(1) The authors succeeded in breeding a cucumber of good quality, bearing fruits at most node all the year round. (2) The varieties used in this breeding were Suyo, Manshuaki and Ochiai No. 1. Suyo is a summer variety belonging to the North Chinese group. The nature of fruit bearing is not affected by day-length and temperature. Flesh is of very .good quality. Manshuaki belongs to the same group that Suyo does. The fruits bear at most node all the year round, but the veins are very feeble. Ochiai No. 1 is a spring variety belonging to the South Chinese group that is sensitive to day-length and temperature; under only short day and low temperature condition the fruits are borne at most node, and the veins are thick and vigorous. (3) Suyo was crossed by Ochiai No. 1 in 1946 and the other Suyo was crossed by Manshuaki in 1947, and line separation of their progenies continued in summer cultivation. The F4 Suyo×Ochiai No. 1.21-6 S-10-2 had 60% in the female node ratio of the main vein. The veins were thick and strong, but somewhat dwarf. On the other hand, the F3 Suyo×Manshuaki 22-4 S-2 had 70.2% in the female node ratio. The veins were slender and feeble. To breed for more vigorous variety 21-6 S-10-2-6 was crossed by 22-4 S-2-7, and line separation was repeated. In 1953, two lines of F3 (F4 Suyo×Ochiai No. 1)×(F3 Suyo×Manshuaki) fixed most important characters; the female node ratio was raised to 84. 3% and 82.0%, veins were strong and thick, and flesh was of high quality. The results of the ecological study in 1954 show that this variety is insensitive to day-length and temperature, and fruit bear at most node. (4) This variety will force the development of the cultivation of cucumber and will be expected to be used as a parent of F1 hybrid for extensive utilization.
1. Some experiments were carried out to know the photoperiod requirement for bulb formation of principal Japanese varieties of onions, in the seasons .of 1948-49 and 1951-52. 2. The minimum day length for bulb formation of each variety was determined as follows. 11.5 hours: Aichi-Shiro (Probably derived from Blanc Hatif de Paris). 12 hours: Kaizuka-Wase (Early strain, derived from Senshuki). 12.5 hours: Kaizuka-Wase (Late strain). Aichi-Kiwase (Similar to Kaizuka-Wase). 13 hours: Senshuki (Early and intermediate strains, believed as offsprings of Yellow Danvers Flat). Kisakigake(Derived from Express Globe). 13 hours: Senshuki (Intermediate and late strain). Ninomiya-Maru(Improved from Senshuki), Yamaguchi-Koda ka (Improved from Sapp-oroki). 14.25? hours: Sapporoki (Derived from Yellow Globe Danvers). 3. There was close relationship between earliness or lateness of bulb formation and minimum day length requirement for bulbing among many varie-ties, and the types requiring shorter photoperiod were earlier and the longer types later. 4. The regional adaptability of the onion varieties tends to be determined by the photoperiod also in Japan. The variety Sapporoki which requires long-est photoperiod in Japan has been grown only in Hokkaido, and the shorter day varieties Aichi Shiro and Kaizuka Wase in mild zones. The distribution of the main variety Senshuki tends to be inconsist-ent, but its early strain is adapted to the southern part of Japan and the late strain to the middle and northern part. 5. The bulb formation is not begun under deficient day length and the thickening of bulb tends to be controlled under excessive day length owing to its rapid maturity, thus a variety demonstrates its abi-lity best, where the minimum temperature and photoperiod for the bulb formation visit at the same time. 6. It may be concluded from the temperature and photoperiod of onion growing regions of this country, that the varieties of 12 hours are adapted best to the Loochoo Archipelago, the 12.5 hours to the middlesouth parts of Kyushu and Shikoku, the 13 hours to the middlesouth part of Honshu and the greater parts of Kyushu and Shikoku, the 13.5 hours to the middle and north part of Honshu, and probably the 14.25 hours to Hokkaido as well as to highlands (over 1400m above the sea) of the middle north part of Honshu. 7. All the varieties tested were not pure concer-ning the genes that determine the minimum photo-period for bulbing. It is very interesting from the standpoint of the evoluton of variety, that varying process of Senshuki (13_??_13.5 hours) to Kaizuka-Wase(12 hours) can be explained from this fact.
