In order to clarify increase of dry weight of warm season grass, coloured guineagrass (Panicum coloratum L.), finger millet (Eleusine coracana GAERTN.) and corn (Zea mays L.) as a contrastive crop, were investigated under different planting density, seeding time or fertilization, at Zentsuji and Matsue, in 1970, 1974 and 1975. The results obtained are summarized as follows ; 1. Relationship between planting density (ρ: plants/m^2) and individual dry weight (ω: g/plant) was expressed by the following equation. 1/ω=A・ρ+B This reciprocal expression was recognized in respective forage crops. 2. General logistic equation (Shinozaki and Kira, 1958) is given as [numerical formula] where s, λ(t) and W(t) are relative growth rate (RGR), growth coefficient and asymptotic value of ω, respectively. And, Y (asymptotic value of dry weight per unit area) equals W・ρ. In this experiment, λ decreased almost linealy with time, conversely, Y increased. 3. It was proved from the results obtained above that general logistic equation was applicable in dry matter production of gramineous forage crops. 4. Seeding time had effects on the values of λ and Y (Exp.1), and fertilizer had a remarkable effect on the value of Y (Exp.2). Therefore, it was found that the both parameters of general logistic equation were influenced by external factors, climatic conditions and fertilizer.

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This study was carried out to make clear the relationship between cell wall content (CWC) and dry matter production of warm season grass. Coloured guineagrass (Panicum coloratum L.), Japanese barnyard millet (Echinochloa utilis OHWI et YABUNO), rhodesgrass (Chloris gayana KUNTH.), finger millet (Eleusine coracana GAERTN.) and corn (Zea mays L.) as a contrastive crop, were investigated in field conditions. CWC was estimated by neutral detergent method. The results obtained are summerized as follows ; 1. General logistic equations were applicable to explain increases of cell content (CC) in finger millet and corn, in the same way as dry weight (DM). There was no difference in asymptotic values (Y_<CC>) in the both species. 2. Although the difference between finger millet and corn was not detected on RGR_<CC> (relative growth rate of CC), CGR/CC (crop growth rate divided by mean CC) of corn was larger than that of finger millet. 3. CWC concentration was increased with time in the four warm season grass species, and closely linear correlations were observed between CWC concentration and dry weight. CWC concentration of coloured guineagrass and rhodesgrass was higher than those of finger millet and Japanese barnyard millet in the later growing period. This was mainly due to the increase of CWC concentration of stem. 4. It was estimated from these results mentiond above that CWC concentration was intensively related to the differences in dry matter production among the different warm season grass species.

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To clarify the possibiliy of using some plant characters as a selection criterion of nonstructural carbohydrate (NSC) concentration of Italian ryegrass in vegetative stage grown in fall, multiple regression analysis between NSC (%) and some plant characters except dry matter content (%) and single correlation (regression) analysis between dry matter content (%) and NSC (%) were carried out. The data used for analysis were derived from 63 diploid and 106 tetraploid varieties, and 522 individuals for 4 years from 1977 to 1980. In multiple regression analysis, 6 and 8 characters were taken up as independent variables in varieties and individuals, respectively. 1) Multiple correlation coefficients were significant both in varieties and individuals. Judging from the frequency of selected variables and standard regression coefficients in multiple regression equations, it is concluded that higher NSC% varieties showed higher top dry weight and stem weight/leaf weight ratio, and thicker leaves with lesser mean weight of tiller. Higher NSC % indivivuals showed lower plant height, smaller number of tillers with higher top dry weight and stem weight/leaf weight ratio. 2) Single correlations (regressions) between dry matter content (%) and NSC% were significant at 0.1% level not only in any experiment taken within a year but also in the experiment taken throughout several years. It is recognized that dry matter content (%) in stem and top would be a selection criterion of NSC concentration because of the positively high correlation coefficients. 3) For higher single correlation coefficients than multiple regression coefficients observed in every experiment, it is concluded that dry matter content (%) is the most suitable trait for a selection criterion of NSC concentration.

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A pasture is not formed by an even distribution but by a mosaic or patches of herbage. Such a spatial pattern of herbage on pasture might be caused by the interactions between animals and vegetation. The following subjects are discussed in this paper: (1) definition of the spatial patterns, i.e., random, aggregated and regular, of herbage on a pasture, (2) a statistical model describing the spatial pattern of plant biomass: gamma distribution, (3) a new index for classifying categories of pasture spatial patterns: p, and (4) several experimental data of pasture changing in the course of grazing, and evaluation of pasture by model and index.

