An induced mutant of rice (designated as M57) showing a quantitative resistance to the Japanese differential races II, III and IV of bacterial leaf blight (BLB) and a qualitative resistance to the races I and V was crossed with the mother variety Harebare which is susceptible to BLB. The results of genetic analysis for the resistance using the F₁ and F₂ plants derived from the cross and the parents suggested that the quantitative resistance was conditioned by polygenes or some minor gene(s) and the qualitative resistance by single dominant genes. However, it was estimated through an allelism test that the qualitative resistance to the races I and V was associated with pollen contamination from the variety Shizutama carrying the BLB resistance genes Xa-1 and Xa-12. The qualitative resistance genes in the F₂ and F₃ tests were not found to be linked with the quantitative resistance genes, though the genes were likely to modify, to some extent, the expression of the relevant genes for the quantitative resistance to the races II, III and IV. It was also observed that the induced genes expressing a quantitative resistance to the races II, III and IV were operative for the races I and V, too. A negative trait for practical use, e.g. dwarfism of the M57 mutant was not linked to the quantitative resistance. In the F ₃ progeny lines, some lines with a quantitative resistance to all the differential races and with a normal plant type like that of the mother variety Harebare, were selected, as they may become useful materials for the cross breeding for BLB resistance.

View full abstract

The crossability between Hordeum vulgare L. and diploid H. bulbosum L. (which was estimated by embryo differentiation and haploid production) was assessed in two separate experiments with 13 Japanese two-rowed barleys and six F₁ hybrids. Percentages of embryo differentiation (embryos obtained / florets crossed) and haploid production (haploids obtained / florets crossed) varied among the cultivars from 11.1 to 59.8% and from 3.4 to 29.5%, respectively in experiment I (1988). In experiment II (1989), the percentages varied from 1.7 to 72.7% and from 0.6 to 26.5%, respectively. Barley cultivar 'Kanto Nijo 25' showed uniquely high crossability with H. bulbosum in both experiments, showing that there was varietal difference of crossability between H. vulgare and H. bulbosum. F₁ hybrids having a parent of 'Kanto Nijo 25' in their parentage had high crossability as that of 'Kanto Nijo 25', showing that the gene(s) for crossability was dominant. Powdery mildew resistance selection was made in haploids obtained from F1 hybrids. There was deviation from the expected 1:1 ratio to resistance in haploids obtained from F₁ hybrid having 'Kanto Nijo 25' in their parentage.

View full abstract

A histological and genetical study was done on intervarietal graft chimeras between "Yo-shin kanran" (green colored) and "Murasaki kanran" (purple colored) in cabbage (Brassica oleracea). When the anthocyanin pigmentation pattern of the chimeric tissues was observed, epidermal and subepidermal cells were mosaic and recognized to be more complicated than the external appearance. The genotypic constitution of germ cells in chimera plants (V₀, V₁) was studied through the segregation pattern of anthocyanin pigmentation in progeny plants derived from each capsule obtained by geitonogamy of chimeras and back crosses with the green parent "Yoshin kanran" and purple parent "Murasaki kanran". No segregation of plant color was observed in most of the progenies of two V₀ chimera plants as well as their vegetatively propagated V₁ chimera platnts. However, segregations were observed in the progeny plants from two capsules of one V₀ chimera plant crossed with "Murasaki kanran" and from two capsules of one V₁ chimera plant by geitonogamy. These segregation phenomena in the progeny plants suggest two possibilities. The first possibility is the chimericity of the germ cell layer in a single flower of the parental chimera plant, the second is gene transfer between different tissues or cells.

