4 days/cycle, for days to tasselling and silking, respectively. The equation for estimating response to selection was obtained from the results of the study. ΔG=0.53ks, where 0.53, k, and s were heritability, selection differential, and standard deviation of each population, respectively. Most traits measured changed significantly due to selection for early flowering. Spring vigor and hundred-kernel weight increased, and stalk length, ear height, and number of effective ears decreased. Also, delay of silking was observed. There was no significant difference among C_0, C_1, and C_2 in combining ability. Within-population variabilities of several traits including flowering were not changed badly due to selection for early flowering.

View full abstract

The extensive utilization of the Japanese lawn grass has been restricted mainly by two factors, viz., unavailability of commercial seeds and extremely poor germinability of seeds. As concerns the former subject, the authors reported previously in the first paper of this series, and so the present paper is concerned with the latter one. Germinability of seeds derived from different clonal lines identical with those of the previously reported was compared as a fundamental study of selecting easily germinable lines. About 30 local clones, which had been grown under uniform garden conditions, provided seed materials for Experiment 1 (1978s seeds) and Experiment 2 (1981s seeds). In both experiments, germination responses were tested using fertile seeds without any treatment (control) and those with various pretreatments for germination acceleration. Two to four replications of 100 seeds each were used in every test. Throughout the two series of experiments, non-treated seeds showed poor germination on an average with a wide range of line to line variation. From the analysis of variance, significant differences between lines were recognized. Germination responses to the given treatment and condition also differed greatly between lines. All germination data were transformed into relative values and averaged over four treatments. Thus, the Relative Germination Degree (RGD) of each line was tentatively given as a general index for the evaluation of germinability. Correlation coefficient of germinability based on the RGD showed r=+0.77 (significant at 1% level) between two series of experiments. This suggests that most of the preserved lines used are able to produce nearly consistently the seeds possessing line-specific-germinability under variable conditions. Using a mean RGD as a basic criterion, 31 preserved lines were classified into four types (A to D) corresponding to their difficulty of germination. From the standpoint of breeding seed-propagation-line, the clonal lines belong to Type D, and some of Type C appear to be of use for its materials.

View full abstract

This study was carried out to make clear the relationship between seedling growth and respiration in summer forage crops. Rhodesgrass (Chrolis gayana KUNTH), African millet (Eleusine coracana GAERTN.), sorghum (Sorghum bicolor (L.) MOENCH.), corn (Zea mays L.) and some comparative crops were investigated under complete dark conditions. The results obtained are summerized as follows ; 1. Seed weight had a strong influence on the reduction rate of endosperm. Species of which seeds were light in weight had higher reduction rate of endosperm (%/day) than that of heavy seed species, and the reduction rate of Rhodesgrass was highest. 2. Reduction rate of endosperm was likely to be related with relative growth rate (RGR). As a whole, species with high reduction rate had higher RGR. The highest RGR was showen in African millet. It was estimated from these results mentioned above that not only reduction rate of endosperm but respiration could couse RGR of summer forage crops in endosperm-dependent seedling growth. 3. Temperature had remarkable effects on the reduction rate of endosperm and RGR, but little effect on the growth efficiency (GE). 4. The specific differences in growth efficiency among summer forage crops were observed, and the value of GE of African millet was higher than that of others. From these results, it was recognized that the high value of GE increased RGR in the seedling growth of African millet.

