The place of origin of Renge, Astragalus sinicus L., was probably in China. It is believed that Renge was introduced into Japan from China as early as the 5 th century A. D., though it is uncertain. This exotic plant spread throughout Japan, because the natural environmental conditions were suitable for its growing. Nowadays, Renge grows all over Japan except Hokkaido-area as valuable manure and forage crops or wild plants. The authors collected numerous strains of Renge growing under various environments and studied the geographical differentiation among them. The results obtained are summarized as follows : ( 1 ) In both cultivated and wild strains, strains collected from cooler climates tended to flower somewhat earlier, to be shorter in plant height, smaller in leaf size and more prostrate in plant type than those from warmer climates. The degree of these variations with latitude is greater in wild strains tb_an in cultivated ones. For example, in regard to the flowering date, an increase of 1° in latitude resulted in a promotion of 1.5-1.9 days in wild strains as compared with 0.2∼0.8 days in cultivated strains. ( 2 ) Not only in the mean value mentioned above, but also in the within-plot-standard deviation, an apparent geographical trend was found in some characters, that is, a continuous gradual decrease in standard deviation was recognized according as the latitude increases. It was fcund in wild strains that correlation coefficients between the latitude and the within-plot-standard deviation were -O. 508** in plant type index, -0.373** in plant height, -O.358** in leaf length and -0.403** in leaflet area index (*'* indicating the significance at the 1% level. ). Contrary to these results, in flowering date and number of stems a positive correlation was calculated, but the values themselves were small and not significant. These results rhay be useful in considering how Ito introduce Renge plants into our country. ( 3 ) Cultivated strains have generally more valuable characteristics as fcrage crops than wild strains as expected. Namely those of more erect plant type, taller plant height, Iarger leaf size, and so on are recommended.

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Studies were made in 1958 and 1959 to clarify the characteristics of synthesized oats derived from amphidecaploids which were induced from five di-ferent pentaploid Auena hybrids, 4 x6x, (see NISHIYAMA 1951, 1959) in a comparison with seven oat varieties, especially "Zensin" which is a leading variety as green fcrage. Experiments were also conducted to study the relation-ship between the growth habit of plants and the date of sowing (1 and 26 October, 1959 and 28 March, 1960). Plants of certain strains showed different growth in response to different dates of sowing. Plants sown on 28 March gave in general undesirable results and were omitted from the followingy observation. Plant height in all 18 synthesized oat strains except in a few was lower than that of the control "Zenshin", during their growth periods. Both width of leaf-blade and thickness of culm were shorter than those of the control. However, it was observed that synthesized oat strains Nos, 10, 18, 22, 27 and 28 showed green forage yield 15-40% higher than the control. This high production was mainly due to the profuse tillering and winter hardiness in Nos. 10 and 18 and to the high tillering capacity after February in Nos. 27 and 28 though they were not so winter hardy. These studies showed that in spite of the marked morphological and physiological variations observed in the strain of synthesized oats, some strains se-emed promising as high yielding varieties for green forage

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In order to make it possible to identify rice varieties, some pigments in rice plants of 630 varieties collected from fifteen countries were observed. For the sake of this observation, the authors have adopted MUNSELL'S color system of which descriptions are considered to be properly objective than the ordinary system. The frequency of appearance of pigments in fourteen characteristics in rice plant is very high in the inner part of leaf sheath, internode, septum, apiculus and stigma at heading stage and in apiculus at maturity stage. Especially, the anthocyanin pigments are observed in all the characteristics in rice plants, while no other pigments are observed in all the characterstics except in the following fcur characteristics ; namely, septum and pulvinus or node at heading stage and apiculus, Iemma and, palea at maturity stage (Table 1). The symbolized color shown according to MUNSELL's 'color system for each charccteristic in rice plant shows a wide range in the hue, value and chroma for the characteristics of septum at heading stage, and apiculus and lemma or palea at maturity stage. The hue shown by MUNSELL'S color system in rice plant is expressed by RP, R, YR and Y, and the anthocyanin pigments are limited to RP (Table 2). In regard to anthocyanin pigments in characteristics of rice plant the data obtained show similiar tendencies to the previous reports (Fig. 1). Taking these results into consideration, only five charctersitics were finally selected for the purpose of the possible discrimination of rice varieties ; namely, innerpart of leaf sheath, septurn and apiculus at heading stage and apiculus, Iemma or palea at maturity stage. Besides MUNSELL'S color system, a method of showing color in numerals was adopted, and the classification of about half of the rice varieties having color pigments was accom-plished by this method (Table 3).

