Two soybean crosses were examined for the estimation of heritability of agronomic characters and genetic correlations between characters. In F₃ Iines derived from Kitami-shiro × Hon-Iku No.65, heritability of branching type expressed by ratio was very high, and genetic correlation between branching type and grain yield was high enough to select high yielders, namely, -0.799, indirectly through selection for branching type, In F₃ Iines derived from Karikachi x Isuzu, genetic correlation between grain yield and total plant weight was also very high, namely, +0.869. Based on these results, signifi-cance of plant types in selection practices, possibility of selection for yield in early generations through plant types, and relation between grain yield and plant types were discussed

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In the species crosses of C. papo var. "Nishikikanro" as pistillate parents, cross-com-patibility of C. Ieeaxileea as a staminate parent is the highest in bud pollination at 7 a. m. of the day before anthesis (Cucurbita-crosses. XIII). As in the present articles, the results of crosses of C. pepo × C. moschata at different timcs demonstrate that only 4 a. m., crosses succeeded in the production of F₁ plant.s. This may be due to high degree of both receptivity of C, papo and fertilization power of C. moschata. F₁ hybrids were self-fertile and could be back-crossed to the parental species. The chromosome configuration at MI is 0.05 Iv+19.50 II+0.40 I per PMC. Seventy-three percent plates at MII receive a balanced number of chromosomes. Normal tetrads were 86.8% and fertile pollen grains, were 79.0% The characteristics of F₁ plants were intermediate between those of their two parental species.

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This study was designed to find a useful method for obtaining the various types of trisomics in rice plants. The use of primary simple trisomic plants is a new valuable method for studies of likage analysis. Autotriploid, completely asynaptic, and partially asynaptic rice plants and their progenies were used. Of 258 plants observed cytologically, 47 were heteroploid with 25∼33 chromosomes in somatic cells. These heteroploid plants were simple, double and triple trisomic plants as indicated by the chromosome configurations at diakinesis and metaphase-I in meiotic division. It is of interest that trisomic plants were easily obtained from the progenies of partially asynaptic rice plants.

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Using twenty cultivated rice varieties and their hybrids, relation between genotype and relative contents of anthocyanin pigments found in apiculus of glumes was investigated by means of paper chromatogra phy. The pigments causing purple or red coloration in the site of apiculus proved to be mainly chrysant-hemin and keracyanin. There were, however, traced two faint spots in the chromatographs which were supposed to show the existence of cyanin and uliginosin from their R_f values. In the plants whose genotype was either C^BA, C^BA^d, C^BpA, C^BpA^d, C^B₁A or C^B₁A^d chrysanthemin and keracyanin were always found in almost equal quantity. In the plants of the genotypes C^BrA and C^B₂A, however, keracyanin was remarkably decreased and it was sometimes indetectable. The two alleles, A and A^d proved to control the quantity of pigments as a whole, but not their relative quantity. An inhibitor or a modifier whose gene symbol is l_p and which changes blackish purple due to C^BA to reddish purple, proved to decrease the content of keracyanin. Such a condition is quite analogous to that when C^B is replaced by C^Br or C^B₂ in the absence of l_p. It has been concluded from the facts abovedescribed that the effect of the two genes, C^Br and C^B₂, are substantially different from that of the other allels forming the C-series.

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ldentification of genotypes in respect to anthocyanin coloration in 23 rice varieties including 7 Japanese, 5 Indian, 3 Chinese, 2 Indonesian, 2 North American, 2 South American, I Viet-Namese and 1 Hawaiian variety was made. The gene system controlling anthocyanin coloration in Japanese rice plant assumed by NAGAO (1951) and TAKAHASHI (1957) is considered to be the most appropriate one among the gene schemes postulated by other workers. They assumed two complementary basic genes, C and A, responsible for the production of anthocyanin pigment together with some other genes which distribute the pigment to various sites of plant body. It has been confirmed from the results of testcrosses of the varieties used with the tester ones of known genotype that NAGAO and TAKAHASHI'S gene scheme is also applicable in the case of foreign varieties. In explaining C-A complementary action in one Indonesian and one South American variety, however, postulation of sotne new alleles in both the C- and A-gene series must be considered. A dominant gene, P_r, which controls the distribution of pigments over the whole surface of glumes has been found in each two Japanese and Indian varieties. Also an inhibitor. I_p, which lightens the color hue of apiculus and awn has been identified in 5 foreign varieties. It lightens blackish purple color due to C_B A to the purple, making to show apparently the phenotype of Cˆ<Bp> A.