View full abstract

In order to clarify the specific differences in growth efficiency (GE) in summer forage crops, sorghum, green panic, Rhodesgrass, African millet and some comparative crops were investigated both in the dark and illuminated conditions. The results obtained are summarized as follows; 1. Relationship between dark respiration rate and relative growth rate (RGR) of seeding (excluding endosperm and scutellum) was expressed by the linear equation in respective species. According to the method of HESKETH et al (1971), maintenance respeiration rate (M) and growth respiration coefficient (Gr) were estimated by the constant and the coefficient of the linear equation, respectively. 2. Temperature had a direct effect upon the maintenance respiration rate (M) of seeding, and the specific differences in the value of M were found. Generally, species of which seeds were light in weight had higher value of M. Rhodesgrass had the highest value of M. 3. Temperature had no effect on the growth respiration coefficient (Gr), and no specific differences were found in the value of Gr. The mean value of Gr at 25°C was 0.224, and estimated value of transformation factor [K=1/(1+Gr] was 0.82. 4. Relationship among growth efficient (GE), transformation factor (K), maintenance respiration rate (M) and relative growth rate (RGR) was expressed by the following reciprocal equation. 1/GE=1/K+M/RGR It was recognized from these results mentioned above that the specific differences in the value of GE (previous report) were found on the differences in M/RGR (MGR: Maintenance respiration-Growth Ratio). 5. On the assumption that the value of K is 0.8, the value of MGR can be calculated numerically from the value of GE in respective species. The specific differences in MGR among summer forage crops were observed, too. And it was recognized that the value of MGR of African millet was lower than that of others.

View full abstract

In vitro dry matter digestibility were measured for the second year's plant materials obtained from the preceding experiment (VII) in order to evaluate digestible dry matter (DDM) yields of the tropical legume-grass mixtures grown in South-Western Islands of Japan. The legumes and the grasses used in this experiment and the treatments were all described in the preceding paper (VII). Endeavour stylo or shofield stylo mixed with the grasses outyielded Townsvill stylo mixed with the grasses in annual DDM. The levels of annual total DDM obtained from these mixtures were equivalent to the mono-cultured Rhodes grass applicated with 250-350kg N/ha/yr.. DDM yields increased in the legumes growing in association with Guinea grass reaching to 40-50cm of plant height at clipping time (40 CL), and Rhodes grass or Setaria grass reaching to 60-70cm of plant height at clipping time (60 CL). Production rates of DDM in the mixtures showed greater seasonal fluctuation in 40 CL and more stressed in 60 CL. IVDMD% of the legumes were higher than the grasses by 4-15% showing higher values in cooler seasons and lower values in warmer seasons. The former were corelated with mean daily temperature and the latter with heat summation above 15℃ during the regrouth periods. From the results above, petential of the subjected tropical legume-grass mixtures were better recognized by evaluating DDM yields as compared to dry matter yields. Shorter clipping intervals and the management for maintaining relatively higher legume ratio were suggested for further increase of DDM yields of the mixtures.

View full abstract

For finding economical methods for establishing tropical legume-grass mixtures, Siratro (M. atropurpureum cv. Siratro) and Endeavour stylo (S. guianensis cv. Endeavour) were oversown into Rhodes grass sod following the suppression of vegetation by full-cultivation, a single light disking, chemical apray, burning, and zero-tillage. Annual total dry matter yields, yet providing with appropriate legume component, were increased by over-sowing each legume following a single light disking or chemical spray. Successufull results were attributable to increased number of the seedlings following the suppression of vegetation by the above two methods. A careful suppression of Rhodes grass sod and sowing rates which give at least 50 seedlings per m^2 were required for sffccessful establishmeshment of Siratro, due to its compatibility being somewhat inferior to Endeavour stylo.

View full abstract

A radiocarbon tracer technique was used to determine the effect of nitrogen levels on the utilization of carbohydrate reserves in the regrowth of orchardgrass. Plants from a clone were grown in the solution for 2 months at four nitrogen levels (N_1=3.76, N_2=15.05, N_3=30.10, N_4=60.20ppm). All of the leaf blades of the plants were defoliated 24h after exporsure to ^<14>CO_2. The ^<14>C-activity of each organ (leaf blade, stubble and root) were measured 0, 2, 4 and 7 days after the defoliation. The dry weight of the leaf during the first 4 days of regrowth was higher under nitrogen levels. The ^<14>C-activity in the stubble and root decreased more at higher nitrogen levels, while ^<14>C-activity in the leaf was similar among the treatments, suggesting that the respiratory losses of ^<14>C0_2 from the stubbles and root were greater at higher nitrogen levels. It was concluded that a small part of the carbohydrate reserves were mobilized to the leaf regrowth irrespective of nitrogen levels, and the most of those were utilized for the respiration during the first 4 days after the defoliation.

