The effects of nitrogen, phosphorus and potassium on the structure of the vegetative shoot apices in rice plants were investigated cyto-histologicaiiy, using the variet of paddy rice "Aichi-Asahi" In the first experimcnt (1956, Soil culture), three plots were provided according to the quality of nitrogen, phosphorus and potassium supplied, and in the second experiment (1957, Sand culture), seven plots (1. N, 2. P, 3. K, 4. NP, 5. NK, 6.PK, 7. NPK) were providee, using the Dr. KASUGAI's complete culture solution for rice plants as the standard solution. Dissected stem tips of the young plants of about middle stage of vegetative growth were fixed in modified Navashin's fluid or F. A. A. and embedded in paraffin wax and serial sections cut at about 7μ were stained with the Delafield's hematoxylin. The results obtained in the experiments are as follows : (1) The structure of the vegetave shoot apices in rice plants shows several cyto-histological changes according to different conditions of mineral nutrients. (2) In the plots of high nitrogen supply or nitrogen only, the number of the tunica layers are increased and 2 or 3, sometimes 4 layered tunica is observed. the anticlinal division in the peripheral region of the apices being promoted. (3) On the contrary, in the plots of hlgh phosphorus supply or phosphorus only, the stratification in the tunica is distutbed and thc number of the tunica layers is decreased to 2 or 1 layer, accampanied by the increase of the all direction division in the corpus. (4) Potassium seems to have an effect to establish the topographical differentiation in a apex distinctly and to restrain the one-sided changes in the number of tunica layers by nitrogen or phosphorus supplied. Refering to the writer's observations on the developmental changes in the structural pattern of thc vegetative shoot apices in rice plants, it is considered that high nitrogen supply tends to strengthen the vegetative characteristics in the apices, and the other way, high phosphorus supply tends to diminish the vegetative features in them.

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The genetic componcnts of six fluc-cured varieties were studied for leaf number, plant height, flowering time and leaf shape by the diallel cross method. The estimates of D and H₁ and H₁/D gave a direct estimate of the degrec of dominance. The ratio of positive allelomorphs to negative. ones, the dominance order of parents, the number of effective factors and the heritability value in diallel cross progeny were czllculated from D, H₁ and the other statistics. From these analysis, it was recognized that generally these exists pilrtial dominance of the genes and a slight specific combining ability for all of the four characters studied between these cultivated varicties. The number of the factors conditioning each of these characters was found to be two or three. Heritability of these characters was known to be of high value. These results are shown in Table 7.

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Indigenous varieties gathered from some isolated islands and mountainous parts of Japan, which are thought to be cultured from year to year since near 100 years ago or more, was cultivated and observed their morphological and ecological characters comparing with several improved varieties of Japanese paddy rice and some of upland and foreign rice. The shape of grains of indigenous varietics was almost the same with improved varicties which are the typical Japonica. However, the former have longer culms and spikes than the former. The length of culms, panicle and leaf, the weight of ear, number of rachis branches and tillers of indigenous show wide variations as foreign rice. The plant type of indigenous, as the result, resembles to them. Though the reaction of paddy to phenol and solubility of grains by KOH, which are used as the discriminant characters between the Japonica and Indica type of rice, some of indigenous varieties reveal positlve to phenol and negative to KOH as some of foreign rice. The photoperiodic response and sexual affinlty of thc indigenous rice also investigated on the phylogenic point of wiew. One of them has a large basic vegetative growth hablt and low sensitivity for The sexual afflnities of the short-day treatment. The sexual affinities oh them to 2 Indica varieties ( Surjamukhi and Charnack ) also variates in wide range. The indigenous varieties of Japan seems to have many genotypes in morhological and ecological characters as foreign rice and breeders in Japan improved them to the special genotypes having the short culm, many Spikes, awnless and short-narrow leaves.