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For the study on self-and cross-incompatibility, 116 varieties of sweet pota:to were introduced into Agricultural Experiment Station, University of the Ryukyu from the Philippines, Japan, and Ryukyu Agricultural Experiment Station. In 1961, the authors made reciprocal pollinations between these varieties and 10 test varieties which belonged to 4 Oross-incompatibility groups (A, B, C and D) to observe germination of pollen grains on stigma. The results were as fcllows : 1) Out of the 106 varieties, 39 belonged to A group, 44 to B, 18 to C, and none to D. Remaining 5 varieties, i. e., Donyu-5, Gokoku x Shichifuku, Suburan, Taino-27, and Yamashiro, were compatible with all the test varieties. From these results, it was considered that they belonged to another group or groups, which was tentatively called X group in this paper, though it must be ascertained whether they belong to one group or not. 2) Seven of the varieties used were self-compatible and the remainder were self-incompatible. 3) The cross-incompatibility groups studied and the places from where all these varieties were introduced are listed in appendix. Among these varieties, 66 were not reported by FUJISE and YUNOUE (1950), and 13 varieties with the same names were fcund to be different in grouping as to incompatibility or morphological characteristics.

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Dry seeds of di-, tetra-, and hexaploid species of Triticum and Avena and of a diploid species of Aegilops, were exposed to thermal neutrons from the beam hole No. 16 of JRRl, and their biological effects were investigated. The seed germination was not affected by the dose of 9.2 x 10¹¹nth/cm² or 1.8x 10¹²n res /cm² (obtained by using 0.5mm Cd-filter to exclude thermal neutrons), but was clearly disturbed by 9.2x10¹²n th/cm², excepting hexaploid species. Seedling heights of diploid species decreased distinctly by 1.8x10¹²n es/cm and extremely by 9.2x10¹2nth/cm², but tetra- and hexaploid species were more tolerant than diploids. Moreover, the experiments indicated that Avena is generally more resistant than Triticum. Both length and width of the first, second, and third leaf-blades were reduced by certain dosages, the first leaf being most tolerant and the third most sensitive. This fact may sugggest that leaves in different developmentai stages show different responses to radiations. LD-50 for thermal neutrons, X-rays and gamma-rays were determined for every species. Comparing the survival rate 100 days after sowing, the dose of about 2.1 x 10⁸nth/cm² of thermal neutrons (plus other contaminating radiations) in JRR-1 was calculated 40

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Evidences on the effect of directional selection for the mammary growth response were reported together with the effect of the selection on the 12- and 35-day-weight of mice. Full-sib mating was continued and the selection for the mammary growth response was taken place every third generation. In the directional selection group, the mammary growth response increased from the 6th to 15th generation by the selection under the intense in'breeding, the body weights showing some increases. According to the estimate of heritability computed from response to the selection, genetic variance in the mammary growth response appeared to be present. Genetic associations of the mammary growth response with the 35-day-weight were suggestive.

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1. As the previous reports (TORIYAMA & FUTSUIIARA 1962), this experiment was conducted with the aim to obtain some beneficial mutants in rice. 2. Water soaked seeds of a rice variety "Fujisa" ka No.5" were irradiated by X-ray. The breeding methods employed in the X₁-X₇ generations are shown in table 1. 3. Consequently, we found a number of mutations, most of which were lower in yield than the control (original variety). 4. However, a high yielding mutant line was obtained from the progeny of X₂ variants selected as small morphological variant types, and was nominated as "Fukei No.54". 5. "Fukei No.54" having more many tiller as compared with that of the control, was higher in yield by about 8% than the original variety.

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The sowing time of wheat and barley in heavy snowfall regions is early and the progress of the ear development in barley varietes in autumn is not always correlated with the degree of spring habit. In the present study, 38 varieties of barley were sown several times in autumn and the degree of the ear development was investigated before the continuous snow-cover. These barley varieties were classified into 6 groups based on the degree of provisionally called "early sown growth habit". On the whole, the varieties which have very low or high "early sown growth habit" almost show very high or low spring growth habit respectively, but some varieties which have I -V degree of growth habit belong to the groups of II and III "early sown growth habit" and these two growth habits are not always correlated to each other. Hence, they are recognized as different characteristics. The spring growth habit, examined by sowing several times in spring, is important in the light snowfall regions, because barley plants are damaged by cold in spring, but the "early sown growth habit", examined by sowing sevaral times in autumn, , is more important from the practical point of view in the heavy snowfall regions, because the cold and snow damage is related to the growth of barley in autumn and early winter. The "early sown growth habit" is to be effectively utilized in the breeding: of the barley varieties in heavy snowfall regions.

