Soybean [Glycine max (L.) Merr. cv. Bay] seeds were irradiated with X-rays (25kR) and the M2 progeny was screened for changes in the fatty acid composition of seed oil. X-ray irradiation remarkably increased the variability of the fatty acid composition in the oil of the Bay cultivar. A mutant in which linolenic acid accounted for 18.4 per cent of the total oil cornpared with 9.4 per cent in the Bay cultivar was identified among 2006 M2 plants. The M3 generation of the mutant also showed a linolenic acid content approximately two times higher than that of the original variety.

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One complete type octoploid and seven hexaploid triticale (X Triticosecale WITTMACK) lines or varieties, among which two were the complete and five were the substituted types, were used in reciprocal crosses. When the octoploid was used as a female parent, crossability, weight of 25 kernels and the percentage of the F₁ plants grown till maturity were superior to those from the reciprocal crosses, except the crossabilities in the cross with those substituted types which were Camel/Pato of 2D/2R, 4D/4R, 5D/5R, Camel of 2D/2R, 4D/4R and Beaver of 2D/2R substitution. In the reciprocal crosses of the substltuted type with the complete type of hexaploid triticale, higher crossability was obtained when the former was used as a female except when the 2D/2R, 4D/4R substltuted variety Welsh was used as felnale. When the substituted type was used as fe-male the F₁ kernel weight was lower. F₁ seeds obtained from the crosses between elther Camel/Pato or Welsh as female and the complete types Beagle and Currency as male had simllar appearance to the kernel of wheat rather than that of triticale or rye. Slmilar results were also obtained in case of the reciprocal corsses between Camel/Pato and Welsh.

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A Chinese landrace of six-rowed barley, Mokusekko 3, has been successfully utllized for introducing its BaYMV resistant gene, Ym, to Japanese malting two-rowed barley. However, information about the location of the Ym locus on a chromosome is limited. The authors almed to confirm the linkage relationship between the Ym locus and complex loci for esterase isozymes, as most of the strains into which the BaYMV resistance from Mokusekko 3 had been introduced showed the same esterase isozyme banding pattern as that of the resistant parent. The linkage analyses revealed that the Ym locus is tightly linked with the complex loci (Est₁-Est₂-Est₄) for the esterase isozymes which are located at the terminal of the long arm of chromosome 3, and that the recombination values ranged from 1.26 to 5.01%. Based on these results, it is concluded that the BaYMV resistant individuals and strains carrying the Ym gene can be easily obtained by selecting the seedlings which show the same banding pattern of esterase isozyme genotype as that of Mokusekko 3, by means of starch gel electrophoresis.

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The object of this study is to clarlfy which characteristics of sink capacity cause the genetic variation of grain-filling process in rice. The grain-filling parameters, rate and duration of filling as a grain basls, and the slnk-capacity traits, grain length, grain width, number of grains on primary branches, number of grains on secondary branches, seed fertility and nulnber 0L panicles per plant were measured on 29 cultivars with a wide range of their sink-capacity tralts. The results clearly demonstrate that the rate of filling correlates positively with the traits related to grain size and negatively with those related to grain number. Canonical correlation analysis suggests that the correlation between the rate of fllllng and the grain-size traits is predominant. The rate of filling in rice is probably regulated by some factors related to the grain slze. The duration of filling exhibits no significant correlations with the rate of filling, final grain weight and all of the sink-capacity traits. The rate and duration of filling seem to be regulated by different systems.

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Mitochondrial (mt) DNAs were prepared from ten strains of rice with cytoplasmic male sterility (cms) and fractionated by agarose gel electrophoresls to investigate plasmid-like DNA in different male-sterile cytoplasms. All of the cytoplasms had plasmid-like DNAs of low molecular weight besides their high-molecular-weight mtDNAs. Cms-R cytoplasm had two plasmid-like DNAS of 1.09 and 0.96kb, cms-UR106 cytoplasm had three plasmid-like DNAs of 1.60, 1.09, and 0.96kb, and the others had four plasmid-like DNAs of 1.60, 1.25, 1.09, ancl 0.96kb. Cytoplasmic properties of Oryza rufipogon and Oryza nivara used as source of male-sterlle cytoplasms are suggested to be closer to Indica rice than Japonica rice. The 1.09-kb DNA molecule from cms-Bo cytoplasm was suggested to be intimately associated wlth protein(s) in linear form and the other three DNA molecules seemed to be circular forms by the experiment of extraction with or without proteinase K. Southern hybridization analyses showed high sequence homology between the plasmid-like DNAS with the same size from different cytoplasms, and low sequence homology between the plasmicl-like DNAs with clifferent size. Some of the plasmid-like DNAs from cms-Bo cytoplasm showed no sequence homology between those in cms-T, cms-C, cms-S, and N cytoplasms of maize.