View full abstract

This experiment was carried out to determine the effects of subsoil acidity of Andosols on the growth and nitrogen uptake of both alfalfa and orchard grass. A well-limed fertilized Andosol was used for the surface soil (0-15cm) of all experimental columns (d. 16cm×h. 50cm) and two kind of untreated Andosols were used for the subsoil of these columns: Zao weak acid soil (allophanic) and Kawatabi very strong acid soil (nonallophanic). Tagged nitrogen fertilizer was used for both basal application and top-dressing. Alfalfa showed normal root growth in allophanic subsoil, but very poor rooting due to Al toxicity in nonallophanic subsoil. In contrast, orchard grass showed normal root growth both in allophanic and nonallophanic subsoils. The nitrification of basal fertilizer ammonium sulfate took place almost within a couple of weeks in the studied soils. Nitrate nitrogen derived from the basal nitrogen moved easily toward the subsoils reflecting the climatic conditions such as high rainfall and low temperature during fall season. Consequently, alfalfa of fall sowing showed severe nitrogen deficiency and drustic reduction of dry matter in nonallophanic soil. On the other hand alfalfa of spring sowing showed water stress in nonallophanic soil, because of both high evapotranspiration and poor precipitation during the first half of June. Orchard grass sown both in fall and spring showed neither nitrogen deficiency nor water stress even in nonallophanic soil. The recovery of basal nitrogen and top-dressed nitrogen by alfalfa sown in fall were 5.3% and 44.6% for nonallophanic soil and 28.2% and 65.0% for allophanic soil respectively, and those by orchard grass were 46.2% and 79.1% for non-allophanic soil and 79.4% and 84.7% for allophanic soil. The differences in recoveries of basal nitrogen described above were mainly due to the root development in the subsoils. On the other hand, the recoveries of basal nitrogen of both alfalfa and orchard grass sown in spring were 51.1% and 55.9% for nonallophanic soil and 64.0% and 53.1% for allophanic soil respectively. About 80% of nitrogen absorbed by alfalfa was soil and rhizobia nitrogen and about 60% of nitrogen absorbed by orchard grass was soil nitrogen. Though the amounts of basal nitrogen absorbed by the plants were small, it played a significant role for the growth at the very early stage.

View full abstract

Seasonal changes in digestibility of herbage plant of pasture were determined. The seperated samples of leaf and stem fractions in orchardgrass, tall fescue, red top, Kentucky bluegrass and white clover, and of dead portion (included all species) were collected from mixed species pasture subjected two different stocking rates. Samples for digestibility test were taken once a month from late April to late October through the two grazing seasons of 1980 and 1981. In vitro dry matter digestibility (IVDMD) of each fraction and dead plant part were measured by successive treatments with nutral detargent and cellulase. Results obtained were as follows: 1) It was generaly observed in leaf-brade and stem with leaf-sheath that IVDMD attained to the highest value in the early spring, decreased in the late spring, and recovered during the fall. Compairing it among species under different stocking rates, differences in IVDMD were scarcely found in leaf-brade for all species, while in stem, it tended to have higher values for heavy grazing than for light grazing through the grazing seasons. Differences in IVDMD between leaf and stem fractions were observed obviously for orchardgrass and tall fescue in the late spring, and for red top and white clover through the seasons. 2) Negative correlations were showed in all grasses between IVDMD of leaf-brade and averages of maximum daily air temperature during regrowth period after grazing. In linear regression analysis, the IVDMD for orchardgrass and red top were higher than for Kentucky bluegrass and tall fescue in about five percent unit through the seasons.

