The kasugamycin resistant mutants of Rhizobium trifolii were used as an inoculum strain for inoculations using the lime-coating and vacuum processing methods. The occupancies by the inoculated strain for the nodules formed on red clover were surveyed for two years after seeding, in a field where indigenous rhizobia populations had colonized. All herbage dry weights and nodule numbers did not differ among two inoculation methods and the uninoculated control throughout the two years of the investigation. However, the results of the identification by antibiotics for nodules demonstrated that the occupancies for the inoculated strain differed significantly among two inoculation methos and the control. The nodule occupancy for strains inoculated using the lime-coating method was considerably higher, being 70% at 2 months afterseeding. It decreased greatly, to 40%, at 1 year, and it continued to decrease slightly up to 2 years after seeding. On the other hand, the occupancies for strains inoculated using the vacuum processing method were approximately half those of the lime-coating inoculations at corresponding intervals. The nodule numbers derived from the inoculum strain, being resistant to antibiotics, were almost constant throughout the two years for each inoculation method, while the nodule numbers derived from the indigenous rhizobia increased gradually year by year.

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In order to breed zoysiagrasses usable under saline irrigation, Sea Water Tolerance (SWT) was studied from morphological and genetic aspects. Accessions of zoysiagrasses were classified into Zoysia japonica and Z. matrella based on their morphological characteristics: 24 accessions in Z. japonica and 7 accessions in Z. matrella, and tested for SWT by applying sea water directly to plants. Then, the genotype was determined by ribosomal DNA (r-DNA), chloroplast DNA and isozymes. Evaluation of SWT revealed that an interspecific variation was obvious between Z. japonica and Z. matrella : Z. japonica were susceptible to sea water except for J7 and J8, while Z. matrella was highly sea water tolerant except for M1 and M4. The SWTs of J7 and J8 were as low as those of M1 and M4, but significantly high within Z. japonica. The r-DNA and isozyme analyses further identified that the heterozygosity based on r-DNA and isozyme loci was the highest in J7, J8 and M1, followed by M4. The cytoplasm of all heterozygotes was that of Z. japonica. These results suggest that the SWT is closely related to the diversity of zoysiagrasses, and is originated from the nucleus of Z. matrella but not maternally inherited.

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In order to evaluate the agronomic importance of amphitetraploid F 1 hybrids between Lolium multiflorum Lam. (2n=4x=28) and Festuca arundinacea var. glaucescens Boiss. (2n=4x=28), several agronomic and cytological characters were examined. The general appearance of F 1 hybrids produced using an embryo-culture was similar to L. multiflorum. Their agronomic characters, including plant height, first heading date and regrowth vigor, tended toward the middle of the parental characters or were rather more similar to the tetraploid L. multiflorum (cv. Aki-aoba). The total fresh weight per year of F 1 hybrids was equal to the tetraploid L. multiflorum and F. arundinacea (2n=6x=42, cvs. Lubrette, Hokuryo). The dry matter digestibility was equal or superior to that of F. arundinacea. The pollen fertility and seed yield were sufficient for ordinary propagation. These results suggest the possibility of producing a new Festulolium line with good agronomic performance from the tetraploid hybrids obtained in this study. Though there was no aneuploid in F 1 hybrids, some multivalents and/or univalents were observed. Parental chromosomes were identified in the F 1 hybrids using genomic in situ hybridization (GISH). GISH was found to be useful in detecting the changes of parental genomes among the progenies in the breeding programs.

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These has been a recent increase in the number of people visiting farms to commune with nature and animals. Therefore, some farms have built resting facilities. However, ordinary facilities for farming or cattle raising have not seen an improvement of their facilities, and they create a less than favorable impression on their visitors. In these facilities, the fence, one of the more conspicuous facilities of the farm, is one facility that can be easily improved. Landscapes with fences were evaluated using photographs of the fences composed of different materials and colors in the same or different backgrounds by 103 Taiwanese and 205 Japanese university students. The result showed that all students prefer wooden post and horizontal board fences to iron post and wire fences, and that they also prefer white as the fence's primary color. Chromatic difference and chromatic degree were measured to analyze the difference of color preference between Taiwanese and Japanese students. Based on the results, the higher the points of chromatic difference between the fence and the pasture, the higher the evaluation of the landscape with fence. Furthermore, it seems that the difference in evaluation was caused by personal preference, national character, and the regional differences concerning colors on the part of Taiwanese and Japanese students.

