(1) There are several species, varieties or strains of fragrant Pelargon;ium which are utilized fcr the production of commercial geranium oil. In Japan Pelargonium roseulee WILLD. was introduced in 1954 for the purpose of increasing production of the oil and its cultivation is now being spread. Previously the leading species cultivated was Pelargoniulec denticulatum. Both species are commonly sterile and do not bear any fruit owing to the complete absence of their fertile pollen. Judging from a stand-point of Pelargoniulmbreeding, it is, especially desirable that such sterile species be able to produce seeds. With the object of breeding Pelargoleiulee species, we attempted to establish the artificial tetr:aploid strain of P. roseum and succeeded. Moreover, we were able to obtain fertility in this species in company with tetraploidy. In this paper we will report briefly on the pr ocess tf cclchicine treatment and some characteristics of the induced tetraploid. (2) Lateral leaf-buds of a cutting of P. roseum, variety called "Bourbon", which was grown in the propagation house, were treated with water solution of 0.3 % colchicine during a week in January of 1956. At the flowering season in April, there appeared some large fertile flowers upon one of the treated branches, in striking contrast to small sterile Llowers of diploid. The branch bearing large flowers proved to be of tetraploidy by the examination of size of stomata of the leaves. Plants were propagated not only by cuttings of the tetraploid branch, but also by sowing seeds obtained from the large flowers .

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It is a well known fact that the hybrid sterility is not found frequently in rice when Japonica type varieties are crossed with Indica type ones.. On the other hand, it is also known that the sterility occurs in tetraploid plants when diploids are artificially doubled in chromosomes. In the previous paper. MASIMA reported with UCHlYAMADA about some relationships between the two types of sterility and concluded that the fertility of subspecific hybrids, showing high sterility in diploid level is recovered in some degree when they are doubled to the tetraploid level (MASIMA and UCHIYAMADA 1955). This reason was considered due to the selective pairing among the four homologous chromosomes which have small structural differences between the two original varieties. Here another brief report is given as we recognize.d the same conclusions by a successive experiment using new materials. Tetraploids were newly induced in 38 Iines using 11. other varieties. They are grouped in to four different kinds of tetraploids, originated from simple varieties, fertile varietal hybrids (intra-subspecific hybrids), semisterile ' varietal hybrids (inter-subspecific hybrids) and sterile varietal hybrids (inter-subspecfic hybrids) .

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The morphological characters of the Sequoia sempervireles seedlings obtained from seeds were investigated. The seeds introduced from California were sown in the spring of 1951, and 15 seedling trees were examined in the autumn of 1953. The characters investigated were height of the tree, diameter of the stem, diameter of the crown, distance between the successive branches on the stem, angle of branches with the stem, Iengti:L Of the branches, Iength of inter-node on the sub-branches, diameter of the branches etc., and at the same time, the height of the tree was measured and the crown color was examined in the winter of 1954. Table I shows the results of investigation. It was considered that there might be differences of growth due to seed activity in seedling stages but TOYAMA (:1948) obseived that these were very small at 2 year old seedlings of Cryptomeria japauica D. DoN. Variations in the growth in this experiment, however, were remarkable. i[ndividual trees showed the differences in the height of seedling trees. The variation of the diameter of stem was wide. The difference of the diameter of crown among individuals was large. And. the correlation between the height of seedling and the stem diameter was high. The tree forin (diameter of crown / height of tree x 100) was divided into three types ; the pyramid type, the cone type and the middle type. The change of ctown color in the autumn and winter was not simple, the discolorizing individuals became brown and the remainder stayed green, and variations in the color change among individuals were large. No. 4 had grown vigorously until the summer of 1954, but the growth, of top stopped in the autumn of the same year. This characteristic was a flaw of this species.

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The induced autotetraploid plants (2n = 24) of Common California Poppy (Eschscholtzia califorleica CHAM. ), which were obtained by treatment with colchicine sc, 1ution, showed an extremely lowered seed fertility in 1956, only producing a small qu, antity of small crumpled seeds, possibly due to the unfavorable higher temperatured envi.ronment of late spring at Utstu'nomiya. After sowing them only one tiny seedling grew up and was soon ascertained tb be haploid in fall of that year. The habit was typically dwarf. Size of its organs, stems, Ieaves and flowers, was all about a half of normal diploids.

