This study aims to find out factors responsible for the frequent occurrence of offtypes in crosses of certain isogenic lines of a rice variety Taichung 65. In the course of backcrosses to establish isogenic lines with alleles on the Ef-1 locus and others controlling heading time, segregants which headed a few days earlier than their sibs were obtained and their progenies produced various non-parental offtypes. In the progeny of such offtypes were found plants showing a wide range of heading time. Their intercrosses and crosses with other fixed lines showed irregular segregation patterns and weak segregants. The occurrence of weak plants was also observed in another series of experiment with an induced early-heading mutant. It was suggested that a transposon could be involved in the gene system.

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To investigate the cytological variation of the species of the genus Secale in eastern Turkey, said to be one of the most probable places for the origin of cultivated rye, we determined the frequency and cytogenetical characteristics of B chromosomes (Bs) of the two species, S. cereale L. and its wild related S. mantanum GUSS., from Turkey. Cytological observation was carried out on 15 Turkish populations (a total of 861 individuals) of S. celleale. Two Turkish populations had plants with two Bs, but the other populations had no plants with Bs. The frequency of plants with Bs varied from 0% to 2.2%. Therefore, we concluded that the Bs frequency in Turkey is low. The Bs detected in this study did not pair with autosomes (As). They were considered to undergo the directed nondisjunction at the first pollen mitosis and the first embryo-sac mitosis, and to be the standard type for their morphology, which are features common to cereale's Bs from various regions of the world. This supports the monophyletic origin of cereale's Bs. Furthermore, no plants with Bs were found among the four Turkish populations (a total of 45 individuals) in S. montanum cytologically analyzed.

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A methods for growing of saffron (Croccus sativus L.) protoplasts immobilized in Ca-alginate is presented in detail. Protoplasts were isolated from the cells of the suspension culture (ISA and OGASAWARA 1988) with a solution of Cellulase "Onozuka" RS Pectolyase Y-23 and Driselase, and embedded in Ca-alginate beads. They were cultured with or without nurse cells in MS medium (MURASHIGE and SKOOG 1962) supplemented with 2, 4-D and Zeatin at 25°C. After several changes of medium, cell-clusters appeared on the surface of the Caalginate beads, although the protoplasts without immobilization in Ca-alginate beads did not display cell division. Growth of the cell clusters in the medium with nurse cells was much better than that in the medium without nurse cells. Then, the beads were transferred onto MS agar medium supplemented with 1-naphtaleneacetic acid and 6-benzylaminopurine, and subcultured at 15°C or 20°C. After 2 to 3 months of culture, shoots and roots regenerated from the callus tissue.

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The fifty-one diploid (2n=2x=30) Ipomoea strains, which have been named I. triloba. I. lacunosa and I. trifida in Kyoto University and Mie University, Japan, and I. triloba. I. lacunosa. I. ramoni and I. cordatotriloba (syn. I. trichocarpa) in the University of Georgia, USA, were studied for further identification by means of multivariate analyses. A total of forty-one characters distributed over various parts were used: (a) stems and leaves 10, (b) inflorescence 8, (c) corollas 10, (d) sepals 6, and (e) capsules and seeds 7. The initial data-base of 51 strains × 41 characters was subjected to the WVGM (weighted variable-group method) cluster analysis. Subsequently, the data-base of the same 51 strains with 25 characters was processed accordlng to principal components analysis. The 25 characters included one addltional root character but other 24 characters were selected from those used in the WVGM analysis. These two analyses represented that the 45 strains are divided into six phenetic groups, A₁, A\2, B, C₁, C₂ and D. The other 6 strains including. I. trifida strain K221 remained ungrouped. Further, the result of analyses demonstrated that the I. trificla strain in question has the most phenetic similarity to group D and the next most similarity to group B. By making a morphological comparison between the phenetic group and taxonomically described species, three groups A₁, A₂ and B were identified as I. trlfloba L., C₁ as I. lacunosa L. and D as I. cordatotriloba DENN. The intermediate position of group C₂ in the taxonomic space suggested that the strains of this group are natural hybrlds, I. × leucantha JACQ. To clarify the interspecific relationships based on crossability within and between the phenetic groups, crossing studies have been carried out. Intragroup hybrldiza-tlon among the stralns In group B or group D showed various degrees of crossabllity, however, none of these strains produced hybrids in crosses with the I. trifida strain K221. The low crossability in intergroup hybridization between the strains of group D and one strain of A₁ suggested the possible genetic divergence of these taxa, I. cordatotl'iloba and I. lacunosa. Crosses of the I. trifida strain K221 with four strains each from group A₁, A₂, C₁ or C₂ were also unsuccessful in obtaining hybrids. These results indicated the presence of a significant reproductive isolating barrier between diploid I. trifida and the other diploid lpomoea taxa studied.

