The diffuse radiation extinction coefficients (k) of component species in orchardgrass-alfalfa mixture sward were investigated in relation to nitrogen application rates. Increased rates of nitrogen application resulted in decreasing of k in the mixture canopy. In the canopy, k of orchardgrass was kept almost constant, but alfalfa's k was varied, being decreased from 0.8 to 0.4 by increasing nitrogen application. There was a significant correlation between alfalfa's k and dry weight per shoot (r=0.99, P<0.05). The higher nitrogen application, the more the poor shoots of alfalfa which had a few leaves clustered around stem were produced by competition. It seems that the horizontal arrangements of alfalfa foliage were changed from at random to clumped distributions by the higher nitrogen rate. The empirical equation for k was obtained as a function of dry weight per shoot.

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A mechanistic model of surface litter decomposition in swards was developed. The model simulates the dry weight changes of decomposing surface litter by predicting the specific rate of litter decomposition from air temperature and litter water content (LWC). To simulate the LWC, a submodel of water budget in litter is incorporated. The model was calibrated to data from one litter-bag experiment in bahiagrass swards and two supplementary experiments. Validation of the model was made against data from two litter-bag experiments in bahiagrass swards, using two indices ; the relative litter mass in the litter-bag and the mean specific rate of litter decomposition. There were significant positive correlations between the predicted and observed values of the two indices. It was concluded that the model is suitable for simulating the surface litter decomposition in bahiagrass swards, if its limitations are well recognized.

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A spatial autocorrelation and cross-correlation statistic was used to study spatial relationships of blue grama (Bouteloua gracilis (H.B.K.) Lag. ex Steud) with other site characteristics of a mixed grass community in southern Arizona. Biomass and density of blue grama and other species, as well as terrain and soil variables were measured. A cross-correlation statistic, which Moran's I is a special case, was used to test for presence of spatial cross-correlations between pair-wise combinations of both vegetation and site characteristics. The test statistic showed that biomass of blue grama, other grasses and forbs, soil rockiness and the slope-aspect index were not spatially correlated within the study area, but instead were randomly distributed over the area. Spatial autocorrelations were observed for density of blue grama, soil pH, percent clay and elevation. Soil pH and clay content were spatially correlated with elevation over the study area as indicated by the significant cross-correlation. Results of other studies of blue grama were also used to interpret the spatial distribution of this species with respect to soil and site characteristics. This study revealed that responses of blue grama to site variables may best be understood through spatial autocorrelation and cross-correlation analysis rather than through the unidirectional approach of most gradient analysis studies. That is, simultaneous analysis of blue grama and environmental factors over multi-directions were made possible using spatial cross-correlation techniques.

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Effects of feeding corn, barley and sugar beet pulp to silage based diet on the nitrogen (N) utilization of goats were studied. These supplements were selected due to having the difference in rumen degradation. Four rumen cannulated goats were fed the diets consisting of wilted ryegrass (Lolium multiftorum Lam) silage and the supplements (4 : 1 on dry matter (DM) basis). Silage was solely used for the control diet and N intake was adjusted by urea added to the diets including supplements. The wilted silage showed the pH value 4.72 and relatively high NH3-N concentration (16.7%/total-N). The soluble fraction of DM in the rumen was 58.0, 26.8 and -1.25%, and the rate of degradation was 0.042, 0.107 and 0.099h^<-1>, for corn, barley and sugar beet pulp, respectively. Dietary inclusion of corn significantly increased DM and organic matter digestibility, and that of barley increased hemicellulose digestibility compared with the control diet. Urinary excretion of allantoin increased when goats fed the supplements, but the difference failed to be significant. Ruminal concentration of NH_3-N and retention of N showed no significant difference among the treatments, but feeding barley tended to lose more N compared with the other supplements in this study.

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The course of napier grass (Pennisetum purpureum Schum.) after ensiling was investigated to know the effects of wilting and molasses addition on silage fermentation by using 900ml laboratory glass bottle silos. In the 1st experiment, the moisture content of the grass decreased from 87.6 to 81.3% during 6 hours wilting. The pH value of silage made from the direct cut grass decreased to 4.21 on the 2nd day after ensiling, while in the wilted grass, it was gradually decreased to 4.18 toward the 14th day. In the 2nd experiment, the grass wilted for 2 days was 71.1% moisture and pH value of the silage was above 4.5 during 35 days experimental period. The wilted grass to which 4% molasses was added decreased the pH value to 4.1 on the 7th day and to 3.8 on the 28th day after ensiling. There was a negative relationship between lactic acid content and pH value of the silages. All the silages mainly produced lactic acid rather than acetic acid, nevertheless napier grass is a tropical grass.

