1. Continued from the previous report on the anomalous segregation of glutinous character in pollens and in xenia in F₁ hybrids between Japanese and foreign varieties (MIZUSHIMA and KONDO, 1961) behaviors in segregation in their F₂ population were described. 2. In eight of the 26 different F₂ strains investigated which were originated from 7 Japanese X Japanese and I IndianXJapanese crosses the segregation took place normally, i.e., g^l+g^l:g^l+g^l :g^lg^l 1 : 2 :1 (Table 1). The other 18 crosses showed abnormal ratios which could be classified into the following 5 different types according to the ratio g^l+g^l+ : g^l+g^l : g^lg^l i ) 2 : 3 : 1-type' ?? ?? 10 crosses (Table 2) ii ) 4 : 5 : 1-type or 4 : 4 : 1-type ?? ?? crosses (Table 3) iii) O.76 : 1.74 : 1.OO-type ?? 2 crosses (Table 4) iv) 4 : 7 : 3-type ?? ?? crosses (Table 5) v) Undefined type ?? ?? cross (Table 6) 3. For the explanation of anomalous segregation ratios observed in xenia in F₁ hybrids we assumed a) three different degrees of partial infunctionality of glutinous pollens, 25, 50 and 75 per cent, in such hybrids as to show a significant decrease in the number of glutinous endosperms and b) about 13 per cent infuhctionality of both non-glutinous pollens and ovules in hybrids showing sig'nificant decrease in the number of non-glutinous endosperms. The three of the above-mentioned 5 types, i), ii), and iv), can be explained as the results due to the cause a) and another one, iii), as that due to the cause b). The undefined type, v), is however, difflcult to explain. 4. The genetic mechanism causing the partial gametic infunctionality in F₁ hybrids was discussed to the effect that it might be due to aco mplementary lethal action of two recessive genes, one of which being linked with gl-gene, or to deficiency of genes brought about by some unknown structural hybridity. 5. Behavior in segregation of C-gene was investigated, which was one of the two fundamentaL genes responsible for anthocyanin pigmentation in the rice plant body and had already been confirmed to be linked with g^l-gene by other workers (Nagao and Takahashi, 1947). As was expected, anomalous mode of C-gene segregation was recognized in the present materials, presenting significant decrease in the number of gametes carrying one allel. 6. The recombination values between x and C and x and g^l were calculated, here x being one of the complementary lethal genes linked with g^l-gene. We obtained the values 0.323 fcr the fcrmer and O.392 for the latter.

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The biological effects of X-rays can be profoundly modified by external conditions and internal properties of irradiated seeds. Of particular significance is the finding that the radiation-induced injury is mitigated with various treatments. The present study is a determination of the effect of some chemical substances after γ-irradiation on induced injury, sterility and mutation. The experiments were conducted with dormant seeds of rice, variety Norin No. 29, which were stored in a desiccator over saturated sodium chlorate until they attained a constant weight. The γ-rays utilized in this experiment were generated by ˆ<60>Co and were applied at 1, 000 r per hour. Germination was initiated by placing the seeds in solutions of 1x10^-3 M cysteine and sodium hydrosulfite (Na₂S₂O₄) fcr a period of 48 hours at 30°C. The influences of cysteine and Na₂S₂O₄ on radiation effects, which were measured by survival at maturity of X₁ plants, degree of sterility in X₁ ears and frequencies of chlorophyll mutations among X₂ populatioris, were compared with the results of γ-irradiation alone. Data on all effects were gath-ered from the sample of seed in four replications of each treatment. Data on the effects of post-treatments with cysteine and Na₂S₂O₄ applied to irradiated rice seeds on the induced iniury, sterility and mutation are presented in tables and figures. The results reported herein demonstrate that both treatments applied during hydration of irradiated seeds modify certain of the radiation effects in rice. The fqllowing findings are of particular interest: 1. Radiation-induced injury as measured by survival at maturity and radiation-induced sterility were reduced by Na₂S₂O₄, 2. Radiation-induced mutation spectra as measured by chlorophyll mutations were affected by cysteine but not by Na₂S₂O₄. That the effects of radiation can be modified differentially with treatment applied during hydration of irradiated seeds should be of considerable interest to the plant breeder, who is using ionizing radiations to produce viable and useful mutations. The data in this report indicate that it is possible to maintain the frequency of radiation-induced mutation and at the same time reduce the accompanying injury and sterility, and that premutational damage is still present' after irradiation.