View full abstract

Fibrous residues (FR) left after the extraction of leaf protein concentrates from sorghum, Italian ryegrass and oats of early heading in maturity were ensiled and the digestibibility in cows of components of them were compared with those of a conventional sorghum silage and a whole crop corn silage. Four Holstein milking cows were divided into 2 groups and fed the silages freely for 4 periods according to the design shown in Table 1 with 12kg of a formula feed and 2kg of beet pulp per head per day. Each period was consisted of 15 days and the feces were collected during the last 5 days. The digestibilities of crude fiber and acid detergent fiber of oats-FR silage and Italian ryegrass-FR silage were significantly higher than those of the other silages. The fibrous materials in sorghum-FR silage was also significantly and a little more digested than those in the conventional sorghum silage and the whole crop corn silage, respectively. The digestible energy (DE) contents of the diets were compared and found to be significantly higher in the diets containing oats-FR silage or whole crop corn silage, followed by the diets containing Italian ryegrass-FR silage or sorghum-FR silage and the lowest in the diet containing conventional sorghum silage. The high DE content of the whole crop corn silage might be attributed to the inclusion of corn grain. The differences in the digestibilities of dry matter and organic matter and the TDN contents among the diets were similar to that observed in the DE content. No signficant differences were found among the diets in the digestibility of crude protein. The milk yield of cows was not affected by the feeding treatments during 2 months' experimental period.

View full abstract

We investigated the variations of chemical compositions due to sampling positions in silo or hay bale, and discussed an adequate sampling method, mainly sample weight, in consideration that small amount is convenient for crush and analysis of many samples. 1) Variations of starch content (wet basis) of corn silage samples obtained from seventeen positions in tower silo was large. It showed thst corn grain existed locally in silage and an adequate sampling was necessary. Range of dry matter (DM) contents between seventeen samples was 7.3%. Variation of cell wall content (CW) was relatively small and it was 7.0% as coefficient of variation. 2) Differences of compositions between 3.0, 2.5, 2.0, 1.5, 1.0, 0.5 and 0.25kg samples obtained by dividing corn silage equally several times were small. It showed that 0.25kg. sample weight was sufficient to predict the compositions of silage. The differences in glass silage were small, too. 3) Dry matter content of 20kg grass silage 24 hours later after taking out of silo was significantly higher than 1 hour later (P<0.01). But difference itself was small, and within 3%. Change of dry matter content of corn silage was small, too. 4) Seventy samples from five hay bales by hay sampler showed that variations of content of moisture, crude protein and CW in a bale were small. And so, one mixed sample which consists of many portions (one portion per one bale) is sufficient to estimate the compositions of bales if bales are made at the same condition.

View full abstract

The fibrous residue left after the extraction of leaf protein from legumes (ladino clover and broad bean) was dried, and its food value was examined in digestion and nitrogen balance trials using sheep fed only the dried residue at 2.0% level of dry matter per kg body weight. The results obtained were as follows; 1) The chemical composition of dried residues was very similar to that of the ensiled fibrous-residue or orchard grass hay. 2) The digestibility of organic matter of the dried residue was 67-72%, and was significantly higher than that of hay or silage made from the same fibrous residue of ladino clover. The digestibility of crude protein was fairly higher than that of hay, and of the ensiled residue (treated). The crude fibre digestibility was 67-72% and was significantly higher than that of hay, and these figures were similar to those of the ensiled fibrous-residue or orchard grass hay. 3) The retained nitrogen was similar in both feedings of dried residues and hay, although the utilizability of digested nitrogen was slightly higher with dried residues than with hay. 4) Ruminal ammonia concentration was similar in both feedings of dried fibrous residues and hay, and the values were higher than, those in feedings of treated ensiled-residues. The concentration of ruminal VFAs was almost the same in both feedings of dried residues and hay. 5) The concentration of blood ureanitrogen tended to be lower with residue diets than with hay. The level of plasma total protein, however, tended to be higher with the dried residue diets than with hay. From the results obtained in this study, it can be concluded that the dried fibrous-residue of legume plant was somewhat superior in food value to Italian ryegrass hay and to the ensiled fibrous-residues as reported previously.

View full abstract

Nutritional study of normal corn silage and browned silage was done concerning of various composition and its digestibility. There was little difference between normal and browned silage in chemical composition. But crude protein (CP) digestibility of browned silage was about 8% lower than normal one. Total digestible nutrient (TDN) contents of Normal and browned silage was 64.4% and 60.8% respectively. The difference of TDN in two silages was caused by digestibility of structural carbohydrates (Table 3). In browned silage, fibrous fraction kept more nitrogen than normal silage. Actually in NDF and ADF, there was about 2 fold of nitrogen than normal one. There were some changes in amino acid composition between two silages, especially low lysine content in browned silage was remarkable phenomenon.