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( 1 ) The writer studied on the developmental process of the oilgland and the secretory duct and thc santonin quantity in Artemisia Kurramensis QAZILBASH. ( 2 ) The oilgland takes its rise in one epldermis cell. This epidermis cell divides into the oilglancl mother cell and as a result of five divisions four stalk cells and eight oilgland cells are completed and the chloroplastid is contained in these cells. These oilglands grow well on the epidermis of stalks, leaves and buds. ( 3 ) As the oilgland grows, reslnous substances are accumulated in the oil sac. On the other hand santonin substances are accumulated In the lowest oilgland cells, and after their quantity increases in there, they are accumulated in the upper oilgland cells gradually, and at last they have been accumulated in the oll sac with resinous substances. ( 4 ) Secretory duct grows along the bundles in the inter tissues of the stem, leaf and bud and it is cornposed of many flat and slender secretory cells and the schizogcnous intercellular space occuring between these secretory cells. On early stage much resinous substances are contained in this secretor duct but after that santonin substances are accumulatecl in it with resinous substances.

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From the cross between Brassica pekiesis "Chifu-Hakusai" (AA, n=10) and B. oleracea "Nozaki-Matsumaki-Kanran" (CC, n=9'), a di-o*-enomic triploid plant (ACC, 2n=28) was obtaiined. The author performed morphological and karyological study of this plant. This plant was partially fertilc and gave various ancuploid offsprings both on opcn and controlled pollinations. From the open pollination, 4 plants were obtained (open F₂-1, -2. -3, -4). Open F₂-1 was morphologically intermeadiate between B. oleracea and B. napus, and had 47 chromosomes in its somatic cells. Open F₂-2 resembled the ACC-plant and had 34 somatic chromosomes. Open F₂-3 showed very weak growth in its early developmental stage, but afterlvards became very vigorous. Its leaves resembled in shape to those of B. rapa, but their surface was waxy. The chromosome number of this plant was 2n=42. Open F₂-4, also showed poor growth, and was like B. chinesis "Shigatsu-Shirona", and its chromosome number was 2n= 25. On selfing, two F₂ plants were obtained (self F₂-1 and -2). Self F₂-1 was similar in morphologv. to open F₂-1 and its chromosomc number was 2n=46. Self F₂-2 looked like cabbage and it showecd 2n=29. From the cross between cabbage "Natsumaki-Kurona-Succession" (CC) (♀) and F₁ ACC (♂), only one plant was obtained, and it showed 2n=20. It was supposed that this plant contained tlvo C-genomes and two extra chromosomes of A-genome origin. In general appearance this plant looked like cabbage, though its leaves were rather softer and less waxy than those of the latter. From the cross between F₁ ACC (♀) and B. rapa "White Globe" (AA) (♂), three plants were obtained (ACC X AA-1, -2 and-3). ACCXAA-1 resembled open F₂-1 and showed the most vigorous growth among all the progenies of F₁ ACC. Its chromosome number was unexpectedly high, i. e., 2n=44. ACC XAA-2 was 2n=29 and ACCXAA-3 was 2n=26, and they were similar in shape to their pollen parent, B. rapa "White Globe". It has been pointed out by scveral lvorkers that the cross between AA- and CC-species is one of the most difficult crosses in Brassica (HOSOOA, 1950 ; OLSSON G., JOSEFFSON A., HAGBERG A. & ELLERSTROM S. 1956 and HOFFMANN W. & PETERS R. 1958). For obtaining synthetic B. napus, it is desirable to take some measures in lessening the incompatibility between the two species. The present results suggest a convenient method for this purpose. ACC-plant crosses with AA-species far easier than in the case AA×CC. Though the gametes produced on ACC arc of recombined nature, being consisted of one C-genome and a varying number of member chromosomes of A-genome, the resulting aneuploids from ACCXAA may be treated by colchicine so as to form a synthetic napus after a few generations. In the present experiment 38 aneuploid offsprings have been obtained by applying pollcns of 4 kinds of AA-species to ACC. Their somatic number of chromosomes ranged from 22 to 29 with two excep-tionally high numbers of 35 and 45. These plants were different from one another in morphology as well as in their mode of growth, but no clear co-relation was noticed between plant-type and number of chromosomes.