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In many cases for the cross-pollinating plants, estimating of heritability and genetic correlation is based on parent-offspring regression, assuming mate being completely random. But this assumption is questionable in the case of usual condition. Therefore, the actual changes of the three strains (E, L and R) were compared with the expected changcs. The mother plants of E and L strain were respectively selected such that the plants were randomly selected from phe earlier or later part of the 'original population. R strain were randomly selected over all population. The performances of the mother plants and their pedigrees are shown in Table 1 and 2, respectively. The expected values of change by selection were obtained according to I.M. Lerner. The expected value of change by selection is composed by two parts, direct response and correlated response, and they are shown in Table 4. The direct response is deviation for a character under selection and the correlated response is deviation for an unselected character correlated with a character under selection. The expected changes did not completely agree with the actual changes but both values were resemble . Accordingly, for estimatingr of change by selection, heritability and genetic correlation above mentioned are useful. In this experiment, the character under selection was date of lodging and for this character selection was effective. In the other hand, shape of bulb significantly changed by selection for date of lodging, that is, the early strain (E) became to be flatter and the late strain (L) giober. These performances were able to predict from the expected values, too.

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The authours intended to make clear the effect of day-length and temperature upon the development of floral organs and its varietal differences. In order to compare the development of floral organs, it is necessary to have a definite criterion on each developmental stages of floral organs. GUARD, A. T. (1931) reported general appearence of development o.f floral organs of the soy-bean, and also, KATO, I. et al. (1954) distinguished 13 stages on the developmental course of floral organs of the soy-bean. GUARD's description is rather rough in .the late developmental stages in spite of the precise description of the early developmental stages. In the description of KATO, I. et al., there are some incorrect points about the development of sepal and petal. In addition, the report of GUARD, A.T. and KATO, I. et al. lack the description of the bractlet formation . In these circumstances, the authors fclt necessity to make a new criterion of developmental stages of floral organs of the soy-bean. To deflne each developmental stages, the authors used the appea-.ance and formation of organs, and their definite morphological changes. In the early developmental course, bract, bractlet, sepal, petal, stamen and pistil appear in this order, and they continue to develop in parallel. Therefore, the authors divided the early developmental course into 8 stages ; bract formation stage, bractlet formation stage, sepal formation stage I, sepal formation, stage II, sepal fcrmation stage III, stamen-pistil formation stage I, stamen-pistil formation stage II, stam.en-pistil formation stage III. The middle and late developmental course were divided into 10 stages by the definite morphological changes of pistil which is the most important organ and in which the most distinguishable changes take place. Pictures of these stages are presented in Fig. 1∼Fig. 38. The defined stages are as follows : Stage O : As yet undifferentiated growth point (Fig.1) Stage I : bract formation stage (Fig.2) . The authors considered this stage as the first stage of flower primordium formation, since, before this stage, it is difficult to determine whether the process of flower primordium formation has already started or not, and before this stage the process is rather reversible. Stage 2 : bractlet formation stage (Fig.3)

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In order to clarify the mechanism of frost injury of barley varieties, the authors investigated in the field ( 1 ) the changes of air temperature at 3, 15, 50, 100 and 150 cm above soil-surface ; ( 2 ) the temperatures of leaf and stem ; and ( 3 ) the progress of frosting on leaves ; with the intervals of one hour or thirty minutes from 1.00 to 8.OO a.m. The results obtained were follows : ( 1 ) For the vertical distribution, the air temperature was the lowest at the height of 15 cm above soil-surface during the tested period. ( 2 ) For the plant temperature, the temperature of leaf was Idwer than that of stem before sun-rise but higher after sun-rise. Moreover, the leaf temperature showed the lowest temperature among all: the temperature measured. The air temperature above the plant-surface was between the leaf temperature and the stem temperature at any time. ( 3 ) In the course of frosting, it dewed finely on leaves first of all, and the dew drops were presently frozen. Before long, the frozen dew drops grew to frost, and the color of leaves changed to, dark green with the progress of frosting. Remarkable varietal differences of frost quantity on leaves were recognized, that is, "Nami", type vras severely frosted, while "Uzu" type was slightly frosted.

