A three-step culture method for rapid regeneration of plants derived from mesophyll protoplasts was previously reported. Since a large number of regenerated plants were produced from protoplasts by this method, the chromosome constitutions of the calli and the regenerated plants were examined throughout the period of culture. In the callus-growing phase of the first and second steps of culture, the number of tetraploid cells increased gradually, but anaphase abnormalities were not detected. In the organization phase of the third step of culture, the tetraploid cells were eliminated and a high frequency of diploid plants was obtained (99%). Furthermore, most of the regenerated plants were uniform in their quantiative characteristics such as plant height, Ieaf shape, flower shape and pollen fertility. On the basis of these results, it was concluded that the three-step culture method for rapid regeneration was effective for the purpose of reducing the occurrance of genetic instability in the plants regenerated from protoplasts.

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Effects of sucrose concentration, pH of media, and culture temperature on anther culture were studied using trifoliate orange (Poncifus trifoliata (L.) RAF.), sour orange (Citrus aurantium L.), and 'Trovita' orange (Citrus sinensis OSBECK). The most effective concentrations of sucrose in forming embryoids were 30g/l for trifoliate orange, 70g/l for sour orange, and 10g/l for 'Trovita' orange. As well, more calli were formed on the media containing more sucrose in all three species. The optimal pH of the media was pH 5 or 6 in forming embryoids or calli for three species. Embryoids effectively appeared at 28°C in trifoliate orange, at 24°C and 28°C in sour orange, and at 24°C in 'Trovita' orange. Calli formed well at 28°C and 24°C in trifoliate orange, at 28°C in sour orange, and at 24°C in 'Trovita' orange. These results suggest that the response of the anthers to the culture conditions differs among close species of citrus.

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Heading responses of barley to temperature and day-length were investigated in order to analyze the physiological characters responsible for early heading in Japanese varieties. Ten varieties were grown under various conditions of temperature (5, 10, 15 and 20%) and day-length (11, 12, 13, 14, 15 and 24hours). When the varieties were grown under a 24-hour day-length regime, heading tirne was accelerated with wihe rise of temperature, regardless of the varieties. There were no appreciable difference in the response to temperature. Varietal differences in heading were observed under short day conditions. When the night temperature was higher than the temperature in the field, heading of earlier varieties was more accelerated. Several materials including early varieties were examined under long day (24 hours) and short day (11 hours) regimes, respectively. The early varieties had generally inherited their insensitivity to short day from the parental varieties or lines. They also showed different responses to both short and long day, due to their adaptation to the producing districts.

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Peroxidase isozymes in 24 populations of the Japanese lawn grass (Zoysia japonica Steud.), collected from all over Japan, were analyzed by thin layer gel electrofocusing. A peroxidase zymogram pattern of the leaf extracts revealed about 20 bands. Intra-population variability was estimated by the mean of the correlation coefficients based on peroxidase zymograms of ten plants in each population. Of the 24 populations analyzed, those from pastures generally showed a very low intra-population variability. The inter-population relationships among the 24 populations were assessed by cluster analysis using the correlation coefficients obtained from the average isozyme activity. No clear trend was noted in the relation between the dendrogram and the geographical location. However, three populations in Hokkaido were significantly distant from all other populations, suggesting a difference at the gene level. Two populations in Miyazaki Prefecture were also differ from all other. The populations in Honshu and Shikoku were close to one another and the similarity among the Oozasa, Sotoyama and Morioka populations was particularly striking.

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Esterase isozyme variation of Camellia sasanqua, C.hiernalis, C.vernalis and C.japonica was examined to reveal interspecific relationships. A band, band 4, whose frequency distribution was a clue to estimate the formation processes of C.sasanqua and C.vernalis was detected. The band was observed with high frequency in C.hielnalis, but in none of the wild C.sasanqua strains. Amdng C.sasanqua cultivars, none of the cultivars with white flowers showed band 4, but many cultivars with reddish flowers and most reimported ones did. It appears that C.sasanqua cultivars carrying reddish or doubled ffowers were formed not only through the selection of wild strains but also through the introgression of C.hiemalis with reddish or doubled flowers. It also appears that some C.vernalis cultivars have been influenced by C.hiemalis. Therefore, we cannot draw distinct boundary lines among the above species. They have introgressed with one another as evidenced in the wide variety of horticultural collections.