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In order to clarify efficiencies of energy conversion from solar radiation to animal production, the investigation was made in pasture dominated by orchardgrass (Dactilys glomerata L.), which lies at the sourthern hillside of Mt. Asama with 1100m altitute and has been given with compound fertilizer totalling N 171kg, P_2O_5 111kg, K_2O 171Kg/ha yr. for about ten years. The pasture of 8.69 ha, which divided into 7 paddocks, had been grazed in rotation by 50-60 heifers for ten years since its establishment, with 500-700 Cow Days per hectare. 55 Holstein steers, 5-7 months old, and 10 heifers of Japanese Black Breed, 11 months old, were used in 1975, and 46 Holstein heifers, 6-7 months old, and 10 heifers of Japanese Black Breed, 10 months old, were used in 1976. Net primary production and herbage intake was investigated in one paddock (0.9 ha) of 7 ones. Barley flake was offered to animals once daily at a rate of 0.69%DM and 0.58%DM per cattle liveweight, respectively, in 1975 and 1976 throughout the grazing season. The results obtained are as follows: 1) Total short wave radiation (I) and photosynthetically active radiation (II) was 731×10^4 Mcal/ha and 322×10^4 Mcal, respectively, throughout the growing season on the average of two years. Net primary production (III), herbage intake (IV) and intake of barley flake (V) was 520×10^2 Mcal (14, 170Kg DM)/ha, 324×10^2 Mcal (8670Kg) and 7160 Mcal (1795Kg)/ha, respectively. Live-weight gain was 2500 Mcal (723Kg)/ha, based on NRC standard. 2) Efficiency of energy conversion (I)→(II), (II)→(III), (III)→(IV), (IV)+(V)→(VI) and (I)→(III) was 44.1%, 1.64%, 62.7%, 6.3% and 0.72%, respectively, throguhout growing season. 3) (IV)→(VI) and (I)→(VI) was 1.38% and 0.0062% (or 0.0041% per year), respectively, using the corrected values of (VI) which subtracted the contribution of (V) from (VI), based on NRC standard. (IV)→(VI) was less than one fourth of (VI)+(V)→(VI), besides, supporsing that live-weight gain 1Kg of cattle corresponds to TDN 7Kg, (I)→(VI) was 0.0253% (or 0.0169% per year). Considering these points and others, it was presumed that 1.38% and 0.0062% described above based on NRC standard were underestimated. 4) (I)→(III) was 0.72%, 0.37% and 1.13% during spring, summer and autumn, respectively. (III)→(IV) was 36.4%, 117.9% and 78.6%, (IV)+(V)→(VI) was 12.3%, 4.1% and 6.1%, (IV)→(VI) based on NRC standard, was 6.2%, -1.2% and 2.9%, during spring, summer and autumn, respectively. It was suggested that efficiency of plant production in autumn was not less than in spring, however, efficiency of animal production was not good as in spring, and both efficiency in summer were considerably inferior in other seasons. 5) Net energy for maintenance was 72% higher than that in NRC standard throughout the grazing season. Net energy for maintenance during spring was lower than that in NRC standard by 33%, however, one during summer and autumn was higher by 95% and by 148%, respectively.

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Seed characteristics were compared between common (C) and early (E) types of Chigaya as a basic study for their seed propagation. The latter type of the species was distinguished from the former one by the authors depending on its glabrous node, larger seed, and early flowering. The materials used were collected from the different localities and years for both types. Mean fertility of seeds was significantly higher and less variable in E- than in C-type. Consequently, greater number of fertile seeds per panicle were consistently produced in E-type regardless of the differences of collecting sites, localities and years. As for seed germinability, no dormancy, in effect, was recognized with either type. The seeds were easily germinated under the optimal conditions, around 30°C with light. However, the temperature range for germination was greater, and the requirement of light was less in E- than in C-type. Moreover, the germination rate was clearly higher in E-type. Accordingly, the germination requirements of E-type are considered to be less rigid than those for C-type. Seed longevity for both types was markedly prolonged by dry-chilled storage, though it was presumed to be several months in the case of the room storage. From the results mentioned above, E-type of the species is considered preferable to C-type in so far the propagation by seeding is concerned.