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Three experiments were carried out to gain more detailed information on the crossability between Italian ryegrass and tall fescue in order to develop an effective breeding program of these intergeneric hybrids. In the first experiment three Italian ryegrass cultivars, as female parents, and 12 tall fescue cultivars and strains, as male parents, were used. There were wide ranges of variations in the crossability between cross combinations. The number of hybrids per spike (crossability) ranged from 16.4 to 103.7 and 17.3 to 145.0 in the cross combinations of 1980 and 1983, respectlvely. A specific tall fescue cultivar showed a high crossability with Italian ryegrass in both years. In the second experiment genotypic effects of Italian ryegrass on crossability were investigated in crosses of four Italian ryegrass clones with six tall fescue clones. There were significant differences in the cross-ability among the female Italian ryegrass clones. Among the male tall fescue clones the differences in the crossability were present, but they were not significant at the 5% level. In the third experiment the inheritance of the high crossability of a clone of Italian ryegrass cv. Waseaoba, W-2, was investigated using its selfed progeny plants. Most of the selfed progeny plants of the W-2 clone showed high levels of crossability (percentage of seed set) with a tall fescue clone. The mean seed set was 84.5% with a range from 61.5% to 95.7%.

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A study was carried out under a collaborative research between MAFF, Japan and IRRI, Philippines, to establish international differentials for identifying of bacterial blight by developing near-isogenic lines with single genes for resistance. The resistance to bacterial blight of two resistant cultivars Zenith and Cempo Selak was analyzed using Japanese and Philippine races of bacterial blight at two locations; TARC in Japan and IRRI in the Philippines. Rice cultivar Zenith had been identified to possess Xa-6 gene, whereas the genetic composition of Cempo Selak, one of IRRI differentials was unknown. The reaction of these cultivars to Japanese and Philippine races was similar to the reaction of Chugoku 45 and Java 14 in our preliminary tests. We carried out genetic analysis of these two cultivars for resistance to bacterial blight and carried out allelic tests with Xa-6 present In Chugoku 45 and Java 14. The reaction of F₁, F₂, and F₃ progenies from the crosses of IR24 with Zenith and Cempo Selak showed that these two cultivars also have Xa-3 for resistance and the gene symbol Xa-6 assigned to the dominant gene of Zenith is redundant.

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Callus-forming ability in anther culture was studied in 7 Japanese rice cultivars, consisting of chilling-resistant and susceptible ones at the pollen-forming stage, after treatment of the panicles at 5, 10 and 15°C for 8, 16, 24, 32 and 40 days. The rate of callus formation (percentage of the number of callus-formlng anthers to that of anthers plated) differed depending on the varieties as well as the temperature and duration of the treatment. The Hayayuki and Norin 20 cultivars in the Hokkaido area, formed a callus at a high rate by the 15°C treatment, while Somewake showed a good response to 10 and 5°C and to prolonged treatment. Hatsunishiki, Sasanishiki, Koshihikari and Norin 21 formed a callus at a fairly high rate by the 10 and 5°C treatments but at a low rate by the 15°C treatment. No significant correlation was observed between the callus formation rate and the chilling resistance in the cultivars. Varietal differences in the callus-forming response to temperature and duration of the pretreatment in anther culture were demonstrated.

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Agrobaclerium-mediated transformation of suspension cells of Citrus and regeneration of transgenic plants have been achieved using a binary vector and a cointegrative vector systems. Three embryo callus lines of 'Washington navel' orange (Citrus sinensis OSBECK), 'Ohta' ponkan and 'Kara' mandarin (C. reticulata BLANCO), and a pollen embyoid callus of 'Trovita' orange (C. sinelesis) were cocultlvated with two strains of A. tumefaciens, A415 or GV3010, for 3, 5 and 7 days. The former strain harbors a binary vector pTRA415 containing a neomycin phosphotransferase II (npt-II) gene. The later strain harbors a cointegrative vector pGV3850 : pMPK110-1lpt containing a hygromycin phosphotransferase (hpt) gene. Callus colonies were formed in calli of 'Washington navel' orange and 'Trovita' orange on selection media containing kanamycin or hygromycin. A relatively high frequency of transformation was observed with 3-day-cocultivation but a lower frequency was observed with 7-day-cocultivation. Embryoids were formed from kanamycin or hygromycin resistant calli and developed into plantlets. Transformation was confirmed on calli and a plantlet by Southern hybrydization.

