Experiments were carried out in 1957, to clear up the varietal difference of the effect of short daylength upon the flower initiation and its development, using 7 varieties of soy-bean including the different ecological types, and upon the seed ripening period, using 17 varieties of soy-bean which belong to the different ecological types. The plants were grown in the outdoor and the greenhouse. The half of them were treated with 10 hours day-length. Other half of them were left under natural day-length. The results are summarized as follows : ( I ) The days from cotyledon expansion to flower bud initiation, the days from fiower bud initiation to blooming and the days from blooming to ripening under natural condition show marked differences between varieties of each ecological type, and these days gradually increase following the order I-II-IV-V and the order a-b-c. And, at the same time, the shortening rate of above days by short-day treatment show remarkable differences, and also these rates increase by the same order. These relationships were similarly recognized under natural temperature (in the outdoor) and high temperature (in the greenhouse) . ( 2 ) It was considered that such differences among these ecological types were not due to the differe* nces of day-length and tetnperature in the growing:: period of each variety, but due to the essential differenc of short photoperiodic responses of soybean varieties. ( 3 ) Variety which had a greater shortening rater on days of fiower initiation by short-day tteatement had a greater shortening rate on days of flower development by the saine treatment. Shortening rate on days of blooming became greater in case of continuous treatment during the flower bud initiation and fiower development than in case of each one treatment. Shortening rate on days of flower bud initiation by short-day treatment was alway. larger than shortening rate on days of flower development and on days of seed ripening, but therer was no relationship between shortening rate on days of flower development and shortening rate on; days of seed ripening. ( 4 ) Such relationships between varieties of these ecological types are the results of only one expression under the given day-length and temperature condition in this experiment. So, it will be necessary to study furthermore under various conditions

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1. Following tLe previous report (TORIYAMA and FUTSUHARA 1960), this experiment were conducted to clarify the relations between cool tolerance and the other characters in the early generations of the rice crosses Somewake×Aomori N0.5 and Kitakei N0.3204×0u N0.187 (cf. Table 1 and 5). 2. The degree of cool tolerance was evaluated by sterile index [sin√ˆ-1<sterility> of the materials tested in cool water irrigated field. 3. Consequently, close relations between cool tolerance and morphological characters investigated were found in F₃ lines of the former cross, as shown in table 2. 4. While, in F₂ population of the latter cross, high cool tolerance was positively correlated with high stem length, but the relations between cool tolerance and the other morphological characters except stem length were not statistically significant (cf. Table 6). 5. In both crosses described above, no close relations between cool tolerance and heading date were found. 6. The former cross showed transgressive segregation for cool tolerance and gave high yielding hybrids combining the favourable characters of both parents.

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Although Renge (Astragalus sinicus L. ) is a very important fcrage crop cultivated during winter season in Japan, studies have been rarely made on its breeding. In view of this status, the possibility of the utilization of hybrid vigor was investigated in this study. Results obtained are summarized as follows : ( 1 ) The F₁ hybrids among the inbred lines of var. Gifu-Daibansei and Funosen No. 24 grew, in general, more vigorously than their parents. The plant height and number of leaves of the F₁ hybrids were significantly larger than those of the parents. A remarkable hybrid vigor was found also in dry matter yields cropped at the flowering time, the F₁ plants showing 60% increase on the average in contrast to the parental inbred line. In addition to it, the seed yields of the F₁ plants were 30% Iarger than those of the parents. Although the hybrid vigor was observed in all of six crosses examined, the degree of the vigor varied considerably with cross combinations in both dry matter and seed yields. This fact suggests that the selection of inbred lines showing high combining ability may be the first step to the utilization of hybrid vigor in Renge.