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A field experiment was conducted in Fukuoka, Japan, to evaluate the effect of cutting frequency on dry matter yield, botanical composition, nutritive value and canopy structure in pure and mixed culture swards of green panic (Panicum maximum var. trichoglume cv. Petrie), and phasey bean (Macroptilium lathyroides). The mixed culture consisted of a 2:1 ratio of grass to legume. In all plots plant density was 100 per m^2. In both pure and mixed cultures, 4 times, 3 times, twice and once cutting frequency were employed. Cumulative dry matter yields showed significant differences among cutting frequencies, but did not between pure and mixed cultures. Cumulative dry matter yield of the mixed culture under 3 cutting frequency out-yielded the green panic pure culture. The proportion of phasey bean in cumulative dry matter yield of mixed culture was 9.9% under 3 cutting frequency, but reduced to 2.0% under twice and once cutting frequencies. The relative yield total (RYT) was 1.2 under 3, 1.0 under 4, lower than 1.0 under twice and once cutting frequency respectively. The relative yield (RY) of each component in mixed culture pointed out that green panic suppressed phasey bean when the cutting interval was prolonged. Nitrogen percentage under 3 cutting frequency in mixed culture was 0.54% units higher than in the green panic pure culture, which was the highest among all cutting frequencies. Nitrogen yields under 4 and 3 cutting frequencies in mixed culture were higher than the respective pure cultures. Under 3 cutting frequency, in vitro dry matter digestibility in the mixed culture was higher than in the green panic pure culture by 3-8% units, and digestible dry matter yield in the mixed culture exceeded those of the pure cultures. Canopy structure and light interception profile under 3 cutting frequency in mixed culture showed efficient utilization of the above ground space. This may be one of the advantage bringing about the out-yielding of dry matter.

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Short day-length and low temperature are two major factors which bring about floral-induction in orchardgrass. There have been, however, a few reports showing that the two factors play different roles in floral-induction and inflorescence differentiation. The studies reported here were carried out to clarify the interaction of these two factors. A clone of "Dactylis glomerata ssp. judaica" were grown under continuous light in a warm (25℃ day/15℃ night) glasshouse for longer than six months. Thereafter, this clone was divided into individual tillers, from which aged tillers were chosen for the experiments. Then the tillers were grown under some treatment conditions of short day-length (10-hour) with two different temperatures (low; 10℃: high; 20℃), and of continuous light with low temperature. In other cases, they were also subjected to treatment-combinations of short day-length following low temperature and vice versa. After the above treatments, their heading behaviour was observed under continuous light in a warm glasshouse (Tables 1 and 2). Floral-induction did not occur under the untreated control regime of continuous light in a warm glasshouse. While floral-induction was promptly brought about under short day-length, it was accelerated still more efficiently by low temperature than by high temperature even under short day-length (Table 3). These findings indicated that low temperature response and short day response promoted the processes of floral-induction reinforcingly. Floral-induction was brought about by low temperature under continuous light, though the period required for floral-induction was conspicuously longer under continuous light than under short day-length (Tables 3 and 6). And low temperature treatment had the promotive effect on heading both immediately before and after short day treatment. The promotive effect of low temperature treatment, however, was markedly greater when applied after the short day treatment than when applied before that (Tables 4 and 5). From these results, it was suggested that low temperature response played relatively more important roles after short day response in floral-induction and inflorescence differentiation. In addition, it was shown that the promotive effect of low temperature treatment on heading occurred within 5 to 7 days after short day treatment (Tables 4 and 7) On the other hand, it was clarified that there was a close relationship between the promotive effect of low temperature on heading and the degree of floral-induction attained under previous short day-length, that is, low temperature treatment immediately after short day treatment substantially promoted the heading of partially induced tillers but retarded the heading of completely induced tillers (Table 7).

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Influences of low-temperature immediately after floral-induction treatment on heading responses were investigated to establish the program of accelerating generation time in orchardgrass. Seedlings of "Nakei EV-No.1", "Aonami" and "Later" were grown under continuous light in a high-temperature (25℃ day/15℃ night) glasshouse for 42 days after sowing. Thereafter, they were subjected to floral-induction treatments of 9-hour day-length under natural low-temperatures in autumn for 26 and 40 days in "Nakei EV-No.1", and for 33 and 54 days in "Aonami" and "Latar" (Table 1). After the treatments, their heading responses were observed under continuous light with two temperature regimes: (1) Control regime, 35 days of high temperature ; (2) Low-temperature regime, 7 days of low-temperature (10℃ const.) followed by 28 days of high-temperature (Fig.1). For all the materials, the percentages of plants with heading tillers were markedly higher under low-temperature regime as compared with control regime after the short periods of floral-induction treatments. Almost all the plants, however, reached heading regardless of temperature regimes after the long periods of treatments. Heading tillers increased as the periods of treatments became longer, and still more increased under low-temperature regime (Table 2). Heading began one to two days later in "Aonami", three to four days later in "Nakei EV-No.1" and "Latar" under low-temperature regime than under control regime. But under low-temperature regime, heading tillers increased promptly after the onset of heading and the periods of heading were apparently shortened in all the materials tested (Fig.2 and Fig.3). On the other hand, there were large variations in the number of heading tillers per plant among individual plants within each material, and the variations were scarecely influenced by temperature regimes (Table 3). From the above results, it is considered to be able to decrease the percentage of nonheading plants, to increase the number of heading tillers and to synchronize their flowering in orchardgrass by promoting inflorescence differentiation under low-temperature immediately after floral-induction treatment.