View full abstract

This research was conducted to elucidate the managerial characteristics of a typical grassland-type dairy farming now being operated in Hokkaido. Subjects for the study were chosen from all over Hokkaido by subjecting them to linear discriminant function analysis using six indices of managerial characteristics. These subjects were classified into two types, the grassland-type dairy farming and the upland-type dairy farming, according to their land use systems, and their production structure was compared. The results obtained are as follows: (1) The grassland-type dairy farming showed the following characteristics in comparison with the upland-type dairy farming: more extensive because of samller land productivity indices such as the number of dairy cattle, milk quantity, production of self-supplied feed, dairy profit, and agricultural income, each per unit area of land; greater in labor efficiency owing to higher productivity indices such as acreage for self-supplied feed production, the number of milk cattle, and milk amount, each per labor-power ; and greater in profitability on account of higher milk cattle productivity indices such as agricultural income per mature cattle. (2) Concerning the production efficiency of self-supplied feed, the grassland-type dairy farming showed the following characteristics, the feed production cost decreased as feed production per ha increased, and tended to be lower than that of the upland-type dairy farming. (3) The milk production cost for the grassland-type dairy farming was lower than that for the upland-type dairy farming. The milk production cost for the grassland-type decreased as the milk amount per head increased, the rate of decrease being higher than that for the upland-type. The percentage of self-supplied feed cost. was higher than that for the upland-type, and decreased as milk quantity per head increased. (4) The profitability of these two types of dairy farming was compared using average marginal productivity. In the grassland-type dairy farming, the amount of increase in dairy profit by additional input of acreage for feed production was less than one half that for the upland-type dairy farming. Although this indicates that even the grassland-type requires considerable increase in feeding of concentrate to augment profits, it is more important to establish a grassland-type dairy farming which enables low-cost milk production based on a high level of productivity of good quality roughage.

View full abstract

This experiment was conducted to evaluate forage productivity and feeding value of arrowleaf clover (cv. Yuchi) compared with red clover (cv. Kenland). Each clover seed was broadcasted at the rate of 150g/a on Sept.29, 1982. Three ewes were experimental animal for digestion trial. DM forage yield of arrowleaf and red clovers at bloom stage were 71.1 (26/May) and 52.3kg/a (10/May). Arrowleaf clover was highly productive than red clover with damage of clover rot (Sclerotinia trifoliorum Eriks.), but poor recovery growth of this clover after cutting was observed in late spring. DCP and TDN contents of arrowleaf clover were 9.1 and 56.7% at bloom stage, and those of red clover at bloom stage were 12.7 and 63.5%, respectively. Mineral contents of arrowleaf clover such as Ca, P, Mg and K were as rich as red clover.

View full abstract

[in Japanese]

View full abstract

Fibrous residue left after the extraction of leaf protein concentrate has been ensiled and used as a roughage feed for ruminant animals. Ensiled fibrous residue from legumes was better in quality than the silages made from the original herbages judging from the pH value. Feeding values of fibrous residue silages were equal to or better than those of good quality hays. Treatment of fibrous residue with a formaldehyde and formic acid mixture before ensiling improved the nutritive value of the nitrogen in the silages. In our most recent study, although a high-moisture broad bean residue silage was utilized as a roughage as same as a timothy hay in sheep, the urinary nitrogen and the water excretions of the sheep fed the silage were higher than those fed the hay. These findings may be attributed to the ammonia production during ensiling and/or the large water consumption in silage feeding since the fibrous-residue silage also has a particular high moisture content. Thus, in practical use of these silages, it is assumed that the utilization of dietary nitrogen would be improved by a restriction of water consumption in sheep. In the present study, therefore, the nitrogen utilization of ensiled fibrous residue left after the extraction of ladino clover leaf protein concentrate was investigated using sheep, when they were given the fibrous residue silage with timothy hay (equal amounts of dry matter). The results obtained were compared with that of our previous experiments.

View full abstract