View full abstract

In order to transfer resistance to Pseudomonas solanacearum from Solanum integrtfolium Poir. (Hiranasu) to S. melongena L. (cv. Shironasu), somatic cell fusion was carried out. The protoplasts derived from cultured cells of S. melongena were treated with 1.0 mM iodoacetamide solution for 15 min. at 5°C, and fused with mesophyll protoplasts of S. integrifolium by dextran method. The protoplasts, which were cultured in MS medium (MURASHIGE and SKOOG, 1962) containing 6-benzylaminopurine (1 mg/l), naphthaleneacetic acid (1 mg/l) and glucose (50 g/l) developed to 4 cell colonies after about 8 weeks. Each colony regenerated plants 2 to 3 weeks later. The characteristics of the regenerated plants were confirmed by morphological studies and isoelectric focusing of acid phosphatase. Resistance to P. solanacearum was tested by culturing offsprings from self-pollinated fertile plants (RW-4) in the solution added P. solanacearum. Some of the offsprings from RW-4 were more resistant than parents. From the present results, it was demonstrated that the selection of somatic hybrids by utilizing the inactivation of S. melongena protoplasts with iodoacetamide and the low cell division ability of S. integrifolium was effective and resistance to P. solanacearum could be transfcrred to S. melongena through protoplast fusion.

View full abstract

To develop near-isogenic lines with monogenic resistance to bacterial blight (BB) in rice, a rice differential cultivar, IR20, was analyzed using Japanese and Philippine BB races. Another rice cultivar, Somora Mangga, identified to be carrying Xa-4^b (an allele of Xa-4) was also studied using Philippine races . Analysis of F₂ and F₃ populations (from the cross IR24/IR20) using Japanese and Philippine races revealed that IR20 has Xa-1 and Xa-12 in addition to Xa-4 which was considered to convey resistance to Japanese race IIIA. The allelism test between IR20 and Java 14 showed that Xa-3 and Xa-4 are very closely linked. The allele test between Semora Mangga and Java 14 showed that Semora Mangga has Xa-3, not Xa-4^b as reported earlier. Thus, gene symbols Xa-4^a and Xa-4^b are redundant. The results show that Xa-4 conveys resistance to Japanese races IA, II, IIIA, and V as well as to Philippine race 1 and moderate resistance to race 4.

View full abstract

To identify an effective method of evaluation of the chilling injury at the seedling stage of rice, 15 combinations of temperature and duration of treatment were examined. Exposure of 12-day-old seedlings to a temperature of five degrees centigrade for 4 days resulted in the widest range of degrees of injury, which produced the optimum conditions for evaluating this character. The reactions to the low temperature indicated wide genetic variations in a total of 2, 151 indigenous varieties which originated from various countries. Most of the varieties from high latitudes, Japan, Europe, USA and USSR, were tolerant (Grades 0 to 2), while the varieties from low latitudes, India and Nepal, were predominantly sensitive (Grades 4 to 6). Most of the varieties from Indonesia and the Philippines were relatively tolerant although those countries are located at lower latitudes. Some varieties from Laos, Thailand, Myanmar and Southwest China cultivated in hilly areas were also tolerant. Distinct geographic clines in the variation then occurred along a latitudinal axis. The areas located in Southwest China, Myanmar, Laos, Thailand, Bhutan and Malaysia exhibited a rich diversity in the variations of this character.

View full abstract

Plant regeneration in mungbean tissues were attained in stem, epicotyl sections with cut apex and cotyledon explants while shoots regenerated from leaf sections. Explants differed in hormonal requirements included in MS or B5 basal medium. Stem, leaf, and epicotyl explants required the addition of 0.2mg/l NAA and 1 or 2 mg/l kenetin or 6-BA at this optimum concentrations for the regeneration of plants or shoots in the case of leaf sections. The addition of auxin is unnecessary in plant regeneration from cotyledon cultures where-in plant regeneration occured only at the proximal ends. Addition of 1 or 2 mg/l kinetin or 6-BA and 100mg/l yeast extract proved sufficient for efficient plant regeneration. Regeneration ability in mungbean varied with the genotype in which different varieties interacted differently with regards to callus and plant morphology in a given hormone composition of a medium. Tissue culture gave rise to the production of somaclonal variants. Plant regeneration from callus however, appeared only among primary cultures.

