It has been reported by rhany investigators that the appearance of variegation in the petal was the somatic mutation of mutable gene. In spite of the mutation rate of the gene changing under different enviromental conditions, the physiological meaning of the mutability has, not yet been clarified. These experiments have been carried out to study the appearance of variegation from the standpoint of physiological genetics in Petunia hybrida. . As variegated plants generally segregate in F₂ generation of crosses between cyanic and acyanic strains and offsprings. of the variegated plant s, egregate into the coloured and white in the ratio 3 : 1, it is believed that the genotype of variegated plant is heterozygous for E gene, which controls the activity of polyphenol oxydase. However, the s.egregation ratio comes off so often from I full coloured : 2 variegated : I white in the offsprings of variegated plant and I variegated : I white in backcross. The ratio of variegated appearance also differs in parent and filial screnerations. Then, the variegation appears as a result of the somatic mutation of E gene. The mutation must bc occuring by the reduction of activity of polyphenol oxydase as proved by the enzyme distribution.

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(1) The mechanis.m as well as the genetical behaviour to the stiffness, in the husking of the naked barley has been invcs, tigated in this, experiment. The stiffness in the husking is determined by means of the artificial separation of glume from the grain. (2) The difference in the degree of stiffness in the husking was found in the naked barley varieties. The degree of separation of glume from the grain were over 90%:, 60%-90% and 3-7% in the s, emi-brachytic type, normal type and aiso in the stifE varieties of the normal type respectively. (3) High correlation between the ratio of the width to length of the opening of the outer glume and the degree of separation of giume from the grain was observed. (4) The difEerence in the s, hape of the grain between the normal type varieties and the semibrachytic varieties were clearly explained by Dr. TAKAHASHI in 1942. In this experiment the authors observed that the difference in the s, hape of the grain was significant among the normal type varietics also and it has, also been found that the round or broad grains were easy to husk in comprison to the narrow grains.. ( 5) The norma] type plants., bearing the grains which are easy to hus.k, have been fourid in the F2 popu]ation of 8 crosses, obtained from the neked, covered, normal and semi-brachytic types. The heritability value of the characters concerning the shape of the grain was, relatively high.

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The Bitter Gourd (Momordica Charantia L.) is known as a kind of vegetables for fruits and, also, of decorative climbing plants for curiousiyshaped and -colored fruits and shading materials, . It is native in the tropical regions properly and then is grown widely in the home gardens of the temperate dis.tricts for long times. In 1954 the original autotetraploid plants (2n=44) were produced by colchicine treatment and then triploid plants (2le=33) were obtained easily by cross.ing between the tetraploid and the diploid (2le=22). The tetraploid plants have larger, shalply se rrated leaves, dicker s, tems and more enlarged flower organs, andseeds than the diploid. However, they are dlstmctly later flowerlng and the fruits are more shortened with very smaller number of seeds. And their fruits have almos, t the s.ame or sometimes smaller quantity of sugars in the deepred endocarp as those of diploids.. The triploid plants can hardly bear fruits although the s.tamens contain a few qu.antity of viable pollen.

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Abnormal behaviors of pollen tube are known to be caused by the specific substances or by the difference of osmotic pressure between pollen tube and style in the case of self-and cross-imcompatibility. In barley plant, though independent of incompatibility, abnormal behaviors of pollen tube are also briefly reported. But in order to obtain more detailed information on this point, this investigation has been particularly fccueed on the types, frequencies and mechanism cf abnormal behaviors of pollen tube. Samples were taken from field-grown plants sown on May 25, about one month later than the usual sowing date in this district. Upon anthesis, the pistils are dusted by her own pollens and then stained by cotton blue solution after ten minutes. Directions of polien tube growth in the stigma hair are divided into two groups ; (1) normal direction, the tube pointing in the direction of ovary and usually growing downward through conducting tissue and (2) revers direction, the tube growing upward and escaping from the top of stigma hair. Shapes of top portion of pollen tubet are divided into four groups, i.e., l) normal type. 2) swollen type, the growing end of pollen, tube swells until it bursts and releases its content out of tissue, 3) running-away type, pollen tube escapes from the stigma hair through intercellular space of papillary cells or intra papillary cell without showing any enlargement of top portion, and 4) Iooping type, the tip portion100ps in the conducting tissue once or more, but normal growth continues.

