In the present study, there are used two kinds of varieties of tetraploid plants of radish (Raphaleus satigus L.), a variety of tetraploid ones of chinese cabbage (Brassica pehilae7esis Rupr.) and their diploid plants, the polyploids being believed to have been derived from the diploids by the colchi ?? ine treatment. The leaves (the 6-8 th ones fro, m the growth 'point) of the plants grown on the iield were taken into the' Iaboratory, where they were put in pure water 'for a day and then in 0.1 KelO solution for a few days, resulting in that the tetraploid plants, are found much waker to the toxicant than the diploid ones. According to the hypotheses proposed by YA, MASAKI, one of the authors, pertain-ing to the :'physiology = of the toxicant resistance, the above noted facts seem to be due. 'co th.e dif-ference between' the tetraploid and diploid ones in the amount of the reducihg matters, such as a, scorbic acid, the reducing sugars, etc, which reduce KCIO, to KCIO, poisonous substance to plants.

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1. The results of comparative study between diploid and artificialy induced tetraploid bu, ckwheats, Phagopyrum esculentum, concerning the groivth habit as well as the change in contents of total nitrogen and sugar in wrious stages of growth were described. 2. The tetraploid seeds were l.arger in size and noticeably slower in germination than the diploid ones. In the early stages of growih the tetraploids were also larger in size than the diploids, owing presumably due to their initial embryonic capital, 'Though, as they grew, ' the sloivness in growth of the fornl;er rendered the size difference radually obscure. After the stae of fiowering the speedier growth of the diploids overcame that of the tetraploids and the size relation was reversed. The general aspect of the growth habit of the tetraploids corresponded with that of other tetrapioids reported by several workers. 3. The content of total nitrogen was found predominant in the tetraploids than in the diploids at the period when the former were showing slower growth, i. e., at the time of germination and the subsequent stages after fiowering.. T.hough, in the subsquent stages after germination, when the tetraloids were retaining larger size, the fotal nitrogen content was conversely less than the diploid.s. 4. The tetraploid seeds proved to contain less amount of total sugar than the diploid ohes. In spite of the fact, the tiny tetfaploid seedlings with fully unfolded cotyledones gave a higher content of total sugar than the diploid ones, showing less consump-tion of sugar in the former than in the latter. In the early Stages of growth folloving the gerroiriation, however, the tetraploids again presehted less cop-tent of total sugar than the diploids as in the case with the total nitrogere content. ' 5. Thus, the ngode of change in the contents of to 1 sugar and total nitrogen in the tetraploids was quite different from that in the diploids. Hence, a result of a fragmental conparison between the two in the contents of these matters made at an arbitrary growth stage cannot be cansider9d to characterize their peculiality.

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In order to compare the pedigree method with the bulk-method, parallel experiments were conduced with the same hybrid poputation of rice. A number of elite-plants were seledted in F₂' and the rest of the population was cultivated in bulk by direct seeding during the follawing two years. In the second year (1947), we had an opportunity to select coldresistant plants since the summer was so cool that m;ost of the cultivated rice varieties tended to steri-lity. A number of panicles were selected and the grains of ach were planted in 1948 in 40 plant-plots with no replication, in order to select among the F familie such which showed the least segregatian with regard to heading, plant height, and other recognizable characters. Of these selected families, the number and weight of panicles and yield of grains per plant were recorded.

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Experiment was carried out in 1950 on the varietal difference of the effect of short day-length upon the ripening period of soy-beans. Vaiieties used were Kisaya (Kagoshima), Norin No. 2(Ibaragi) and lwate No. 2 (Iwate). The plants were grown in soil by pot culture and the half oi them were treated with 8 hours day'length, from 8 a.m. to 4 p.m, every day, durin.g the period fronl bloommg to, maturity. Other half of them were left under natural day-length. The results are summartized as follows : (1) Apparen responses of ripening period to the short day treatment were observed. Yellowing and hedding of leaves and nlaturity " were acceleratedby short photoperiod and consequently the piriod from blooming to ripening of pods becon):es shorter. The acceleratton was remarkably larger in variety STE:12q:ERG, R. A. and GARNER, W. W. (1936) : Response of certain plants to length of day and temperture under controlled con: dition. Jour Agric. Res. 52 (12) 94-960 of long ripening period (lwate No. 2) than variety of short ripening, period (Kisaya) .(2) The growth of p. ods was accelerated by short photoperiod, but the varietal difference of this effect was not discussed becal;se the measurement was made too late. Weight and shape of seeds were also effected by short-day tratment. Weight of seed, length, thickness and wideness of seeds were maller in treated plots than control plots. This trend was less obvious in Kisaya, but obvious in varieties Norin No. 2 and lwate No. 2. (3) These facts will be useful to explain the distribution of soy-bean varieties and further to select the stlitable varieties at any place or to make soy-bean breeding. Moreover the facts will be availetble for the ecologicai interpretation of so-called seed-home of soy-beans.