Effect of light on the germination of vegetable seed was studied in this report. In addition, dorm-ancy of shungiku (Chrysanthemum coronarium L.) and temperature relation to the germination of onion seed were investigated. Three grades of temperature of 20°, 25°, and 30°C were used in most cases. Light was supplied from fluorescent lamp. Effect of wave-length of radiation was studied by the same method as is the case reported by NAKAMURA 15) 1. In Cruciferae, the germination of radish seed is inhibited by light, and seed of Brassica vegeta-bles is favored by light. The former is inhibited by light strongly at low temperature for a while after harvest. This strong light-inhibiting action at low temperature disappears with aging of seed, but radish seed is inhibited by light to some degree for over many years. Brassica seed is forced by light only in the period of dormancy. Both of radish and Brassica seeds lose their photo-sensitivity by such dormancy-breaking treatment as prechilling, thiourea treatment, etc. 2. Germination of dormant seed of shungiku is promoted by thiourea. 3. Seed of mitsuba (Chryptotaenia japonica HASSK.) is favored by light at any temperature. By alternating temperatures, these seeds are ger-minated almost completely in darkness. Photosensi-tivity of mitsuba seed is indifferent to seed age. Celery seed is also favored by light indifferently to seed age. 4. Germination speed of onion and Welsh onion seeds is retarded by light to some extent, and this light-inhibiting action is more remarkable in Welsh onion. Temperature of over about 28°C supresses germination of onion seed. Alternating temperatures of 33° to 25°C is effective, but 33° to 28°C is not. 5. Germination of egg-plant and tomato seeds is retarded by light at every temperature. Germination rate is also often lowered at 20°C in egg-plant, at 20° and 30°C in tomato. Germination of pepper seed is retarded by electric light at every temperature, but not retarded by fluorescent light. Seed of egg-plant does not lose itt photo-sensitivity by the removal of seed coat. 6. Seeds of watermelon, squash, calabash gourd, wax gourd, and balsum pear are hindered by light at any temperature, and the degree is greater at low temperature. Seeds of cucumber, melon, and shirouri (Cucumis melo var. conomon MAKINO) are inhibited by light only at low temperature. Vegetable sponge falls in between the two groups. Photo-sensitivity of Cucurbitaceous vegetable seeds is indifferent to their seed age, and light condition is not replaced by such factors as chemical treatment, alternating temperatures, prechilling, etc.. In the case of decoated seeds, too, the photosensitivity does, not disappear, and sometimes it will even augment. 7. Seed of perilla is favored by light at every temperature. Ramie seed is also promoted by light at any temperature. Photo-sensitivity of perilla and ramie seeds is indifferent to their seed age. 8. In the case of shungiku, carrot, spinach, beet, and Leguminosous seeds, no light effect was observed in our study. 9. Concerning the relation to the wave-length of radiation, that of mitsuba, celery, perilla, and ramie seeds is about the same as in edible burdock. In Cucurbitaceae, germination is inhibited at infr-ared and blue region, but not at green region. Egg-plant, tomato, and pepper seeds are strongly inhibited only at short infrared region, and also Brassica seed was inhibited to some degree only at this region. Onion and Welsh onion seeds did not show any reaction to the spectrum. 10. It is interesting that in the seeds retaining their photosensitivity in seed coat, their photo-sensitivity is related closely to their dormancy, accordingly it disappears or diminishes accomp-anying to the breaking of dormancy. On the contrary in the seeds which retain their photo-sensitivity in their embryo,