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It was shown in the prvivus paper from the results of estrogen administration to 60days old W. L. chickcn that the individual sensitiuity has relation to her family's sensitivity. Breedineg, experiments were carriccl out for thc purpose of ascertaining the possibility of establishmcnt of two inbred strains with sensitive or nonsensitive charactcrs on the days necessary for serum vitellin reaction. Brother-sister mating system was succeedcd up to the 3 rd generation. Rcsults obtained are as follows : 1) In respective generation, the sensitve group showed higher percentages of positive rection than the nonsensitive group. In the total of three generations, more significant difference was observed. 2) In analysis of variance of the days necessary for positive reaction, significant difference was observed between families composed of full sibs. and intra-class correlation coefflcients obtained in full-sib and full sisters were significant. 3) Sexual differences were observed in thc percentages of positive reatction and means of the days neccssary for positive reaction. In vitellin reaction, the female chickens were more sensitive than the male to estrogenic stimulation.

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Rice variety Norin 33 of the same origin was cultivated through its whole growth pc.riod under thc nutritional condition of nitrogen or phosphoric acid deflciency for a few generations, and then tested for their after-effects on the next generation groen under the condition of complete nutrition in regard to their growth and heading date. The results were summarized as follows. ( 1 ) It was recognized that the deficiency in nitrogen or phosphoric acid was inhibitory for growth of rice plants, and the inhibitory effects of the continuous exposure to the deficiency in nitrogen or phosphoric acid were cumulative from generation to generation (cf. table 1). ( 2 ) The cumulative inhibitory effects were recongnized in the next generation grown under the condition of the complete nutrition (cf. table 2). The after-effects, however, faded away after the cultivation uncler the complete nutritional condition for one generatiorl. ( 3 ) In regard to heading date, the accidental earliness was rccognized on the next gcneration of the plants grown under the nutritional condition of phosphoric acid deflciency for three generations. However, such earliness was not genetical, because the earliness was faded away after the cultivation undcr the complete nutritional condition for one. generation (cf, table 3).

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Wheat yellow mosaic virus has been occurring at Tokai-Kinki Agricultural Experiment Station farm since 1957 as described in the report 1. Wheat varieties, Shinchunaga, Norin Nos. 20, 43, and 61, decided previously resistant to yellow mosaic virus ranged from severe to lighter degree of infection which could be dctectcd by the X-body as a weak symbol. The methods of testing the yellow mosaic inheritance remains same as clescribed in report l. Rcsults shown in the report are brieny summerized as follows : 1. Three genes controlling the occurrences of yellow mosaic virus behave in the same way as in case of green mosaic virus described in the. report 1. 2. Among these 3 genes, H and M are susceptiblc genes and these 2 genes affect thc occurrences of mosaic infection. Another one, A, is a modifying gene and it in hibits of H gene. It seems to be controlling the occurrence of yellow mosaic virus. 3. Judging from these genes interaction, the action of M gene seems to have close relationship, with the infection of the yellow mosaic virus.

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During two years period of 1956 and '57, we tested the resistibility to low temperature at secdling stage and the sensitivity of heading to high temperature on 27 varieties of upland rice, comparing with 27 varieties of paddy rice. ( 1 ) On the resistibility to low temperature for the growth injury at seedling stage, generally speaking, upland rice varieties are weaker than paddy rice varieties. varietal differenes of upland rice are wider than those of paddy rice. The degree of this resistibility does not concern lvith earliness or lateness of heading time and latitude of cultivated regions of the varieties in this experiment. ( 2 ) The degree of sensitivity to high temperature for thc response of heading in uplanrl rice is the same as in paddy rice, in this experiment. Varietal differences of paddy rice on the sensitivity to temperature are wide, and the degree of this sensitivity has minus correlation with earliness or lateness of heading time, but these appearances are not noticed on upland rice varieties. ( 3 ) It is seemed that the number of days hastened of heading by high tempcrature is the same with the sum of the number of days hastened of leafing before differentiation of young ear and shortened by decrease of leaves under high temperature.