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Two types of traetor-PTO-powered grassland renovators have been developed in order to renovate grassland in a simple and economic manner and without interrupting grass production. They are based on a rotary cultivator in their concept. One is for grass seed pellets and the other is for seeds. The machine for seed pellets performs tilling (ditching narrow furrows), sowing with pellets in the furrows and pressing by press wheels in one trip. The tilling device is a combination of straight blades and L-shaped blades. The machine for seed pellets with the 2.2 m working width performed renovation work with good accuracy in its test. The machine for seeds carries out tilling, fertilizing, seeding, soil covering and packing in one trip. Prototype No.2 has an 8-row tilling mechanism, fertilizing, seeding, and pressing devices, and has the working width of 2.16m. Two straight blades and four L-shaped blades are attached to a flange of the rotary shaft. Grassland renovation with this machine proved to be effective in improving grassland vegetation and increasing pasture yield. The tractor power required for the prototype No.2 was estimated at 44 kW or more.

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Seasonal changes in regrowth of Phalaris arundinacea sward in the 2nd harvest year were compared with those of Dactylis glomerata and Festuca arundinacea by means of growth analysis. Dry weight of green material was the highest in Dactylis, followed by Festuca and Phalaris up to the middle stage of each regrowth. But at the late stage in summer, the dry weight was the highest in Phalaris, followed by Dactylis and Festuca, as Phalaris had more stem and less senescence. In spring, the extended sward height, dry weight of the clipped part and top were higher, and LAI was lower than in summer and autumn. At the early stage of regrowth, percentage light penetration at a given time was higher and its value at a given LAI was lower in Phalaris than in the others. Changes in dry weight and LAI with regrowth were fitted well by cubic regression curves. CGR(dw/dt) was obtained by differentiation of a cubic regression equation of the dry weight of green material, and NAR was calculated by CGR (quadratic equation)/LAI (cubic equation). CGR and NAR, at a given time and a given LAI, were higher in spring than in summer and autumn, as the stem weight was high and LAI was maintained at the suitable level even in the late stage of regrowth. Compared with other grasses, CGR and NAR of Phalaris were lower at the early stage of regrowth in any season, and the values were higher from the middle to the late stage in summer and at the late stage in spring.The result suggests that Phalaris needs a longer period of regrowth than Dactylis and Festuca in spring and summer.

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Swinecress is a winter annual weed which infests Italian ryegrass sward in the Kyushu District. When cows eat the grass contaminated with this weed, they often produce the feed flavor milk having strong odor of the weed. Field experiments were conducted to control swinecress in Ital ian ryegrass sward by dense sowing from October, 1995 to May, 1996. Dense sowing of the ryegrass at 500g/a sowing rate controlled swinecress adequately. Post-emergence application of thifensulfuron-methyl controlled the weed, but it decreased the ryegrass yields both of first and second crops. When swinecress was grown at the sowing rate of 50, 100, 150 and 200g/a by mix-culture with the ryegrass sown at 250 and 500g/a rate, dry weight of swinecress in the ryegrass at harvest time was influenced more by the ryegrass sowing rate than by the swinecress sowing rate. It was suggested that dense sowing of the ryegrass was effective cultural method for the control of swinecress even in a field seriously infested by this weed. In a sensory test, panel members did not recognize the swinecress odor in the milk collected from the cow fed with the swinecress twice as much as that contained in dense sowing plot. In our experiments, it was concluded that dense sowing of Italian ryegrass is an effective cultural method for the control of swinecress in ryegrass sward.

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Twelve multiparous Holstein cows (average weight, 606 kg) in early lactation were used in switch-back experiment with three periods, which consists of 2-week for adaptation and 1-week for sample collection to evaluate effects of forage source on feed intake, milk production, and feed cost. Cows were fed either timothy silage (TS) or timothy-red clover mixed silage (MS) ad libitum, with supplemental concentrate to meet the nutrient requirements of NRC. Concentrate and forage were offered separately. TS contained 8.6% CP, 58.6% TDN, and MS contained 13.2% CP, 63.2% TDN. Total DM intake were similar to each treatment, but DM intake of MS was greater than that of TS. The forage : concentrate ratio were 50 : 50 and 40 : 60 for MS treatment and TS treatment, respectively. There were no significant difference between forage source on milk fat and milk protein, but yield of milk, FCM and protein were significantly higher for MS than for TS. Feed costs of silage calculated from production cost (timothy silage=22.1yen/kg, mixed silage=17.2yen/kg) were similar to each treatment but concentrate cost for TS was higher than for MS. Total feed cost for MS (24 yen/4% FCM 1 kg) was significantly lower than for TS (29 yen/4% FCM 1 kg). These results suggest that forage quality strongly affects on feed intake, milk production and feed cost.