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Capsicum annuurn consists of two varieties, wild var, minimum and cultivated var. annuum. To elucidate the cytogenetical relationship between them, meiotic chromosome pairing in intraspecific hybrids of C.annuum was examined. Consequently, it was clarified that structural differentiation of chromosomes occurs among the wild forms. In the present study, three types of chromosome structure differing from each other by reciprocal translocation were detected and designated as A, B and C types. Most of the strains examined were classified into the A type group, which makes A the most common among these three types. B and C type strains are assumed to have derived independently from A type strains through reciprocal translocation. The chromosomes of cultivated forms, on the other hand, were not structurally differentiated. All samples of the cultivated forms examined were classified into the A type group. From the present cytogenetical evidence, it was concluded that cultivated C.annuum clearly originated from the A type of wild variety.

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The varieties of spring wheat Druzhina 1 (d1D2D3), Salute (D1d2d3) and Saratovskaya 29 (d1D2d3 ; d1d2D3) with genes for hybrid dwarfness and triticale variety Inia Armadillo "S" (2n=42) were used as parent materials. The crosses between the two wheat varieties (Druzhina 1 and Salute) and a triticale variety resulted into 30∼40% narrovv-leaved F₁ interspecific hydrids, which were not observed in crosses with wheat varieties without genes for hybrid dwarfness. Backcrosses of F₁ narrow-leaved hybrids with Druzhina 1 and Salute gave 50∼60% plants with extremely narrow-leaves and higher fertility. The narrow-leaved forms of dwarf and semidwarf wheats possessed some valuable traits from rye via triticale, viz. pubescent upper internodes, hairy spikes and stem solidness which were absent in the wheat varieties used. Thus it is possible to get short competitive (short stemmed, narrow- and few-leaved) forms of wheat and triticale which are capable of producing higher seed rates and able to utilize the natural resources more rationally.

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Caffeine, flavanols and amino acids in the frst flush shoot leaves of 23 species belonging to the genus Camellia were assayed by gas and high performance liquid chromatography Based on these results, principal component analysis was performed. Camellia sinensis and C.taliensis of section Thea contained caffeine, five flavanols (catechins) and theanine (the most abundant amide in tea), whereas C.irrawadiensis of the same section was characterized by the absence of caffeine. Chemically, C.taliensis was closely related to C.sinensis. Most species in sections other than Thea did not contain detectable amounts of caffeine or theanine, except for a clone of C.kissi of section Paracamellia that contained a small amount of caffeine and C.furfuracea of section Heterogenea which contained theanine. An approximate correlation of the flavanol patterns with subgeneric sections was made. ECG (epicatechin gallate) and EGCG (epigallocatechin gallate) were present in only the plants of section Thea. In most of the species studied, the EC (epicatechin) content was higher than that of (+)-C ((+)-catechin), but in four species, C.furfurabea and C.granthamiana of section Heterogenea, and C.oleifera of section Paracamellia and C.japonica subsp. hozanensis of section Camellia, (+)-C w, as the predominant flavanol. The flavanol gas chromatograms of C.sasanqua, C.saluenensis and C.japonica subsp. hozanensis showed 4 marked peaks derived from unidentified components.

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KTI (Kunitz trypsin inhibitor) in cultivated soybean (Glycine max) seeds and KTILPs (Kunitz trypsin inhibitor like proteins) in wild Glycine species seeds were purified by DEAE cellulose ion exchange chromatography, and immunochemical and electrophoretic properties of those proteins were studied in order to get information on the speciatlon or phylogenesis of the genus Glycine. Seven lines or varieties listed in Table 1 (including 4 species of G.tomentella, G.tabacina, G.clandestina, G.canescens in the subgenus Glycine, and 1 species of G.wightti in the subgenus Bracteata, and 2 species of G.soja and G.max in the subgenus Soja) were used as materials.

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The effect of irradiation on the survival rates and embryonic development of Brassica pekinensis RUPR. (Varieties; Kashin, Kohai 65 nichi and kairyochitose) was investigated. The purpose of this study was to seek ways of increasing the survival rates of embryos such as B.oleracea obtained through embryo culture techniques after irradiation doses affecting seed fertility and germination, for the purpose of increasing mutation rates. Embryos at different developmental stages ranging from the globular to the early heart stages were irradiated with 20 KR of gamma rays at the daily rate 0L 20 KR or 10KR (Fig.1 and Table 1). The embryos were excised from ovules 4 to 10 days after irradiation and cultured on White's medium. The shooting and rooting rates on the 34th day of culture were higher at the dose of lOKR/day than 20KR/day and were lower when the materials were irradiated at the young embryonic stage (Table 3). Varietal differences in the shooting and rooting rates were also observed. The irradiated embryos survived mainly in the state of callus. It was concluded that the embryo culture technique was successful when applied to irradiated embryos excised at the young embryonic stage and that the technique affected B.pekinensis less than B.oleracea.

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