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[in Japanese]

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Experiments were conducted repeatedly from 1953 to 1959 to study the aftereffects of vernalization and the cumulative effects of the repeated treatments. These experiments were conducted by raising barley and wheat in 1957, wheat in 1958 in the field, and wheat in 1958 in the greenhouse. It is impossible to judge whether the effect of the low temperature treatment on the succeeding crop is significant or not, unless the effect is very conspicuous. Fortunately because of the very warm growing seasons, the effect of the treatment was remarkable in both years. After effects caused by the low temperature treatment chiefly appeared during the period between early tillering and heading. These effects seemed to influence the height of plants, number of tillers, type of plant form, shooting period of leaf, size of leaf blade, and date of heading. With repeated treatments great effects of vernalization were observed, though their cumulative effects on morphological characters were not quite apparent in the field. In the greenhouse the aftereffects were especially remarkable because of more favorable growing condition for the expression of the efects of the treatment, and at the same time some cumulative effects on visible characters were also observed.

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"Hlraki-komugi" Is a local variety of wheat which is being cultivated widely in the acid soil areas distributed around Mt. Daisen, Tottori prefecture. This variety is well known, because of its high resistance to soil acidity, and it has been used as a valuable material for the breeding of varieties with high resistance to the soil-acidity. A native population of this variety was grown simultaniously at the Thaku Branch of Tottori Prefectural Agr. Exp. Sta., Kurayoshi and at the Natl. Inst. of Genetics, Misima. From the popula-tion, 49 plants were selected at random at Misima, and likewise, 36 plants were selected at Kurayo-shi. These two groups of lines were designated as A and B, respectively. Data may be summarized as follows: 1) These groups of lines were compared in both locations and data were analyzed statistically. As the result of which, the statistically significant differences were found between the lines in the almost of agronomic characters. 2) Lines examined were discriminated most effectively by three morphological characters, namely, culm length, ear length and awn length. Then, b ased on these data, type index of each line was calculated. Differences in type i, ndex value were statistically significant, while no interaction was found between years. 3)These lines were grown under the acid soil and the ordinal soil conditions, and data taken in each soil were compared in each pair of lines. Soilacidity resistance was different between lines, and difference was significant in both groups. Interac-tion betvJeen lines and soils showed significance, and it has suggested that the varietal differentia-tion for soil-acidity resistance could occur, if this population were grown under various soil conditions. Thus, a kind of edapic race of a crop variety should be orig:inated from such a population. 4) Based on these findings, it was concluded that the original population of this variety should be constituted of a quite number of lines which are different genetically in various agronomic characters. 5) Among the lines examined there were several heterozygous lines, and segregation was found in the progeny test. Frequency of heterozygous lines was rather high, and it has suggested the high rate of natural crossing.

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In the previous paper, the author reported that there was some tendency among cold resistance trees, which included many individuals of late-ripe legurne or late-flowering trees. This paper is concerned with the inheritance of correlation between the cold-resistance and the ripe period of legume. The materials used were natural pollinated progenies of seven trees and each of the trees differing in ripening period of the legumes, Radicular epidermis of the 4-day-old seedlings (4 days after germination) was used as the material fcr plasmolysis. Germination of the seedlings was done in the ther-mostat. The 40-day-old seedlings were used in order to look for the effect of low temperature and of the toxic action of chlorate. Four reagents, CO(NH₂)₂, KN0₃, CaCl₂, and KC1+Cal₂ (8 : 2), were used as the plasmolyticum. The correlation between the degree of plasmolysis and the strains was found in the CaCl₂ solution alone, but not in other three reagents. There exi-sted the negative correlation between the damage' of seedlings by the low temperature at -2°C∼-3°C for 24 hours, and susceptibility to KC1O₃. These results agreed with those of the previous workers. Among the plasmolysis with the CaC12 solution, thet injury by low temperature treatment, the suscepti-bility to KC1O₃ and the ripe period of legume (or flowering period) existed the high correlation. The strains of later ripe period of legume had a stronger power of resistance to the low temperature. This results agrees with that of the previous paper. This correlation may be the inheritant character.

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