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In 1949 young F1 seedlings of 9 penta.ploid crosses between A1;elace barbceta (n=14) and some culti-vated varieties of Ave, na sativa (n=21) as well as A. nuda(u=21) vrere treated with 0.05% colchi cine solution according to L., b. CUA's method(951). It was already reported that pentploid Aveu hybrids were highly sterlie (I:ISHlYAltlA 1929, 19 39). Howeveir, same of the: treated hybrids were found to exhibit different degrees of fertility. It was further noted that different ears in one and the same plant often showed a great var'iation in fertility ranging from 'highly fertile to completly sterile (Table 2) . In the present case it is beyond doubt that 'che fertile plants would be amphidirp lojds of pentaploid hybrids. A preliminary investigation rewaled that some seedlings from fertile plants hd 70 omatic chromosomes as expected. Basing on the degree of fertility the auth=0f elas-sified the treated plants as 4la plants (high fer-t, ile), 2 u:1a mixoploids (either low in fertility or having soine ears that, are highly fer'ti', , e but the others age sterile) and 2n plants (nearly colenpietely sterile-). The resits are given in Tables I and . In this work 6 different amphidiploids (dctoploid oat) were succesefully obtines and the offspring ar, e novT'grow. ing vigorqusly in the field.

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Genetical results hitherto obtai.ned have proved W-chromosome deternl;ined alone the famale sex in silkworm (Hashimoto 1933. Tazima 1944) . Even if the sexual characters are excluded, various differences exist in regard to the quantit.ative characters, among which include many available ones for silkworrn bteeding, between male and female. Silce vchromosore is responsible to the sex determination, it should bc also tb the sexual difference in quanti'ca+Live characters. Here, The problems will arise concerning with the capacity of W-chro-mosome to influence on the, m, especially frorn the standpoint of thremmatological view whether raciaJ difference of it will be existed or not. This experiment was carried out in order L-o eluci-date the point tbove men:tioned. W, chronl:osorle of two races, OIO and 72, were chooen to ntaterials. The former is a europian univoltin014s race characterized with its remarkable abu. ndance of cocoon layer, weight of it almost turns the scale 8 at 70 dg in average' number of 25 batches and the la'L'Ler rather a meagre one, 37 og. To the F₁ hybrids of OIO( Q+ ) x72( ) and 72( ) x OIO(), backcross mating was continuously re-peated by the same nl:ale of 72 from Bl generation to B5' In each generation quantitative characters, etpecially weight of whole coc06n, qocoon layer and cocoon layer ratio, were corchparatively eamined between the 'two series. The resuits are sumrorized as follows : i) No difference in The physiolotical effects on increase and tlecrease in the weight of whole co-coon, cocoon layer, cdnsequently cocoon layer ratio also, has been found between the strains. 2) Concerning with the degrees of vigor and growth in silkworm stage and propagation o.f moth, no dissinailaritis has appeared between them. 3) For the resistance to flacherie which was unexpectedly and fcrtunately observed in early autumn rearing of B silkworms, both strains showed almost inert as well as the original race 72. 4) All of the results obtained at present proyed that there exists no racial difference wi ?? h the action of W-chronosome between the rices OIO and 72. Nei, ther the physiological condition of individual form nor the state of egg-plasnla in which the worm has to develope in embryonal stage, are atte-cted in different way by the replacement W-chromosome of a race with another. And the facts are not unrea*onable and incomprehnsile matters in accordance with che geneticai conception of sp called inert chrom;osome as W. 5) Nevertheless the uthors are inclined to remain a question, if the transportion of nucleus will be carried out by that of OIO race instead of 72, the result may be possibly turn to another one.

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It is generally assumed that the strains oi Senshu-ki onion(this variety is derived from Yellow Danvers and widely cultivated in fall-sowing resion of Ja-pan) produced in some districts such as Fnkushima, , Niigata and Naga.no Prefec'tures are inferior as comjared with so called "home " strains. This 'study has been undertaken to determine the relative merits of the strains collected from various seed groiving destricts and to elucidate the causes of differences, if a'ny, amon'g their abilities. Extensive tests were carried out, on the Horticulttiral Stations of N. ipomiya and Kurume during 1946-47, 1948 49 and 1945-50, and the following, results were obtained . Most of the " home " strains which were produced in Osaka arid Wakayama were excellent, and some of strains produced in other districts were also excellent, but there were sorb;e fair or poor strains in the " foreign " stQcks produced in other districts, especially in "Fnkushima, Niigata and Nagano. In such strains; yield is generally low and percentage of premature bolting is rather high. ' Sensus on seed growing systems revealed that the causes how those poor strains have been deve-loped were as follows : in such districts, mother bulbs used for seed production were of low grade and vere not str.ictly selectd, ' and there were chan -ces of crossing between inferior strains nearby grown, if mother bulbs were of high grade. If proper system of seed growing is applyed, it may be possible that excellent strains are roduced bn such notorious dlstricts, as a few of them proved to be so.