1. Studies on flower bud differentiation and de-velopment of three Spanish types and two Virginia types of peanut varieties were carried out at Hira-tsuka, Kanagawa-ken, from 1948 to 1950. 2. In the Spanish type varieties, the first flower bud primordia was formed on the first node of the primary lateral stem, and it differentiated when the second leaf appeared on the main stem. The flower clusters were formed in succession on the primary lateral stem, but were formed scarecely on the se-condary one. 3. In the Virginia type varieties, the first flower bud primordia was formed on the primary lateral stem at some distance from the base, and it differe-ntiated when the fourth leaf appeared on the main stem. The clusters were formed at intervals on the primary lateral stem but were formed abundantly on the secondary one. 4. Pollen and ovule formation began about 20 days after flower bud differentiation, and they flo-wered still 10 days later (Table 1) . 5. The flower cluster contains several flower buds of various stages of development. Two of them develop more rapidly and bloom earlier than the rest. Under favorable conditions, the remaining three or more buds develop and bloom normally. 6. In Spanish type varieties, 100 or more flower buds were formed about one month after the plan-ting, although only about 30 buds were formed in Virginia type varieties. 7. The flower buds formed at an early stage of the growth developed more vigorously, and also-they flowered and fruited more favorably than those formed at a later stage. 8. In Virginia type varieties, the number of flo-wer buds was greater on the second lateral stem than on the first one, but that of fruits was grea-ter on the first one as in the case of Spanish type varieties. 9. The application of nitrogenous fertilizer at an early stage of the growth, determination of planti-ng time and selection of varieties in peanut culture are discussed, based on the above facts.
In 1953, the experiments were conducted in two years old sod blocks of orchard grass and Ladino clover, to study what sort of practise of cutting were effective on conservation of soil moisture and available nitrogen (NH4+N03), and following results were obtained: 1. Frequent grass cuttings improved soil mois-ture conservation under the sod from surface to deep layers, but rare cutting effected only on the surface and kept deep layer as dry as in untreated sod plots. 2. Frequent grass cuttings reduced root growth of the sod and consequently it seemed to be effec-tive on reduction of soil moisture consumption by grass. 3. Soil moisture reduction under orchard grass sod were significant in earlier season, while under Ladino clover sod it appeared later. The effect of cutting treatment was more remarkable under the former than the latter. The fact shows that orchard grass sod are able to be managed more easily than Ladino clover to keep moderate soil moisture con-tent. 4. Grass cutting may be rather effective on the conservation of available soil nitrogen, but not so clearly as of soil moisture, for available nitrogen in the soil increased more or less about ten days after cutting. But when fruit trees suffer from shortage of nitrogen severely, being absorbed by grass, application of additional fertilizers or leaf sprays of urea may be desirable. 5. Orchard grass sod may need more careful fertilizer management than Ladino clover sod, for the former can not fix air nitrogen by itself.
Experiments were made on dormant spray for the control of black spot disease (Alternaria Kikuchiana) of Japanese pears by means of spore formation test in vivo, spore germination test in vitro and spraying experiment in the field. Sprays used were of the following: Bordeaux mixture, lime sulfur, mercury fungicide (Riogen), sodium pentachlorophenate (PCP-Na), mixture of sodium pentachiorophenate and lime sulfur (LS-PCP-Na), and mixture of pentachlorophenol and machine oil emulsion (Oil-PCP). (1) The mixture of lime sulfur and sodium pentachlorophenate (LS-PCP-Na), showing much more effect in retardation of both spore germination in vitro and spore formation on the disease spots of twigs, was more effective in the field experiments than single spray of these two chemicals. (2) Each of Riogen, sodium pentachlorophenate (PCP-Na) and the mixture of pentachlorophenol and machine oil emulsion (Oil-PCP), being little effica-cious to retard spore germination, but showed remar-kable effect in retarding spore formation and also in the field experiments. (3) Lime sulfur, usually applied as a dormat spray, being an ineffective remedy against spore germination in vitro and spore formation in vivo, showed little effect in controlling the disease in the field. (4) The Bordeaux mixture was superior both in retarding of spore germination and in adhesiveness to any other fungicide, but was inferior in retarding of spore formation, and it showed no marked effect in the field experiments. (5) Results of the present experiments led the authors to conclude that strong fungitoxicity and good penetration are requisite to dormant spray for efficient control of the black spot disease, while adherence is not so important.