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The reduction division in PMC's was studied in 3 interspecific hybrids : 4x N. labaculee XN. alata, 4x N. tabacum X N. Ialegsdorffii and 4x N. tabacum X N. benavid esii. 1) F₁ of 4x N. tabaculee (n=48) X N. alata (n=9) This hybrid was produced for the purpose of introducing a gene or genes for immunity agn"inst mil, dew and black shank, and for resi.stance against wild fire and anthracnose from N. alata into cultiv, ated tobacco. At MI in PMC's of this hybrid, tb.e total number, of bivalents and trivalents per cell was 24. The number of trivalents most frequently ranged from 1 to 4 but O, 5 and 6 were rare. At meiosis of the F₁ of N. tabacumXN. alata, the, author (1956) observed 1-6 bivalents and the most frequent configurations found were 311+171 and 4n +15_I' According to KOSTOFF'S description (1943), the same hybrid N. tabacumxN. alata contained 5-9 l)ivalents and also some polyvalents. Further, the :number of trivalents in the hybrid, 4x N. tabacumX N. alata, generally agreed with that of bivalents in the'hybrid, N. tabacum X N. alata, observed by myself, but did not agree with Kostoff's findings. At AI of PMC's, chromosome bridges and strayed chromosomes outside the spindle were frequently seen. At 2nd division, they form small nuclei and, are the cause of polyspory at tetrad stage. 2) F₁ of 4x N. tabacum (n=48) X N. Iaecgsdorffii (n=9) The purpose of producing this hybrid was to introduce a gene or genes for immunity to mildew and for resistance to black root rot from N. Iaeegs, dorffli into cultivated tobacco. At MI in PMC's of the F₁ of 4x N. tabacum X N., laeegsdorffii, the tbtal number of bivalents and trivalents per cell was 24. The number of trivalents ranged from O to 5, with the mode at 1. PMC's with 4 or 5 trivalents were very rare. In my laboratory, Dr. HU (1956) obeserved meiosis of the hybrid between N. tabaculee and N. Ialegsdorffii and found a range from 5 to 12 chromosome pairs with the mode at 11. Considering his data, more trivaents than those observed by myself may be expected in the F₁ of 4x N. tabacum X N. Iangsdorffii. But the small number of trivalents found in this hybrid may be due to saturation of the affinity between homologous chromosomes by the two ch-romosome sets of N. tahoculee pr6sent in this hybrid. 3) F₁ of 4x N.tsbacum (n=48) x N. benavidesii (n=12) This hybrid was produced for the purpose of introducing a gene or genes for immunity against the common mosaic disease from N. beleavidesii into cultivated tobacco. At MI in PMC's of this hybrid, the total number of bivalents and trivalents per cell was 24. The number of trivalents ranged from O to 6, with the mode at 2, . PMC's with 5 or 6 trivalents were very rare. At meiosis of the F₁ of 2x N. tabacumxN. beleevidesii, GOODSPEED (1954) observed the range of chromosome pairs to be from O to 6, with the mode at 3. Considering that in my study hybrid plants with two chrotnosome sets of N. tabacum and one chromosome set of N. benavidesii have been used, it may be said that the results of my observations are generally in agreement with GOODSPEED'S data, because the affinity between homologous chromosomes may in this hybrid be saturated by the presence of two chromosome sets of N. tabacum

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The reduction thvision in PMC's was studied in 4 hybrids between N. paleiculata and 4 other species Of section Alatae, namely N. paniculata x N, alata, N. paniculata X N. Ialegsdorffii, N. paleiculata X N. plumbaginifolia and N. paniculata x N. Iolegiflora. 1) F₁ of N. paleiculata (n=12) x N. alata(n=9). At MI of PMC's of this hybrid, the number of bivalents ranged from 0 to 6, with the mode at 3. The frequency of PMC's with 4 and 2 bivalents followed that of PMC's with 3 bivalents. PMC's with I and 5 bivalents were occasionally found but those with 6 bivalents or without bivalents were very rare. In the same hybrid, KOSTOFF (1943) found that the number of bivalents ranged from 2 to 7 and observed occasionally a few trivalents. His obeservation of trivalents is doubtful because the trivalentlike chromosomes in my preparation were hetero-morphic bivalents. Otherwise KOSTOFF'S results generally agree with mi.ne. 2) F₁ of N. paniculata (n=12) X N. Iaeegsdorffii (n=9) . At MI of PMC's of this hybrid, the bivalent range was from 0 to 4 with the mode at 1 and 2. The frequency of PMC's with O bivalents followed that of PMC's with Ilor 2 bivalents. PMC's with 3 bivalents were occasionally fcund but those with 4 bivalents were very rare. In the same hybrid, GOODSPEED(1954) found that the number of bivalents ranged from O to 4, with the mode at 2. His results agree with mine. According to KOSTOFF'S description (1943), he and also DREMLUG observed in the same hybrid that the number of bivalents ranged from 0 to 7 and some trivalents were present. The difference bctween the results observed by GOODSPEED and also myself and those of KOSTOFF and DREMLUG is too large to be attributed to different strains used by the authors. 3) F₁ of N. paniculata (n=12) X N. plulecbagilei-folia (n=10) . So far as I know, no investigation of this hybrid has been published. At the MI of PMC's, the bivalent range was from 0 to 3, with the mode at O. Accordingly N. paleiculata is assumed to be less related to N. plueebagileifolia than to N. alata and N. Iaecgsdorffii. 4) F₁ of N, paleiculata(n=12) X N. Iongiflora (n=1O) . No findings on this hybrid have been reported till now, so far as I know. At MI of the PMC's of this hybrid, the number of bivalents ranged from O to 2, with the mode at O. N. Iongiflora is very closely related to N. plumbagilcifolia, and the chromosome pairing in hybrids N. paeeiculata X N. Ioleiflora and N. palciculata x N, plumbagilcifolia was similar. From the results of the chromosome pairing in the four hybrids mentioned above, it is assumed that N. paniculata is not related to the above four species belonging to section Alatae.

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