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In 1959 the authors succeeded in breeding of 20 amphidiploid plants (genom zic, 2n=19) by the crossing between B. campestris ssp. rapa (variety Shogoin-kabu, aa, n=10. C-symbol) and B. oleracea (variety Cohlrabi, cc, n=9. O-symbol) by bud-pollination by means of cutting style or vegetative approximation (grafting) at relatively low tempe-rature (lower than 20°C). However, no seeds were obtained from crossing between non-treated C and O (Tab. 2). The cross between O and C by the same methods with above mentioned produced no seed at all (Tab. 3). These hybrid seeds were grown in pots in the vinyl house and their chromosomes were duplicated by O.3% colch.icine teatment. Their chromosome numbers in PMC were 2n=38 (aacc) and were named "COK 59" which mean the hybrids C and O crossed that carried out at Komaba(Tokyo) in 1959. The F1 plants at the early stage were smaller than the parents but at four months were far better than the latter. Self-fertility was low but some seeds were obtained by self-pollination In F₂, 50% were 2n=38. Three types of root appeared, namely, rutabaga, cohlrabi and rutabaga-cohlrabi type (Fig. 5). The rutabaga type which had good fertility was found in plants of 2n=38. Many F₃ seeds were harvested by self- and open-pollination. All F₃-plants from self-pollination of F₂ With 2n=38 were also 2n=38, but roots cha-racteristic of many plants was generally unlike rutabaga, nevertheless some plants resembling ru-tabaga with fat roots. Rutabaga type was generally the progeny of F1 with fat root. Then, in 1962 F₃ COK 62 were crossed with cultivated rutabaga (variety White fleshed neckless) and many seeds were obtained. These new hybrids were named "SSR 62" which meaned semi-synthetic rutabaga, 1962 (Tab. 10 & 11). The strains SSR 62-I∼III were obtained from the crossing between rutabaga types and cultivated rutabaga, and SSR 62-IV were from the crossing between the cohlrabi type and cultivated rutabaga. The strains SSR 62-I∼III have better characteristics than SSR 62-IV, and thls comes to the mind th. at the strains of SSR 62-I-III will meet our expectation.

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1. Vernalized seeds of two winter barley varieties, HASHIRIHADAKA and H. spontaneum leigrum, were grown under short day (8 hr.) or long day (24 hr.) for definite number of days, then transfe-rred to reverse day length condition and the effect of conversion of day length to the heading was investigated. 2. When the plant was transferred to long day (LD) after short day (SD) treatment, the number of days from sowing to flag leaf emergence increased with the increasing pre-treatment of short day. But the number of days from transfer to flag leaf emergence decreased in HASHIRIHADKA and not changed in H. spoletaleeulee leigrum. The former is an early variety and the latter is a late one. 3. When the plant was transferred to SD after LD treatment, the number of days from sowing to flag leaf emergence decreased with the increasing pretreatment of LD and the number of days from transfer to flag leaf emergence also decreased. But the amount of decreasing was different between varieties. When plants were transferred to SD after 20 days treatment of LD, they headed as well as under continuous illumination. But if we look at the leaf numbers, the plant treansferred to SD after 8 (HASHIRIHADAKA) or 6 (H. spolctaneueec Ieigrulec) days treatment of LD, headed on same leaf. numbers to the plants grown under continuous illumination. These differences will be explained by increasing length of flag leaf and comparatively long durations for expansion of leaves with decreasing long day pre-treatment.