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The present paper deals with the differences in morphogenesis between various flower-types of Cosmos with special reference to the expression of rays. Materials used in this experiment were single type (S type), malformed types (Mt, Vt, Np types) and sub-petaled type (MS type). Buds at successively higher levels of development could be gathered from the lower part to the top of the stens from each individual plant, and the differences in floral development were clarifcd by comparing the buds of the different flower-types at the same stage of development in materials dissected under magnification of moderate degrees. The development of S-type flower-head flollows the next sequence. The change from vegetative to reproductive activity in the apical meristem becomes evident after a short day treatment for one week. An individual capitate primordium is a broad and giobose protuberance from the bottom to the top of which appear the floret primordia like so many warts. The individual floret primordia become larger from the bottom to the top of the capitate primordium. Then the growth of the top part of each floret primordium begins to fall behind, and as the result a special cup-1ike structure appears. After a time, the structural difference between ray and disk florets becomes noticeable. In the development of disk florets, 5 growing points appear at the same interval along the margin of the cup-like primordium. With further growth, the five-parted petals with united base develop sympetalous actinomorphic structure of florets. In the development of rays, on the other hand, only the three growing points along the outside margin early on division and the other two along the inside are inhibited from making further divisions. Consequently, zygomorphic structure of florets with three petals united at the base follows. In the malformed types of flower-heads (ss genotype), the developmental pattern of disk florets fcllows the same pattern as that of S type. But the ontogeny of the rays of these types is quite different from that of S type. The developmental process at the earlier stages of the rays of these types resembles more those of disks of single or malformed types, that is, it follows the actinomorphic pattern of development. But later, as the floral development. advances, the growth rates between the outside and inside region of florets become increasingiy distinct, and at the fiowering stage the differences among three flower-types, Mt, Vt, Np, become distinct according to the degree in the developmental diffe

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In a variegated rice variety, "Fukuijima", a mutant strain was found which assumed yellw colour on the stem and leaf at the seedling stage. The expression of this character was strongly affected by varying temperatures. Some other effects on the expression of the mutant character were as follows : 1. The sparser it was sown, the clearer the colour appeared on the seedling. 2. Unscreened direct sun-light brought about more marked development of the colour than that screened with a covering of bleached white cotton cloth. 3. Generally speaking, the seedlings in the fertilized plots showed a clearer expression cf yellow character. No ccnsiderable difference wels usuallly observable between completely and incompletely fertilized plots, but sometimes a higher grade of yellow character was observed in the former. 4. The seedlings treated with a gibberellin solution (10 ppm) became yellower in colour than those untreated. 5. Measurements of plant height were conducted in the plots with various densities, with difierent amounts of fertilizer, and with or without gibberellin treatment, respectively, with the results that plants excelling in height were distinctively yellow whereas shorter ones were dark green in colour 6. In view of the above results some considerations are given on the appearance of the yellow character cr leaf pigment in relation to intensity of light, amount of fertilizer, etc., as well as partly on the plant growth.

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The RT homozygotes, 10 lines of 108 (Pei-ko), 7 lines of 521 (Kissin) and 10 lines of 504 (Taichung No. 65) were tested in a randomized block experiment. Various agronomic characters which are controlled by p. olygenes were measured and variance analysis was made. It was found that the translocation lines are generally homogeneous in agronomic characters and may be regarded as having the same genotype for translocation. However, translocation may sometimes be accompanied by genic changes. It was assumed, further, that the translocation method may be used to some extent for locating quantitative charadters on chromosomes. Literature cited

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