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Two-Rowed whole-crop barley was harvested at the milk-ripe, dough-ripe and yellow-ripe stages. The forage harvested at milk-ripe stage was ensiled directly or after wilting. At the dough-ripe and yellow-ripe stages, unwilted forages were ensiled with or without the following additives : (1) Untreated (Control) (2)0.1% lactic acid bacteria (LAB) inoculant (3)0.02% acremonium cellulase (4)0.1% LAB inoculant+0.01% acremonium cellulase (5)0.1% LAB inoculant+0.02% acremonium cellulase. All the silages were well preserved no matter how the silages were treated with enzyme and LAB inoculant, either alone or in combination. They had lower pH value and higher total fermentation acids content compared with the control. There was an evidence of synergism between LAB inoculant and higher level of application of the enzyme in increasing lactic acid and total fermentation products. Digestibility of the silage crude protein, crude fat and crude fiber decreased as plant maturity proceeded ; NFE digestibility increased as maturity advanced. Milk stage silages had higher DCP content than dough and yellow-ripe stage silages. TDN content was highest at the yellow-ripe stage silage. The DCP yield (kg/a) was decreased in the following descending order : milk-ripe (9.5) > yellow-ripe (6.2) > dough-ripe (5.1). TDN yield (kg/a) followed the order : yellow-ripe (93.9) > dough-ripe (72.9) > milk-ripe (65.2). The acremonium cellulase with and without LAB had no remarkable effect on DCP content and DCP yield but improved TDN content and TDN yields of the silages.

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Plants of phasey bean, Macroptilium lathyroides, grown in pots under normal irrigation, flooding and drought conditions were offered for their dry weight determination, chemical analysis and in vitro digestibility measurement. Samples of leaves and stems were taken in the manner described previously (NAGASHIRO et al. 1992. J. Japan. Grassl. Sci. 38, 207). When compared with the case of normal irrigation, the flooding brought about the increase of dry weight of stems which resulted from their elongation and thickening, and hence, in the chemical composition, enhanced the proportion of structural carbohydrates in stem DM and diminished its CP content. The drought ceased growth and led, contrarily to the flooding effect, to increase the CP content of stems. The in vitro digestibilities of DM, OM, and CP in the flooded plants were lower than those in the normally irrigated plants, but those in the drought suffered plants were similar or higher than in the control plants. The influence of flooding and drought was discussed on the basis of nutrient yields and digestible nutrients yields calculated.

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Variation in productivity of somatic embryos was investigated in the progeny populations from a male sterile genotype, MS, of alfalfa (Medicago sativa L.). The three traits, number of somatic embryos, stability of embryo formation and days to embryo formation, were referred to as the productivity of somatic embryos in this study. The progeny populations from the crosses between MS and four male fertile pollen parents, regardless of their regeneration ability, showed more somatic embryo production than in MS itself which showed low productivity of embryos. Six genotypes were selected from the crossed progeny populations according to their productivity of somatic embryos. For further analysis, these genotypes were crossed with two genotypes, and one had the regeneration ability and the other had no regeneration ability. In average through each pollen parental genotype the progeny populations from the regenerable pollen parent were superior to those from the non-regenerable genotype for productivity of somatic embryos as well as regeneration frequency. However, one of the six genotypes showed superior embryo production in the crossed progeny population with the non-regenerable genotype parent to that with the regenerable genotype.