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1. In 1953, 1036 flowers on 60 spikes, of Triticum pyra.midale were pollinated with the pollen of Secale africanum, and two F₁ plants were obtained the percentage of the raised F₁ Individuals to the number of all the pollinated flowers being 0.19 percent. 2. Almost all the external characters, of the F₁ plant, excepting the length of spike, were intermediate between those of the parents, (Table 1), the length of spikes, showing closer value to the pollen parent. 3. The number of sornatic chromosomes of F₁ plant was counted to be 21, and corresponds to the sum of the gametic number of the parents. 4. In the heterotypic division of PMC's of the F1 plants, 0-3 bivalents or 21-15 univalents, were observed (Table 2). The frequency of bivalents in PMC's, was shown in Table 2, the case, of zero in the number of bivalents, appeared to be the nlode. These 0-3 bivalents might probably be derived from autosyndesis between the chromosomes of AB genomes of Tritic+ulee pyramidale used as the mother plant.

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Fifteen demissum hybrids have been inoculated with three strains of Phytaphtora iufestales, H₁, H₂ and H₃ on both leaves and tubers in 1954. Three types have been distinguished in reactions to strains of both leaves, and tubers ; I, resistant to s, train H1 and H₂ and susceptible to strain H₃ ; II, resistant to strain H₁ and H₃ and susceptible to strain H₂ ; and III resistant to all strains applied. Of thes, e, the type 11 is of weaker kind, giving mycelial growth to some exlent in tuber test (table 3). Nearly complete positive correlation between leaf and tuber res, istance has been observed (41 out of 42). This may have resulted from a little' different way of qualifying resistance in tubers. In this test tubers were put in category of resistant' when they gave brown discoloration upon, inoculation earlier than the appearance of aerial mycelium. This has been introduced on the basis, of the idea that the genes for resistance act as accelerators, of a defence reaction, that is has, ten the death of cells infected and do not directly affect the mycelial growth which will be conditioned by secondary effects or some other factors., such as. nutrition available for the. fungrus..

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1. From the view point of plant breeding, we carried out this investigation to clarify the hereditary mechanism of grain yield in rice, taking into account an association between heading time and yield. In this invertigation 431 Iines or 33227 individuals of the F₃-F₆ generations from three crosses were used. The crosses concerned were(A) AikokXGinbozu, (B) Kyoto-Aasahi XAikoku and ( C ) Kyoto-asahi XGinbozu, with which the genetic constitution for heading time has already been analysed (SYAKUDO et al., 1954). 2. Aikoku is a variety of early heading and poor yield, Kyoto-asahi a late and high yield type, and Giobozu a medium heading and medium yield type. 3. The heading of a plant was indicated by the date when the top of its first ear emerged from the flag leaf. The heading time was measured by the number of days from the sowing to the heading. While ear weight per plant was measured by the total ear weight of each plant, after drying them in the wind. The design of field experirilents was analogous with that deq-cribed in the previous paper (SYAKUDO, 1948-b), although the sowing and transplanting dates of each year differed by a few days.

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Based on the study of chalacter assoilation among rice varieties collected from different Asian countries, one of the writer(OKA 1953) formerly pointed out that the varieties could bc classified into two groups, "Contlnental " and "Insular " (so named in accordance with geographical distribution but largely corres, ponding to the s.o-called Indica and Japonica t-ypes, ), and that the latter could be subdivided into two minor proups (" Tropical-Insular " and "Ternperate-Insular"), but the variation appeared to be continuous because of the presence of intermediate varieties. In order to illustrate the pattern of this variation more clearly, varieties appearing to be repres, entatives of the "Continental", " Tropical-Insular " and "Temperate-Insular " groups, their numbers being 40, 23 and 15 respectively, were chosen, and discrirtlinant functions for maximanizing the difference between variety-groups were computed using measurements on nine different characters (1. KCIO₃ resis, tance, 2. Iow temperature resistance, 3. drought resistance, 4. days of germination, 5. weight for shedding, 6. length-width ratio of grain, 7.. Iength of apiculus hair, 8. Iength of awn, and 9. degree of destruction of endos, perm in KOH solution ; the same data as used in the first paper of this, series).'The method described by MATHER and PHILP (1949) was used.