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From 908 unpollinated ovules in tetraploid Chinese chive (Allium tuberosum ROTTL.), 132 tetraploids and two dihaploids were obtained through three successive cultures; budpreculture, ovule culture and embryo culture. The high frequency of tetraploids in the ob-tained plants suggests an unreduced ernbryo sac formation at a considerable frequency. The occasional dihaploid induction, however, indicates that some ovules have the eusporous embryo sac. One of the two dihaploids was an aneuploiclal dlhaploid with 2n=17 and the other was a dlhaploid with 2n=16 having exactly half the tetraploid number of chromosomes. The three-step culture method established in the present study can contribute towards the understanding of the embryological and genetical mechanlsms of the apomixis in Chinese chive.

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Camellia japonica (2x) grown naturally in Japan and C. pitardii var. pitardii (2x), C. pitardii var. yulenaleica (6x), C. reticulata (6x) and C, saluenelesis (2x) all grown naturally in Yunnan, the People's Republic of China were computatively compared on the basis of the following slx quantitative characters: (1) petal length; (2) petal width; (3) petal area; (4) Ieaf length; (5) Ieaf width; and (6) Ieaf area. The scatter diagrams of the leaf characters showed character correlation and the main close-relatlonship order of the C. saluenensis-japonica, itardii var. yunnanicaTpitardii var. pitardii-reticulata. The close-relationships proportional to the size of the flowers suggested the successive order of C. salueleensisjapoleica-pitardii var. pitardii-pitardii var. yunnanica-reticulata. Although the size of leaves in C. reticulata from Tengchong, Yunnan, was twice as large as that in C. saluenensls, the ratios of leaf width of both species were quite similar to each other, 2.335 and 2.337, respectrvely Some plants of C. reticulata from Tengchong were morphologlcally quite similar to C. japonica. Camellia pitardii var. yunnanica was consldered conspecific with C. reticulata. Artificial crosses among the four species were readily made. The present biosystematic approach showed the five taxa to be quite closely related to each other and to be isolated only by their geographical distribution.

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The husk in malting barley plays an important role, such as protecting the ernbryo from mechanical damage or serving as a filter in the beer brewing process. On the other hand, it is a negative aspect of the husk that the husk is not converted into a malt extract and some of the components in the husk cause muddiness in the beer. The husk content is the weight ratio of the husk to the whole grain. The negative correlation between husk content and malt extract is generally recognized. The following experiments were undertaken in order to clarify the inheritance of the husk content and to confirm its selection response in malting barley breeding. The LUFF method was used for measuring the husk content in each experiment.

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Seventy seven Japanese varieties of rice were grown from sowing to heading using the water culture method in growth cabinets with artificial light under a 12 hr. day-length and 25°C air temperature regime. These varieties were exposed to 6 different levels of cool tem-perature (17.5°C to 22.5°C) at 1°C intervals under low radiation conditions (5.5 MJ) for 20 days from heading. The critical low temperature(CLT), at which the varietles were able to ripen with 80% of perfectly mature grains owing the 20 day treatment from heading, was determined by the percentage of perfectly mature grains at 6 Ievels of cool treatment. It was recognized that the CLT ranged from 17.5°C to 22.5°C, and higher among 77 varieties. The varieties with lower CLT values displayed a stronger degree of cool tolerance at the heading and flowering stages than the varieties with higher CLT values. On the basis of the CLT values of the varieties, 77 varieties were classified into 7 groups corresponding to the degree of cool tolerance at the headlng and flowering stages.

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To analyze the differences in the rate of seedling emergence and seedling height among rice ecospecles at different soil reduction levels, five blocks were prepared containing soils with different amounts of starch, i.e. 10, 20, 30, 83 and 167g per block, and no starch addition block (control) was also prepared. The mean rate of seedling emergence and seedling height were increased by the addition of a maximum amount of 20g starch per block in the three ecospecies. However, the mean rate of seedling emergence markedly decreased with the increase of the amount of starch added over 20g per block. The mean rate of seedling emergence in the japoeeica cultivar group was higher than that in the iudica cultlvar group at all the redox potential levels, whereas that in the javanica cultivar group was intermediate. However, the rate of increase and/or decrease of the mean seedling height with changes in starch amount added was almost similar in the three ecospecies.

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