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In the field of "mutation breeding" in normally self-pollinating cereals, which takes aim at the utilization of the genetic variation increased with the application of ionizing radiation, some spikes have been picked up from the individual plant in R₁ (treated) generation and each spike has been sown separately as one strain for the detection of various deviants appeared in the R₂ generation. It is expected, that about 1/4 of the grains of a spike will be homozygous for mutated allele, from the description that the vast majority of induced mutants are completely or partially recessive to the original type. Therefore, NYBOM (1954) reported that the spikes of R₁ plants were sown secparately in R2, being one strain with max. 20 plants from eacg spike of barley. Althougll the minimum number of plants neccssary to find one mutant out of a certain mutated strain in R₂ is determined by the knowledge of the segregation ratio of homozygous plants for the mutated allele, there are some difficulties to estimate directly the above ratio for the decreasc of kernels in R_l-spike due to radiationinduced sterility. Accordingly, the proportions of chlorophyll mutants in R₁-spike strain, which were produced from the irradiated seeds of rice (Tables 1, 2 and 3; cf. MATSUO et al., (1958), were estimated by using FISHER's sib method. The estimate gave O. 2305±0. 0084 for X-irradiation and O. 1774± O. 0092 or the treatment of thermal neutrons of "Rikuu No. 132" and also O. 1770±O. O111 for the irradiation of thermal neutrons of "Norin No. 29". Two proportions in the case of neutron-irradlated seeds deviated very significantly from the value of O.25 that would be expected if mutated character was a simple recessive. The deficiency of mutants is probably caused by gametic elimination after meiosis (cf. MOH and NILAN, 1956). It is interesting that the defective transmission for mutated character seems to demonstrate fundemental differences in the mode of action of two kinds of ionizing radiations; namely thermal neutrons seems to induce in much greater relative abundance either the simultaneous mutations of two closely linked loci, one of which being the chlorophyll mutation and the other the delctcrious mutation upon the development of gamete, or small deletions (cf. MULLER, 1954'). As a result of the calculation bascd on thc abovegiven estimates, the number of R₂ plants in one spike-strain necessary to detect at lcast one mutant within a mutated strain with the probability of 99% was attained 18 plants in a case of X--irradiation and was obtained 24 plants in a case of the treatment of thermal neutrons (Table 4).

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1. A haploid plant of rice varity, Norin no. 8 produced panicles with fertile seeds which showed the diploid numbcr of chromosomes in somatic cells. Plants from thc seeds and from foundation seed of the same variety were propagated in pedigrees. In order to makc comparisons between them, 30 lines taken from each of the three populations belonging to the third and fourth generations of the diploidfrom-haploid and foundation seed, respectively, were tested in a randomized block experiment with six replications. Plant height. panicle length, panicle number, grain yield per plant and other characters were measured on a single plant basis. 2. The diploid-from-haploid plants and those from foundation seed showed no difference in the characters measured. The difference between line means in each of the three populations was also found to be insignificant, except that in plant height the lines from foundation seed were found to be significant. It seems, therefore, that diploid-fromhaploid plants are genetically as pure as or purer than foundation seed. The occurrence of genetic variability due to spontaneous mutations of genes could not be detected within the four generations investigated. 3. In the standard deviation for individual variations, no significant difference was found between the diploid-fromhaploid and foundation seed lines. It may then be said that genetical purification does not bring about a tendency toward inbreeding depression in rice. 4. Triploid plants were found in the second and third generations of diploid-from-haploid plants with 1/40 and 1/80 frecluencies, respectively.

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1. The immature embryos of wheat and barley were excised and immediateiy transplanted into the growing young endosperms of foreign grains. After the operated grains ripened, the transplanted embryos were excised again to measure their size, (length, breadth and thickness). 2. The transplanted young embryo was abie to grow further in the foreign endosperms and reach about the same size as the embryo of intact seed (Table 1). And also, the transplanted embryo was proved to enlarge its size along with the further differentiation of its organs. 3. The increase in length, breadth and thickness of the transplanted embryo was nearly similar, except some embryos which showed surplus growth in breadth or in thicknessf(Table 2). About half of the total number of transplanted e.mbryus grew five times or nlore as large in size as young embryo at the time of excision ; about one-fourth, ten times or more. The earlicr the embryo was tranplanted the larger the growth ratio became (Table 3). 4. The number of embryos longer than 1. 5 mm, which is reported to be able to germinate easily, amounted to about 24 percent of the total number of embryos transplanted. This figure is close to the highest percentage of germinaition (26%), which was obtained in 1956 by the author. 5. These facts indlcate that thc transplanted embryo can take a large amount of nutrition from the host endosperm and continue its normal embryonic growth, so the younger the embryo is the more it depends upon the host endospcrm, and that the transplantcd embryo in the foreign endosperm can grow similarly to that of the embryo in the intact seed In spite of the drastic operation.