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In order to evaluate the allelopathic potential of plant species commonly grown in semi-natural grassland, lettuce seed bioassay for 141 plants was conducted in laboratory. Lettuce seeds were germinated in petri dishes containing aqueous extracts of shoot from each plant. Three days after seeding, percentage of the germination was determined and radicle and hypocotyl length were measured. The results obtained are summarized as follows : Based on the strong reaction in both germination and seedling growth to the extracts, Anthoxanthum odoratum, Gnaphalium affine, Rhododendron japonicum and Corydalis heterocarpa may be classified in the plants with the most inhibitory activity. Aqueous extracts of Anthoxanthum odoratum, Ixeris stolonifera, Gnaphalium affine, Glechoma hederacea, Rhododendron japonicum, Plantago asiatica, Plantago lanceolata, Barbarea orthoceras, Corydalis heterocarpa and Sisyrinchium atlanticum strongly inhibited germination of lettuce seed. Aqueous extract of 15 species, such as Anthoxanthum odoratum, Briza minor, Trifolium repens, Pueraria labota, Indigofera pseudotinctoria, Gnaphalium afnne, Eupatorium chinense, Rubus parvifolius, Rhododendron japonicum, Hydrocotyle raminora, Polygala japonica, Corydalis heterocarpa, Haloragis micrantha, Solanum carolinense and Phytolacca americana, considerably reduced radicle and hypocotyl growth of lettuce seedling. Some of the species described above were well known as the alien plants that had become naturalized in Japan.

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Perennial ryegrass (Lolium perenne L.), one of the most important forage grasses for temperate regions, exhibits lower winter survival than the other temperate grasses. Freezing hardiness is one of the primary factors associated with winter survival. The purpose of this study is to consider the freezing hardiness in relation to winter survival in diploid and tetraploid cultivars of perennial ryegrass. Twelve diploid and seven tetraploid cultivars were evaluated for viability over winter under field condition, and for freezing hardiness using the modified technique of Lorenzetti et al. The results obtained are summarized as follows. 1) Between-cultivar differences in winter survival were assessed for both diploid and tetraploid cultivars. Tetraploids had a higher degree of winter survival compared to the diploids. 2) Freezing hardiness varied greatly among the diploid cultivars, but not among the tetraploids. Tetraploids overall had lower freezing hardiness compared to the diploids. 3) These results suggest that the contribution of freezing hardiness to winter survival may be different between diploids and tetraploids. Therefore, the improvement of freezing hardiness in tetraploids would enhance the degree of winter survival in perennial ryegrass cultivars.

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Perennial ryegrass (Lolium perenne L.), one of the most widely utilized forage grasses for temperate regions, has differentiated in winter survival among various cultivars. Freezing hardiness is one of the primary factors associated with winter survival. The purpose of this study is to elucidate the inheritance of freezing hardiness in perennial ryegrass. The results obtained are summarized as follows : 1) We made a diallel analysis with F_1 progenies of a diallel cross among four cultivars which showed different levels of freezing hardiness. Each cultivar was represented by 2 genets which were understood to provide each cultivar mean. 2) Freezing hardiness varied significantly among the genotypes ; the variation was largely attributable to the between-cultivar component. 3) Both additive and dominance components were detected with the magnitude of the former component being higher than that of the latter one. The heritability value was extremely high, suggesting that selection for freezing hardiness may be successful. 4) The average reciprocal effect was found to be significant, suggesting also that cytoplasmic factors contribute to freezing hardiness in perennial ryegrass.

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In this paper, pedigree assessment in 24 maize inbred lines was performed using the DNA markers generated by RAPD (random amplified polymorphic DNAs). 128 fragments generated by 32 primers of arbitary sequence were used to assess the level of DNA variation. Identification of 24 maize inbred lines was carried out by polymorphic DNAs generated from two primers. It was revealed that it was possible to assess DNA polymorphisms using RAPD without any information of DNA sequences. From the data of cluster analysis, 24 inbred lines were divided into six groups. It was suggested that there were long genetic distances between dent inbred lines and flint ones. It was supposed that inbred lines used in this study were derived from different origins. Polymorphic band characteristic to flint inbred lines was also observed. It was suggested that analysis of the functional gene may be possible from the results of our study.

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Subclimax grassland is seen on the area of little rain or well permeability. Mts. Hakone, Fugi and Yatsu-gadake situate on the southern part of Fossa Magna which is biggest tectonic fall valley in Japan. There is a vast wild grassland sarraunding Mt. Hakone. This grassland is built vasalt laver hills and the bottom basement of it is volcanic rock which enable rain to permeate easily through down. Among foothills of Mt. Fuji, the east and south hills are covered scoria and mud-flow, and are used as maneuvers lands and afforestfields of cedars. Only on the northwest hill, Asagiri highland, dairy farming on. South plateau of Mt. Yatsugadake is covered with mudflow, and there is no grassland on it, although paddy field can be seen. On the east and west slopes which are alluvial-fan, forage crops and vegetables are grown. On the north laver plateaus are suited for grazing grassland.

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