View full abstract

Inheritance of the color and the hardness of fruits was investigated in the progenies of intercrosses between two varieties, Egoma and Shiso, which belong to Perilla frutescens. The results of experiments showed that the fruit color (white vs. brown) is controlled by an incomplete dominant gene W, which is responsible for the thickening of the epidermal cell wall of pericarp. On the other hand, the hard fruit proved to be due to duplicate genes, T₁ and T₂, which cause the unusual thickening of the stone cell layer in pericarp.

View full abstract

Abyssinian mustard (Brassica carinata BRAUN, BC genomes 2n=34) was repeatedly backcrossed with broccoli "Green Comet" (F₁ hybtids) (B.oleracea L.var.italica PLENCK, C genome, 2n=18). In the process of cytoplasm-substitution (Fig. 1), seed fertility in plants increased exponentially as their chromsome numbers became nearer to 2n=18 (Fig. 2). In B₂ generation, plants with 2n=18 chromosomes were obtained. Juging from their chromosome association of 9II, they were assumed to be C genome plants with Abyssinian mustard cytoplasm. Then these 2n=18 Plants with Abyssinian mustard cytoplasm were reciprocally crossed with broccoli plants with normal cytoplasm. Through the comparison of some characters between these reciprocal F₁ plants, alloplasmic effect on broccoli was examined. It was found that alteration of flower shape and male sterility which appeared in cytoplasm-substituted plants were the effect of Abyssinian mustard cytoplasm (Tables 1, 2 and Fig. 3). Photosynthetic rate and chlorophyll content were lower in alloplasmic plants than in normal plants (Table 3 and Fig. 4). Alloplasmic plants were more severely damaed than normal cytoplasmic plants when they met accidental one-night cold-waves (-5∼-6'C, ca. 8h) (Table 4). Therefore, cold tolerance which is universal in C-genornic species of Brassica may be concerned with not only nucleic genes but also cytoplasmic factors.

View full abstract

The high molecular weight (HMW) subunits of wheat seed storage proteins in 376 cultivars were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The highest molecular weight subunit designated as 145 kD subunit was found frequently in Japanese cultivars (Fig. 1). This subunit has identical electrophoretic mobility of the glutenin high molecular weight subunit 2.2 as reported by PAYNE et al. (1983). The 145 kD subunit separated by SDS-PAGE was electroblotted onto a polyvinylidene difluoride membrane filter and the blotted subunit was sequenced by a gas-phase sequencer. The N-terminal amino acid sequence of the 145 kD subunit determined was consistent with that of the HMW glutenin subunits reported previously (Table 1). The 145 kD subunit was concluded to be one of the glutenin seed storage proteins. The size and number of hard crystal particles which characterize hard wheat flours (Fig. 2), varied depending on the presence or absence of the glutenin 145 kD subunit (Table 2); The cultivars without the 145 kD subunit always produce hard flours. The frequency of cultivars with the 145 kD subunit was higher in the southern part of Japan than the northern part (Fig. 3); Most of the cultivars predominant to the northern part of Japan (Hokkaido, Tohoku, Hokuriku and Nagano Districts) have no 145 kD subunit but many large crystal particles in the flours. However, most of the cul-tivars in the south Japan (Kyushu District) have this subunit but not many large crystal particles. These results suggest that the 145 kD subunit plays an important role in determining the hardness of wheat flours. The crossing test revealed that the expression of the 145 kD subunit is controlled by a single gene (Table 3, Fig. 4). The trace back of pedigree shows that the genotypes with and without the 145 kD subunit were preferably selected in each step of the wheat breeding procedures in the southern and northern part of Japan, respectively (Fig. 5).