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(1) Previously the author (1951) reported on the spontaneous occurrence of the male-sterility in Japanese radish (Raphanus sativeis L.) and also explained that it was caused by a Mendelian reccssive gene. Results of histological observations carried out with anthers of both the sterile and its comparable fertile individuals are reported in this present paper. Flower buds or anthers were fixed with Carnoy's fluid. Usual methods of dehydrating and embedding in paraffin were employed. Sections were cut 10, h thick and stained with Heidenhain's iron-alum haematoxylin. (2) Development of the anther and formation of the pollen grains in the normal fertile radish : Tissues of a very young, anther consist of two parts, i.e., archesporial and parietal tissues. Archesporium situated in the center is surrounded by three or four layers of parietai cells. Cells of the former tissue are somewhat larger and rounder, and stained more densely with haematoxylin than those of the latter (Fig. 1). With the progress of auther development one layer of tapetal cells differentiates in the innermost part of the parietal tissues, enclosing the archesporium. Tapetal cells are clearly larger and angular or rather irregular in shape, and appear densely stained with haematoxylin than those of other neighboring tissues (Figs. 2 and 3). Such normal tapetal tissue begins, in turn, to degenerate when the pollen grains are formed, and it even disappears completely before the blooming time. On the other hand, the endothecium of the parietal tissue becomes thick and fibrous, so it can play an important rale for the dehiscence of anther walls (Fig. 4). Microsporgenesis proceeds quite normally and the mature pollen grains are seen well dispersed at the flowering.

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Genetical constitutions of the wheat varieties as to Ear-scab have been proved to be 3 different factors, by author (3). The fact that Infected kernel percentage in the case of Ear-scab was reported is highly correlated to the infected percent of spikelet and spike by author ( 4 ). Kernels iufected by fusarial head blight produced large amount of alcohol and varietal differences as to Ear-scab depend on amount of alcohol produced by the addition of fusarium fungus. by author (5). Susceptible varieties as to the toxic reaction of KCI03 has A-factor and A-subs, tance produced by A-factor proved to be fructose by author ( 6 ). Varieties havingf fas, ter decolorization speed of the methylene blue, containing B-factor and B-substance produced by B-factor has large amount of giucose by author ( 7 ). Author ( 8) proved that large content of phosphorous, of the wheat varieties. was related Lo C-factor. From the fa'cts mentioned above, author carried out the followin*cf experiments on relation among the sus, ceptible susbtances and susceptible factors and corresponding enzymes.

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15 crosses were used to study on the inheritance of kernel texture in wheat varieties which affects mealy and glassy of kernels and results were shown in table 1 and figure 1. From these results, the inheritance of kernel texture was proved to be influenced by factors in the generation of F₂ seed. The method of testing of kernel texture may be described as follows : After harvested, each kernel of parents and F₂ Seed was cut off middle part of kernel (cross section) by razer blade on the glass plate, and cross section of kernel was magnifyed by the magnifying glass (2. 5 fold) and selection which was made after a thorough comparison can be classified as follows. Glassy kernel (G) decided to select completely glassy, semi-glassy kernel (g) was selected almost parts (over 80%) of cross section were occupied by glassy, semi-mealy kernel (m) are occupied by mealy over 80% and mealy kernei (M) completely mealy. Segregation ratios was compared with glassy (contained G and g) and mealy (contained M and m). The results of segcrregation ratios to lernel texture of F₂ Seed generation, the factor hypothes and factor analysis were applied in this report as mentioned above. Results obtained may be summerized as follows.

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1. The hybridization was carried out. amohg three species of Digitaria, and F₁ seeds were obtained from D. ciliaris PERS. (2n=54) X D. ischaemum MUHL. (2n=36). The average crossability was about 28% in two years. 2. Although the F₁ seeds were smaller than the mother seeds, and the number of days necessary for germination was irregular and larger than that of the parents, their rate of germination was about 66%No viable seeds were obtained in the reciprocal cross. 3. As the F₁ plants were not vigorous, many of them died in the younger stage owing to the high temperature of the midsummer. The growth of F₁ plants was poor as compared with that of the parents. Many of the morophological characters of F₁ jwere resembling with those of the mother plant. 4. F₁ plants were almost cornpletely pollen sterile with 0.26% of apparently normal pollen, and the anther did not dehisce. Therefore, no F₂ seed was obtained by self, open and back cross pollinations.

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