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In the previous paper the author made an observation on rapid growth in induced hexaploid Edgeworthia papyrifera. Edgeworthia papyrifera is divided into two or three races, an'.ong which Shizuoka-race is t.he most widespread one and Kochi-race is of the most superior quality. They are both tetraploid, but genom constitution are partly different from each other. An octaploid plant of Shizuoka-race was induced by treatment with coicllicine and many hexaploid plants were obtained from its cross with tetraploid. Some economic characters of hexaploid plants were compared with those of Shizuoka and Kochi races. In this investigation four year old plants were used. As can be seen in Table 1, yield of green bark weight and the -white bark (partly refined bark without outer colored layer) ratios m hexaploids were the high st of the other two races. The finai yield of white bark reached more than twice that of Shizuoka-race. The ratio of the effective fibers (Table 2) was also found to be the, highest in the hexaploid. Its fibers were longer than those of the other two races, and thicker in diameter than those of Shizuoka-race, . The strength (the breaking length and the bursting strength ratio) of the paper made from them was measured. The results showed that the strength of the paper made from hexaploid plants was much the others better than that from Sizuoka-race and even exceeded the Kochi-race. In short, the hexaploid plants are qmte supenor not only m thelr yleld of bark or fibers but also in their quality.

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It is necessary to make clear the action of embryo factor which is closely related to growth of the very young embryo in plants, for establishing the technique of ile vitro culture of the plant embryo. In this report, the author has studied action of auxin and embryo factor on embryonic growth. The growth of embryo of cucumber in a medium containing malt extract or Cucurbita endosperm extract, showed the existance of embryo factor in malt extract and also Cucurbita endosperm extract (cf. photo. 2) . By means of avena curvature method, it was shown that embryo and endosperm of Cucurbita makima contained the free auxin and bound auxin (alkali released) at all stages of seed development (cf. table l). and also the above mentioned malt extract and endosperm extract of Cucurbita contained both the free a ?? d bound auxin (cf. table 2). Therefore, the author thinks t'nat the auxin plays a very important role in the growth of embryo. Then the growth of embryo of cucumber (1ate heat stage-early torpedo stage) in a medium containing IAA and also in a medium containing embryo factor, had been compared from morphological and histological point of view. In morphological observation, the, fomer (only high concentration ; IAA 2 ppm. ) was similar to the later (cf. table 3) . In histological observation, only cell elongation was recog, nized in using IAA, but in using embryo factor, both the cell elongation and cell division were recognized (photo 3, 4) . And then, the existance of starch grain in the cells of cultured embryo showed that the action of embryo factor is related to the action of auxin. So the author thinks the embryo factor contains auxin and other factors which accelerate the cell division in plant embryo.

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In this experiment the writers tried to synthesize 6x-amphidiploids by artificial hybridization between T. Timopheevi ZHUK. and Aegilops comosa SIBTH. et SM., with the aim to combine the leaf-rust resistant genes that were possessed separately by these two species iinto a single one, and to make this new wheat a good source of resistance to leaf-rust in wheats. By applying 0.05% colchicine solution to the F1 seeds a number of mature amphiploids were obtained successfully in addition to two aneuploids, one showing 2n = 41 (monosoItnic), and the other, 2n=43 (trisomic). In the root-tip cells of F₁ plant, 21 somatic chromosomes were confirmed, which obrre, spond to the sum of reduced numbers of their parents, and in those of amphidiploids 42 chromosomes were clearly counted corresponding to the multiple number of chromosomes of F₁ plant.

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In this expenment the vanety chosen was " Sekitori Sai No.1", a six-rowed barley, now widely cultivated in Kanto area in Japan. Dormant seeds which had been stored under laboratory conditions since the previous harvest were used for irradiation. The seeds were placed in open petri dishes at about 9 cm. from " target" of a 60 kVp X-ray plant, run at 4 mA., where the dose rate was 235 r. per minute. After doses of 435 r. to 25, 000 r. were given, the seeds were sown in the field together with unirradiated seeds from the same sources. Contrary to expectation, even with higher X-ray doses maOrity of barley seeds produced plants up to maturity. The plant growth determined by measurements of the total height of the 18-day seedling after was sowing inhibited with the higher dose of X-rays. As regards the shape of the grbwth / dose curve, the X-rays gave a sigmoid curve (Fig. 1). The average spike fertility, as evidenced by seed set of the irradiated generation, decreased due to X-irradiation. The average spike fertility is the function of X-ray dose as illustrated by Fig. 2. Regression analysis indicated that relationship was linear. Three to five spikes were removed from each plant, and the seeds were sown for seedling mutation studies. The mutations observed resulted from chlorophyll deficiencies, and a linear relation between dose and frequency of mutations was obtained (Fig. 3). While at low doses the frequency of mutations per spike proge'ny and per dose unit was almost constant, at higher dcse there was a drop in the amount of effect produced per dose unit (Table 1). Also, in this experiment, the phenotypic effects, differed in response to varying doses, i.e., tlle mutation freqliency of viridis increased linearly with dose, while that of albilea showed a similar linear response to lower doses but somewhat decrement in the frequency of mutation at high doses. Most of the mutants were produced in the same relative frequencies as observed by earlier workers (Table 2).