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Near infrared reflectance spectroscopy (NIRS) was used to predict total digestible nutrients (TDN) contents of hay and grass silage. Calibration for each of hay, grass silage and those pooled samples were developed with 35, 37 and 72 samples, respectively. In addition, another samples of hay (17) and grass silage (16) were used to test the calibration equation. Samples for TDN prediction were including hay and grass silage composed mainly timothy, Italian ryegrass and alfalfa. TDN value of these feeds were obtained by digestion trials carried out with sheep. Accuracy of the prediction was evaluated by the correlation coefficients (r) and standard error of prediction (SEP). The 'r' and SEP value of TDN for all samples were 0.85-0.89 and 2.9-3.4, respectively. These results indicated that TDN contents in hay, grass silage and those pooled samples can be predicted by using NIRS techniques with an acceptable accuracy.

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Genotypic differences in tiller development in autumn to early winter and their relations to overwintering ability in 6 varieties in Panicum maximum and Panicum coloratum were investigated. Tiller development and overwintering ability varied considerably with the varieties. The following four characteristics were considered to be important as the factors promoting the overwintering ability ; higher percentage of vegetative tillers by number in early winter, smaller number of aerial tillers per reproductive tiller, tiller development from lower nodes to upper ones in underground parts of mother tillers, and subterranean nodes located deep in the ground. Makarikari-grass fully met these conditions, followed by Tayutaka, Gatton and Green panic. Also varieties ranked Makarikari-grass>Tayutaka and Gatton>Green panic for overwintering ability. Natsukaze and Tamidori which did not meet the conditions were unable to overwinter successfully. These results show that tiller development, particularly tiller composition before wintering, affects the overwintering ability in Panicum.

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Thirteen cultivars and breeding lines with moderate to relatively high resistance to Lepto-leaf spot (caused by Leptosphaerulina briosiana) were used for the estimation of individual variation in disease severity. Severities of Lepto-leaf spot were visually evaluated under natural infection in fall as 1 (least) to 9 (most severe). Maximum difference among the entries was 1.5 in mean scores of disease severity. "MSA-PL-L" was the lowest in the scores of severity, which was a check cultivar for Lepto-leaf spot resistance in U.S.A., and was followed by "Hisawakaba". Large individual variation in Lepto-leaf spot resistance was recognized within each entry. Standard deviation of severity was from 1.0 to 1.5 and the range of scores was from 6 to 8. Bidirectional mass selections by visual inspection of plants for Lepto-leaf spot resistance were conducted for two cycles using "Kitawakaba". The realized heritabilities of Lepto-leaf spot resistance, obtained by regression equation of the selection response on the cumulative selection differential, were 0.89 and 0.77 in the selection for resistance and susceptibility, respectively. The mean severity was 2.2 in the second generation selected for resitance and was significantly lower than that of "MSA-PL-L".

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A field experiment was carried out in orchardgrass (Dactylis glomerata L.), timothy (Phleum pratense L.) and meadow fescue (Festuca elatior L.) to clarify the effect of applied nitrogen regarding the relationships among the leaf area index (LAI), the net assimilation rate (NAR) and the crop growth rate (CGR), and to assess the interactions between nitrogen absorption and those three parameters. Two treatment levels of nitrogen (0g m<-2> and 8g m<-2>) were used in this study. Applied nitrogen increased the LAI, but had no great influence on the NAR. The CGR rose according to increased LAI, resulting in a higher yield of dry matter at the time of first cutting. The dry matter yield had the greatest timothy, followed by orchardgrass and meadow fescue during both treatment levels of nitrogen used. This ranking was derived from the CGR responses to nitrogen applied in the three grasses tested. The wide differences occurring in the CGR of the three grasses were attributable to the differences in the nitrogen absorption rates:A low absorption rate of meadow fescue is reflected by a low LAI, and the difference between the nitrogen absorption rate of timothy and orchardgrass is reflected in the NAR.

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