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A variegated strain named Fukuijima bears many white stripes in stems and leaves. At the young stage, these stripes are not found excepting mosaic individuals in a small number (p), ' but those appear, accordin to the progress of development and become, most remarkably before the heading ce) . For this strain, a genetical tes't was under taken:by the.preun-der authors. The results are summarized as follow. (1) rn the pedigree cul'ture, the occurrence of. albino eedlings was counted in various degrees from 306 to 60b approximately, but no difference between ce and p groups, avove m;entioned, could, be detec'ted (Tab. 1).

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Ear-scab dissase injury of wheat is enormous almost every year in Tokai-Kinki District. So, it is vety important problem for us to breed up scab-resistant wheat varieties. During the 3 yeaf course of investigation of varietal resistance, of this disease, we noticed a morphological character of varieties had some relacion to the resistance in case of wheat, that Was the leaf-angle between I st and 2 nd nor-m.al leaves of wheat seedling. Seedlings were grown on several conditions and 'Lhe leafangle ivere meaSured btweeil I st and 2 nd normal leaves at 3 rd leaf stage, about 10 days after germination. Sdme representative varieties were chosen accord-ing to resistant and susceptible groups. The results indicated, as shown on Table I, 2, 3 and Figure 1, 2, that those varieties of narrower leaf-angle showed to be more resistant, as a whole, than wider ones, though the reason was not yet clear. The correlation coef:cients between leaf-angles and scab-resistance were as follows : r.=0. 6341:!::O. 0648 (88 varie'ties 1950), rO. 5203::O. 0898 (66 varieties 1951).

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A sterile mutant was found in 1946 from the population of a rice variety Ebisu-Mochi and was named, Compact-paniculous sterile" by the authors. As compared viith the original variety, this mutant is taller in stem heig:ht, Iess in tillering, Ionger and broader in leaf sizes preseriting sonewhat staut appearance as well as deeper green color. If must be stated, furthermore; that this mutant shows high sterility, the seed setting amounting about 20 per cent of a panicle, and that there are observed variotis types of spikelets where deformations, excessive developments take place ip floral organs such as glumes, pistil, anthers, Iodicules as. well as ovu-les. " ' It may be considered that the sterility of this mutant is exolusively owing to the abnormal development and degerneration in embryoac, the occurrence of which amounting about 50 per cent of the observed embryosacs under microscope, whereas the polen grains are recrarded to be complete and healthy in the view of the, results of germinat-ion experiment and morphologicai observations. This mutant ever breeds true for generations. The mode of its inheritance remains to be proved in detail fot further investigation, however, this possively seems to be a case of point mutation that occurs in a certain chr.omoome locus. Plant Breeding Institute, Faculry of Agricultufe, Hokkaido Universlty, Sapporo.

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1. In this work, the writers intend to make clear, from the view point of plant--breeding, the genetical function in determining the culm height of the known genes A, E, H, Iand In which mainly gnoven the length of awn or ear in barley. Materials used were F (1940.) and F₇ (1934) generation of three different combinations of crosses. 2. The conditions of cultivation of plant and the . methods of investigation we, re the same as those already described in the senior wri.ter's previous reports (Sl:A, KUDO, 1949-a, -b, 1950). 3. The effects of the inhibtors li and I, ta the culm height are accumulative a;nd of inperfect do-minance, while those of the genes A, E and H to the same ar, e of perfect dom.inance. And the qualifying effects the genes ll and 12 tothe culm height are additive, while those of the genes A, E and H to the same are mt.Itiplicative' to the value of the basic gene-complex. 4. The qualifying values of the genes 11 and 12 for the culm height as calculated with the Prof. TA, KEZA, KI'S (1927) Ieast square method are 1.76:i:: O. 288(cnl;) and 1. 43:tO. 299(cm) respectively, while those of the genes A, E and H are as follow :

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The full purple leaf character of rice designated as Murasaki-Ine (Purle rice). develobs in the presence of the gene P1 in combination with apiculus color genes C Sp. The gene C is concerned with the formatioh of chromogen and five allles CB, CBp, Cp and c are know at C-locus. The gene Sp has CBt to do with the formation of reducer ior C and three alleles Sp, Sp1 and sp at Sp-locus are known. The phenotypic expression of 'che Pl is dependent on the constitution of these nes of apiculus coloring. Thus Pl Inay be said to be one of the modifying gene which in responsible for distributing the pigment substance produced in apiculus over the. whole sufarse on leaf blade, Ieaf sheath, purvinus, auricle, liule, stem and stem node. The effect of Pl is diminished by the presence of the inhibitor for Pl (genic symbol ll) that inhibits the coloration at the centre of leaf blade. Pl gene links with the genes d2 ior "Ebisu " dwarf and lg for liguleless. The recombination values are as follows 38-39 per cent for d, and Pl, 18-16 per cent for PI and lg and 42-50 per cent for d, and lg, suggesting that the order of these genes is dPling. Histologically the coloration of Murasaki-Ipe is due to the coloring cell sap in epidermis, paren-chyma, sclerenchyma and motor cells.

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