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Studies were made on the external morphology, meiotic divisions, pollen fertility and pollen size in three main Japanese varieties of Amorphophallus Konjac : Bittyu Zairai and Chinese (Shina). (1) These three varieties resemble mutually in external morphology except for some differences in size of the spot on leafstalk ; size, number and colour of leaflet ; etc. (2) At diakinesis and metaphase-1 of meiosis, partially asynaptic cells were observed in the three varieties, the proportions of these cells being approximately 15% in Chinese (Shina), 26% in Zairai and 40% in Bittyu, respectively. The cause of the partial asynapsis in these cases is unknown, but it might be due to the effect of the low temperature on the gene action. An early variety as Bittyu, in which meiosis takes place during late March and early April, would be more affected by the low temperature, while a late variety as Chinese (Shina) would be less affected. (3) The early variety Bittyu showed 25∼35 % pollen sterility and non-dehiscent anthers, probably resulting from the irregular meiosis. (4) Mainly on the basis of the chromosomal affinity shown in the F₁ hybrid between Chinese (Shina) and Zairai, it can be stated that their genomic constitutions are identical (AA).

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The present paper is devoted to the observation of histochemical phenomena in anther tissue of cytoplasmic maie-sterile sugar beets contrasted with those in normal strains. I. Hydrogen-ion concentration in anther tissue. Based on several observations using pH indicators (Methyl red or Brom thymol blue), following conclusions could be drawn(Table 1, 2, 3 and Fig. 1, 2, 3). In the early stage of microsporogenesis, the pH values in anther tissue of both rnormal and malesterile types are rather high ranging: from 6.6 to 7.0. As the age of anthers of normal types advances to the microspore stage, the pH values decrease to about 6.2, then they increase agnin to about 6.8 at the D. ollen-grrain stage, and, at the anthesis, the pH values decrease to about 6.2. On the other hand, the pH values observed in anthers of male-sterile types never show such zig-zag curves as those of normal strains during the microsporogenesis, but gradually decrease to about 6.2 at the anthesis.

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The hybrids derived from the crossing, Tulipa Gesneriana L. X T. Fosteriana Hoog., are called Darwin Tulip-hybrids. In Holland, they succeeded to make popular and promising varieties from this crossing, and some of them were imported to Japan recently. Being combined several features of T. Fosteriana, such as a big flower with glossy scarlet color, earliness of flowering time and resistance to disease, with that of Darwin Tulips, these varieties are very excellent. Although parental varieties used to make these hybrid varieties are not known entirely in our country, some workers have begun to hybridize Darwin Tulips with T. Fosterialea so as to make new varieties. As an exact knowledge with reference to the chromosornal constitutions of the existing Darwin Tulip-hybrid varieties is rea-sonably considered to be suggestive to give satisfa-ctory results in such breeding programs, the au-thors has begun to make cytological studies on them.

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In Korea, the crop " Wangul " had been widely cultivated since old times, and was one of the most important fiber crops. This is utilized as mats, fine pieces of knitting-work, which are made of the cortical portion of stem, and slippers, made of the medullary portion of stem. For the purpose of studying the characters and the classification of the crop, the author collected 383 varieties from all the parts of Korea, and arranged the results of the experiments which were carried out at the Chosen Government Agricultural Experitnent Station (Suwon, Kyengkwi prefecture) and the South Branch (Iri. N. Chella pref.) during l935-1943. The experiments consist of the following three parts : (I) Identification of species included in a crop named " Wangul " in Korea. (II) Investigation of characters of varieties in each species of " Wangul ". (III) Classification of varieties of each species of " Wangul" by using the experimental results obtained in ( II ). The results obtained from the studies ( I ) show that almost all varieties (382) of " Wangul " cultivated in Korea belong to Cyperus lwasakii M., and a few (3) of them to C. glomeratus L.

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[in Japanese]

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