View full abstract

Plant opal, a plant-derived silica body (SiO₂) excavated from archaeological sites, has been used to analyze various characteristics of past vegetation and crops relevant to the archaeological and palaeobotanical studies. We attempted to distinguish japonica varieties from indica ones based on the morphological features of the silica body extracted from living leaves of rice cultivars, so as to establish a methodology to determine whether plant opal was derived from indica or japonica varieties. In the present experiment, ninety-six cultivars classified into indica and japonica by SATO's discriminant function (Z₂, see SATO et al. 1986) were exarnined. Silica bodies were extracted from living leaves, and four dimensions shown in Fig. 1 (a, b, c and d) were measured for 50 samples of each cultivar. Silica bodies were classified into the α-type (smaller a, b and d, and larger b/a) and β-type (reverse of α-type, see Fig. 1 FUJIWARA, 1976). A preliminary test revealed that the silica bodies of typical indica showed the α-type, while those of typical japonica the β-type. To represent the varietal variaiton in the shape of the silica body, the discriminant function Z₁ was calculated as follows: Z_l=0.049 (a+b)-0.019 (c)+0.197 (d)-4.792 (b/a)-2.614

View full abstract

The cool damage at heading and flowering stages of rice variety Fujiminori, which is affected by exposed duration to various combinations of temperature and radiation intensity, was examined in growth cabinets with artifical light using water culture method. Temperature tested were constant (22.5, 20, 17.5, 15, 12.5 and 10°C and alternating (dayiime(12h.) -nighttime(12h.) : 22.5-17.5, 20-15, 17.5-12.5, 15-10, 12.5-7.5 and 10-5°C), radiation intensities tesl;ed were standard(15.4 MJ/m²/day) and low(5.5 MJ/m²/day), and durations tested were 2, 4, 6, 8, 10 and 12 days. The degree of cool damage was evaluated by percentage of perfectly mature grains. The preserving duration of fertility(PDF) after heading was determined by the duration of each cool treatment. Within days of PDF, rice plants are able to ripen more than 80% of total grains. The cool damage at heading and flowering stages between 10 and 15°C depended on the length of cool duration rather than on the intensity of radiation, degree of coolness, and maximum and minimurn temperature of day and night, and the PDF of Fujiminori between 10 and 15°C of two radiation intensities was 6 to 8 days with a variation within 2 days.

View full abstract

Soybean plants belonging to eight varieties originating from Japan and from low latitude regions of South America were exposed to short photoperiods at different ages for varietal comparison of the effect of short photoperiods on flowering in relation to plant age. Thirteen to 33 day-old plants were exposed to a 12.5h photoperiod. The number of days to flowering and number of trifoliate leaves on the main stem which increased during the period of the treatrnent decreased linearly with the plant age at the onset of the treatment, and significant differences were observed in the rate of the decrease with age among the varieties. Thirteen to 33 day-old plants which were defoliated except for the uppermost two leaves, as well as intact plants at the same age, were exposed to photoperiods of 12h and 12.5h. Altb.ough the number of days to flowering varied with the plant age and photoperiod, no significant differences were observed between the defoliated plants and intact ones. Seven day-old sedlings were grafted onto one of the branches which had developed from the axils of primary leaves of stock plants. The grafted plants were exposed to a 12h photoperiod after defoliation of either scions or stocks. The number of days to flowering of the scions was the same as or smaller than that of the stocks. Thus, it was suggested that the enhancement of the flower induction effects of short photoperiods with plant age was not due to the increase of the sensitivity of the growing points to the floral stimulus but to the increase of the response of the uppermost leaves to short phtotoperiods.

View full abstract

Interspecific hybrids between Allium chiuense (=) and A. thunbergii (=) were obtained through in vitro culture of hybrid embryos. In embryo culture, nine fertilized embryos were excised from 49 flowers, and five of them developed to whole plants by culture on MS medium (MURASHIGE and SKOOG 1962). In in ovulo embryo culture, all four fertilized embryos excised from precultured ovules developed to whole plants. Thus hybrid plants were produced more efficiently by using embyos excised from precultured ovules, than by using embryos without ovule culture.

View full abstract