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Since the authors have. been engaged in the breeding of colchicine induced tetraploids in Astragalus sinicus L. The tetraploids show the gigantic appearance in many physical characteristics. They give a 30 per cent incrcase in green crop yield over the diploid progenies. Furthermore they are superior in chemical contcnts of total nitrogen, crude protein and P₂O₅. The undesirable features of tetraploids are the low fertility, slow growth and the increase of hard seed number. The reciplocal crosses between diploids and tetraploids were usually unsuccessful although there were obtained a few seeds from which plants with triploid or unexpected number of chromosomes were grown. Three promising strains 14-8-1, 8-2-1 and 1103 have been found by successive selection and refinement of numerous characters.

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Although the mammary growth response in mice may be the index of the early selection for milk yield at lactation period, it takes much time and labor to obtain the response. For the purpose of investigating a simple way of selection for the mammary growth response, the efficiency of selection for mamrnary growth response througn selection for body weight every generation were compared with that by the direct sclection for mammary growth response evcry third gcneration. The micc usccl were 627 of Kasukabe female mice. They were injected five times with total dose of 12.5 I. U. of estrogen from 20 days of birth. On 35 th day, mammary glands were preparcd to obtain manmmary growth response after wcighing. Results oblained are as follows : 1. Intra-litter correlation, intra-litters correlation and heritability were O. 37, O. 12 and O. 51 in mammary growth respnsc and O. 65, 0.26 and O.55 in body weight by the use of analysis of variance. 2. In the case of selection for body weght, selection accuracy using a measure of body weight of a mouse is higher than that using average body weight of family which is composed in full-sister. 3. In the case of direct selection for mammary growth response, the use of the average mammary growth response of more than eight mice is more accurate thanm the use of a measure of mammary growth responsc of a mouso. 4. In consideration of sclcction interval, the selection of a mouse in family for body weight is more effcient selection for mammary growth response compared with the direct selection of a mouse for mammary growth response.

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[in Japanese]

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[in Japanese]

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A selection expcrimcnt was conducted under three fertilizer levels, namely, a (half amounts) b (standard amounts) and c (double amounts) in a winter wheat cross, Minturki x Tohoku No. 103. In F₄ generation, yield of each of 15 line-groups selected under the three growing conditions was compared under three test conditions, namely, A (half amounts of fertilizer). B (standard amounts), ancl C (double amounts), respectively. As the results of which, superior lines were obtained more frequently from the a growing conditron than th*e other conditions and the a dcrived lines showed a more wide range of adaptability to fertilizer levels, comparing the others. It was found that the degree of h² of yield under the a growing condition was higher than the other conditicns. Problems connecting with the best or better environments for selection were analysed and discusscd.

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The influence of temperature upon the expression of genes in relation to flowert-ypes has been investigated by using materials whose genotypes are known from gene analyses. Expelrments were conducted in rooms where temperature was artificially kept at 30°C, 20°C, 1O°C as well as in natural temperature (out of doors). Fifteen strains of different flower-types were propagated from cuttings, and the comparison of flower-heads was made within the same clone. Remarkable transmutation of flower-typew was observed in malformed petaled types. Higher temperature brought about Np type from Vt or Mt type, while lower temperature produced highly developed Mt type (Fig 5). The most conspicuous changes were brought about. in the semi-doubled type of flower-heads. A lower temperature produced flowers highly-doubled but with no pollen while a higher temperature prcduced flowers of the apparently single type with abundant pollen (Fig 6 and 7). According to these results, it was postulated that what was affectecd by temperature might possibly be the character which is under the control of modifiers whose various expressions are subject to changes of temperature.

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[in Japanese]

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