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Dormant seeds of a rice variety, "Norin No.29", were treated with nitrogen mustatd, methyl-bis-(2-chloroethyl)-amine hydrochloride, its N-oxide derivative, methyl-bis-(2-chloroethyl)-amine-N-oxide hydrochlorid. e, or X-radiation. Nitrogen mustard presents the more toxic effect on germinating ability than it is the case with X-ray or N-oxide treatments (Fig. 1). A chi-square-analysis performed after a correction of discontinuity for 2 x 2 table gave the indication on mutagenic action of nitrogen mustard (Table 2). In comparison with ionizing radiation (X-rays or fa.st neutrons), nitrogen m'u:stard snows a significant difference in its ability to induce the mutations destroying chlorophyll formation of striata type (Table 3) . This suggests the possibility of+ controlling experimentaily the mutation process of rice. When dormant seeds of rice were exposed to N-oxide of nitrogen mustard, it showed the same tendency in sterility of the treated generation, production of seedling mutants and, the relative frequency of chlorophyll mutations, as that found in X-rayed material (Fig. 4 and Table 3). For seeds, N-oxide mus't, however, be considered as a less favourable mutagen than X-radiation, as clear froicn the relation between the toxic and mutagenic effects shown in Fig. 5.

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Some varietal differences of the chemical constituent in the bark of tree in relation tothe resistance to the mulberry-bli.ght were investigated.The results obtained are summarized as follows : ( 1 ) Quantity of the total carbohydrates in the bark was not so changed regardless of variety, Iocality and season (at both the times after falling of leaves and thawing)., ( 2 ) Tendencies in (iecrease of total sugar content were found in all materials, especially, in weak varieties, the remarkable decrease in the total sugar occurred accompanied by an increase in insoluble carbohydrates during winter. ( 3 ) It was obviously noticed that the insoluble carbohydrate content/total sugar content ratio in the bark at the time after falling of leaves was higher in strong varieties than in weaker ones. In other words, the barks of strong varieties are more advanced in degrees of hardening than those of weaker at this time. Similar analytical result was found between nitrogen fractions. ( 4 ) No correlation was found between water content and the blight resistance. ( 5 ) From the results mentioned above, it was suggested that the degree of debility of mulberry-tree under snow layer was deeply related to the physiological characteTistics of varieties before snow cover.

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The necessity of breeding new early variety of wheat existing high correlation between growth habit ahd heading time and ripening period is long over-due in our country. So the work to breed new early varieties as to growth habit dn wheat has been continued at Tokai-Kinki National Agricultural Experiment Station, in Japan. Results of 10 crosses made to study the inheritance of growth habit of wheat varieties, segregation ratios obtained as to erect and prostrate in F₂ are shown in figure 1 and table 2, respectively. Relations between growth habit and lo:eading time, and ripening date are shown in table 3, 4, 5, and 6 respectively. The methods of testing the growth habit and heading, and ripening date :are as follows : the growth habit of F₂ Was decided from the parent and factor hypothesis and factor analysis as shown in report. The results obtained can be briefly summarized as follows : 1. Factors affecting the growth habit of wheat correspond to 3 genes. 2. E factor is epistatic to P and T factor, P factor is medium and T factor is substatic to E and P factors. 3. E factor determines erect-type, both P and T factors control prostrate-type, but differ in their effect on prostrate. 4. Factors affecting growth habit and heading time and ripening period on wheat seem to be the same.

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Wheat varieties grown on the drained paddy fields frequently suffer from injury caused by excess water of the soil, being noticed as " Wet-injury ". Such a wet-injury occured throughout Japan, especially in Tokai-Kinki districts. The work to breed new varieties resistant to wet-injury has been continued at National Tokai-Kinki Agricultural Experiment Station, in Japan. Results obtained are shown in table 1. The method of selecting plants resistant to wet-injury was carried out in paddy field by irrigatin*" at growing sta:ge, strong plant decided as one ripened in the paddy field and weak as one which could not show heading, as shown fig. 2. 1. There are two factors affecting the wet-injury of wheat. 2. N factot is epistatic to C factor as to wet injury. 3, N factor when accompanies C factor shows very weak reaction to wet injury.

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