This paper reports the results of the studies on the effect of foliage thiamin sprays on the thiamin content of the sweet potato plants. Five varieties, Norin No. 1, Norin No.2, Norin No.4, Kanto No. 24, and Taihaku, were used. Thiamin was dete-rmined by the thiochrome reaction (Permutit met-hod, NISHIO 1946). The results obtained were as follows. 1. Thiamin in water solution sprayed on the leaves of the sweet potatoes was absorbed by all organs of plants in 24 hours. Moreover, thiamin absorbed by the plants was accumulated in the parts of high activity. 2. Greater parts of the thiamin absorbed by the leaves of the sweet potatoes were of free form immediately after absorption, but some parts of them were transformed to combined form as time elapsed. 3. Thiamin was absorbed more easily through the lower surface than through the upper surface in the sweet potato leaves.
1. In the tall variety, Kentucky Wonder, the number of flowers was only about 20_??_30% of the number of flower buds which had differentiated by the 45th day from seed-sowing date. Percentae of pod setting against the number of flowers was about 20_??_35%. So the set percentage of pods against the number of flower buds was very low, i. e. only 4.5_??_10.8%. 2. The causes of this sparseness of set are dis-cussed in this paper, comparing other leguminous vegetables. Competition in nutrition and high tem-peratures seem to be the two important causes. Competition in nutrition among flower buds of whole plant and of the same inflorescence and competition between the flower bud differentiation and vegetative growth will cause the many flower and pod drop-ping. 3. Many effective flower buds were distributed densely near the tenth node in the tall variety. 4. As the seed-sowing date was delayed, the percentages of pod setting against both the number of flower buds and the number of opened flowers were lowered. 5. The mode of anthesis time lied between 5_??_7 am. Few flowers opened at abont 2 am. already. The anthesis of flowers was observed till 10 am.
(1) Effect of phyto-hormones on parthenocarpy was different according to the species and the st-rains of cucurbits. (2) Heteroauxin was effective to Pepo and mos-chata species, but was not effective to maxima spe-cies. (3) α-naphthaleneacetic acid (0.0005_??_0.001, ) was most effective among the phyto-hormones tested. (4) The treatments with 0.02% Tomatotone solution and with 0.1_??_0.2% ACA solution were not effective to induce parthenocarpy in the three species of cucurbits.
Effects of fractional application of nitrogenous fertilizers, ammonium sulfate, ammonium nitrate, and rape cake, on vine growth, blossom number and yield of cucumber were tested in 1954. Am-monium and nitrate nitrogen contents in the soil and nitrogen contents in the plant were periodically analyzed. 1. In the experimental plots of ammonium sul-fate, ammonium and nitrate contents in the soil were maintained at relatively higher level until the later part of the growing season. The best vine growth, largest number of blossoms, and the high-est yield of cucumber were obtained where every fifth was applied in five times, and the lowest was in the treatment where total amount of the ferti-lizer was applied at the time of planting. 2. In the ammonium nitrate plots, effects were nearly the same as in the ammonium sulfate plot; i.e. the highest growth was in the plot every fifth were applied in five times and the lowest were in the treatment where total amount of the fertilizer was applied at the time of planting. But growth and yield were less in general as compared with the plot recieved the other fertilizers. 3. In the rape cake plots, less difference was observed among the methods of application of the fertilizer. The highest yield of cucumber was ob-tained where total amount of the fertilizer was applied at the planting time, or every half amount of the fertilizer was applied twice than the plots where the fertilizer was fractionally applied in several times.