1. Two soybean varieties, 'Chakotsubu' and Akidaizu' (Table l), were sown separately and mixed. together, respectively, in a randomized block design vfith three replications. Additionally a set of plots was prepared for the measurement at the young stages of growth. To find the effect of competition orl assimilative activity, "half-leaf weighing method was adopted by the fcllowing procedure. Eighteen leaf-disks of I sq. cm in area were temoved from each of four normally grown plants of each variety in each plot at 6 a. m. and 5 p.m., respectively, on Aug. 21 (Fig.3). Seventy-two disks of leaf per variety w, ere dried as a set in an oven and weighed. Total nitrogen content of the leaves of representative four plants of each variety in the twq sowing methods was analysed by Kjeldahl method, to find the effect of competition on nitrogen metabolism.

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1. Native strain of red clover produced at Nat. Inst.' Agr. Sci. (Chiba, Japan) was sown on Apr. 27, 1951, in two sub plots. af thick and thin plantings arranged at random in three main plots of nitrogen-fertilization, nodule bacteriainoculation and non-treatment, the treatments being triplicated. The number of plants per unit area in a thin planting plot was one-fourth as many as in a thick one so as to grow a plant per 10xl2cm area in the former and per 5x6cnl area in the latter. The piants were taken up from the ground on Aug. 8 in the early bloom stage, and plant lleight and tol'o flesh weight were measured per plant. The same treatments were carried out in the pot experiment to find the individuai difference of scveral quantitative characters of the seedlings and the effect of treatments. one hundred' swelled seeds were sown in each pot filled with the **oil sterilized with formalin. The seedlings were dugged up from the pots+ on Juni 15, Jun. 21 and Jul. 2, respectively. The measurement was made of several characters of tops and root.

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Taking two varieties (A and B) nearly related but differed in the fertility of hyb.rids with the third variety(C), in the same way as mentioned in the preceding paper, ( I ), variation of good pollen percentage in (AxB) xC and Cx (AxB) was observed. Two kinds of variety combinations (l08x143) : 563 and (108x101): 521 were used (see Table I ). As demonstrated in the previous work, it was recognized again tb.at genes necessary for the development of gametes are duplicated and a hybrid befween varieties havir.g recessive genes at different loci produces double recessive or sterile ganietes in a deflnite ratio and thus resuIts hybrid sterility. In addition to this, CX(AXB) was found to segregate more sterile plants than (AxB)xC, and it was inferred that poiien possessing two dominant gamete-development-genes was lower in fertilizing capacity than pollen possessilng one dominant gene. This phenomenon seems to take some part, along with the degeneration of douhle recessive gametes, in the second and iater generations of a sterile hybrid to iricrease definit kinds of gene combinations which are simiiar with those of parental varieties.

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1. As mentioned in the preceding paper (3), hybrid sterility among rice varieties seems to be due to that genes necessary for the development of gamete are duplicated and a hybrid between varieties having different recessive genes produces double recessive or sterile game tes in a deflnite ratio. When a gene (A or a ) controlling a character was linked with such a gamete-developnlentgene, the segregation ratio of A : a would be modified aild it should be expected that sterile plants be higher in frequency among heterozygotes Aa than among homozygotes AA or aa. 2. The relation between the gene above mentioned and the gamete-development-genes is inferrable from a certain method of calculation based on the phenotypic ratio of A : a and the differences in the mean as well as in the variance of fertility between phenotypically dominant plants and recessive ones in the F₂ or back cross of a sterile hybrid. This was verifledin dealing with the change. of segregation ratios of grain tip pigmentatioh gene and glutinous gene in some varietal crosses.

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From the restilts obtained so far by the authors, it is clear that the photoperiodic response in spring wheats is infiuenced by the day-length in the period during which the three leaves already formed in the embryo are eloirgating, and as long as the dark period ls not interst. itial during that poriod described above, these spring wheats convert to the reproductive growth with the minimum vegetative growth(5-6 Ieaves, being cdnstant, in different varieties). However, as the period during which the three leaves already formed in the embryo are elongating and developing corresponds also to the period receiving the effects of endosperm, it is inferred that the facts described above niay be due to the influence of differenbes of endosperm. As reported in the previous paper, there was no variation in the basic vegetative growth but some deviations were to be seen in the develbping-velocity of each leaf on the nlain culm. However, in: the experiment reported in the previous paper, the usual intact seeds not subjected to the trarisplanting treatment were used as the control, no definite conclusion couid be drawn concerning to the infiuence of differences of endosperm.

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In common strain of yellow lupine, Lmpinus luteus L., a positive reaction for alkaloid occurs, denoting purple colour in various parts of young plant. On the other hahd, sweet lupine (strain) has no colouring and alkaloid reaction. These two strains were crossed with each other and the progenies were tested. It is found from the result that two characters inherited independently as a dihybrid type. Thus two new combinations were brought as coloured and no-alkaloid, and no-coloured and alkaloid positive. Such facts will atract our attent, ion for the cultivation of forage crops.

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1. The experiment was carried out to obtain the multiple translocation line of barley which will be used in the Oenothera method of establishing homozygous lines. Synthesis and application of the translocation line with a type of (8)+ (6) are aimed as a provisional goal. 2. Homozygous lines were made on various reciprocal translocations with the types (6), (4)+ (4) and (4), which were induced by the X-ray treatment, 3. In the hybrids between these translocation lines, the plants with (8) or (6) +(4) set seeds about 28% and the plants with (6) or (4)+(4) abbut 45 % . 4. Considering the fertilities of plants with (8) or (6), plants with (8)+(6), which would be obtained as an end product, are supposed to retain some fertility.

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