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A new substance named phleichrome was extracted from culture filtrate of the causal organism of timothy purple spot. Phleichrome increased in the culture filtrate until 20th day in the dark, while it did up to 15th day and then decreased in the light. When applied to timothy leaf blades, phleichrome [>10^<-4>M] produced lesions similar to purple spot naturally produced by the pathogen. The reaction of timothy to phleichrome did not differ with resistance or susceptibility of tested clonal lines. Phleichrome was also toxic to some of leaf-surface microorganisms of timothy, and its effect on bacteria was stimulated by the light, especially at 260 or 274nm, i.e. maximum absorption wavelength of phleichrome. The photodynamic reaction of phleichrome on the micro-flora of timothy leaf surface is discussed in relation to the pathogenesis of timothy purple spot.

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Sixty four lines of wild oats which covered eleven species were inoculated with two stem rusts, Puccinia graminis PERS. f. sp. dactylidis GUYOT et MASSENOT and P. graminis PERS. f. sp. avenae ERKISS. et HENN. Six common hosts which were susceptible to both rusts were detected from three species ; one each from two diploid species, A. longiglumis DUR. and A. hirtula LAG., and four from a tetraploid species, A. barbata POTT. No common host of both rusts was found in any hexaploid species. Lower ploidy level of chromosome might be a noticeable feature of the common host. Another important feature might be their restricted geographical distribution. Five of six common hosts were collected on the eastern half of the Mediterranean coast ; three in Libya and one each in Syria and Turkey. Another one was collected in Iran, apart from the Mediterranean area. Common hosts reserve such an old nature as not to distinguish two rusts. They may be relics of the old period when grasses have not fully differentiated and stem rust have also not achieved host specialization among grasses.

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The fitness of equations predicting nutrient yield of corn silage from the ear corn and stover yield per unit area was investigated using 6 early maturing varieties 3 medium maturing varieties and 4 late maturing varieties cultivated in Tokachi district, Hokkaido, during the years from 1974 to 1980. The results are summarized as follows. (1) The yearly weather as judged by the crop, was normal in 1974, 1977 and 1979, good in 1975, 1978, and poor in 1976, 1980. Each year, the crops were harvested between 24 and 26 of September. Maturity stages of the crops at that time differed widely depending on the years and varieties. Generally, they fell between early yellow dent to overripe stage with the early maturing varieties, late dough and yellow dent with the medium ones, and early milk and early dent stages with the late ones. (2) The yield of dry ear corn ranged from 228 to 920kg, and dry stover yield from 365 to 1025kg per 10 are. (3) The ranges of dry matter (DM) recovery of silages, total digestible nutrient (TDN) contents, digestible energy (DE) contents were ; 87.4-96.1% for DM recovery, 60.7-73.7% for TDN, 2.72-3.29kcal/g・DM for DE contents, respectively, and the yield of TDN and DE of silages ranged ; 611-1123kg for TDN, 2911-4882 therm for DE per 10 are. (4) A significant correlation was recognized between the yield of TDN or DE (Y) and that of dry ear corn (X_1) and dry stover (X_2). However, the TDN yield predicted by the so-called Shintoku's equation tended to give significantly higher values than those obtained by presnt measurements. The resulting over-estimates seemed to be due to the fact that the Shintoku's prediction system neglects the dry matter loss which occurs during the process of silage making, and also it is likly to over-estimate the nutritive value of stover especially in late maturities. From the analysis of our experimental results, the authors are inclined to suggest the substitution of coefficients in the prediction equation, which will give better approximation to the actual values of nutrient yield. The improved equations thus derived are as following. TDN yield Y=0.8×dry ear corn weight (X_1)+0.5×dry stover weight (X_2) DE yield Y=3.3×dry ear corn weight (X_1)+2.4×dry stover weight (X_2).

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