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The crossabilities of five wheat varieties with four clones of Hordeum bulbosum and eight genotypes of maize were investigated using the injection treatment of 2, 4-dichlorophenoxyacetic acid (2, 4-D) after pollination. Three of the five wheat varleties were not crossable with H. bulbosum regardless of the 2, 4-D treatment. On the other hand, an average of 22.1% of wheat florets from all these varieties formed immature embryos when pollinated with maize and followed by the 2, 4-D treatment. For 20 wheat varieties from West Asia and North Africa, an average of 9.5% of wheat florets pollinated with maize produced wheat haploids. This contrasts with a frequency of 0.2% in case of pollination with H. bulbosum.

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We have found that inhibitors of the cyanide-insensitive respiratory pathway induce male sterility in Broccoli (Brassica oleracea L. cv. De Cicco). All three major specific inhibitors; salicylhydroxamic acid (SHAM), propyl gallate and disulfiram (tetraethylthiuram disulfide), were effective in inducing male sterility whenever they were applied to the flower buds with anthers less than about 2mm in length, which those pollen developing stages corresponded to be earlier than early microspore stage. These chemlcally induced male sterile flowers which were characterized by shorter filaments and a reduction in the number of total and fertile pollen grains per flower, were similar to the cytoplasmic male sterile flowers. However, when pollinated with normal pollen, the percentage of seed-setting in the chemically induced male sterile flowers decreased considerably in comparison with that in the cytoplasmic male sterile flowers. All the progeny plants derived from the male sterillty (female) × normal pollen grains showed male fertility. Morphological characters of the progeny plants were very similar to those of normal Broccoli. Although the physiological sign{ficance of the cyanide-insensitive respiratory pathway remains unknown, some physiological pathways, such as the alternative pathway may be associated with male sterility in Brassica species.

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Image analysis method has been employed in order to establish an objective evaluation method of pearling grade in barley which has been usually evaluated by observation with naked eyes. Pearled barley grains were stained pink (endosperm) or blue to black (furrow, seed coat, aleurone layer and embryo) with M. G. solution (Fig. 1). Grey values for each region were measured by monochromatic image analysis method (Table 1, Fig. 2), and these two regions were classified by critical grey value. In this report, critical grey value was found to be 50 (Fig. 3). The proportion of the area of regions with grey value 0-50 to the whole grain area with grey value 0-150 was measurecl, and was used as the index of pealing prade. The adequate number of grains measured was found to be 60 (Table 2). Evaluation of standard samples (classifiecl 5 grades by observation) by image analysis methocl was in Table 4. The value of the index was in inversely related to the degree of pearling grade. The degree of pearling grade by image analysis method could be divided into four statistically significant categories (Table 5). Comparison between conventional observa-tion method and image analysis method showed that the results of eye evaluation were not always based on standard samples (Fig. 4). These results suggest that pearling grade of barley could be evaluated objectively by im-age analysis method.

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The 29 accessions of wild taro (Colocasia esculenta SCHOTT) were collected in southern Japan and Taiwan. The collection sites were from Honshu, Kyushu, Hachijo Island, through most of the islands in the Nansei Archipelago and Taiwan. However, they were not found in the southern coastside of Shikoku, a few islands in the Nansei Archipelago and Peel (Chichi-jima) and Coffin (Haha-jima) Islands in Bonin Archipelago. The taros grew naturally along roadsides, around creeks and around and inside of rice cropping paddy fields. All the accessions derived from Taiwan and the Nansei Archipelago were diploids (2n=28) and the others were triploids (2n=42). The taros were cultivated in the experimental fields with one of the oldest cultivars, 'Eguimo', to observe the vegetative and inflorescence morphology in details. Their. plant form, leaf shape and petiole color were variable among the accessions. The triploids had cormel typed lateral branches and the diploids did runner typed ones. All the accessions produced spadices. Length of the portions of spadix varied among the accessions. They do not seem to be wild, but escape. And because their edible characters such as cormel yield are infcrior to those of the current cultivars, they are thought to have been introduced in the areas before the arrival of current cultivars.

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Karyotype analysis of Lilium nepalense D. Don was carried out. Karyotype was 2n=24=4V+2v+18J, or 2n=24=2M_ST+2M+2m+2ST_ST+4ST+12T. This karyotype which was similar to that of L. concolor L. callosum and L. pumilum, was In good agreement with the systematic relationship in the genus Lilium.

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Somatic embryo production was screened on 290 Glycine max (L.) MERRILL and 5 Glycine gracilis genotypes. Among them, we identified a G. max genotype which produced an outstanding number of somatic embryos.

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